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Sample records for lherzolitic shergottite yamato

  1. Sm-Nd isotopic systematics of lherzolitic shergottite Yamato-793605

    USGS Publications Warehouse

    Misawa, K.; Yamada, K.; Nakamura, N.; Morikawa, N.; Yamashita, K.; Premo, W.R.

    2006-01-01

    We have undertaken Sm-Nd isotopic studies on Yamato-793605 lherzolitic shergottite. The Sm-Nd internal isochron obtained for acid leachates and residues of whole-rock and separated mineral fractions yields an age of 185 ??16 Ma with an initial ??Nd value of +9.7??0.2. The obtained Sm-Nd age is, within analytical errors, identical to the Rb-Sr age of this meteorite as well as to the previous Rb-Sr and Sm-Nd ages of Allan Hills-77005 and Lewis Cliff 88516, although the ??Nd values are not identical to each other. Elemental abundances of lithophile trace elements remain nearly unaffected by aqueous alteration on the Martian surface. The isotopic systems of lherzolitic shergottites, thus, are considered to be indigenous, although disturbances by shock metamorphism are clearly observed. "Young ages of ??? 180 Ma" have been consistently obtained from this and previous Rb-Sr, Sm-Nd and U-Pb isotopic studies and appear to represent crystallization events. ?? 2006 National Institute of Polar Research.

  2. 39Ar - 40Ar Studies of Lherzolitic Shergottites Yamato 000097 and 984028

    NASA Technical Reports Server (NTRS)

    Park, J.; Nyquist, L. E.; Bogard, D. D.; Garrison, D. H.; Shih, C.-Y.; Mikouchi, T.; Misawa, K.

    2010-01-01

    Yamato 984028 (Y984028) was discovered by the Japanese Antarctic Research Expedition (JARE) in 1998 and recently classified as a lherzolitic shergottite with large pyroxene oikocrysts enclosing rounded olivine and chromites. It also contains shock veining and maskelynite. Y984028 is paired with the more recent lherzolitic shergottite finds Y000027/47/97 based on similarities in mineralogy and chemistry, as well as isotopic composition. We present here the studied Ar-39-Ar-40 of Y-984028 whole rock (WR) and pyroxene (Px), in order to gain better understanding of trapped Ar components with a comparison of the possibly-paired Y000097 Ar release.

  3. Rb-Sr Isotopic Studies Of Antarctic Lherzolitic Shergottite Yamato 984028

    NASA Technical Reports Server (NTRS)

    Shih, C.-Y.; Nyquist, L. E.; Reese, Y.; Misawa, K.

    2009-01-01

    Yamato 984028 is a Martian meteorite found in the Yamato Mountains of Antarctica. It is classified as a lherzolitic shergottite and petrographically resembles several other lherzolitic shergottites, i.e. ALHA 77005, LEW 88516, Y-793605 and Y-000027/47/97 [e.g. 2-5]. These meteorites have similarly young crystallization ages (152-185 Ma) as enriched basaltic shergottites (157-203 Ma), but have very different ejection ages (approximately 4 Ma vs. approximately 2.5 Ma), thus they came from different martian target crater areas. Lherzolitic shergottites have mg-values approximately 0.70 and represent the most mafic olivine-pyroxene cumulates. Their parental magmas were melts derived probably from the primitive Martian mantle. Here we present Rb-Sr isotopic data for Y-984028 and compare these data with those obtained from other lherzolitic and olivine-phyric basaltic shergottites to better understand the isotopic characteristics of their primitive mantle source regions. Corresponding Sm-Nd analyses for Y-984028 are in progress.

  4. The lherzolitic shergottite Grove Mountains 99027: Rare earth element geochemistry

    NASA Astrophysics Data System (ADS)

    Hsu, Weibiao; Guan, Yunbin; Wang, Henian; Leshin, Laurie A.; Wang, Rucheng; Zhang, Wenlan; Chen, Xiaoming; Zhang, Fusheng; Lin, Chengyi

    2004-05-01

    We report here on an ion probe study of rare earth element (REE) geochemistry in the lherzolitic shergottite Grove Mountains (GRV) 99027. This meteorite shows almost identical mineralogy, petrology, and REE geochemistry to those of the lherzolitic shergottites Allan Hills (ALH) A77005, Lewis Cliff (LEW) 88516, and Yamato (Y-) 793605. REE concentrations in olivine, pyroxenes, maskelynite, merrillite, and melt glass are basically comparable to previous data obtained from ALH A77005, LEW 88516, and Y-793605. Olivine is the dominant phase in this meteorite. It is commonly enclosed by large (up to several mm) pigeonite oikocrysts. Non-poikilitic areas consist of larger olivine grains (~mm), pigeonite, augite, and maskelynite. Minor merrillite (up to 150 mm in size) is widespread in non-poikilitic regions, occurring interstitially between olivine and pyroxene grains. It is the main REE carrier in GRV 99027 and has relatively higher REEs (200-1000 Å CI) than that of other lherzolitic shergottites. A REE budget calculation for GRV 99027 yields a whole rock REE pattern very similar to that of other lherzolites. It is characterized by the distinctive light REE depletion and a smooth increase from light REEs to heavy REEs. REE microdistributions in GRV 99027 strongly support the idea that all lherzolitic shergottites formed by identical igneous processes, probably from the same magma chamber on Mars. Despite many similarities in mineralogy, petrography, and trace element geochemistry, subtle differences exist between GRV 99027 and other lherzolitic shergottites. GRV 99027 has relatively uniform mineral compositions (both major elements and REEs), implying that it suffered a higher degree of sub-solidus equilibration than the other three lherzolites. It is notable that GRV 99027 has experienced terrestrial weathering in the Antarctic environment, as its olivine and pyroxenes commonly display a light REE enrichment and a negative Ce anomaly. Caution needs to be taken in future

  5. Yamato 980459: The Most Primitive Shergottite?

    NASA Technical Reports Server (NTRS)

    McKay, G.; Le, L.; Schwandt, C.; Mikouchi, T.; Koizumi, E.; Jones, J.

    2004-01-01

    The Antarctic Research Center of the Japanese National Institute of Polar Research (NIPR) recently announced the discovery of a new Martian shergottite, Y98(0459). This sample is a member of the subgroup of basaltic shergottites that contain abundant olivine phenocrysts, and are thus olivine- phyric. Y98 may have special significance among the basaltic shergottites because (1) it appears to have been the most magnesian Martian magma yet found, and thus can provide valuable clues to magma petrogenesis on Mars; (2) it contains no late-crystallizing phases, but instead contains approx. 30% interstitial glass, which can provide unambiguous incompatible element patterns of the parent melt; and (3) it carries an LREE-depleted signature similar to QUE 94201, whose isotopic characteristics are the most primitive of all basaltic shergottites.

  6. ComparisonsBetween RBT 04262 and lherzolitic Shergottites (ALHA 77005 and LEW 88516)

    NASA Astrophysics Data System (ADS)

    Shearer, C. K.; Burger, P. V.; Papike, J. J.; Karner, J.

    2009-03-01

    In this poster, we compare lithology A in RBT 04262 to two other lherzolitic shergottites to gain a better understanding of the petrogenesis of RBT 04262 and the lherzolitic shergottites, and their relationship to the basalts that produced the complete suite of shergottites.

  7. Northwest Africa 1950: Mineralogy and comparison with Antarctic lherzolitic shergottites

    NASA Astrophysics Data System (ADS)

    Mikouchi, Takashi

    2005-11-01

    NWA 1950 is a new lherzolitic shergottite recently recovered from Morocco and is the first sample of this group found outside Antarctica. Major constituent phases of NWA 1950 are olivine, pyroxenes, and plagioclase glass ("maskelynite") and the rock shows a two distinct textures: poikilitic and non-poikilitic typical of lherzolitic shergottites. In poikilitic areas, several-millimeter-sized pyroxene oikocrysts enclose cumulus olivine and chromite. In contrast, pyroxenes are much smaller in non-poikilitic areas, and olivine and plagioclase glass are more abundant. Olivine in non-poikilitic areas is more Fe-rich (Fa29-31) and shows a narrower distribution than that in poikilitic areas (Fa23-29). Pyroxenes in non-poikilitic areas are also more Fe-rich than those in poikilitic areas that show continuous chemical zoning suggesting fractional crystallization under a closed system. These observations indicate that pyroxene in non-poikilitic areas crystallized from evolved interstitial melts and olivine was re-equilibrated with such melts. NWA 1950 shows similar mineralogy and petrology to previously known lherzolitic shergottites (ALH 77005, LEW 88516, Y-793605 and GRV 99027) that are considered to have originated from the same igneous body on Mars. Olivine composition of NWA 1950 is intermediate between those of ALH 77005-GRV 99027 and those of LEW 88516-Y-793605, but is rather similar to ALH 77005 and GRV 99027. The subtle difference of mineral chemistry (especially, olivine composition) can be explained by different degrees of re-equilibration compared to other lherzolitic shergottites, perhaps due to different location in the same igneous body. Thus, NWA 1950 experienced a high degree of re-equilibration, similar to ALH 77005 and GRV 99027.

  8. Tracking the Martian Mantle Signature in Olivine-Hosted Melt Inclusions of Basaltic Shergottites Yamato 980459 and Tissint

    NASA Technical Reports Server (NTRS)

    Peters, T. J.; Simon, J. I.; Jones, J. H.; Usui, T.; Moriwaki, R.; Economos, R.; Schmitt, A.; McKeegan, K.

    2014-01-01

    The Martian shergottite meteorites are basaltic to lherzolitic igneous rocks that represent a period of relatively young mantle melting and volcanism, approximately 600-150 Ma (e.g. [1,2]). Their isotopic and elemental composition has provided important constraints on the accretion, evolution, structure and bulk composition of Mars. Measurements of the radiogenic isotope and trace element concentrations of the shergottite meteorite suite have identified two end-members; (1) incompatible trace element enriched, with radiogenic Sr and negative epsilon Nd-143, and (2) incompatible traceelement depleted, with non-radiogenic Sr and positive epsilon 143-Nd(e.g. [3-5]). The depleted component represents the shergottite martian mantle. The identity of the enriched component is subject to debate, and has been proposed to be either assimilated ancient martian crust [3] or from enriched domains in the martian mantle that may represent a late-stage magma ocean crystallization residue [4,5]. Olivine-phyric shergottites typically have the highest Mg# of the shergottite group and represent near-primitive melts having experienced minimal fractional crystallization or crystal accumulation [6]. Olivine-hosted melt inclusions (MI) in these shergottites represent the most chemically primitive components available to understand the nature of their source(s), melting processes in the martian mantle, and origin of enriched components. We present trace element compositions of olivine hosted melt inclusions in two depleted olivinephyric shergottites, Yamato 980459 (Y98) and Tissint (Fig. 1), and the mesostasis glass of Y98, using Secondary Ionization Mass Spectrometry (SIMS). We discuss our data in the context of understanding the nature and origin of the depleted martian mantle and the emergence of the enriched component.

  9. Igneous cooling history of olivine-phyric shergottite Yamato 980459 constrained by dynamic crystallization experiments

    NASA Astrophysics Data System (ADS)

    First, Emily; Hammer, Julia

    2016-07-01

    Dynamic crystallization experiments were performed on a liquid having the bulk composition of olivine-phyric shergottite Yamato 980459, to constrain the igneous thermal history of this meteorite. Key characteristics of the meteorite's mineralogy and texture, including several morphologically distinct olivine and pyroxene crystal populations and a glassy mesostasis devoid of plagioclase, were replicated upon cooling from 1435 to 909 °C at 1 atmosphere under reducing conditions. Three sequential cooling ramps are required to produce synthetic samples with textures and compositions matching Yamato 980459. Olivine phenocrysts formed at <1 °C h-1, presumably at depth in the Martian crust. Pyroxene phenocrysts formed mainly at ~10 °C h-1, consistent with crystallization within a lava flow at depths of 25-45 cm. Increased cooling rate (~100 °C h-1) in a third stage suppressed the formation of plagioclase and produced groundmass crystals, consistent with crystallization at lava flow depths of 5-7 cm. Although Y 980459 is unique among Martian meteorites (i.e., preserving a primary glassy mesostasis), its emplacement did not require unique physical conditions. Rather, the second and third cooling stages may reflect cooling within the core of a pāhoehoe-like flow and subsequent breakout on the surface of Mars.

  10. Determining the Origin of Phosphates in Lherzolitic Shergottites Through Phosphate Saturation Experiments

    NASA Astrophysics Data System (ADS)

    Calvin, C.; Rutherford, M.

    2007-12-01

    Phosphorous has been correlated with sulfur and chlorine in martian soils with some soils containing several wt % P2O5 and high-P2O5 layer covers many rocks. However, using the RAT to remove the top few mm of some rocks revealed zones of low-P2O5 in the outer mm relative to the interior composition. This suggests that some igneous rocks of Mars are high in P2O5 and that over time phosphorous has been mobilized into the martian soils. In martian meteorites, phosphorous has been detected in high concentrations relative to terrestrial basalts and cumulates. High intensity x-ray maps of lherzolitic shergottite ALH 77005 reveal phosphates in olivine-hosted melt inclusions and P2O5 zoning in the host-olivine. Analyses of rehomogenized olivine-hosted melt inclusions reveal high-P2O5 glasses (>5 wt %). As phosphates are the major reservoir of REE in martian meteorites, determining if the phosphates are primary igneous or secondary sedimentary minerals may have significant consequences for use of REE as oxybarometers and radiogenic-isotopic dating systems in these meteorites. Therefore, an experimental investigation was initiated to determine whether the phosphates are primary igneous minerals or secondary weathering products. The phosphate saturation curve in SNC magmatic compositions has been studied experimentally by synthesizing the parental melt composition of lherzolitic shergottite ALH 77005 and performing anhydrous crystallization experiments in TZM pressure vessels. The parental melt composition was then doped with 5 wt % P2O5 in the form of CaHPO4 and the crystallization experiments were repeated. ALH 77005's parental melt saturated phosphate near 7 wt % at 1165°C and 5 wt % at 1150°C. These saturation values illustrate how high-P2O5 would have to build up before phosphates would nucleate and are consistent with high-2O5 content found in rehomogenized olivine-hosted melt inclusions. These saturation values are higher than the reported saturation for lunar and

  11. Concordant Rb-Sr and Sm-Nd Ages for NWA 1460: A 340 Ma Old Basaltic Shergottite Related to Lherzolitic Shergottites

    NASA Technical Reports Server (NTRS)

    Nyquist, L. E.; Shih, C-Y; Reese, Y. D.; Irving, A. J.

    2006-01-01

    Preliminary Rb-Sr and Sm-Nd ages reported by [1] for the NWA 1460 basaltic shergottite are refined to 336+/-14 Ma and 345+/-21 Ma, respectively. These concordant ages are interpreted as dating a lava flow on the Martian surface. The initial Sr and Nd isotopic compositions of NWA 1460 suggest it is an earlier melting product of a Martian mantle source region similar to those of the lherzolitic shergottites and basaltic shergottite EETA79001, lithology B. We also examine the suggestion that generally "young" ages for other Martian meteorites should be reinterpreted in light of Pb-207/Pb-206 - Pb-204/Pb-206 isotopic systematics [2]. Published U-Pb isotopic data for nakhlites are consistent with ages of approx.1.36 Ga. The UPb isotopic systematics of some Martian shergottites and lherzolites that have been suggested to be approx.4 Ga old [2] are complex. We nevertheless suggest the data are consistent with crystallization ages of approx.173 Ma when variations in the composition of in situ initial Pb as well as extraneous Pb components are considered.

  12. Experimental Petrology of the Basaltic Shergottite Yamato 980459: Implications for the Thermal Structure of the Martian Mantle

    NASA Technical Reports Server (NTRS)

    Dalton, H. A.; Musselwhite, D. S.; Kiefer, W.; Treiman, A. H.

    2005-01-01

    Yamato 980459 (Y98) is an olivine-phyric basaltic shergottite composed of 48% pyroxene, 26% olivine, 25% mesostasis, and 1% other minerals. Unlike the other Martian basalts, it contains no plagioclase. Olivine in Y98 is the most magnesian of all Martian meteorites. Thus Y98 is believed to be the most primitive and its composition may be the closest to a primary or direct melt of the Martian mantle. As such, it provides a very useful probe of the mineralogy and depth of its mantle source region. Toward this end, we are conducting crystallization experiments on a synthetic Y98 composition at Martian mantle pressures and temperatures.

  13. Spinels and oxygen fugacity in olivine-phyric and lherzolitic shergottites

    NASA Astrophysics Data System (ADS)

    Goodrich, C. A.; Herd, C. D. K.; Taylor, L. A.

    2003-12-01

    We examine the occurrences, textures, and compositional patterns of spinels in the olivine- phyric shergottites Sayh al Uhaymir (SaU) 005, lithology A of Elephant Moraine A79001 (EET-A), Dhofar 019, and Northwest Africa (NWA) 1110, as well as the lherzolitic shergottite Allan Hills (ALH) A77005, in order to identify spinel-olivine-pyroxene assemblages for the determination of oxygen fugacity (using the oxybarometer of Wood [1991]) at several stages of crystallization. In all of these basaltic martian rocks, chromite was the earliest phase and crystallized along a trend of strict Cr-Al variation. Spinel (chromite) crystallization was terminated by the appearance of pyroxene but resumed later with the appearance of ulvospinel. Ulvospinel formed overgrowths on early chromites (except those shielded as inclusions in olivine or pyroxene), retaining the evidence of the spinel stability gap in the form of a sharp core/rim boundary (except in ALH A77005, where subsolidus reequilibration diffused this boundary). Secondary effects seen in chromites include reaction with melt before ulvospinel overgrowth, reaction with melt inclusions, reaction with olivine hosts (in ALH A77005), and exsolution of ulvospinel or ilmenite. All chromites experienced subsolidus Fe/Mg reequilibration. Spinel-olivine-pyroxene assemblages representing the earliest stages of crystallization in each rock essentially consist of the highest-Cr#, lowest-fe# chromites not showing secondary effects plus the most magnesian olivine and equilibrium low-Ca pyroxene. Assemblages representing the onset of ulvospinel crystallization consist of the lowest-Ti ulvospinel, the most magnesian olivine in which ulvospinel occurs as inclusions, and equilibrium low-Ca pyroxene. The results show that, for early crystallization conditions, oxygen fugacity (fO2) increases from SaU 005 and Dhofar 019 (~QFM -3.8), to EET-A (QFM -2.8) and ALH A77005 (QFM -2.6), to NWA 1110 (QFM -1.7). Estimates for later conditions indicate

  14. Ar-Ar Studies of Lherzolitic Shergottites Yamato 000097 and 984028

    NASA Technical Reports Server (NTRS)

    Park, J.; Nyquist, L. E.; Bogard, D. D.; Garrison, D. H.; Shih, C.-Y.; Mikouchi, T.; Misawa, K.

    2010-01-01

    The approx.170 Ma age of the rock(s) is (likely) preserved in minor phases of high K content. Terrestrial Ar appears to have a nearly ubiquitous presence in the gas release, and mixes with Martian Ar in variable proportions. The intermediate temperature release of the plag separate shows an apparently higher approx.270 Ma age, and suggests the presence of terrestrial Ar that "torques" the correlation to a steeper slope than for 170 Ma. The intermediate temperature data of the pyroxene is consistent with a "young" age (either approx.170 to approx.270 Ma) and mostly Martian trapped Ar. The low temperature (needs checking) data also are essentially consistent with the approx.170 Ma age, but an intercept near the terrestrial value is suspicious. Would not have had terrestrial Ar on Mars, so this is more likely a mixing line. Admixtures of terrestrial Ar in the pyroxene extractions seems pervasive, but can t explain the variation in 39/36 along the intermediate temp. "isochron".

  15. Constraints on Mantle Plume Melting Conditions in the Martian Mantle Based on Improved Melting Phase Relationships of Olivine-Phyric Shergottite Yamato 980459

    NASA Technical Reports Server (NTRS)

    Kiefer, Walter S.; Rapp, Jennifer F.; Usui, Tomohiro; Draper, David S.; Filiberto, Justin

    2016-01-01

    Martian meteorite Yamato 980459 (hereafter Y98) is an olivine-phyric shergottite that has been interpreted as closely approximating a martian mantle melt [1-4], making it an important constraint on adiabatic decompression melting models. It has long been recognized that low pressure melting of the Y98 composition occurs at extremely high temperatures relative to martian basalts (1430 degC at 1 bar), which caused great difficulties in a previous attempt to explain Y98 magma generation via a mantle plume model [2]. However, previous studies of the phase diagram were limited to pressures of 2 GPa and less [2, 5], whereas decompression melting in the present-day martian mantle occurs at pressures of 3-7 GPa, with the shallow boundary of the melt production zone occurring just below the base of the thermal lithosphere [6]. Recent experimental work has now extended our knowledge of the Y98 melting phase relationships to 8 GPa. In light of this improved petrological knowledge, we are therefore reassessing the constraints that Y98 imposes on melting conditions in martian mantle plumes. Two recently discovered olivine- phyric shergottites, Northwest Africa (NWA) 5789 and NWA 6234, may also be primary melts from the martian mantle [7, 8]. However, these latter meteorites have not been the subject of detailed experimental petrology studies, so we focus here on Y98.

  16. Evidence for the exsolution of Cl-rich fluids in martian magmas: Apatite petrogenesis in the enriched lherzolitic shergottite Northwest Africa 7755

    NASA Astrophysics Data System (ADS)

    Howarth, G. H.; Pernet-Fisher, J. F.; Bodnar, R. J.; Taylor, L. A.

    2015-10-01

    Martian meteorite Northwest Africa 7755 is a new example of an enriched, lherzolitic shergottite, containing some of the coarsest-grained apatite yet identified in shergottite meteorites. Their size has permitted detailed observations of volatile distributions within single grains. We have demonstrated that some apatites have been invaded by shock melts, which act to devolatilize parts of grains, resulting in significant Cl-enrichment in the adjacent regions. The extent of chemical heterogeneity within single grains must be carefully considered in other shergottites, so that the effects of secondary modification of apatites are well-constrained, prior to interpreting the volatile contents and primary magmatic processes. Apatite grains unaffected by shock melts are OH-F enriched and Cl-poor (∼F50Cl14OH36), relative to interstitial apatites reported in other shergottites. The volatile compositions are similar to interstitial apatites reported in terrestrial mafic intrusions. Such apatites in terrestrial intrusions are argued to have formed after significant Cl-loss due to the exsolution and migration of Cl-rich brines. Calculated relative F2, Cl2, and H2O fugacities for NWA 7755 apatites show a trend of degassing rather than fractionation, noted in previous studies. Indeed, we interpret the volatile contents of apatites analyzed in the cumulate shergottite NWA 7755 to represent snapshots of the evolving late-stage residual liquid during exsolution of a Cl-rich brine. This fluid phase has subsequently been lost from an open magma system, migrating upward through the cumulate sequence enriching residual liquids in Cl. Alternatively, it formed a hydrothermal system in the martian crust surrounding the intrusion. Furthermore, by comparison with terrestrial examples, we suggest that the late-stage evolution of volatile-bearing phases in NWA 7755 is similar to that of comparable terrestrial mafic rocks. Primary cumulus apatites are F-rich, whereas interstitial apatites

  17. Yamato 980459: Crystallization of Martian Magnesian Magma

    NASA Technical Reports Server (NTRS)

    Koizumi, E.; Mikouchi, T.; McKay, G.; Monkawa, A.; Chokai, J.; Miyamoto, M.

    2004-01-01

    Recently, several basaltic shergottites have been found that include magnesian olivines as a major minerals. These have been called olivinephyric shergottites. Yamato 980459, which is a new martian meteorite recovered from the Antarctica by the Japanese Antarctic expedition, is one of them. This meteorite is different from other olivine-phyric shergottites in several key features and will give us important clues to understand crystallization of martian meteorites and the evolution of Martian magma.

  18. Experimental Crystallization of Yamato 980459

    NASA Technical Reports Server (NTRS)

    Jones, John H.; Galenas, M. G.; Danielson, L. R.

    2009-01-01

    Currently, only two martian meteorites QUE 94201 (QUE) and Yamato 980459 (Y98) have been experimentally shown to me true melt compositions. Most martian meteorites are instead, cumulates or partial cumulates. We have performed experiments on a Y98 composition to assess whether QUE could be related to Y98 by some fractionation process [1]. Y98 is a basaltic shergottite from the SNC (Shergotty, Nakhla, Chassigny) meteorite group. Y98 is composed of 26% olivine, 48% pyroxene, 25% mesostasis, and no plagioclase [2]. The large size of the olivine megacrysts and absence of plagioclase suggest that the parental melt which formed this meteorite had begun cooling slowly until some mechanism, such as magma ascent, caused rapid cooling [3]. Y98 s olivines have the highest Mg content of all the shergottites suggesting that it is the most primitive [4]. Y98 has been determined to be a melt composition by comparing the composition of experimental liquidus olivines with the composition of the cores of Y98 olivines [4]. The liquidus of Y98 is predicted by MELTS [5] and by experimentation [6] to be 1450 C. Analyses of Y98 show it to be very depleted in LREEs and it has similar depleted patterns as other shergottites such as QUE [7].

  19. Rb-Sr and Sm-Nd Studies of Olivine-Phyric Shergottites RBT 04262 and LAR 06319: Isotopic Evidence for Relationship to Enriched Basaltic Shergottites

    NASA Technical Reports Server (NTRS)

    Nyquist, L.E.; Shih, C.-Y.; Reese, Y.

    2009-01-01

    RBT 04262 and LAR 06319 are two Martian meteorites recently discovered in Antarctica. Both contain abundant olivines, and were classified as olivine-phyric shergottites. A detailed petrographic study of RBT 04262 suggested it should be reclassified as a lherzolitic shergottite. However, the moderately LREE-depleted REE distribution pattern indicated that it is closely related to enriched basaltic shergottites like Shergotty, Zagami, Los Angeles, etc. In earlier studies of a similarly olivinephyric shergottite NWA 1068 which contains 21% modal olivine, it was shown that it probably was produced from an enriched basaltic shergottite magma by olivine accumulation . As for LAR 06319, recent petrographic studies suggested that it is different from either lherzolitic shergottites or the highly LREE-depleted olivine-phyric shergottites. We performed Rb-Sr and Sm-Nd isotopic analyses on RBT 04262 and LAR 06319 to determine their crystallization ages and Sr and Nd isotopic signatures, and to better understand the petrogenetic relationships between them and other basaltic, lherzolitic and depleted olivine-phyric shergottites.

  20. Rb-Sr and Sm-Nd Isotopic Studies of Shergottite Y980459 and a Petrogenetic Link Between Depleted Shergottites and Nakhlites

    NASA Technical Reports Server (NTRS)

    Shih, C.-Y.; Nyquist, L. E.; Wiesmann, H.; Misawa, K.

    2004-01-01

    Y980459 was found near the Minami-Yamato Nunataks, Antarctica in 1998 and was recently classified as an olivine-bearing shergottite. It petrographically resembles many other olivine-phyric shergottites mostly found in hot deserts, e.g. DaG476/489, SaU005/094, Dohfar 019, NWA 1068/1110, NWA 1195 and EETA 79001 lith.A. However, Y980459 is unique among these meteorites in several respects. It is apparently very fresh and only weakly shocked. Also, it completely lacks plagioclase, but contains abundant residual volcanic glass. This group of olivine-phyric shergottites is characterized by variable crystallization ages from approx.172 Ma to approx.575 Ma and ejection ages from approx.1 Ma to approx.20 Ma. They probably represent volcanic melts originated from the deep Martian mantle. We performed Rb-Sr and Sm-Nd isotopic analyses on Y980459 to determine its crystallization age and compared its age and isotopic signatures with those obtained from other olivine-phyric shergottites and QUE 94201, the other Antarctic olivine-free shergottite. QUE 94201 and some olivine-phyric shergottites e.g. DaG, SaU, Doh and EETA lith A have similar depleted-LREE patterns and are herein referred to as depleted shergottites. A petrogenetic model correlating depleted shergottites and nakhlites is also proposed. Preliminary Rb-Sr and Sm-Nd isotopic data for Y980459 were presented earlier at the NIPR, Japan, in 2003.

  1. Evaluating Crustal Contamination Effects on the Lithophile Trace Element Budget of Shergottites

    NASA Technical Reports Server (NTRS)

    Brandon, A. D.; Ferdous, J.; Peslier, A. H.

    2017-01-01

    The origin of the incompatible trace element (ITE) enriched compositions of shergottites has been a point of contention for decades [1-2]. Two scenarios have been proposed, the first is that enriched shergottite compositions reflect an ITE-enriched mantle source, whereas in the second, the ITE enrichment reflects crustal contamination of mantle-derived parent magmas. Evidence supporting the first scenario is that the ITE-enriched shergottite compositions are consistent with the outcomes of magma ocean crystallization [3], and that Os-Nd isotope relationships for shergottites cannot be explained by realistic crustal contamination models [4]. In contrast, Cl and S isotopes are consistent with shergottite magmas interacting with Mars crust [5,6], and ITE-enriched olivine-hosted melt inclusions and interstitial glass are found in depleted shergottite Yamato 980459 [7]. These findings indicate that some level of crustal interaction occurred but the question of whether ITE-enrichments in some bulk shergottites reflect crustal contamination remains open. Recently, a Mars crustal breccia meteorite has been found, NWA 7034 and its paired stones, that is our best analogue to an average of Mars ancient crust [8-10]. This allows for better constraints on crustal contamination of shergottite magmas. We modeled magma-crust mixing and assimilation-fractional crystallization (AFC) using ITE-depleted shergottite compositions and bulk NWA 7034 and its clasts as end-members. The results of these models indicate that crustal contamination can only explain the ITE-enriched compositions of some bulk shergottites under unusual circumstances. It is thus likely that the shergottite range of compositions reflects primarily mantle sources.

  2. Radiocarbon datings of Yamato meteorites

    NASA Technical Reports Server (NTRS)

    Kigoshi, K.; Matsuda, E.

    1986-01-01

    The terrestrial ages of five Yamato Meteorites were measured by the content of cosmic-ray-produced carbon-14. Three Yamato Meteorites Y-74013, Y-74097, and Y-74136, which are all diogenites, were found at sites from one to two kilometers apart from each other. Evidence is presented for these three meteorites being a single meteorite. Also presented is a method adopted in the experimental procedure which includes a check for modern carbon contamination in the meteorites.

  3. The parent magma of xenoliths in shergottite EETA79001: Bulk and trace element composition inferred from magmatic inclusions

    NASA Technical Reports Server (NTRS)

    Treiman, Allan H.; Lindstrom, David J.; Martinez, Rene R.

    1994-01-01

    The SNC meteorites are samples of the Martian crust, so inferences about their origins and parent magmas are of wide planetologic significance. The EETA79001 shergottite, a basalt, contains xenoliths of pyroxene-olivine cumulate rocks which are possibly related to the ALHA77005 and LEW88516 SNC lherzolites. Olivines in the xenoliths contain magmatic inclusions, relics of magma trapped within the growing crystals. The magmatic inclusions allow a parent magma composition to be retrieved; it is similar to the composition reconstructed from xenolith pyroxenes by element distribution coefficients. The xenolith parent magma is similar but not identical to parent magmas for the shergottite lherzolites.

  4. Constraints on the Parental Melts of Enriched Shergottites from Image Analysis and High Pressure Experiments

    NASA Technical Reports Server (NTRS)

    Collinet, M.; Medard, E.; Devouard, B.; Peslier, A.

    2012-01-01

    Martian basalts can be classified in at least two geochemically different families: enriched and depleted shergottites. Enriched shergottites are characterized by higher incompatible element concentrations and initial Sr-87/Sr-86 and lower initial Nd-143/Nd-144 and Hf-176/Hf-177 than depleted shergottites [e.g. 1, 2]. It is now generally admitted that shergottites result from the melting of at least two distinct mantle reservoirs [e.g. 2, 3]. Some of the olivine-phyric shergottites (either depleted or enriched), the most magnesian Martian basalts, could represent primitive melts, which are of considerable interest to constrain mantle sources. Two depleted olivine-phyric shergottites, Yamato (Y) 980459 and Northwest Africa (NWA) 5789, are in equilibrium with their most magnesian olivine (Fig. 1) and their bulk rock compositions are inferred to represent primitive melts [4, 5]. Larkman Nunatak (LAR) 06319 [3, 6, 7] and NWA 1068 [8], the most magnesian enriched basalts, have bulk Mg# that are too high to be in equilibrium with their olivine megacryst cores. Parental melt compositions have been estimated by subtracting the most magnesian olivine from the bulk rock composition, assuming that olivine megacrysts have partially accumulated [3, 9]. However, because this technique does not account for the actual petrography of these meteorites, we used image analysis to study these rocks history, reconstruct their parent magma and understand the nature of olivine megacrysts.

  5. Exposure history of shergottites

    NASA Technical Reports Server (NTRS)

    Nishizumi, K.; Arnold, J. R.; Klein, J.; Middleton, R.; Elmore, D.

    1986-01-01

    The cosmogenic nuclides Cl-36, Al-26, Be-10, and Mn-53 were analyzed in Shergotty, ALHA 77005, and EETA 79001 shergottites by means of accelerator mass spectrometry and neutron activation. The cosmogenic radionuclide data were combined with noble gas data and cosmic ray track data to obtain the exposure ages, terrestrial ages, preatmospheric radii, and ablation depths for the three shergottites. The results indicate that none of the three meteorites was irradiated measurably by cosmic rays on its parent body, and that all three objects were ejected from greater than a 3-m depth in their parent bodies. The EETA 79001 meteorite was ejected in an event distinct from that of ALHA 77005 and Shergotty. All three shergottites show a very small amount of ablation, suggesting low velocities on entry into the earth's atmosphere.

  6. Exposure history of shergottites

    NASA Technical Reports Server (NTRS)

    Nishizumi, K.; Arnold, J. R.; Klein, J.; Middleton, R.; Elmore, D.

    1986-01-01

    The cosmogenic nuclides Cl-36, Al-26, Be-10, and Mn-53 were analyzed in Shergotty, ALHA 77005, and EETA 79001 shergottites by means of accelerator mass spectrometry and neutron activation. The cosmogenic radionuclide data were combined with noble gas data and cosmic ray track data to obtain the exposure ages, terrestrial ages, preatmospheric radii, and ablation depths for the three shergottites. The results indicate that none of the three meteorites was irradiated measurably by cosmic rays on its parent body, and that all three objects were ejected from greater than a 3-m depth in their parent bodies. The EETA 79001 meteorite was ejected in an event distinct from that of ALHA 77005 and Shergotty. All three shergottites show a very small amount of ablation, suggesting low velocities on entry into the earth's atmosphere.

  7. Melt Inclusion Analysis of RBT 04262 with Relationship to Shergottites and Mars Surface Compositions

    NASA Technical Reports Server (NTRS)

    Potter, S. A.; Brandon, A. D.; Peslier, A. H.

    2015-01-01

    Martian meteorite RBT 04262 is in the shergottite class. It displays the two lithologies typically found in "lherzolitic shergottites": one with a poikilitic texture of large pyroxene enclosing olivine and another with non-poikilitic texture. In the case of RBT 04262, the latter strongly ressembles an olivine- phyric shergottite which led the initial classification of this meteorite in that class. RBT 04262 has been studied with regards to its petrology, geochemistry and cosmic ray exposure and belongs to the enriched oxidized end-member of the shergottites. Studies on RBT 04262 have primarily focused on the bulk rock composition or each of the lithologies independently. To further elucidate RBT 04262's petrology and use it to better understand Martian geologic history, an in-depth study of its melt inclusions (MI) is being conducted. The MI chosen for this study are found within olivine grains. MI are thought to be trapped melts of the crystallizing magma preserved by the encapsulating olivine and offer snapshots of the composition of the magma as it evolves. Some MI, in the most Mg-rich part of the olivine of olivine-pyric shergottites, may even be representative of the meteorite parent melt.

  8. Geochemical diversity of shergottite basalts: Mixing and fractionation, and their relation to Mars surface basalts

    NASA Astrophysics Data System (ADS)

    Treiman, Allan H.; Filiberto, Justin

    2015-04-01

    The chemical compositions of shergottite meteorites, basaltic rocks from Mars, provide a broad view of the origins and differentiation of these Martian magmas. The shergottite basalts are subdivided based on their Al contents: high-Al basalts (Al > 5% wt) are distinct from low-Al basalts and olivine-phyric basalts (both with Al < 4.5% wt). Abundance ratios of highly incompatible elements (e.g., Th, La) are comparable in all the shergottites. Abundances of less incompatible elements (e.g., Ti, Lu, Hf) in olivine-phyric and low-Al basalts correlate well with each other, but the element abundance ratios are not constant; this suggests mixing between components, both depleted and enriched. High-Al shergottites deviate from these trends consistent with silicate mineral fractionation. The "depleted" component is similar to the Yamato-980459 magma; approximately, 67% crystal fractionation of this magma would yield a melt with trace element abundances like QUE 94201. The "enriched" component is like the parent magma for NWA 1068; approximately, 30% crystal fractionation from it would yield a melt with trace element abundances like the Los Angeles shergottite. This component mixing is consistent with radiogenic isotope and oxygen fugacity data. These mixing relations are consistent with the compositions of many of the Gusev crater basalts analyzed on Mars by the Spirit rover (although with only a few elements to compare). Other Mars basalts fall off the mixing relations (e.g., Wishstone at Gusev, Gale crater rocks). Their compositions imply that basalt source areas in Mars include significant complexities that are not present in the source areas for the shergottite basalts.

  9. Origin of water and mantle-crust interactions on Mars inferred from hydrogen isotopes and volatile element abundances of olivine-hosted melt inclusions of primitive shergottites

    NASA Astrophysics Data System (ADS)

    Usui, Tomohiro; Alexander, Conel M. O'D.; Wang, Jianhua; Simon, Justin I.; Jones, John H.

    2012-12-01

    Volatile elements have influenced the differentiation and eruptive behavior of Martian magmas and played an important role in the evolution of Martian climate and near-surface environments. However, the abundances of volatiles, and in particular the amount of water in the Martian interior, are disputed. A record of volatile reservoirs is contained in primitive Martian basalts (shergottites). Olivine-hosted melt inclusions from a geochemically depleted shergottite (Yamato 980459, representing a very primitive Martian melt) possess undegassed water with a chondritic and Earth-like D/H ratio (δD≤275‰). Based on volatile measurements in these inclusions, the water content of the depleted shergottite mantle is calculated to be 15-47 ppm, which is consistent with the dry mantle hypothesis. In contrast to D/H in the depleted shergottite, melt from an enriched shergottite (Larkman Nunatak 06319), which either formed by melting of an enriched mantle or by assimilation of crust, exhibits an extreme δD of ˜5000‰, indicative of a surface reservoir (e.g., the Martian atmosphere or crustal hydrosphere). These data provide strong evidence that the Martian mantle had retained the primordial low-δD component until at least the time of shergottite formation, and that young Martian basalts assimilated old Martian crust.

  10. Northwest Africa 4797: A strongly shocked ultramafic poikilitic shergottite related to compositionally intermediate Martian meteorites

    NASA Astrophysics Data System (ADS)

    Walton, E. L.; Irving, A. J.; Bunch, T. E.; Herd, C. D. K.

    2012-09-01

    Northwest Africa (NWA) 4797 is an ultramafic Martian meteorite composed of olivine (40.3 vol%), pigeonite (22.2%), augite (11.9%), plagioclase (9.1%), vesicles (1.6%), and a shock vein (10.3%). Minor phases include chromite (3.4%), merrillite (0.8%), and magmatic inclusions (0.4%). Olivine and pyroxene compositions range from Fo66-72,En58-74Fs19-28Wo6-15, and En46-60Fs14-22Wo34-40, respectively. The rock is texturally similar to "lherzolitic" shergottites. The oxygen fugacity was QFM-2.9 near the liquidus, increasing to QFM-1.7 as crystallization proceeded. Shock effects in olivine and pyroxene include strong mosaicism, grain boundary melting, local recrystallization, and pervasive fracturing. Shock heating has completely melted and vesiculated igneous plagioclase, which upon cooling has quench-crystallized plagioclase microlites in glass. A mm-size shock melt vein transects the rock, containing phosphoran olivine (Fo69-79), pyroxene (En44-51Fs14-18Wo30-42), and chromite in a groundmass of alkali-rich glass containing iron sulfide spheres. Trace element analysis reveals that (1) REE in plagioclase and the shock melt vein mimics the whole rock pattern; and (2) the reconstructed NWA 4797 whole rock is slightly enriched in LREE relative to other intermediate ultramafic shergottites, attributable to local mobilization of melt by shock. The shock melt vein represents bulk melting of NWA 4797 injected during pressure release. Calculated oxygen fugacity for NWA 4797 indicates that oxygen fugacity is decoupled from incompatible element concentrations. This is attributed to subsolidus re-equilibration. We propose an alternative nomenclature for "lherzolitic" shergottites that removes genetic connotations. NWA 4797 is classified as an ultramafic poikilitic shergottite with intermediate trace element characteristics.

  11. The role of sulfides in the fractionation of highly siderophile and chalcophile elements during the formation of martian shergottite meteorites

    NASA Astrophysics Data System (ADS)

    Baumgartner, Raphael J.; Fiorentini, Marco L.; Lorand, Jean-Pierre; Baratoux, David; Zaccarini, Federica; Ferrière, Ludovic; Prašek, Marko K.; Sener, Kerim

    2017-08-01

    The shergottite meteorites are ultramafic to mafic igneous rocks whose parental magmas formed from partial melting of the martian mantle. This study reports in-situ laser ablation inductively coupled plasma mass spectrometry analyses for siderophile and chalcophile major and trace elements (i.e., Co, Ni, Cu, As, Se, Ag, Sb, Te, Pb, Bi, and the highly siderophile platinum-group elements, PGE: Os, Ir, Ru, Rh, Pt and Pd) of magmatic Fe-Ni-Cu sulfide assemblages from four shergottite meteorites. They include three geochemically similar incompatible trace element- (ITE-) depleted olivine-phyric shergottites (Yamato-980459, Dar al Gani 476 and Dhofar 019) that presumably formed from similar mantle and magma sources, and one distinctively ITE-enriched basaltic shergottite (Zagami). The sulfides in the shergottites have been variably modified by alteration on Earth and Mars, as well as by impact shock-shock related melting/volatilization during meteorite ejection. However, they inherit and retain their magmatic PGE signatures. The CI chondrite-normalized PGE concentration patterns of sulfides reproduce the whole-rock signatures determined in previous studies. These similarities indicate that sulfides exerted a major control on the PGE during shergottite petrogenesis. However, depletions of Pt (and Ir) in sulfide relative to the other PGE suggest that additional phases such discrete Pt-Fe-Ir alloys have played an important role in the concentration of these elements. These alloys are expected to have enhanced stability in reduced and FeO-rich shergottite magmas, and could be a common feature in martian igneous systems. A Pt-rich PGM was found to occur in a sulfide assemblage in Dhofar 019. However, its origin may be related to impact shock-related sulfide melting and volatilisation during meteorite ejection. In the ITE-depleted olivine-phyric shergottites, positive relationships exist between petrogenetic indicators (e.g., whole-rock Mg-number) and most moderately to

  12. Zirconology of lherzolites in the Nurali Massif

    NASA Astrophysics Data System (ADS)

    Krasnobaev, A. A.; Rusin, A. I.; Anfilogov, V. N.; Valizer, P. M.; Busharina, S. V.; Medvedeva, E. V.

    2017-06-01

    The age trend (SHRIMP U/Pb) of the evolution of zircon is obtained for the first time in lherzolites of the Nurali Massif. Zircons are subdivided into groups by the crystallomorphological and geochemical features. These specific features in zircon development are confirmed by the age dates. Precambrian dates (no younger than 1190 Ma) correspond to mantle sources of the lherzolite block. The Early Silurian (445-448 and 439-440 Ma) wass the time of lherzolite magmatism of 10-15 Ma in duration. The Middle Devonian (382.9 ± 8.7 Ma) corresponded to postmagmatic processes related to the effect of gabbro-diorite intrusions crowning in the Nurali Massif.

  13. Lead isotope study of orogenic lherzolite massifs

    NASA Astrophysics Data System (ADS)

    Hamelin, Bruno; Allègre, Claude J.

    1988-12-01

    Orogenic lherzolites allow for almost "in-situ" observation of mantle isotopic heterogeneities on a restricted geographical scale, in contrast to basalts for which melting processes have averaged original mantle compositions over uncertain scales. Pb isotopes from whole rocks and clinopyroxenes from the massifs of Lherz (Pyrenees), Lanzo (Alps), Beni Bousera (Morocco) and Zabargad (Red Sea) show internal heterogeneities that encompass the entire range of variation observed in oceanic basalts. Some depleted lherzolites have a very unradiogenic composition similar to that of the most depleted ridge tholeiites. Pyroxenites from mafic layers generally have more radiogenic compositions, some of them comparable to the most radiogenic oceanic island results. The isotopic differences between lherzolites and pyroxenites vanish where layers are very closely spaced ( < 2 cm). In this case, the lherzolites may have equilibrated with the more Pb-rich pyroxenites through solid-state diffusion under mantle conditions. These results directly illustrate the smallest scales at which Pb isotopic heterogeneity may survive within the mantle. The genesis of these heterogeneities are discussed within the framework of the "marble cake" mantle model [1], where lherzolites are residues left over after oceanic crust extraction, whereas pyroxenites represent either basaltic or cumulate portions of the oceanic crust, reinjected by subduction and stretched by solid-state mixing during mantle convection. The Pb isotope data suggest that each massif was involved in several cycles of convective overturn, segregation and reinjection of the oceanic crust, during periods well over 1 Ga. If the upper mantle is made of interlayered radiogenic and unradiogenic layers, basalt heterogeneities may result from preferential melt-extraction from different layers depending on the degree of melting, as well as from large-scale, plume-related mantle heterogeneities. Orogenic lherzolites therefore allow direct

  14. Yamato: Bringing the Moon to the Earth ... Again

    NASA Technical Reports Server (NTRS)

    Lam, King; Martinelli, Scott; Patel, Neal; Powell, David; Smith, Brandon

    2008-01-01

    The Yamato mission to the lunar South Pole-Aitken Basin returns samples that enable dating of lunar formation and the lunar bombardment period. The design of the Yamato mission is based on a systems engineering process which takes an advanced consideration of cost and mission risk to give the mission a high probability of success.

  15. Anhydrous Liquid Line of Descent of Yamato 980459 and Evolution of Martian Parental Magmas

    NASA Technical Reports Server (NTRS)

    Rapp, J. F.; Draper, David S.; Mercer, C. M.

    2013-01-01

    Martian basalts represented by the shergottite meteorites reflect derivation from highly depleted mantle sources (high Nd, strong LREE depletions, low fO2)[1-3], with evidence of mixing with a much more enriched and oxidized reservoir, most likely a late-stage product of crystallization of an initial martian magma ocean [3-6]. The martian basaltic meteorites Yamato 980459 (Y98) and QUE 94201 (QUE) have bulk compositions that appear to represent bonafide liquids, rather than products of protracted crystallization. These two meteorites also represent the most primitive and evolved examples of the depleted basaltic shergottite suite. Magmatic liquids serve as effective probes of their source regions, and thus studying the potential relationship between magmas represented by Y98 and QUE can yield important information on the formation and evolution of martian basalts. Although the ages of these meteorites preclude that they are petrogenetically related to each other, they represent the best existing candidates for genuine liquids (other meteorites are suggested to represent liquid compositions, including LAR 06319 [7] and NWA 5789 [8], but only Y98 and QUE have been verified experimentally). They span much of the bulk-compositional range of martian basaltic meteorites, and represent end-member liquid compositions likely to arise from partial melting of the martian mantle. Recent efforts to model Y98-like parent liquid evolution by fractional crystallization using MELTS [6] produced a derivative liquid composition that closely matches QUE bulk composition, although it required a some-what unusual crystallization sequence. Experimental endeavours to verify this result at 1 bar have, however, been inconclusive [9].

  16. Melts of garnet lherzolite: experiments, models and comparison to melts of pyroxenite and carbonated lherzolite

    USGS Publications Warehouse

    Grove, Timothy L.; Holbig, Eva S.; Barr, Jay A.; Till, Christy B.; Krawczynski, Michael J.

    2013-01-01

    Phase equilibrium experiments on a compositionally modified olivine leucitite from the Tibetan plateau have been carried out from 2.2 to 2.8 GPa and 1,380–1,480 °C. The experiments-produced liquids multiply saturated with spinel and garnet lherzolite phase assemblages (olivine, orthopyroxene, clinopyroxene and spinel ± garnet) under nominally anhydrous conditions. These SiO2-undersaturated liquids and published experimental data are utilized to develop a predictive model for garnet lherzolite melting of compositionally variable mantle under anhydrous conditions over the pressure range of 1.9–6 GPa. The model estimates the major element compositions of garnet-saturated melts for a range of mantle lherzolite compositions and predicts the conditions of the spinel to garnet lherzolite phase transition for natural peridotite compositions at above-solidus temperatures and pressures. We compare our predicted garnet lherzolite melts to those of pyroxenite and carbonated lherzolite and develop criteria for distinguishing among melts of these different source types. We also use the model in conjunction with a published predictive model for plagioclase and spinel lherzolite to characterize the differences in major element composition for melts in the plagioclase, spinel and garnet facies and develop tests to distinguish between melts of these three lherzolite facies based on major elements. The model is applied to understand the source materials and conditions of melting for high-K lavas erupted in the Tibetan plateau, basanite–nephelinite lavas erupted early in the evolution of Kilauea volcano, Hawaii, as well as younger tholeiitic to alkali lavas from Kilauea.

  17. The source crater of martian shergottite meteorites.

    PubMed

    Werner, Stephanie C; Ody, Anouck; Poulet, François

    2014-03-21

    Absolute ages for planetary surfaces are often inferred by crater densities and only indirectly constrained by the ages of meteorites. We show that the <5 million-year-old and 55-km-wide Mojave Crater on Mars is the ejection source for the meteorites classified as shergottites. Shergottites and this crater are linked by their coinciding meteorite ejection ages and the crater formation age and by mineralogical constraints. Because Mojave formed on 4.3 billion-year-old terrain, the original crystallization ages of shergottites are old, as inferred by Pb-Pb isotope ratios, and the much-quoted shergottite ages of <600 million years are due to resetting. Thus, the cratering-based age determination method for Mars is now calibrated in situ, and it shifts the absolute age of the oldest terrains on Mars backward by 200 million years.

  18. Tracking the Depleted Mantle Signature in Melt Inclusions and Residual Glass of Basaltic Martian Shergottites using Secondary Ionization Mass Spectrometry

    NASA Technical Reports Server (NTRS)

    Peters, Timothy J.; Simon, Justin I.; Jones, John H.; Usui, Tomohiro; Economos, Rita C.; Schmitt, Axel K.; McKeegan, Kevin D.

    2013-01-01

    Trace element abundances of depleted shergottite magmas recorded by olivine-hosted melt inclusions (MI) and interstitial mesostasis glass were measured using the Cameca ims-1270 ion microprobe. Two meteorites: Tissint, an olivine-­phyric basaltic shergottite which fell over Morocco July 18th 2001; and the Antarctic meteorite Yamato 980459 (Y98), an olivine-phyric basaltic shergottite with abundant glassy mesostasis have been studied. Chondrite-­normalized REE patterns for MI in Tissint and Y98 are characteristically LREE depleted and, within analytical uncertainty, parallel those of their respective whole rock composition; supporting each meteorite to represent a melt composition that has experienced closed-­system crystallization. REE profiles for mesostasis glass in Y98 lie about an order of magnitude higher than those from the MI; with REE profiles for Tissint MI falling in between. Y98 MI have the highest average Sm/Nd and Y/Ce ratios, reflecting their LREE depletion and further supporting Y98 as one of our best samples to probe the depleted shergotitte mantle. In general, Zr/Nb ratios overlap between Y98 and Tissint MI, Ce/Nb ratios overlap between Y98 MI and mesostasis glass, and Sm/Nd ratios overlap between Y98 mesostasis glass and Tissint MI. These features support similar sources for both, but with subtle geochemical differences that may reflect different melting conditions or fractionation paths during ascent from the mantle. Interestingly, the REE patterns for both Y98 bulk and MI analyses display a flattening of the LREE that suggests a crustal contribution to the Y98 parent melt. This observation has important implications for the origins of depleted and enriched shergottites.

  19. Lu-Hf and Sm-Nd Isotopic Studies of Shergottites and Nakhlites: Implications for Martian Mantle Sources

    NASA Technical Reports Server (NTRS)

    Debaille, V.; Yin, Q.-Z.; Brandon, A. D.; Jacobsen, B.; Treiman, A. H.

    2007-01-01

    We present a new Lu-Hf and Sm-Nd isotope systematics study of four enriched shergottites (Zagami, Shergotty, NWA856 and Los Angeles), and three nakhlites (Nakhla, MIL03346 and Yamato 000593) in order to further understand processes occurring during the early differentiation of Mars and the crystallization of its magma ocean. Two fractions of the terrestrial petrological analogue of nakhlites, the Archaean Theo's flow (Ontario, Canada) were also measured. The coupling of Nd and Hf isotopes provide direct insights on the mineralogy of the melt sources. In contrast to Sm/Nd, Lu/Hf ratios can be very large in minerals such as garnet. Selective partial melting of garnet bearing mantle sources can therefore lead to characteristic Lu/Hf signatures that can be recognized with Hf-176/Hf-177Hf ratios.

  20. The superconducting MHD-propelled ship YAMATO-1

    NASA Technical Reports Server (NTRS)

    Sasakawa, Yohei; Takezawa, Setsuo; Sugawara, Yoshinori; Kyotani, Yoshihiro

    1995-01-01

    In 1985 the Ship & Ocean Foundation (SOF) created a committee under the chairmanship of Mr. Yohei Sasakawa, Former President of the Ship & Ocean Foundation, and began researches into superconducting magnetohydrodynamic (MHD) ship propulsion. In 1989 SOF set to construction of a experimental ship on the basis of theoretical and experimental researches pursued until then. The experimental ship named YAMATO-1 became the world's first superconducting MHD-propelled ship on her trial runs in June 1992. This paper describes the outline of the YAMATO-1 and sea trial test results.

  1. The superconducting MHD-propelled ship YAMATO-1

    NASA Astrophysics Data System (ADS)

    Sasakawa, Yohei; Takezawa, Setsuo; Sugawara, Yoshinori; Kyotani, Yoshihiro

    1995-04-01

    In 1985 the Ship & Ocean Foundation (SOF) created a committee under the chairmanship of Mr. Yohei Sasakawa, Former President of the Ship & Ocean Foundation, and began researches into superconducting magnetohydrodynamic (MHD) ship propulsion. In 1989 SOF set to construction of a experimental ship on the basis of theoretical and experimental researches pursued until then. The experimental ship named YAMATO-1 became the world's first superconducting MHD-propelled ship on her trial runs in June 1992. This paper describes the outline of the YAMATO-1 and sea trial test results.

  2. An absarokite from a phlogopite lherzolite source

    NASA Astrophysics Data System (ADS)

    Tatsumi, Yoshiyuki; Koyaguchi, Takehiro

    1989-03-01

    An absarokite (SiO2 47.72 wt %, K2O 3.41 wt %) occurs in the Katamata volcano, SW Japan. The rock carries phenocrysts of olivine, phlogopite, clinopyroxene, and hornblende. Chemical compositions of bulk rock (FeO*/ MgO 0.73) and minerals (Mg-rich olivine and phlogopite, Cr-rich chromite) suggest that the absarokite is not differentiated. Melting experiments at high pressures on the Katamata absarokite have been conducted. The completely anhydrous absarokite melt coexists with olivine, orthopyroxene, and clinopyroxene at 1310° C and 1.0 GPa. The melt with 3.29 wt % of H2O also coexists with the above three phases at 1230° C and 1.4 GPa; phlogopite appears at temperatures more than 80° C below the liquidus. On the other hand, the melt is not saturated with lherzolite minerals in the presence of 5.13 wt % of H2O and crystallizes olivine and phlogopite as liquidus phases; the stability limit of phlogopite is little affected at least by the present variation of H2O content in the absarokite melt. It is suggested that the absarokite magma was segregated from the upper mantle at 1170° C and 1.7 GPa leaving a phlogopite lherzolite as a residual material on the basis of the above experimental results and the petrographical observation that olivine and phlogopite crystallize at an earlier stage of crystallization sequence than clinopyroxene. The contribution of phlogopite at the stage of melting processes is also suggested by the geochemical characteristics that the absarokite is more enriched in Rb, K, and Ba and depleted in Ca and Na than a typical alkali olivine basalt from the same volcanic field.

  3. Solar proton produced neon in shergottite meteorites

    NASA Technical Reports Server (NTRS)

    Garrison, D. H.; Rao, M. N.; Bogard, D. D.

    1994-01-01

    Cosmogenic radionuclides produced by near-surface, nuclear interactions of energetic solar protons (approx. 10-100 MeV) were reported in several lunar rocks and a very small meteorites. We recently documented the existence and isotopic compositions of solar-produced (SCR) Ne in two lunar rocks. Here we present the first documented evidence for SCR Ne in a meteorite, ALH77005, which was reported to contain SCR radionuclides. Examination of literature data for other shergottites suggests that they may also contain a SCR Ne component. The existence of SCR Ne in shergottites may be related to a Martian origin.

  4. Basaltic Shergottite NWA 856: Differentiation of a Martian Magma

    NASA Technical Reports Server (NTRS)

    Ferdous, J.; Brandon, A. D.; Peslier, A. H.; Pirotte, Z.

    2016-01-01

    NWA 856 or Djel Ibone, is a basaltic shergottite discovered as a single stone of 320 g in South Morocco in April, 2001. This meteorite is fresh, i.e. shows minimal terrestrial weathering for a desert find. No shergottite discovered in North Africa can be paired with NWA 856. The purpose of this study is to constrain its crystallization history using textural observations, crystallization sequence modeling and in-situ trace element analysis in order to understand differentiation in shergottite magmatic systems.

  5. Shock Metamorphism of the Dhofar 378 Basaltic Shergottite

    NASA Technical Reports Server (NTRS)

    Mikouchi, T.; McKay, G.

    2006-01-01

    Shock metamorphism is one of the most fundamental processes in the history of Martian meteorites, especially shergottites, which affect their mineralogy and chronology. The formation of "maskelynite" from plagioclase and shock melts is such major mineralogical effects. Dhofar 378 is one of the recently found desert shergottites that is mainly composed of plagioclase and pyroxene. This shergottite is important because of its highly shocked nature and unique plagioclase texture, and thus has a great potential for assessing a "shock" age of shergottites. We have been working on a combined study of mineralogy and chronology of the same rock chip of Dhofar 378. This abstract reports its mineralogical part.

  6. Maximizing the science return from 3.3 g of martian meteorite: A consortium study of olivine-phyric shergottite NorthWest Africa 6234

    NASA Astrophysics Data System (ADS)

    Filiberto, J.; Abernethy, F.; Butler, I. B.; Cartwright, J.; Chin, E. J.; Day, J. M.; Goodrich, C.; Grady, M.; Gross, J.; Franchi, I.; Herd, C. D.; Kelley, S. P.; Ott, U.; Penniston-Dorland, S. C.; Schwenzer, S. P.; Treiman, A. H.

    2011-12-01

    The ~382kg of sample returned from the lunar surface during the Apollo missions ranged from samples of gram to kilogram masses. However, any sample return mission from the martian surface will bring back small samples. Learning to get the most of each sample, while keeping enough material for future explorations, will require strategic planning and international consortium studies, as exemplified by studies of Apollo samples. Here we report on an international consortium study of 3.3 grams of olivine-phyric martian meteorite NWA 6234 as an example of what can be gleaned from a small martian sample. NWA 6234 was selected because its unusually fine grained texture suggests that it may approach a melt composition. To date, we have obtained bulk major and trace elements abundances (including highly siderophile elements; HSE), mineral compositions, Re-Os isotopes, and Li isotopes. A 100 mg slice from the interior of the sample containing an impact melt has also been scanned using high resolution X-ray computed tomography. Analyses of NWA 6234 in progress include: Ar isotopes ratios (including a separate of the impact melt vein); abundances and isotope ratios for all noble gases (for resolution of martian interior and atmosphere components using step heating); stepped combustion analyses of C and N to determine current residual and initial magmatic volatile components; melt inclusion mineralogy and chemistry to constrain original magma composition and crystallization sequence; and Sm-Nd isotope ratios to further elucidate the mantle source and age of the meteorite. So far we know that NWA 6234 has a bulk Mg# of 59 and phenocryst olivine of Fo 67. This suggests that the meteorite is more evolved than Yamato 980459 and NWA 1068. NWA 6234 has bulk REE abundances intermediate between the enriched end members (NWA 1068) and depleted (Yamato 980459) martian compositions, similar to those of basaltic shergottite Zagami. This similarity suggests another possible connection

  7. A More Reduced Mantle Source for Enriched Shergottites; Insights from the Olivine-Phyric Shergottite Lar 06319

    NASA Technical Reports Server (NTRS)

    Peslier, A. H.; Hnatyshin, D.; Herd, C. D. K.; Walton, E. L.; Brandon, A. D.; Lapen, T. J.; Shafer, J.

    2010-01-01

    A detailed petrographic study of melt inclusions and Cr-Fe-Ti oxides of LAR 06319 leads to two main conclusions: 1) this enriched oxidized olivine- phyric shergottite represents nearly continuous crystallization of a basaltic shergottite melt, 2) the melt became more oxidized during differentiation. The first crystallized mineral assemblages record the oxygen fugacity which is closest to that of the melt s mantle source, and which is lower than generally attributed to the enriched shergottite group.

  8. Volatile compounds in shergottite and nakhlite meteorites

    NASA Technical Reports Server (NTRS)

    Gooding, James L.; Aggrey, Kwesi E.; Muenow, David W.

    1990-01-01

    Since discovery of apparent carbonate carbon in Nakhla, significant evidence has accumulated for occurrence of volatile compounds in shergotties and nakhlites. Results are presented from a study of volatile compounds in three shergottites, one nakhlite, and three eucrite control samples. Shergotties ALHA77005, EETA79001, and Shergotty, and the nakhlite Nakhla, all contain oxidized sulfur (sulfate) of preterrestrial origin; sulfur oxidation is most complete in EETA79001/Lith-C. Significant bulk carbonate was confirmed in Nakhla and trace carbonate was substantiated for EETA79001, all of which appears to be preterrestrial in origin. Chlorine covaries with oxidized sulfur, whereas carbonate and sulfate are inversely related. These volatile compounds were probably formed in a highly oxidizing, aqueous environment sometime in the late stage histories of the rocks that are now represented as meteorites. They are consistent with the hypothesis that shergottite and nakhlite meteorites originated on Mars and that Mars has supported aqueous geochemistry during its history.

  9. Northwest Africa 5298: A Basaltic Shergottite

    NASA Technical Reports Server (NTRS)

    Hui, Hejiu; Peslier, Anne; Lapen, Thomas J.; Brandon, Alan; Shafer, John

    2009-01-01

    NWA 5298 is a single 445 g meteorite found near Bir Gandouz, Morocco in March 2008 [1]. This rock has a brown exterior weathered surface instead of a fusion crust and the interior is composed of green mineral grains with interstitial dark patches containing small vesicles and shock melts [1]. This meteorite is classified as a basaltic shergottite [2]. A petrologic study of this Martian meteorite is being carried out with electron microprobe analysis and soon trace element analyses by laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS). Oxygen fugacity is calculated from Fe-Ti oxides pairs in the sample. The data from this study constrains the petrogenesis of basaltic shergottites.

  10. The age of the martian meteorite Northwest Africa 1195 and the differentiation history of the shergottites

    SciTech Connect

    Symes, S; Borg, L; Shearer, C; Irving, A

    2007-04-05

    Samarium-neodymium isotopic analyses of unleached and acid-leached mineral fractions from the recently identified olivine-bearing shergottite Northwest Africa 1195 yield a crystallization age of 348 {+-} 19 Ma and an {var_epsilon}{sub Nd}{sup 143} value of +40.1 {+-} 1.3. Maskelynite fractions do not lie on the Sm-Nd isochron and appear to contain a martian surface component with low {sup 147}Sm/{sup 144}Nd and {sup 143}Nd/{sup 144}Nd ratios that was added during shock. The Rb-Sr system is disturbed and does not yield an isochron. Terrestrial Sr appears to have affected all of the mineral fractions, although a maximum initial {sup 87}Sr/{sup 86}Sr ratio of 0.701614 {+-} 16 is estimated by passing a 348 Ma reference isochron through the maskelynite fraction that is least affected by contamination. The high initial {var_epsilon}{sub Nd}{sup 143} value and the low initial {sup 87}Sr/{sup 86}Sr ratio, combined with the geologically young crystallization age, indicate that Northwest Africa 1195 is derived from a source region characterized by a long-term incompatible element depletion. The age and initial Sr and Nd isotopic compositions of Northwest Africa 1195 are very similar to those of Queen Alexandra Range 94201, indicating these samples were derived from source regions with nearly identical Sr-Nd isotopic systematics. These similarities suggest that these two meteorites share a close petrogenetic relationship and might have been erupted from a common volcano. The meteorites Yamato 980459, Dar al Gani 476, Sayh al Uhaymir 005/008, and Dhofar 019 also have relatively old ages between 474-575 Ma and trace element and/or isotopic systematics that are indicative of derivation from incompatible-element-depleted sources. This suggests that the oldest group of meteorites is more closely related to one another than they are to the younger meteorites that are derived from less incompatible-element-depleted sources. Closed-system fractional crystallization of this suite of

  11. New Titanium Monosulfide Mineral Phase in Yamato 691 Enstatite Chondrite

    NASA Technical Reports Server (NTRS)

    Nakamura-Messenger, K; Clemett, S. J.; Rubin, A. E.; Choi, B.-G.; Zhang, S.; Rahman, Z.; Oikawa, K.; Keller, L. P.

    2011-01-01

    Yamato 691, an EH3 enstatite chondrite, was among the first meteorites discovered by chance in Antarctica by the Japanese Antarctic Research Expedition (JARE) team in 1969. This discovery led to follow-up searches for meteorites in Antarctica [1]. These international searches have been very successful recovering over 40,000 total specimens (and still counting), including martian and lunar meteorites. Titanium is partly chalcophile in enstatite-rich meteorites. Previous occurrences of Ti-bearing sulfides include troilite, daubrelite and ferroan alabandite in enstatite chondrites and aubrites [2], and heideite with 28.5 wt% Ti in the Bustee aubrite [3]. Here we report a new mineral from Yamato 691, ideally stoichiometric TiS, titanium monosulfide, a simple two-element mineral phase, yet with a very unique crystal structure that, to our knowledge, has not been observed previously in nature.

  12. Modal comparison of Yamato and Allan Hills polymict eucrites

    NASA Technical Reports Server (NTRS)

    Delaney, J. S.; Prinz, M.; Takeda, H.

    1983-01-01

    Seven Yamato and six Allan Hills polymict eucrite specimens were compared by modal analysis. The analyses reveal differences of plagioclase and pyroxene content between the two groups. The Yamato suite has more 'pigeonitic' pyroxene and less plagioclase and low-calcium pyroxene than the Allan Hills suite. Variations within each suite are small and three sections of Allan Hills A78040 are more variable than the Allen Hills suite considered as a group. Modal data provides a basis for pairing polymict eucrite specimens when used together with mineralogical and petrographic criteria. Modal data furthermore confirms the presence of several rock types previously identified using pyroxene crystallography and hints at the presence of an augite-rich component.

  13. Amino acids in the Yamato carbonaceous chrondrite from Antarctica

    NASA Technical Reports Server (NTRS)

    Shimoyama, A.; Ponnamperuma, C.; Yanai, K.

    1979-01-01

    Evidence for the presence of amino acids of extraterrestrial origin in the Antarctic Yamato carbonaceous chrondrite is presented. Hydrolyzed and nonhydrolyzed water-extracted amino acid samples from exterior, middle and interior portions of the meteorite were analyzed by an amino acid analyzer and by gas chromatography of N-TFA-isopropyl amino acid derivatives. Nine protein and six nonprotein amino acids were detected in the meteorite at abundances between 34 and less than one nmole/g, with equal amounts in interior and exterior portions. Nearly equal abundances of the D and L enantiomers of alanine, aspartic acid and glutamic acid were found, indicating the abiotic, therefore extraterrestrial, origin of the amino acids. The Antarctic environment and the uniformity of protein amino acid abundances are discussed as evidence against the racemization of terrestrially acquired amino acids, and similarities between Yamato amino acid compositions and the amino acid compositions of the Murchison and Murray type II carbonaceous chrondrites are indicated.

  14. Isotopic Petrology: The Curious Case of the Shergottite Meteorites

    NASA Astrophysics Data System (ADS)

    Jones, J. H.

    2009-05-01

    The shergottites comprise a diverse suite of martian basalts and basaltic cumulates. As of 1985, there were three proposed igneous ages for this group of basaltic rocks: (i) 4-4.5 b.y. [1; Caltech]; (ii) 1.3 b.y. [2; JSC]; and (iii) 360 m.y. [3; Mainz]. At that time I proffered that petrographic observations demanded that the shergottites were only 180 m.y. old [4]. By 1985, all the above geochronology groups had presented evidence of a young 200 m.y. age, but interpreted that as a metamorphic resetting. My observation was considered extremely controversial. However, John Longhi was instrumental, perhaps pivotal, in causing this new, controversial interpretation to be accepted, at least among petrologists. John then used this newfound knowledge to infer the Nd isotopic composition of the martian crust [5]. This new interpretation of shergottite chronology has led to petrologic insights that would not otherwise have been possible: (I) There were melt extraction events in the shergottite mantle immediately(?) preceding shergottite formation; and (II) the variation in enriched vs. depleted characteristics of the shergottites is best explained by assimilation of ancient, enriched crust by young magmas from a depleted source region. I. Internal, mineral isochrons of the shergottites (15 years later) vary from 165 m.y. to 575 m.y. [6]. Without exception, the Sm/Nd ratios of the shergottites themselves are larger than the time-integrated Sm/Nd ratio of their source regions [7]. This means that there has been a LREE-enriched phase that has fractionated from the shergottites. There are no solid phases in the martian mantle that are capable of this. This implies that LREE-enriched magmas escaped the shergottite source regions just prior to shergottite petrogenesis. II. Therefore, the shergottites can be characterized in terms of three Sm-Nd components: (i) a primitive shergottite magma from a depleted source region; (ii) an enriched crust; and (iii) a missing LREE

  15. Crystallization and Alteration Ages of the Antarctic Nakhlite Yamato 000593

    NASA Technical Reports Server (NTRS)

    Musawa, K.; Shih, C.-Y.; Wiesmann, H.; Nyquist, L. E.

    2003-01-01

    Nakhlites are unbrecciated, olivine-bearing clinopyroxenites that probably came from Mars. A total of eight nakhlites have been identified, including five recent finds: two samples (104 g and 456 g) from the hot desert of Morocco (NWA 817 and NWA 998), and three samples, a total weight of approx.15 kg, from the Yamato Mountains of Antarctica (Y000593, Y000749 and Y000802). Preliminary isotopic results for Y000593 have been given by Shih et al.. In this report, we present Rb-Sr and Sm-Nd isochron data for Y000593 and discuss the age correlation with other nakhlites and the timing of aqueous alteration on Mars.

  16. Lherzolite, anorthosite, gabbro, and basalt dredged from the Mid-Indian Ocean Ridge

    USGS Publications Warehouse

    Engel, C.G.; Fisher, R.L.

    1969-01-01

    The Central Indian Ridge is mantled with flows of low-potassium basalt of uniform composition. Gabbro, anorthosite, and garnet-bearing lherzolite are exposed in cross fractures, and lherzolite is the bedrock at the center of the ridge. The lherzolites are upper-mantle rock exposed by faulting.

  17. The variability of ruthenium in chromite from chassignite and olivine-phyric shergottite meteorites: New insights into the behavior of PGE and sulfur in Martian magmatic systems

    NASA Astrophysics Data System (ADS)

    Baumgartner, Raphael J.; Fiorentini, Marco L.; Baratoux, David; Ferrière, Ludovic; Locmelis, Marek; Tomkins, Andrew; Sener, Kerim A.

    2017-02-01

    The Martian meteorites comprise mantle-derived mafic to ultramafic rocks that formed in shallow intrusions and/or lava flows. This study reports the first in situ platinum-group element data on chromite and ulvöspinel from a series of dunitic chassignites and olivine-phyric shergottites, determined using laser-ablation ICP-MS. As recent studies have shown that Ru has strongly contrasting affinities for coexisting sulfide and spinel phases, the precise in situ analysis of this element in spinel can provide important insights into the sulfide saturation history of Martian mantle-derived melts. The new data reveal distinctive differences between the two meteorite groups. Chromite from the chassignites Northwest Africa 2737 (NWA 2737) and Chassigny contained detectable concentrations of Ru (up to 160 ppb Ru) in solid solution, whereas chromite and ulvöspinel from the olivine-phyric shergottites Yamato-980459 (Y-980459), Tissint, and Dhofar 019 displayed Ru concentrations consistently below detection limit (<42 ppb). The relatively elevated Ru signatures of chromite from the chassignites suggest a Ru-rich ( 1-4 ppb) parental melt for this meteorite group, which presumably did not experience segregation of immiscible sulfide liquids over the interval of mantle melting, melt ascent, and chromite crystallization. The relatively Ru-depleted signature of chromite and ulvöspinel from the olivine-phyric shergottites may be the consequence of relatively lower Ru contents (<1 ppb) in the parental melts, and/or the presence of sulfides during the crystallization of the spinel phases. The results of this study illustrate the significance of platinum-group element in situ analysis on spinel phases to decipher the sulfide saturation history of magmatic systems.

  18. Terrestrial C-14 age of the Antarctic shergottite, EETA 79001

    NASA Technical Reports Server (NTRS)

    Jull, A. J. T.; Donahue, D. J.

    1988-01-01

    The terrestrial age of the Elephant Moraine shergottite EETA 79001 (lithology A) has been determined from measurement of its cosmogenic C-14 content as 12 +/- 2 kyr. The results on saturated and blank samples of 1 g or less are also discussed. The age calculated for EETA 79001 is compared to exposure and terrestrial ages of other shergottites in the light of possible origins of these meteorites on Mars.

  19. The Origin and Impact History of Lunar Meteorite Yamato 86032

    NASA Technical Reports Server (NTRS)

    Yamaguchi, A.; Takeda, H.; Nyquist, L. E.; Bogard, D. D.; Ebihara, M.; Karouji, Y.

    2004-01-01

    Yamato (Y) 86032 is a feldspathic lunar highland breccia having some characteristics of regolith breccia. The absence of KREEP components in the matrix in Y86032 indicates that these meteorites came from a long distance from Mare Imbrium, perhaps from the far-side of the moon. One ferroan anorthosite (FAN) clast in Y86032 has a very old Ar-Ar age of approximately 4.35-4.4 Ga. The negative Nd of this clast may suggest a direct link with the primordial magma ocean. The facts indicate that Y86032 contains components derived from a protolith of the original lunar crust. Detailed petrologic characterization of each component in this breccia is essential to understand the early impact history and origin of the lunar highland crust. We made a large slab (5.2 x 3.6 cm x 3-5 mm) of Y86032 to better understand the relationship of various lithologies and their petrologic origin.

  20. Jarosite in the Shergottite Que 94201

    NASA Technical Reports Server (NTRS)

    Ross, D. K.; Ito, M.; Rao, M. N.; Hervig, R.; Williams, L. B.; Nyquist, Laurence E.; Peslier, A.

    2010-01-01

    Veins of the hydroxylated, potassium ferric sulfate mineral jarosite - KFe3(SO4)2(OH)6 - have been identified in the martian meteorite Queen Alexandra Range (QUE) 94201. Iron potassium sulfate had been reported in QUE 94201 by Wentworth and Gooding. Jarosite has been reported in other Martian meteorites - Roberts Massif (RBT) 04262, Miller Range (MIL) 03346, and Yamato 000593 - and it has been identified on the Martian surface by Moessbauer spectroscopy. Given the presence of jarosite on Mars, and the burgeoning interest in water-rock interactions on Mars, the question arises whether jarosite in Martian meteorites is formed by aqueous alteration on Mars, or in Antarctica. Hydrogen isotopes are potentially sensitive indicators of the site of formation or last equilibration of hydrous alteration minerals, because of the large difference between D/H ratio of the Martian atmosphere (and also presumably the cryosphere) and terrestrial hydrogen. The Martian atmospheric delta D(sub SMOW) ratio is approximately +4200%o, igneous minerals with substantial hydrogen (phosphates) have high D, +2000%o to +4700%o versus terrestrial waters with approximately 480%o to +130%o. The crystal chemistry and structure of jarosite are reviewed in Papi ke et al. Here we report hydrogen isotopes measured in jarosite in QUE 94201 by ion microprobe, and also report on the major element composition of jarosite measured by electron microprobe.

  1. Martian mantle primary melts - An experimental study of iron-rich garnet lherzolite minimum melt composition

    NASA Technical Reports Server (NTRS)

    Bertka, Constance M.; Holloway, John R.

    1988-01-01

    The minimum melt composition in equilibrium with an iron-rich garnet lherzolite assemblage is ascertained from a study of the liquidus relations of iron-rich basaltic compositions at 23 kb. The experimentally determined primary melt composition and its calculated sodium content reveal that Martian garnet lherzolite minimum melts are picritic alkali olivine basalts. Martian primary melts are found to be more picritic than terrestrial garnet lherzolite primary melts.

  2. Shergottite Lead Isotope Signature in Chassigny and the Nakhlites

    NASA Technical Reports Server (NTRS)

    Jones, J. H.; Simon, J. I.

    2017-01-01

    The nakhlites/chassignites and the shergottites represent two differing suites of basaltic martian meteorites. The shergottites have ages less than or equal to 0.6 Ga and a large range of initial Sr-/Sr-86 and epsilon (Nd-143) ratios. Conversely, the nakhlites and chassignites cluster at 1.3-1.4 Ga and have a limited range of initial Sr-87/Sr-86 and epsilon (Nd-143). More importantly, the shergottites have epsilon (W-182) less than 1, whereas the nakhlites and chassignites have epsilon (W-182) approximately 3. This latter observation precludes the extraction of both meteorite groups from a single source region. However, recent Pb isotopic analyses indicate that there may have been interaction between shergottite and nakhlite/chassignite Pb reservoirs.Pb Analyses of Chassigny: Two different studies haveinvestigated 207Pb/204Pb vs. 206Pb/204Pb in Chassigny: (i)TIMS bulk-rock analyses of successive leaches and theirresidue [3]; and (ii) SIMS analysis of individual minerals[4]. The bulk-rock analyses fall along a regression of SIMSplagioclase analyses that define an errorchron that is olderthan the Solar System (4.61±0.1 Ga); i.e., these define amixing line between Chassigny’s principal Pb isotopic components(Fig. 1). Augites and olivines in Chassingy (notshown) also fall along or near the plagioclase regression [4].This agreement indicates that the whole-rock leachateslikely measure indigenous, martian Pb, not terrestrial contamination[5]. SIMS analyses of K-spars and sulfides definea separate, sub-parallel trend having higher 207Pb/206Pbvalues ([4]; Fig. 1). The good agreement between the bulkrockanalyses and the SIMS analyses of plagioclases alsoindicates that the Pb in the K-spars and sulfides cannot be amajor component of Chassigny.The depleted reservoir sampled by Chassigny plagioclaseis not the same as the solar system initial (PAT) andrequires a multi-stage origin. Here we show a two-stagemodel (Fig. 1) with a 238U/204Pb (µ) of 0.5 for 4.5-2.4 Gaand a µ of

  3. Crystallization Age of NWA 1460 Shergottite: Paradox Revisited

    NASA Technical Reports Server (NTRS)

    Nyquist, L. E.; Shih, C-Y.; Reese, Y. D.; Irving, A. J.

    2004-01-01

    We have determined the Rb-Sr age of basaltic shergottite NWA 1460 to be 312 +/- 3 Ma, and the Sm-Nd age to be 352 +/- 30 Ma. The initial Sr and Nd isotopic compositions of NWA 1460 suggest it is an earlier melting product of a Martian mantle source region similar to those of the Iherzolitic shergottites and basaltic shergottite EETA79001, lithology B. The new ages of NWA 1460 and other recently analyzed Martian meteorites leads us to reexamine the paradox that most of the Martian meteorites appear to be younger from the majority of the Martian surface. This paradox continues to pose a challenge to determining a reliable Martian chronology.

  4. Thermobarometry for spinel lherzolite xenoliths in alkali basalts

    NASA Astrophysics Data System (ADS)

    Ozawa, Kazuhito; Youbi, Nasrrddine; Boumehdi, Moulay Ahmed; Nagahara, Hiroko

    2016-04-01

    Application of geothermobarometers to peridotite xenoliths has been providing very useful information on thermal and chemical structure of lithospheric or asthenospheric mantle at the time of almost instantaneous sampling by the host magmas, based on which various thermal (e.g., McKenzie et al., 2005), chemical (e.g., Griffin et al., 2003), and rheological (e.g., Ave Lallemant et al., 1980) models of lithosphere have been constructed. Geothermobarometry for garnet or plagioclase-bearing lithologies provide accurate pressure estimation, but this is not the case for the spinel peridotites, which are frequently sampled from Phanerozoic provinces in various tectonic environments (Nixon and Davies, 1987). There are several geobarometers proposed for spinel lherzolite, such as single pyroxene geothermobarometer (Mercier, 1980) and geothermobarometer based on Ca exchange between olivine and clinopyroxene (Köhler and Brey, 1990), but they have essential problems and it is usually believed that appropriated barometers do not exist for spinel lherzolites (O'Reilly et al., 1997; Medaris et al., 1999). It is thus imperative to develop reliable barometry for spinel peridotite xenoliths. We have developed barometry for spinel peridotite xenoliths by exploiting small differences in pressure dependence in relevant reactions, whose calibration was made through careful evaluation of volume changes of the reactions. This is augmented with higher levels of care in application of barometer by choosing mineral domains and their chemical components that are in equilibrium as close as possible. This is necessary because such barometry is very sensitive to changes in chemical composition induced by transient state of the system possibly owing to pressure and temperature changes as well as chemical modification, forming chemical heterogeneity or zoning frequently reported from various mantle xenoliths (Smith, 1999). Thus very carful treatment of heterogeneity, which might be trivial for

  5. Lunar meteorite Yamato-86032 - Mineralogical, petrological, and geochemical studies

    NASA Technical Reports Server (NTRS)

    Koeberl, Christian; Kurat, Gero; Brandstaetter, Franz

    1990-01-01

    Yamato-86032 is a shock-lithified anorthositic fragmental breccia. It consists mainly of highly feldspathic meta-breccias and meta-meltrocks and possibly contains a small contribution from mare lithologies, but there is no indication of a KREEP component. In many respects Y-86032 is similar to the previously described lunar meteorites Y-82192/3, but there are some notable differences. We have analyzed about 40 major and trace elements in bulk matrix, impact melt, and clast samples from two chips of Y-86032. The abundances of most lithophile and incompatible elements are lower in Y-86032 than in Y-82192 (which contains very low abundances compared to normal lunar highland rocks). The REE abundances are comparable to those of Y-82192. The elements Sc, Cr, Mn, Fe and Co have significantly lower abundances than in Y-82192, and the siderophile element pattern is also different. Since cosmic ray exposure data indicate pairing of Y-86032 with Y-82192/3, the source region for these meteorites on the moon must have been fairly heterogeneous.

  6. Lead Isotopes in Olivine-Phyric Shergottite Tissint: Implications for the Geochemical Evolution of the Shergottite Source Mantle

    NASA Technical Reports Server (NTRS)

    Moriwaki, R.; Usui, T.; Simon, J. I.; Jones, J. H.; Yokoyama, T.

    2015-01-01

    Geochemically-depleted shergottites are basaltic rocks derived from a martian mantle source reservoir. Geochemical evolution of the martian mantle has been investigated mainly based on the Rb-Sr, Sm-Nd, and Lu-Hf isotope systematics of the shergottites [1]. Although potentially informative, U-Th- Pb isotope systematics have been limited because of difficulties in interpreting the analyses of depleted meteorite samples that are more susceptible to the effects of near-surface processes and terrestrial contamination. This study conducts a 5-step sequential acid leaching experiment of the first witnessed fall of the geochemically-depleted olivinephyric shergottite Tissint to minimize the effect of low temperature distrubence. Trace element analyses of the Tissint acid residue (mostly pyroxene) indicate that Pb isotope compositions of the residue do not contain either a martian surface or terrestrial component, but represent the Tissint magma source [2]. The residue has relatively unradiogenic initial Pb isotopic compositions (e.g., 206Pb/204Pb = 10.8136) that fall within the Pb isotope space of other geochemically-depleted shergottites. An initial µ-value (238U/204Pb = 1.5) of Tissint at the time of crystallization (472 Ma [3]) is similar to a time-integrated mu- value (1.72 at 472 Ma) of the Tissint source mantle calculated based on the two-stage mantle evolution model [1]. On the other hand, the other geochemically-depleted shergottites (e.g., QUE 94201 [4]) have initial µ-values of their parental magmas distinctly lower than those of their modeled source mantle. These results suggest that only Tissint potentially reflects the geochemical signature of the shergottite mantle source that originated from cumulates of the martian magma ocean

  7. Crystallization kinetics of olivine-phyric shergottites

    NASA Astrophysics Data System (ADS)

    Ennis, Megan E.; McSween, Harry Y.

    2014-08-01

    Crystal size distribution (CSD) and spatial distribution pattern (SDP) analyses are applied to the early crystallizing phases, olivine and pyroxene, in olivine-phyric shergottites (Elephant moraine [EET] 79001A, Dar al Gani [DaG] 476, and dhofar [Dho] 019) from each sampling locality inferred from Mars ejection ages. Trace element zonation patterns (P and Cr) in olivine are also used to characterize the crystallization history of these Martian basalts. Previously reported 2-D CSDs for these meteorites are re-evaluated using a newer stereographically corrected methodology. Kinks in the olivine CSD plots suggest several populations that crystallized under different conditions. CSDs for pyroxene in DaG 476 and EET 79001A reveal single populations that grew under steady-state conditions; pyroxenes in Dho 019 were too intergrown for CSD analysis. Magma chamber residence times of several days for small grains to several months for olivine megacrysts are calculated using the CSD slopes and growth rates inferred from previous experimental data. Phosphorus imaging in olivines in DaG 476 and Dho 019 indicate rapid growth of skeletal, sector-zoned, or patchy cores, probably in response to delayed nucleation, followed by slow growth, and finally rapid dendritic growth with back-filling to form oscillatory zoning in rims. SPD analyses indicate that olivine and pyroxene crystals grew or accumulated in clusters rather than as randomly distributed grains. These data reveal complex solidification histories for Martian basalts, and are generally consistent with the formation at depth of olivine megacryst cores, which were entrained in ascending magmas that crystallized pyroxenes, small olivines, and oscillatory rims on megacrysts.

  8. Lherzolite, anorthosite, gabbro, and basalt dredged from the mid-Indian ocean ridge.

    PubMed

    Engel, C G; Fisher, R L

    1969-11-28

    The Central Indian Ridge is mantled with flows of low-potassium basalt of uniform composition. Gabbro, anorthosite, and garnet-bearing lherzolite are exposed in cross fractures, and lherzolite is the bedrock at the center of the ridge. The Iherzolites are upper-mantle rock exposed by faulting.

  9. Provenance and Concentration of Water in the Shergottite Mantle

    NASA Technical Reports Server (NTRS)

    Jones, J. H.; Usui, T.; Alexander, C. M. O'D.; Simon, J. I.; Wang, J.

    2012-01-01

    The water content of the martian mantle is controversial. In particular, the role of water in the petrogenesis of the shergottites has been much debated. Although the shergottites, collectively, contain very little water [e.g., 1,2], some experiments have been interpreted to show that percent levels of water are required for the petrogenesis of shergottites such as Shergotty and Zagami [3]. In this latter interpretation, the general paucity of water in the shergottites and their constituent minerals is attributed to late-stage degassing. Y980459 (Y98) is a very primitive, perhaps even parental, martian basalt, with a one-bar liquidus temperature of approx.1400 C. Olivine is the liquidus phase, and olivine core compositions are in equilibrium with the bulk rock [e.g., 4]. Petrogenetically, therefore, Y98 has had a rather simple history and can potentially help constrain the role of water in martian igneous processes. In particular, once trapped, melt inclusions should not be affected by subsequent degassing.

  10. Rare Earth elements in individual minerals in Shergottites

    NASA Technical Reports Server (NTRS)

    Wadhwa, Meenakshi; Crozaz, Ghislaine

    1993-01-01

    Shergottites (i.e., Shergotty, Zagami, EETA79001, ALHA77005, and LEW88516) are an important set of achondrites because they comprise the majority of the SNC group of meteorites (nine, in total, known to us), which are likely to be samples of the planet Mars. Study of these meteorites may therefore provide valuable information about petrogenetic processes on a large planetary body other than Earth. Rare earth element (REE) distributions between various mineral phases were found to be useful in geochemically modeling the petrogenesis of various rock types (terrestrial and meteoritic). However, with the exception of a few ion microprobe studies and analyses of mineral separates, there has previously not been any comprehensive effort to characterize and directly compare REE in individual minerals in each of the five known shergottites. Ion microprobe analyses were made on thin sections of each of the shergottites. Minerals analyzed were pyroxenes (pigeonite and augite), maskelynite, and whitlockite. The REE concentrations in each mineral type in each shergottite is given.

  11. New constraints on the formation of shergottite Elephant Moraine 79001 lithology A

    NASA Astrophysics Data System (ADS)

    Liu, Yang; Balta, J. Brian; Goodrich, Cyrena A.; McSween, Harry Y.; Taylor, Lawrence A.

    2013-05-01

    Previous studies of Elephant Moraine (EET) 79001 disagreed upon the nature of the magnesian olivine and orthopyroxene grains, and generally considered the formation of EET 79001 at low pressure conditions. New observations on mineral associations, and trace-element abundances of olivine-hosted melt inclusions, in lithology A (EET-A) of EET 79001 lead to new constraints on the formation of this meteorite. The abundances and chondrite-normalized REE pattern of the average melt inclusions in olivine of Mg# 75-61 are similar to those of the bulk-rock composition of lithology A, suggesting that the Mg# <77 olivines are phenocrysts. We also report the widespread occurrence of round orthopyroxene (En78.9-77.9Wo2.2-2.5) inclusions in disequilibrium contact with their olivine hosts (Mg# 73-68). Compositions of these inclusions are similar to xenocrystic cores (Mg# ⩾77; Wo ⩽4) in pyroxene megacrysts. These observations indicate that orthopyroxene xenocrysts were being resorbed while Mg# 77-73 olivine was crystallizing. Combined, these observations suggest that only small portions of the megacrysts are xenocrystic, namely orthopyroxene of Mg# ⩾77 and Wo ⩽4, and possibly also olivine of Mg# ⩾77. The volume percentages of the xenocrystic materials in the rock are small (⩽1 vol.% for each mineral). Compositions of the xenocrystic minerals are similar to cores of megacrysts in olivine-phyric shergottite Yamato (Y) 980459 and Northwest Africa (NWA) 5789. Considering the small fraction of xenocrysts and the similarity between REE abundances of the early-trapped melt and those in bulk EET-A, we re-evaluated the possibility that the bulk-rock composition of EET-A is close to that of its parent melt. Results of pMELTS modeling indicate that polybaric crystallization of the EET-A bulk composition (corrected by removal of xenocryst material) can reproduce the crystallization sequence of EET-A, in contrast to the conclusions of previous workers. We estimate that the EET

  12. Putative Indigenous Carbon-Bearing Alteration Features in Martian Meteorite Yamato 000593

    PubMed Central

    Gibson, Everett K.; Thomas-Keprta, Kathie L.; Clemett, Simon J.; McKay, David S.

    2014-01-01

    Abstract We report the first observation of indigenous carbonaceous matter in the martian meteorite Yamato 000593. The carbonaceous phases are heterogeneously distributed within secondary iddingsite alteration veins and present in a range of morphologies including areas composed of carbon-rich spheroidal assemblages encased in multiple layers of iddingsite. We also observed microtubular features emanating from iddingsite veins penetrating into the host olivine comparable in shape to those interpreted to have formed by bioerosion in terrestrial basalts. Key Words: Meteorite—Yamato 000593—Mars—Carbon. Astrobiology 14, 170–181. PMID:24552234

  13. Solubility of Sulfur in Shergottitic Silicate Melts Up to 0.8 GPA: Implications for S Contents of Shergottites

    NASA Technical Reports Server (NTRS)

    Righter, K.; Pando, K.M.; Danielson, L.

    2009-01-01

    Shergottites have high S contents (1300 to 4600 ppm; [1]), but it is unclear if they are sulfide saturated or under-saturated. This issue has fundamental implications for determining the long term S budget of the martian surface and atmosphere (from mantle degassing), as well as evolution of the highly siderophile elements (HSE) Au, Pd, Pt, Re, Rh, Ru, Ir, and Os, since concentrations of the latter are controlled by sulfide stability. Resolution of sulfide saturation depends upon temperature, pressure, oxygen fugacity (and FeO), and magma composition [2]. Expressions derived from experimental studies allow prediction of S contents, though so far they are not calibrated for shergottitic liquids [3-5]. We have carried out new experiments designed to test current S saturation models, and then show that existing calibrations are not suitable for high FeO and low Al2O3 compositions characteristic of shergottitic liquids. The new results show that existing models underpredict S contents of sulfide saturated shergottitic liquids by a factor of 2.

  14. Petrology, Mineralogy, and Radiogenic Isotopic Composition of Enriched Mafic Shergottite Northwest Africa 10134

    NASA Astrophysics Data System (ADS)

    Tait, K. T.; Irving, A. J.; Kuehner, S. M.; Andreasen, R.; Righter, M.; Lapen, T. J.; Gregory, D. A.

    2015-07-01

    Northwest Africa 10134 is a new enriched shergottite from the Royal Ontario Museum's meteorite collection. A combined isotopic, petrographic and mineralogical study on the meteorite will be discussed.

  15. Dipeptides and Diketopiperazines in the Yamato-791198 and Murchison Carbonaceous Chondrites

    NASA Astrophysics Data System (ADS)

    Shimoyama, Akira; Ogasawara, Ryo

    2002-04-01

    The Yamato-791198 and Murchison carbonaceous chondrites were analyzed for dipeptides and diketopiperazines as well as amino acids and hydantoins by gas chromatography combined with mass spectrometry. Glycylglycine (gly-gly) and cyclo(gly-gly) were detected at the concentrations of 11 and 18 pmol g^-1, respectively, in Yamato-791198, and 4 and 23 pmol g^-1, respectively, in Murchison. No other dipeptide and diketopiperazine were detected. Five hydantoins were detected at 8 to 65 pmol g^-1 in Yamato-791198 and seven in Murchison at 6 to 104 pmol g^-1. Total concentration of the glycine (gly) dimers is approximately four orders of magnitude less than the concentration of free gly in Yamato-791198, and three orders of magnitude less than that in Murchison. The absence of L- and LL-stereoisomers of dipeptides consisting of protein amino acids indicates that gly-gly and cyclo(gly-gly) detected are native to the chondrites and not from terrestrial contaminants. A possibility was discussed that the gly dimers might have been formed by condensation of gly monomers but not formed through N-carboxyanhydrides of gly.

  16. An Experimental Investigation of the Shergottite NWA 6162

    NASA Technical Reports Server (NTRS)

    Barnett, R. Gaylen; Jones, John H.; Draper, David S.; Le, Loan H.

    2012-01-01

    The Martian meteorite North West Africa 6162 (NWA 6162) is a shergottite found in Morocco in 2010. The meteorite has large olivine crystals with Mg-depleted rims as low as FO(sub 65) and Mg-rich cores of up to FO(sub 74). It is similar both in appearance and composition to another shergottite, SaU 005. Our objective is to determine if NWA 6162 represents a liquid or if it is a product of olivine accumulation. Olivine accumulation would leave the parent melt Mg-depleted and the complementary olivine cumulates would be Mg-enriched. Therefore, if NWA 6162 is a partial cumulate we would expect that liquidus olivines grown from this bulk composition would be more magnesium than olivines in the natural sample.

  17. AR-39-AR-40 "Age" of Basaltic Shergottite NWA-3171

    NASA Technical Reports Server (NTRS)

    Bogard, Donald D.; Park, Jisun

    2007-01-01

    North-West-Africa 3171 is a 506 g, relatively fresh appearing, basaltic shergottite with similarities to Zagami and Shergotty, but not obviously paired with any of the other known African basaltic shergottites. Its exposure age has the range of 2.5-3.1 Myr , similar to those of Zagami and Shergotty. We made AR-39-AR-40 analyses of a "plagioclase" (now shock-converted to maskelynite) separate and of a glass hand-picked from a vein connected to shock melt pockets.. Plagioclase was separated using its low magnetic susceptibility and then heavy liquid with density of <2.85 g/cm(exp 3). The AR-39-AR-40 age spectrum of NWA-317 1 plag displays a rise in age over 20-100% of the 39Ar release, from 0.24 Gyr to 0.27 Gy.

  18. APXS ANALYSES OF BOUNCE ROCK: THE FIRST SHERGOTTITE ON MARS

    NASA Technical Reports Server (NTRS)

    Ming, Douglas W.; Zipfel, J.; Anderson, R.; Brueckner, J.; Clark, B. C.; Dreibus, G.; Economou, T.; Gellert, R.; Lugmair, G. W.; Klingelhoefer, G.

    2005-01-01

    During the MER Mission, an isolated rock at Meridiani Planum was analyzed by the Athena instrument suite [1]. Remote sensing instruments noticed its distinct appearance. Two areas on the untreated rock surface and one area that was abraded with the Rock Abrasion Tool were analyzed by Microscopic Imager, Mossbauer Mimos II [2], and Alpha Particle X-ray Spectrometer (APXS). Results of all analyses revealed a close relationship of this rock with known basaltic shergottites.

  19. Shergottite Impact Melt Glasses Contain Soil from Martian Uplands

    NASA Technical Reports Server (NTRS)

    Rao, M. N.; McKay, D. S.

    2002-01-01

    Martian meteorite (shergottite) impact melt glasses that contain high concentrations of martian atmospheric noble gases and show significant variations in Sr-87/Sr-86 isotopic ratios are likely to contain Martian surface fines mixed with coarser regolith materials. The mixed soil constituents were molten due to shock at the time of meteoroid impact near the Martian surface and the molten glass got incorporated into the voids and cracks in some shergottite meteorites. Earlier, Rao et al. found large enrichments of sulfur (sulfate) during an electron-microprobe study of several impact melt glass veins and pods in EET79001,LithC thin sections. As sulfur is very abundant in Martian soil, these S excesses were attributed to the mixing of a soil component containing aqueously altered secondary minerals with the LithC precursor materials prior to impact melt generation. Recently, we studied additional impact melt glasses in two basaltic shergottites, Zagami and Shergotty using procedures similar to those described by Rao et al. Significant S enrichments in Zagami and Shergotty impact melt glass veins similar to the EET79001, LithC glasses were found. In addition, we noticed the depletion of the mafic component accompanied by the enrichment of felsic component in these impact melt glass veins relative to the bulk host rock in the shergottites. To explain these observations, we present a model based on comminution of basaltic rocks due to meteroid bombardment on martian regolith and mechanical fractionation leading to enrichment of felsics and depletion of mafics in the fine grained dust which is locally mobilized as a result of saltation and deflation due to the pervasive aeolian activity on Mars.

  20. Shergottite Impact Melt Glasses Contain Soil from Martian Uplands

    NASA Technical Reports Server (NTRS)

    Rao, M. N.; McKay, D. S.

    2002-01-01

    Martian meteorite (shergottite) impact melt glasses that contain high concentrations of martian atmospheric noble gases and show significant variations in Sr-87/Sr-86 isotopic ratios are likely to contain Martian surface fines mixed with coarser regolith materials. The mixed soil constituents were molten due to shock at the time of meteoroid impact near the Martian surface and the molten glass got incorporated into the voids and cracks in some shergottite meteorites. Earlier, Rao et al. found large enrichments of sulfur (sulfate) during an electron-microprobe study of several impact melt glass veins and pods in EET79001,LithC thin sections. As sulfur is very abundant in Martian soil, these S excesses were attributed to the mixing of a soil component containing aqueously altered secondary minerals with the LithC precursor materials prior to impact melt generation. Recently, we studied additional impact melt glasses in two basaltic shergottites, Zagami and Shergotty using procedures similar to those described. Significant S enrichments in Zagami and Shergotty impact melt glass veins similar to the EET79001, LithC glasses were found. In addition, we noticed the depletion of the mafic component accompanied by the enrichment of felsic component in these impact melt glass veins relative to the bulk host rock in the shergottites. To explain these observations, we present a model based on comminution of basaltic rocks due to meteoroid bombardment on martian regolith and mechanical fractionation leading to enrichment of felsics and depletion of mafics in the fine grained dust which is locally mobilized as a result of saltation and deflation due to the pervasive aeolian activity on Mars.

  1. How to identify garnet lherzolite melts and distinguish them from pyroxenite melts

    NASA Astrophysics Data System (ADS)

    Grove, T. L.; Holbig, E.; Barr, J. A.; Till, C.; Krawczynski, M. J.

    2013-12-01

    Liquids form in equilibrium with garnet lherzolite sources when the Earth's mantle melts at depths of greater than ~ 60 km. We present a phase equilibrium investigation of Tibetan plateau olivine leucitites from 2.2 to 2.8 GPa and 1380 to 1480 °C. The resulting liquids were multiply saturated with spinel and garnet lherzolite assemblages (olivine, orthopyroxene, clinopyroxene and spinel +/-garnet) under nominally anhydrous conditions. These SiO2-undersaturated liquids and published experimental data have been used to develop a new model that parameterizes the major element compositions of garnet lherzolite partial melts, allowing the prediction of melt compositions from depleted to metasomatically enriched peridotite. The model is calibrated over the pressure range of 1.9 to 6 GPa. The model also predicts the suprasolidus pressure and temperature of the spinel to garnet lherzolite phase transition for natural peridotite compositions. Combined with the recent parameterization of melting in the plagioclase- and spinel- lherzolite facies (Till et al., 2012, JGR, 117, B06206), the new model distinguishes between melts of garnet vs. spinel vs. plagioclase lherzolites, but can also be used to distinguish between melts of lherzolitic vs. pyroxenitic source regions, allowing source lithology to be uniquely identified. Pyroxenite melts fall into two compositionally distinct groups; an olivine-normative, SiO2-undersaturated group and quartz-normative, SiO2-oversaturated group. Melts of plagioclase, spinel, and garnet lherzolite plot between these two types of pyroxenitic melts in mineral normative composition space. When our model is applied to high-K lavas erupted in the Tibetan plateau, we find that these magmas are derived from both pyroxenite and lherzolite source regions. Distinctive enrichments in compatible trace elements (Ni, Cr) are observed in the lherzolite-derived magmas. Applied to Hawaiian basalts, our model suggests the transitional and weakly alkaline pre

  2. A Sr and Nd isotopic study of five Yamato polymict eucrites and a comparison to other Antarctic and ordinary eucrites

    NASA Technical Reports Server (NTRS)

    Wooden, J. L.; Takeda, H.; Nyquist, L. E.; Wiesmann, H.; Bansal, B.

    1983-01-01

    Sr and Nd isotopic analysis of five Yamato polymict eucrites indicate that these samples formed at about 4.6 Ga ago with initial Sr and Nd ratios essentially the same as the analyzed non-Antarctic eucrites. The Yamato eucrites have Sr, Sm, and Nd concentrations that consistently lie among the highest found in eucritic samples. This characteristic identifies these Yamato samples as a closely related group. Comparisons between these Yamato samples and other Antarctic polymict eucrites clearly estabishes that they all share some characteristic trace element features. Comparisons of Antarctic polymict eucrites with non-Antarctic ordinary eucrites reveal consistent differences. The most obvious is an enrichment of Rb in the polymict eucrites. These comparisons suggest that the Antarctic polymict eucrites belong to a single large family of material that is itself fairly diverse and distinct from the non-Antarctic eucrites.

  3. Evaluation of thermobarometry for spinel lherzolite fragments in alkali basalts

    NASA Astrophysics Data System (ADS)

    Ozawa, Kazuhito; Youbi, Nasrrddine; Boumehdi, Moulay Ahmed; McKenzie, Dan; Nagahara, Hiroko

    2017-04-01

    Geothermobarometry of solid fragments in kimberlite and alkali basalts, generally called "xenoliths", provides information on thermal and chemical structure of lithospheric and asthenospheric mantle, based on which various chemical, thermal, and rheological models of lithosphere have been constructed (e.g., Griffin et al., 2003; McKenzie et al., 2005; Ave Lallemant et al., 1980). Geothermobarometry for spinel-bearing peridotite fragments, which are frequently sampled from Phanerozoic provinces in various tectonic environments (Nixon and Davies, 1987), has essential difficulties, and it is usually believed that appropriated barometers do not exist for them (O'Reilly et al., 1997; Medaris et al., 1999). Ozawa et al. (2016; EGU) proposed a method of geothermobarometry for spinel lherzolite fragments. They applied the method to mantle fragments in alkali basalts from Bou Ibalhatene maars in the Middle Atlas in Morocco (Raffone et al. 2009; El Azzouzi et al., 2010; Witting et al., 2010; El Messbahi et al., 2015). Ozawa et al. (2016) obtained 0.5GPa pressure difference (1.5-2.0GPa) for 100°C variation in temperatures (950-1050°C). However, it is imperative to verify the results on the basis of completely independent data. There are three types of independent information: (1) time scale of solid fragment extraction, which may be provided by kinetics of reactions induced by heating and/or decompression during their entrapment in the host magma and transportation to the Earth's surface (Smith, 1999), (2) depth of the host basalt formation, which may be provided by the petrological and geochemical studies of the host basalts, and (3) lithosphere-asthenosphere boundary depths, which may be estimated by geophysical observations. Among which, (3) is shown to be consistent with the result in Ozawa et al. (2016). We here present that the estimated thermal structure just before the fragment extraction is fully supported by the information of (1) and (2). Spera (1984) reviewed

  4. Effect of Opening of Yamato Basin on Miocene Adakites in Northeast Japan

    NASA Astrophysics Data System (ADS)

    Lee, Changyeol

    2017-04-01

    Among the geneses of adakites in subduction zones, partial melting of the oceanic crust of the subducted slab (ca. slab melting) is thought to occur when the subducted slab is very young (< 25 Ma). However, the sporadic distributions of the adakites in Northeast Japan from Early to Middle Miocene cannot be explained by slab melting because the subducted slab during the period was too old ( 100 Ma) to be molten. Thus, numerous studies suggested that the heat source for increasing the slab surface temperature was originated from the back-arc mantle (e.g., active or passive injection of the hot asthenosphere into the mantle wedge during the opening of the Yamato Basin). Although the opening of the Yamato Basin was concurrent with the eruptions of the adakites in Northeast Japan, the basin opening was not considered in most of the numerical model studies. In this study, we evaluate the effect of the opening of the Yamato Basin on the Miocene Adakites in Northeast Japan. Our three-dimensional numerical models consider buoyancy and rheology of the mantle wedge and back-arc mantle. The subduction history of the Pacific plate since 60 Ma is considered. The symmetric opening of the Yamato Basin is assumed to occur from 21 to 15 Ma at a spreading rate of 1.5 cm/y and the spreading axis was migrated to the back-arc at a rate of 1.5 cm/y to consider the retreat of the Pacific plate. Our model calculations show that strengthened vigor of the mantle inflow into the mantle wedge during the back-arc opening resulted in localized increases of the slab surface temperature, yielding the sporadic eruptions of the adakites in Northeast Japan. Since the opening of the Yamato Basin ceased, temperature of the mantle wedge decreased because of the weakened mantle inflow into the mantle wedge, and hot finger-like temperature anomalies were developed and sustained to the present. Our model calculations indicate that the opening of the Yamato Basin is responsible for the sporadic distribution

  5. The harzburgites-lherzolite cycle: depletion and refertilization processes

    NASA Astrophysics Data System (ADS)

    Dijkstra, A. H.

    2011-12-01

    Lherzolites or clinopyroxene-rich harzburgites sampled at the ocean floor are now generally interpreted as refractory harzburgites refertilized by melt-rock reaction or melt impregnation at the spreading center, rather than as relatively undepleted bulk upper mantle. The key evidence for a melt refertilization origin is often textural. Critically, the refertilization can mask the underlying very refractory character: oceanic peridotites prior to melt refertilization at the ridge are often too refractory to be simple mantle residues of bulk upper mantle that was melted at the ridge. This suggests that the upper mantle contains large domains that record prior melting histories. This is supported by ancient rhenium-depletion ages that are common in oceanic peridotites. In this presentation, I will discuss some key examples (e.g., Macquarie Island [1], Pindos, Totalp, Lanzarote) of refertilized oceanic peridotites, which all have recorded previous, ancient depletions. I will show the textural and geochemical evidence for melt refertilization. It has often been assumed that melt refertilization occurs by interaction with mantle melts. However, there is now evidence for melt refertilization through a reaction with eclogite-derived melts, probably at the base of the melting column underneath the ridge system. These eclogitic mantle heterogeneities themselves do not normally survive the melting underneath the spreading center, but their isotopic signature can be recognized in the reacted peridotites. In summary, we have moved away from the idea that oceanic mantle rocks are simple melting residues of homogeneous bulk upper mantle. The picture that emerges is a rich and complex one, suggesting that oceanic mantle rocks record dynamic histories of melting and refertilization. In particular, the melting event in refertilized peridotites can be much older than the age of the ridge system at which they are sampled. Many oceanic peridotites contain evidence for a Mesoproterozoic

  6. An experimental study of the kinetics of lherzolite reactive dissolution with applications to melt channel formation

    NASA Astrophysics Data System (ADS)

    Morgan, Zachary; Liang, Yan

    2005-11-01

    The kinetics of lherzolite dissolution in an alkali basalt and a basaltic andesite was examined experimentally at 1,300°C and 1 GPa using the dissolution couple method. Dissolution of lherzolite in basaltic liquids produces either the melt-bearing dunite-harzburgite-lherzolite (DHL) sequence or the melt-bearing harzburgite-lherzolite sequence depending on whether the reacting melt is or close to olivine saturation (alkali basalt) or olivine + orthopyroxene saturation (basaltic andesite). The dunite in the DHL sequence is pyroxene-free and the harzburgites in both sequences are clinopyroxene-free. The melt fraction and olivine grain size in the dunite are larger than those in the harzburgite. The olivine grain size in the dunite and harzburgite in the DHL sequence also increases as a function experimental run time. Across the sharp dunite-harzburgite and harzburgite-lherzolite interfaces, systematic compositional variations are observed in the reacting melt, interstitial melt, olivine, and to a lesser extent, pyroxenes as functions of distance and time. The systematic variations in lithology, grain size, mineral chemistry, and melt compositions are broadly similar to those observed in the mantle sections of ophiolites. The processes of lherzolite dissolution in basaltic liquids involve dissolution, precipitation, reprecipitation, and diffusive transport in the interstitial melts and surrounding minerals. Preferential dissolution of olivine and clinopyroxene and precipitation of orthopyroxene in the basaltic andesite produces the melt-bearing harzburgite-lherzolite sequence. Preferential dissolution of clinopyroxene and orthopyroxene and precipitation of olivine results in the melt-bearing DHL sequence. Preferential mineral dissolution can also affect the composition of the through-going melt in a dunite channel or harzburgite matrix. Systematic variations in melt fraction and mineral grain size in the peridotite sequences are likely to play an important role in the

  7. On the chondrite-achondrite transition - Mineralogy and chemistry of Yamato 74160 (LL7)

    NASA Technical Reports Server (NTRS)

    Takeda, H.; Huston, T. J.; Lipschutz, M. E.

    1984-01-01

    Petrology, mineralogic properties and contents of major elements and trace elements Ag, Au, Bi, Cd, Co, Cs, Ga, In, Rb, Se, Te, Tl, U and Zn are reported (determined by radiochemical neutron activation analysis) in Yamato 74160, interpreted as an LL7 chondrite. All properties are consistent with this meteorite having been recrystallized and partially melted locally once at temperatures well above 1090 C under conditions such that some minerals (e.g. plagioclase, euhedral pyroxene, tetrataenite) grew from melt pockets and siderophilic and chalcophilic elements were lost by extraction into eutectic melt that drained away. Inhomogeneous plagioclase compositions and mobile element loss suggest shock as the most likely heat source. Yamato 74160, while inferentially chondritic, is a larval achondrite: even higher temperatures and longer times would have been required to cause the separations necessary to transform it to an identifiable achondrite type.

  8. Putative indigenous carbon-bearing alteration features in martian meteorite Yamato 000593.

    PubMed

    White, Lauren M; Gibson, Everett K; Thomas-Keprta, Kathie L; Clemett, Simon J; McKay, David S

    2014-02-01

    We report the first observation of indigenous carbonaceous matter in the martian meteorite Yamato 000593. The carbonaceous phases are heterogeneously distributed within secondary iddingsite alteration veins and present in a range of morphologies including areas composed of carbon-rich spheroidal assemblages encased in multiple layers of iddingsite. We also observed microtubular features emanating from iddingsite veins penetrating into the host olivine comparable in shape to those interpreted to have formed by bioerosion in terrestrial basalts.

  9. Crustal structure of the western Yamato Basin, Japan Sea, revealed from seismic survey

    NASA Astrophysics Data System (ADS)

    No, T.; Sato, T.; Kodaira, S.; Miura, S.; Ishiyama, T.; Sato, H.

    2015-12-01

    The Yamato Basin is the second largest basin of the Japan Sea. This basin is important to clarify its formation process. Some studies of crustal structure had been carried out in the Yamato Basin (e.g. Ludwig et al., 1975; Katao, 1988; Hirata et al., 1989; Sato et al., 2006). However, the relationship between formation process and crustal structure is not very clear, because the amount of seismic exploration data is very limited. In addition, since there is ODP Leg 127 site 797 (Tamaki et al., 1990) directly beneath our seismic survey line, we contributed to the study on the formation of the Yamato Basin by examining the relation between the ODP results and our results. During July-August 2014, we conducted a multi-channel seismic (MCS) survey and ocean bottom seismometer (OBS) survey to study the crustal structure of the western Yamato Basin. We present an outline of the data acquisition and results of the data processing and preliminary interpretations from this study. As a result of our study, the crust, which is about 12 km thick, is thicker than standard oceanic crust (e.g., Spudich and Orcutt, 1980; White et al., 1992) revealed from P-wave velocity structure by OBS survey. A clear reflector estimated to be the Moho can be identified by MCS profiles. The characteristics of the sedimentary layer are common within the survey area. For example, a strong coherent reflector that is estimated to be an opal-A/opal-CT BSR (bottom simulating reflector) (Kuramoto et al., 1992) was confirmed in the sediment of all survey lines. On the other hand, a coherent reflector in the crust was confirmed in some lines. It is identified as this reflector corresponding with the deformation structure in the sediment and basement.

  10. The Martian Surface is old and so are Shergottites

    NASA Astrophysics Data System (ADS)

    Bouvier, A.; Blichert-Toft, J.; Vervoort, J. D.; Albarede, F.

    2005-12-01

    We report new Sm-Nd, Lu-Hf, and Pb-Pb mineral and whole-rock (WR) isotope data for the basaltic shergottite (BS) Zagami (Zag), as well as Pb-Pb WR isotope data for the BS Los Angeles (LA). The isotopic analyses were carried out by MC-ICP-MS at ENSL. The Sm-Nd and Lu-Hf data for Zag yield internal isochron ages of 155±9 Ma (MSWD=0.45) and 185±36 Ma (MSWD=1.2), respectively. While these young ages overlap with earlier Rb-Sr, Sm-Nd, and U-Pb ages (2), the Pb-Pb age does not. Our Pb isotope data on Zag and LA lie on the same Pb-Pb array as previous analyses of BS by (1), which, if interpreted as an isochron, indicate an age of ~4 Ga. The range of δ18O (3.9-5.2 permil) observed in shergottites (3, 4) is too broad to be accounted for by igneous processes only and attests to low-T interaction with fluids. The Martian surface appears to be covered with sulfates, while essentially lacking carbonates (5, 6), implying that the surface of Mars was once covered with acidic water bodies of unknown depths (7). An important observation is that apatite is a common phase in Zag and LA, as in all the shergottites (8), and explains why most of the REE, Th, U, and some fraction of Pb can be removed by leaching (9). The main inventory of Pb, however, resides in maskelynite. The Pb isotope data on shergottites, in conjunction with the existing body of geochemical and geophysical evidence, have important implications for the history of the Martian surface and lithosphere. A fundamental problem with the young crystallization ages for the Martian meteorites has been that these ages are difficult to reconcile with the large 182W and 142Nd isotopic anomalies present in these meteorites. On one hand, the anomalies from the extinct radionuclides appear to require a static, non-convecting mantle, whereas widespread volcanism on Mars as young as 150 Ma seems to require an actively convecting mantle. We suggest, based on the Pb isotope systematics of shergottites, that the Martian surface is

  11. Are spinel lherzolite xenoliths representative of the abundance of sulfur in the upper mantle

    SciTech Connect

    Lorand, J.P. )

    1990-05-01

    In order to address systematic discrepancies of sulfur contents between orogenic lherzolites and ultramafic xenoliths in alkali lavas, a study combining whole-rock sulfur geochemistry and microscopic investigation in reflected light has been performed on 40 type-I spinel lherzolite xenoliths from the Neogene alkali basalts in the French Massif Central. These measurements yield sulfur contents ranging between 0 and 90 ppm S, with most values being below 60 ppm S, irrespective of rock texture and/or chemistry. Spinel lherzolite xenoliths are strongly depleted in S relative to similar rocks found in orogenic spinel lherzolite bodies or to the average sulfur content of 300 ppm calculated for the MORB mantle source region. Microscopic studies indicate S loss during secondary oxihydration of mantle-derived solid sulfides. This alteration seems to be independent of the effect of the host basalts and probably is related to late-stage circulation of meteoric water. It is concluded that, except for a few samples armoured in massive basaltic lava flows, almost all the spinel lherzolite xenoliths in continental basalts analyzed so far do not provide representative analyses of the sulfur content in the upper mantle.

  12. Formation of Secondary Lherzolite and Refertilization of the Subcontinental Lithospheric Mantle: The Record of Orogenic Peridotites

    NASA Astrophysics Data System (ADS)

    Garrido, Carlos J.; Varas-Reus, María Isabel; Bodinier, Jean-Louis; Marchesi, Claudio; Bosch, Delphine; Hidas, Károly

    2016-04-01

    Correlations observed between major and minor transition elements in tectonically-emplaced orogenic peridotites have classically been ascribed to variable degrees of melt extraction. There is a growing body of evidence indicating that these chemical variations mostly reflect melt redistribution and near solidus reactions superimposed onto previous melting depletion events. Here we will assess this hypothesis using a large database of peridotites from orogenic peridotites in the westernmost Mediterranean (Ronda and Beni Bousera peridotites). We show that lherzolite samples show some trends in major elements and modal variations that are inconsistent with their interpretation as depleted MORB mantle (DMM). These trends are more consistent with the secondary formation of lherzolites by refertilization processes involving a least two different near-solidus, melt-processes: refertilization by pyroxenite-derived melts and by hydrous melts leading, respectively, to secondary lherzolites with Ol/Opx and Cpx/Opx ratios greater than those expected from residues from a primitive upper mantle source. Together with their N-MORB, LREE-depleted pattern, their fertile lherzolitic composition may have been acquired as a result of melt-rock interaction processes associated with the thermomechanical erosion of lithospheric mantle by asthenosphere. Major refertilization of depleted subcontinental mantle is an alternative to the small degrees of melt extraction to account for LREE depletion in otherwise fertile orogenic lherzolites.

  13. Enriched Shergottite NWA 5298 As An Evolved Parent Melt: Trace Element Inventory

    NASA Technical Reports Server (NTRS)

    Hui, Hejiu; Peslier, Anne H.; Lapen, Thomas J.; Shafer, John; Brandon, Alan; Irving, Anthony

    2010-01-01

    Martian meteorite Northwest Africa 5298 is a basaltic shergottite that was found near Bir Gandouz (Morocco). Its martian origin was confirmed by oxygen isotopes [1], as well as Mn/Fe ratios in the pyroxenes and K/anorthite ratios in the plagioclases [2]. Here we present a petrographic and geochemical study of NWA 5298. Comparison of mineralogical and geochemical characteristics of this meteorite with other Martian rocks shows that NWA 5298 is not likely paired with any other known shergottites, but it has similarities to another basaltic shergottite Dhofar 378.

  14. Rare earth patterns in shergottite phosphates and residues

    NASA Technical Reports Server (NTRS)

    Laul, J. C.

    1987-01-01

    Leaching experiments with 1M HCl on ALHA 77005 powder show that rare earth elements (REE) are concentrated in accessory phosphate phases (whitlockite, apatite) that govern the REE patterns of bulk shergottites. The REE patterns of whitlockite are typically light REE-depleted with a negative Eu anomaly and show a hump at the heavy REE side, while the REE pattern of apatite (in Shergotty) is light REE-enriched. Parent magmas are calculated from the modal compositions of residues of ALHA 77005, Shergotty, and EETA 79001. The parent magmas lack a Eu anomaly, indicating that plagioclase was a late-stage crystallizing phase and that it probably crystallized before the phosphates. The parent magmas of ALHA 77005 and Shergotty have similar REE patterns, with a subchondritic Nd/Sm ratio. However, the Sm/Nd isotopoics require a light REE-depleted source for ALHA 77005 (if the crystallization age is less than 600 Myr) and a light REE-enriched source for Shergotty. Distant Nd and Sr isotopic signatures may suggest different source regions for shergottites.

  15. Rare earth patterns in shergottite phosphates and residues

    NASA Technical Reports Server (NTRS)

    Laul, J. C.

    1987-01-01

    Leaching experiments with 1M HCl on ALHA 77005 powder show that rare earth elements (REE) are concentrated in accessory phosphate phases (whitlockite, apatite) that govern the REE patterns of bulk shergottites. The REE patterns of whitlockite are typically light REE-depleted with a negative Eu anomaly and show a hump at the heavy REE side, while the REE pattern of apatite (in Shergotty) is light REE-enriched. Parent magmas are calculated from the modal compositions of residues of ALHA 77005, Shergotty, and EETA 79001. The parent magmas lack a Eu anomaly, indicating that plagioclase was a late-stage crystallizing phase and that it probably crystallized before the phosphates. The parent magmas of ALHA 77005 and Shergotty have similar REE patterns, with a subchondritic Nd/Sm ratio. However, the Sm/Nd isotopoics require a light REE-depleted source for ALHA 77005 (if the crystallization age is less than 600 Myr) and a light REE-enriched source for Shergotty. Distant Nd and Sr isotopic signatures may suggest different source regions for shergottites.

  16. PGE distribution in deformed lherzolites of the Udachnaya kimberlite pipe (Yakutia)

    NASA Astrophysics Data System (ADS)

    Ilyina, O. V.; Tychkov, N. S.; Agashev, A. M.; Golovin, A. V.; Izokh, A. E.; Kozmenko, O. A.; Pokhilenko, N. P.

    2016-04-01

    The results of the first study of the PGE distribution in deformed lherzolites of the Udachnaya kimberlite pipe (Yakutia) are presented here. The complex character of evolution of the PGE composition in the Deformed lherzolites is assumed to be the result of silicate metasomatism. At the first stage, growth in the amount of clinopyroxene and garnet in the rock is accompanied by a decrease in the concentration of the compatible PGE (Os, Ir). During the final stage, the rock is enriched with incompatible PGE (Pt, Pd) and Re possible due to precipitation of submicron-sized particles of sulfides in the interstitial space of these mantle rocks.

  17. Lead Isotope Compositions of Acid Residues from Olivine-Phyric Shergottite Tissint: Implications for Heterogeneous Shergottite Source Reservoirs

    NASA Technical Reports Server (NTRS)

    Moriwaki, R.; Usui, T.; Yokoyama, T.; Simon, J. I.; Jones, J. H.

    2015-01-01

    Geochemical studies of shergottites suggest that their parental magmas reflect mixtures between at least two distinct geochemical source reservoirs, producing correlations between radiogenic isotope compositions and trace element abundances. These correlations have been interpreted as indicating the presence of a reduced, incompatible element- depleted reservoir and an oxidized, incompatible- element-enriched reservoir. The former is clearly a depleted mantle source, but there is ongoing debate regarding the origin of the enriched reservoir. Two contrasting models have been proposed regarding the location and mixing process of the two geochemical source reservoirs: (1) assimilation of oxidized crust by mantle derived, reduced magmas, or (2) mixing of two distinct mantle reservoirs during melting. The former requires the ancient Martian crust to be the enriched source (crustal assimilation), whereas the latter requires isolation of a long-lived enriched mantle domain that probably originated from residual melts formed during solidification of a magma ocean (heterogeneous mantle model). This study conducts Pb isotope and trace element concentration analyses of sequential acid-leaching fractions (leachates and the final residues) from the geochemically depleted olivine-phyric shergottite Tissint. The results suggest that the Tissint magma is not isotopically uniform and sampled at least two geochemical source reservoirs, implying that either crustal assimilation or magma mixing would have played a role in the Tissint petrogenesis.

  18. Noble gases in twenty Yamato H-chondrites: Comparison with Allan Hills chondrites and modern falls

    NASA Technical Reports Server (NTRS)

    Loeken, TH.; Scherer, P.; Schultz, L.

    1993-01-01

    Concentration and isotopic composition of noble gases have been measured in 20 H-chrondrites found on the Yamato Mountains ice fields in Antarctica. The distribution of exposure ages as well as of radiogenic He-4 contents is similar to that of H-chrondrites collected at the Allan Hills site. Furthermore, a comparison of the noble gas record of Antarctic H-chrondrites and finds or falls from non-Antarctic areas gives no support to the suggestion that Antarctic H-chrondrites and modern falls derive from differing interplanetary meteorite populations.

  19. An "Andestic" Component in Shergottites with Restored LREE Abundances?

    NASA Technical Reports Server (NTRS)

    Nyquist, L. E.; Shih, C.-Y.; Wiesmann, H.; Barrat, J. A.

    2002-01-01

    The shergottite Martian meteorites present a variety of oft-confusing petrologic features. In particular, represented among this subgroup are basalts with very depleted LREE abundances, as well as those with nearly chondritic overall REE abundances. The LREE-depleted basalts appear to more closely record the REE and isotopic features of their mantle source regions. Those basalts with more nearly chondritic REE abundances appear to contain an extra component often referred to as a "crustal" component. The addition of the crustal component tends to restore the overall REE abundance pattern towards chondritic relative abundances. Here we suggest that the crustal component could derive from "andesitic" rocks observed remotely to occur on the Martian surface, and which were analysed at the Pathfinder site.

  20. An "Andesitic" Component in Shergottites with Restored LREE Abundances?

    NASA Technical Reports Server (NTRS)

    Nyquist, L. E.; Shih, C.-Y.; Wiesmann, H.; Barrat, J. A.

    2002-01-01

    The shergottite Martian meteorites present a variety of oft-confusing petrologic features. In particular, represented among this subgroup are basalts with very depleted LREE abundances, as well as those with nearly chondritic overall REE abundances. The LREE-depleted basalts appear to more closely record the REE and isotopic features of their mantle source legions. Those basalts with more nearly chondritic REE abundances appear to contain an extra component often referred to as a "crustal" component. The addition of the crustal component tends to restore the overall REE abundance pattern towards chondritic relative abundances. Here we suggest that the crustal component could derive from andesitic rocks observed remotely to occur on the Martian surface, and which were analysed at the Pathfinder site.

  1. An experimental study of the kinetics of lherzolite reactive dissolution: Implications for contrasting styles of melt transport in the mantle.

    NASA Astrophysics Data System (ADS)

    Liang, Y.; Morgan, Z. T.

    2004-12-01

    It has been suggested that dunite dikes or veins found in harzburgite and lherzolite hosts in the mantle sections of ophiolites are high porosity channels through which basaltic magmas were extracted from their source regions. The formation of such channels may involve pervasive melt flow and reactive dissolution. In order to better understand the kinetics of reactive dissolution we conducted two series of lherzolite dissolution experiments: one in an alkali basalt and the other in a basaltic andesite. Dissolution experiments were run at 1300° C and 1 GPa using lherzolite-melt reaction couple method. The lherzolite dissolution experiments produce a reactive boundary layer (RBL) that consists of distinct lithological units separated by sharp mineralogical interfaces. The details of the RBL depend on the relative stabilities of the lherzolite minerals with respect to the reacting melt. Dissolution of lherzolite in the basaltic andesite resulted in 2 distinct regions: harzburgite (45% ol, 45% opx, 10% melt) and lherzolite (45% ol, 35% opx, 12% cpx, 8% melt). In contrast, dissolution of lherzolite in the alkali basalt resulted in 3 distinct rock units: dunite (75% ol, 25% melt), harzburgite (60% ol, 30% opx, and 10% melt), and lherzolite (50% ol, 30% opx, 10% cpx, 10% melt). The average grain size of the dunite is greater than the average grain size of unreacted lherzolite, whereas the average grain size of the harzburgite in the two sets of dissolution experiments are nearly the same as the average grain size of the lherzolite. This implies that the permeability of the dunite is larger than either the newly created harzburgite or the unreacted lherzolite, and that the permeabilities of the harzburgite and lherzolite are about the same within the DHL sequence. Hence dunite dikes in the mantle are capable of serving as melt channels, whereas harzburgites may not. Systematic compositional variations in the interstitial melt, olivine, and to a lesser extent, pyroxenes in

  2. Petrology and trace element geochemistry of Tissint, the newest shergottite fall

    NASA Astrophysics Data System (ADS)

    Balta, J. Brian; Sanborn, Matthew E.; Udry, Arya; Wadhwa, Meenakshi; McSween, Harry Y.

    2015-01-01

    AbstractThe fall and recovery of the Tissint meteorite in 2011 created a rare opportunity to examine a Martian sample with a known, short residence time on Earth. Tissint is an olivine-phyric <span class="hlt">shergottite</span> that accumulated olivine antecrysts within a single magmatic system. Coarse olivine grains with nearly homogeneous cores of Mg# >80 suggest slow re-equilibration. Many macroscopic features of this sample resemble those of LAR 06319, including the olivine crystal size distribution and the presence of evolved oxide and olivine compositions. Unlike LAR 06319, however, no magmatic hydrous phases were found in the analyzed samples of Tissint. Minor and trace element compositions indicate that the meteorite is the product of closed-system crystallization from a parent melt derived from a depleted source, with no obvious addition of a LREE-rich (crustal?) component prior to or during crystallization. The whole-rock REE pattern is similar to that of intermediate olivine-phyric <span class="hlt">shergottite</span> EETA 79001 lithology A, and could also be approximated by a more olivine-rich version of depleted basaltic <span class="hlt">shergottite</span> QUE 94201. Magmatic oxygen fugacities are at the low end of the <span class="hlt">shergottite</span> range, with log fO2 of QFM-3.5 to -4.0 estimated based on early-crystallized minerals and QFM-2.4 estimated based on the Eu in pyroxene oxybarometer. These values are similarly comparable to other depleted <span class="hlt">shergottites</span>, including SaU 005 and QUE 94201. Tissint occupies a previously unsampled niche in <span class="hlt">shergottite</span> chemistry: containing olivines with Mg# >80, resembling the enriched olivine-phyric <span class="hlt">shergottite</span> LAR 06319 in its crystallization path, and comparable to intermediate olivine-phyric <span class="hlt">shergottite</span> EETA 79001A, depleted olivine-phyric <span class="hlt">shergottite</span> DaG 476, and depleted basaltic <span class="hlt">shergottite</span> QUE 94201 in its trace element abundances and oxygen fugacity. The apparent absence of evidence for terrestrial alteration in Tissint</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/1993GeCoA..57.2111B','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/1993GeCoA..57.2111B"><span>Antarctic polymict eucrite <span class="hlt">Yamato</span> 792769 and the cratering record on the HED parent body</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Bogard, D.; Nyquist, L.; Takeda, H.; Mori, H.; Aoyama, T.; Bansal, B.; Wiesmann, H.; Shih, C.-Y.</p> <p>1993-05-01</p> <p>Compared to most other <span class="hlt">Yamato</span> polymict eucrites, <span class="hlt">Yamato</span> Y792769 eucrite includes fewer and smaller eucritic clasts with homogenized pyroxenes, and its fine-grained matrix is shock-compacted and sintered. In this work, the relationships between the Antarctic eucrite Y792769, monomict eucrites, polymict eucrites, and isotopic ages are investigated, using results of Ar-39/Ar-40 method to date the time of the major thermal event on the Y792769 body and the Rb-Sr and Sm-Nd methods to determine whether relict older ages might have been preserved in some of the breccia materials. The Ar-39/Ar-40 time of the last thermal event which produced the Y792769 texture is 3.99 +/- 0.04 Ga. The complete resetting of the Ar-39/Ar-40 age is consistent with the texture of Y792769 observed in TEM, suggesting that shock compaction converted part of the matrix plagioclase to maskelynite. The Sm-Nd data give an age of 4.23 +/- 0.12 Ga, reflecting partial resetting of the Sm-Nd system during breccia formation. The 3.9 Ga Ar-39/Ar-40 age probably reflects a period of intense meteoroid bompardment which affected the entire inner solar system.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2004M%26PS...39.2033T','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2004M%26PS...39.2033T"><span>Ion microprobe U-Th-Pb dating and REE analyses of phosphates in nakhlites: Lafayette and <span class="hlt">Yamato</span>-000593/000749</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Terada, Kentaro; Sano, Yuji</p> <p>2004-12-01</p> <p>U, Th, and Pb isotopes and rare earth elements (REEs) in individual phosphate grains from martian meteorites, Lafayette and <span class="hlt">Yamato</span>-000593/000749, were measured using a sensitive high- resolution ion microprobe (SHRIMP). Observed U-Pb data of 12 apatite grains from <span class="hlt">Yamato</span>-000593/ 000749 are well represented by linear regressions in both "conventional" 2D isochron plots and the 3D U-Pb plot (total Pb/U isochron), indicating that the formation age of this meteorite is 1.53 +/- 0.46 Ga (2?). However, the data of nine apatite grains from Lafayette are well represented by planar regression rather than linear regression, indicating that its formation age is 1.15 +/- 0.34 Ga (2?) and that a secondary alteration process slightly disturbed its U-Pb systematics as discussed in the literature regarding Nakhla. The observed REE abundance patterns of the apatites in Lafayette and <span class="hlt">Yamato</span>-000749, normalized to CI chondrites, are characterized by a progressive depletion of HREEs, a negative Eu anomaly, similarity to each other, and consistency with previously reported data for Nakhla. Considering the extensive data from other radiometric systems such as Sm-Nd, Rb-Sr, Ar-Ar, and trace elements, our results suggest that the parent magmas of the nakhlites, including the newly found <span class="hlt">Yamato</span>-000593/000749, are similar, and that their crystallization ages are ~1.3 Ga.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=20040059922&hterms=interstitial&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26Nf%3DPublication-Date%257CBTWN%2B20000101%2B20170228%26N%3D0%26No%3D70%26Ntt%3Dinterstitial','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=20040059922&hterms=interstitial&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26Nf%3DPublication-Date%257CBTWN%2B20000101%2B20170228%26N%3D0%26No%3D70%26Ntt%3Dinterstitial"><span>Lunar and Planetary Science XXXV: Martian Meteorites: Petrology</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p></p> <p>2004-01-01</p> <p>The session "Martian Meteorites: Petrology: included the following reports:Volatile Behavior in Lunar and Terrestrial Basalts During Shock: Implications for Martian Magmas; Problems with a Low-Pressure Tholeiitic Magmatic History for the Chassigny Dunite; Fast Cooling History of the Chassigny Martian Meteorite; Rehomogenized Interstitial and Inclusion Melts in <span class="hlt">Lherzolitic</span> <span class="hlt">Shergottite</span> ALH 77005: Petrologic Significance; Compositional Controls on the Formation of Kaersutite Amphibole in <span class="hlt">Shergottite</span> Meteorites; Chemical Characteristics of an Olivine-Phyric <span class="hlt">Shergottite</span>, <span class="hlt">Yamato</span> 980459; Pb-Hf-Sr-Nd Isotopic Systematics and Age of Nakhlite NWA 998; Noble Gases in Two Samples of EETA 79001 (Lith. A); Experimental Constraints on the Iron Content of the Martian Mantle; and Mars as the Parent Body for the CI Carbonaceous Chondrites: New Data.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=19830057480&hterms=gpa&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D20%26Ntt%3Dgpa','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=19830057480&hterms=gpa&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D20%26Ntt%3Dgpa"><span>Solidus and liquidus temperatures and mineralogies for anhydrous garnet-<span class="hlt">lherzolite</span> to 15 GPa</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Herzberg, C. T.</p> <p>1983-01-01</p> <p>Strong convergence is noted, in experimental data for systems pertaining to anhydrous fertile garnet-<span class="hlt">lherzolite</span> in the 6.5-15 GPa range, either to a common temperature or to temperatures differing by only about 100 C. The major element composition of magmas generated by even minor degrees of partial melting may be similar to the composition of the primordial, bulk silicate earth in an upper mantle stratigraphic column more than 160 km deep. Whether or not the solidus and liquidus intersect, the liquidus mineralogy for undepleted garnet-<span class="hlt">lherzolite</span> compositions is found to change from olivine, at low pressures, to pyroxene, garnet, or a solid solution of both, at pressures greater than 10-15 GPa.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2008MinPe..94...27S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2008MinPe..94...27S"><span>Origin and significance of spinel pyroxene symplectite in <span class="hlt">lherzolite</span> xenoliths from Tallante, SE Spain</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Shimizu, Yohei; Arai, Shoji; Morishita, Tomoaki; Ishida, Yoshito</p> <p>2008-09-01</p> <p>We found spinel pyroxene symplectites in <span class="hlt">lherzolite</span> xenoliths from Tallante, SE Spain, and investigated their petrographical and geochemical signatures. The spinel pyroxene symplectites are divided into two types, a spinel-type (= opx + cpx + sp) and a plagioclase-type (= opx + cpx + sp + pl) symplectites. The symplectites are always surrounded by lenticular aggregates of coarser-grained spinel pyroxene. The petrography and major-element chemistry of bulk symplectites indicate an origin through subsolidus reaction between olivine and garnet like at Horoman (Japan; Morishita and Arai, Contrib Mineral Petrol 144:509 522, 2003). The spinel pyroxene symplectites at Tallante were of garnet origin. However, the bulk Tallante spinel pyroxene symplectites show a relatively flat rare earth element (REE) distribution with slight light REE (LREE) enrichment, i.e. there was no trace-element signature typical of mantle garnet. They also differ from the Horoman symplectites that occasionally preserve a garnet trace-element signature, i.e. depletion of LREE and enrichment of heavy REE. These conflicting results indicate that the symplectites record slight enrichment in pyroxene compositions during or after depletion by melt extraction and breakdown of garnet by decompression, and all the minerals including symplectite constituents have been homogenized in the stability field of spinel to plagioclase <span class="hlt">lherzolite</span>, with the assistance of some melt (possibly an alkaline silicate melt; Downes, J Petrol 42:233 250, 2001). Moreover, some of the spinel-type symplectites experienced heating by injection of Si-rich melt, and consequently have been transformed to the plagioclase-type symplectite. The Tallante spinel pyroxene symplectites developed from garnet + olivine and were carried from the garnet <span class="hlt">lherzolite</span> stability field to the spinel and to the plagioclase <span class="hlt">lherzolite</span> stability fields. Our data indicates mantle upwelling (mantle diapirism) beneath the Betic Rif zone in southern Spain.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/20170001698','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/20170001698"><span>Evaluating Crustal Contamination Effects On The Lithophile Trace Element Budget Of <span class="hlt">Shergottites</span>, NWA 856 As A Test Case</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Brandon, A. D.; Ferdous, J.; Peslier, A. H.</p> <p>2017-01-01</p> <p>The issue of whether crustal contamination has affected the lithophile trace element budget of <span class="hlt">shergottites</span> has been a point of contention for decades. The evaluation has focused on the enriched <span class="hlt">shergottite</span> compositions as an outcome of crustal contamination of mantle-derived parent magmas or, alternatively, the compositions of these stones reflect an incompatible trace element (ITE) enriched mantle source.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/1983LPSC...14..229S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/1983LPSC...14..229S"><span>Mineral chemistry of the <span class="hlt">shergottites</span>, nakhlites, Chassigny, Brachina, pallasites and urelites</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Smith, J. V.; Steele, I. M.; Leitch, C. A.</p> <p>1983-11-01</p> <p>The mineral chemistry is compared for selected achondrites. Olivine in the ALHA 77005 and EETA 79001 <span class="hlt">shergottites</span>, olivine-rich Chassigny and Brachina, and the nakhlites, contains Ni indicative of oxidizing conditions, whereas pallasitic and ureilitic olivines contain much lower Ni due to reducing conditions. The Brachina olivine and pyroxene have distinctively higher Fe/Mn than the <span class="hlt">shergottites</span> and Chassigny, further indicating that Brachina is unique. The Chassigny and 77005 olivines contain lower Cr2O3 (0.03 wt. pct) than the Brachina and 79001 olivines. Values of Fe/Mn for cumulus augites in nakhlites are higher than for the <span class="hlt">shergottites</span>, whereas those for ferropigeonites are not. The 77005 <span class="hlt">shergottite</span> contains troilite FeS in contrast to 79001, Shergotty, Zagami, and Chassigny, which contain pyrrhotite. Further analyses are needed, but the present survey indicates that at least Brachina is not chemically cogenetic with the other 'oxidized achondrites', and that the Fe/Mn ratio of the cumulus augites in nakhlites is a problem for the assignment of the nakhlites, <span class="hlt">shergottites</span>, and Chassigny to a single genetic group.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/1993Metic..28..451T','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/1993Metic..28..451T"><span>Xenoliths in the EETA 79001 <span class="hlt">Shergottite</span>: Geological and Astronomical Implications of Similarities to the ALHA 77005 and LEW 88516 <span class="hlt">Shergottites</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Treiman, A. H.</p> <p>1993-07-01</p> <p>The EETA79001 <span class="hlt">shergottite</span> basalt contains xenoliths (to 1 cm diameter) that are comparable to the nonpoikilitic lithologies in the ALHA77005 and LEW88516 <span class="hlt">shergottites</span>. The xenoliths are fragments of an olivine-low-Ca-pyroxene rock, with lesser augite, chromite, and maskelynite; their textural patterns suggest an original heteradcumulate igneous rock [1,2] similar to ALHA77005 and LEW88516 [3,4]. Mineral phases in the xenoliths have experienced some chemical exchange with the host basalt [5]; however, their core compositions, especially pyroxenes, are nearly identical to those in LEW88516, and somewhat less restricted than those in ALHA77005 (new data; [1]; [2]; G. McKay, personal communication). Olivines in the xenoliths contain multiphase inclusions, ellipsoidal aggregates (to 200 micrometers diameter) of augite, alkali-rich, and Si-rich glasses, chromite, and a phosphate, in radiating or variolitic textures. These are interpreted as magmatic inclusions, remnants of original magma trapped in the olivines, and are petrographically identical to magmatic inclusions in the olivines of ALHA77005 and LEW88516 [4,6,7]. Shock effects in the xenoliths include zones of brown pleochroism in olivine, mosaickism of both olivine and pyroxene, formation of maskelynite from original plagioclase, recrystallization, and melting; these same effects are present but more severe in ALHA77005 and LEW88516 [8,9]. These many similarities among ALHA77005, LEW88516, and the EETA79001 xenoliths suggest that all were derived from similar, closely related igneous rocks (radioisotope ratios apparently preclude a comagmatic origin for ALHA77005 and the EETA79001 xenoliths [7,10,11]). If these three lithologies are closely related, they may be contemporaneous, and thus older than the EETA79001 basalt (host to the xenoliths). This inference may be consistent with radiometric crystallization ages: for ALHA77005 the age is 187 +- 12 (2 sigma) m.y. [11,5] or 154 +- 6 (2 sigma) m.y. [7]; for the EETA</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/20120011726','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/20120011726"><span>Complex Formation History of Highly Evolved Basaltic <span class="hlt">Shergottite</span>, Zagami</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Niihara, T.; Misawa, K.; Mikouchi, T.; Nyquist, L. E.; Park, J.; Hirata, D.</p> <p>2012-01-01</p> <p>Zagami, a basaltic <span class="hlt">shergottite</span>, contains several kinds of lithologies such as Normal Zagami consisting of Fine-grained (FG) and Coarse-grained (CG), Dark Mottled lithology (DML), and Olivine-rich late-stage melt pocket (DN). Treiman and Sutton concluded that Zagami (Normal Zagami) is a fractional crystallization product from a single magma. It has been suggested that there were two igneous stages (deep magma chamber and shallow magma chamber or surface lava flow) on the basis of chemical zoning features of pyroxenes which have homogeneous Mg-rich cores and FeO, CaO zoning at the rims. Nyquist et al. reported that FG has a different initial Sr isotopic ratio than CG and DML, and suggested the possibility of magma mixing on Mars. Here we report new results of petrology and mineralogy for DML and the Olivine-rich lithology (we do not use DN here), the most evolved lithology in this rock, to understand the relationship among lithologies and reveal Zagami s formation history</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=19870038806&hterms=Beryllium&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D30%26Ntt%3DBeryllium','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=19870038806&hterms=Beryllium&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D30%26Ntt%3DBeryllium"><span>Beryllium-10 contents of <span class="hlt">shergottites</span>, nakhlites, and Chassigny</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Pal, D. K.; Tuniz, C.; Moniot, R. K.; Savin, W.; Kruse, T.</p> <p>1986-01-01</p> <p>Accelerator mass spectrometry gives the following Be-10 contents (dpm/kg) for the SNC meteorites: Shergotty, 13.0 + or - 1.5 and 17.3 + or - 2.7; Zagami, 18.6 + or - 2.5 and 20.0 + or - 3.2; ALHA 77005, 15 + or - 3; EETA 79001A, 7.8 + or - 1.1 and 6.3 + or - 0.5; EETA 79001B, 8.5 + or - 1.1; Nakhla, 19.7 + or - 3.3; Lafayette, 18.1 + or - 2.5; Governador Valadares, 25.6 + or - 3.6; Chassigny, 20.5 + or - 3.1. The Be-10 contents of the NC meteorites indicate that significant accumulation of cosmogenic nuclides occurred in decimeter rather than planetary-size bodies. The agreement of the He-3, Ne-21, and Be-10 exposure ages of the <span class="hlt">shergottites</span> also supports small-body irradiation. A long terrestrial age for EETA 79001 appears unlikely.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/20170000786','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/20170000786"><span>Ultra-Refractory Calcium-Aluminum-Rich Inclusion in an AOA in CR Chondrite <span class="hlt">Yamato</span>-793261</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Komatsu, M.; Fagan, T. J.; Yamaguchi, A.; Mikouchi, T.; Yasutake, M.; Zolensky, M. E.</p> <p>2017-01-01</p> <p>CR chondrites are a group of primitive carbonaceous chondrites that preserve nebular records of the formation conditions of their components. We have been investigating a set of Antarctic CR chondrites from the Japanese-NIPR collection in order to study variations within this group. During our study, we have found an AOA that encloses an ultrarefractory (UR) CAI in <span class="hlt">Yamato</span>-793261 (Y-793261). UR CAIs are rare in carbonaceous chondrites, and only three UR CAIs in AOAs have been identified so far. UR CAIs can provide information on crystallization processes at very high temperatures in the solar nebula. Here we describe the petrology of Y-793261, and preliminary results on this newly discovered AOA enclosing a UR CAI.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=19910054777&hterms=Koeberl&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAuthor-Name%26N%3D0%26No%3D20%26Ntt%3DKoeberl','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=19910054777&hterms=Koeberl&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAuthor-Name%26N%3D0%26No%3D20%26Ntt%3DKoeberl"><span>Preliminary examination of the <span class="hlt">Yamato</span>-86032 lunar meteorite. II - Major and trace element chemistry</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Koeberl, Christian; Warren, Paul H.; Lindstrom, Marilyn M.; Spettel, Bernhard; Fukuoka, Takaaki</p> <p>1989-01-01</p> <p>Results of the chemical composition analysis of <span class="hlt">Yamato</span>-86032, found in Antarctica in 1986, are summarized. The meteorite may be classified as an anorthositic breccia, but its trace element composition is different from the composition of the other known lunar meteorites. The major element chemistry of Y-86032 is similar to the other lunar meteorites, except for the iron content, which is lower by a factor of about 1.4. The abundances of incompatible and lithophile elements such as Zr, Hf, Ta, Th, or the REEs are very low and comparable to Y-82192/3. Other elements, in particular Fe, Ti, Sc, Cr, Mn, and Co, have lower abundances in Y-86032 than in Y-82192/3. Variations between individual analysis demonstrate that the rock itself is heterogeneous.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=19940016420&hterms=Koeberl&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAuthor-Name%26N%3D0%26No%3D20%26Ntt%3DKoeberl','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=19940016420&hterms=Koeberl&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAuthor-Name%26N%3D0%26No%3D20%26Ntt%3DKoeberl"><span>Consortium reports on lunar meteorites <span class="hlt">Yamato</span> 793169 and Asuka 881757, a new type of mare basalt</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Yanai, Keizo; Takeda, Hiroshi; Lindstrom, M. M.; Tatsumoto, M.; Torigoe, N.; Misawa, K.; Warren, P. H.; Kallemeyn, G. W.; Koeberl, C.; Kojima, H.</p> <p>1993-01-01</p> <p>Consortium studies on lunar meteorites <span class="hlt">Yamato</span> 793169 and Asuka 881757 (formerly Asuka-31) were performed to characterize these new samples from unknown locations in the lunar mare. Both meteorites are coarse-grained mare rocks having low Mg/Fe ratios (bulk mg'=30-35) and low TiO2 (1.5-2.5 percent in homogenized bulk samples). They are intermediate between VLT and low-Ti mare basalts. Although these meteorites are not identical to each other, their mineral and bulk compositions, isotopic systematics, and crystallization ages are remarkably similar and distinct from those of all other mare basalts. They appear to represent a new type of low-Ti mare basalt that crystallized at about 3.9Ga. These meteorites are inconsistent with the canonical correlation between the TiO2 contents and ages of mare basalts and suggest that our knowledge of lunar volcanism is far from complete.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.osti.gov/scitech/biblio/5921155','SCIGOV-STC'); return false;" href="https://www.osti.gov/scitech/biblio/5921155"><span>Thermal history of the shock-melted Antarctic LL-chondrites from the <span class="hlt">Yamato</span>-79 collection</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Okano, Osamu; Nakamura, Noboru ); Nagao, Keisuke )</p> <p>1990-12-01</p> <p>The Sr and rare gas isotopic compositions and abundances of lithophile trace elements (K, Rb, Sr, Ba, and REEs) were determined for a series of shock-melted <span class="hlt">Yamato</span>-79 LL-chondrites to investigate their late thermal history and the chemical features of shock processes. All meteorites show similarities in shock ages ({approximately}1.2 Ga) as confirmed by Rb-Sr internal isochron and K-Ar dating, rare gas compositions as well as cosmic-ray exposure ages ({approximately}28 Ma), petrographic textures, and sampling sites in Antarctica. These results indicate that all of thee meteorites are part of the same fall. The 1.2 Ga shock event caused a severe (partial to total) melting followed by recrystallization of olivine and clinopyroxene, vesiculation, shock-induced alkali homogenization, and local isotopic equilibration or perturbation of the Rb-Sr system. The degrees of shock effects are variable from specimen to specimen and from portion to portion, even in a single specimen. Model calculations of Fe diffusion in olivine suggest that hot and cold materials were in close contact in the impact ejecta sheets of the parent body. From these model calculations and the evidence provided by cosmogenic rare gas compositions, it is concluded that an impact melt ejecta pile composed of hot and cold brecciated materials had formed at depth (>2 m, shielded from cosmic rays) in an impact crater by the 1.2 Ga event. The parent body was fragmented to meter-size stones by an additional collision at {approximately}28 Ma resulting in the formation of the parent material of the <span class="hlt">Yamato</span>-79 shocked condrites.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2010JGRC..11512001F','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2010JGRC..11512001F"><span>Iron distributions in the water column of the Japan Basin and <span class="hlt">Yamato</span> Basin (Japan Sea)</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Fujita, Satoshi; Kuma, Kenshi; Ishikawa, Satoko; Nishimura, Shotaroh; Nakayama, Yuta; Ushizaka, Satomi; Isoda, Yutaka; Otosaka, Shigeyoshi; Aramaki, Takafumi</p> <p>2010-12-01</p> <p>In the Japan and <span class="hlt">Yamato</span> basins (Japan Sea), dissolved Fe ([D-Fe], <0.22 μm fraction) was characterized by surface depletion, mid-depth maxima, then a slight decrease with depth in deep water and uniform concentration in bottom waters because of biological uptake in the surface water and release by microbial decomposition of sinking organic matter in mid-depth waters. Total Fe concentrations ([T-Fe]) in the surface water of the Japan Sea were 1-4 nM, a little higher than those in the surface waters of the nutrient-deficient subtropical western North Pacific and extremely higher than the nutrient-rich subarctic western North Pacific and the nutrient-deficient subtropical central North Pacific, resulting from high atmospheric Fe input to nutrient-depleted surface water of the Japan Sea. In the Japan Basin, the [T-Fe] in bottom water were lower than those in deep water, resulting from (1) the injection of new bottom water with the lower [T-Fe] into the Japan Basin bottom water, (2) the particulate Fe removal by particle scavenging during the bottom water circulation of the Japan Basin, or (3) the injection of deep water with the higher [T-Fe] into the Japan Basin deep water. On the other hand, the [T-Fe] in deep water of the <span class="hlt">Yamato</span> Basin and the slope regions were variable with different [T-Fe] levels among stations and depths. We found a significant relationship between [T-Fe] and water transmittance in deep water, probably resulting from the iron supply into the deep water because of the lateral transport of resuspended sediment from the slope.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/19980018466','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/19980018466"><span>The <span class="hlt">Shergottite</span> Age Paradox and the Relative Probabilities of Ejecting Martian Meteorites of Differing Ages</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Borg, L. E.; Shih, C.-Y.; Nyquist, L. E.</p> <p>1998-01-01</p> <p>The apparent paradox that the majority of impacts yielding Martian meteorites appear to have taken place on only a few percent of the Martian surface can be resolved if all the <span class="hlt">shergottites</span> were ejected in a single event rather than in multiple events as expected from variations in their cosmic ray exposure and crystallization ages. If the <span class="hlt">shergottite</span>-ejection event is assigned to one of three craters in the vicinity of Olympus Mons that were previously identified as candidate source craters for the SNC (<span class="hlt">Shergottites</span>, Nakhlites, Chassigny) meteorites, and the nakhlite event to another candidate crater in the vicinity of Ceraunius Tholus, the implied ages of the surrounding terranes agree well with crater density ages. EN,en for high cratering rates (minimum ages), the likely origin of the <span class="hlt">shergottites</span> is in the Tharsis region, and the paradox of too many meteorites from too little terrane remains for multiple <span class="hlt">shergottite</span>-ejection events. However, for high cratering rates it is possible to consider sources for the nakhlltes which are away from the Tharsis region. The meteorite-yielding impacts may have been widely dispersed with sources of the young SNC meteorites in the northern plains, and the source of the ancient orthopyroxenite, ALH84001, in the ancient southern uplands. Oblique-impact craters can be identified with the sources of the nakhlites and the orthopyroxenite,, respectively, in the nominal cratering rate model, and with the <span class="hlt">shergottites</span> and orthopyroxenite, respectively, in the high cratering rate model. Thus, oblique impacts deserve renewed attention as an ejection mechanism for Martian meteorites.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016Litho.260...28S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016Litho.260...28S"><span>Melt extraction and enrichment processes in the New Caledonia <span class="hlt">lherzolites</span>: Evidence from geochemical and Sr-Nd isotope data</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Secchiari, Arianna; Montanini, Alessandra; Bosch, Delphine; Macera, Patrizia; Cluzel, Dominique</p> <p>2016-09-01</p> <p>The New Caledonia ophiolite (Peridotite Nappe) is dominated by mantle lithologies, composed of forearc-related refractory harzburgites and minor <span class="hlt">lherzolites</span> in both the spinel and plagioclase facies. In this study, a comprehensive geochemical data set (major, trace elements and Sr-Nd isotopes) is used to constrain the mantle evolution of the <span class="hlt">lherzolites</span> and their relationships with the basalts from the Poya Terrane, which tectonically underlies the mantle rocks. The majority of the <span class="hlt">lherzolites</span> are low-strain porphyroclastic tectonites. They likely record an asthenospheric origin followed by re-equilibration at lithospheric conditions, as supported by geothermometric estimates (T = 1100-940 °C and 920-890 °C for porphyroclastic and neoblastic spinel-facies assemblages, respectively). Olivine composition (Fo = 88.5-90.0 mol%), spinel Cr# ([molar 100 • Cr/(Cr + Al)] = 13-17) and relatively high amounts (7-8 vol%) of Al2O3- and Na2O-rich clinopyroxene (up to 0.5 and 6.5 wt.%, respectively) indicate a moderately depleted geochemical signature for the spinel <span class="hlt">lherzolites</span>. Bulk rock and clinopyroxene rare earth elements (REE) patterns display a typical abyssal-type signature, i.e. steeply plunging LREE accompanied by nearly flat HREE to MREE. Clinopyroxene REE compositions of the spinel <span class="hlt">lherzolites</span> may be reproduced by small amounts of fractional melting of a garnet <span class="hlt">lherzolite</span> precursor ( 4%), followed by 4%-5% melting in the spinel peridotite field. The plagioclase <span class="hlt">lherzolites</span> show melt impregnation microstructures, Cr- and Ti-rich spinels and incompatible trace element enrichments (REE, Ti, Y, and Zr) in bulk rocks and clinopyroxenes. Impregnation modelling for these elements suggests that the plagioclase <span class="hlt">lherzolites</span> originated from residual spinel <span class="hlt">lherzolites</span> by entrapment of highly depleted (non-aggregated) MORB melt fractions in the shallow oceanic lithosphere. Nd isotope compositions of the investigated peridotites are consistent with derivation from an</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=19940007610&hterms=noble+gases&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D30%26Ntt%3Dnoble%2Bgases','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=19940007610&hterms=noble+gases&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D30%26Ntt%3Dnoble%2Bgases"><span>Noble gases in LEW88516 <span class="hlt">shergottite</span>: Evidence for exposure age pairing with ALH77005</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Bogard, D. D.; Garrison, D. H.</p> <p>1993-01-01</p> <p>LEW88516 contains excess amounts of radiogenic Ar-40 and Xe-129 that are slightly greater than those observed in ALH77005, but in the same relative proportion as much larger excesses observed in EET79001. Cosmogenic He-3 and Ne-21 abundances in LEW88516 are very similar to those for ALH77005 and are consistent with a common initiation of cosmic ray exposure -2.8 Myr ago for four of the five <span class="hlt">shergottites</span>. Exposure of these four <span class="hlt">shergottites</span> could have been under different shielding in a common meteoroid, or in several objects.</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_4");'>4</a></li> <li><a href="#" onclick='return showDiv("page_5");'>5</a></li> <li class="active"><span>6</span></li> <li><a href="#" onclick='return showDiv("page_7");'>7</a></li> <li><a href="#" onclick='return showDiv("page_8");'>8</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_6 --> <div id="page_7" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_5");'>5</a></li> <li><a href="#" onclick='return showDiv("page_6");'>6</a></li> <li class="active"><span>7</span></li> <li><a href="#" onclick='return showDiv("page_8");'>8</a></li> <li><a href="#" onclick='return showDiv("page_9");'>9</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="121"> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/20130003564','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/20130003564"><span>Water in Nominally Anhydrous Minerals from Nakhlites and <span class="hlt">Shergottites</span></span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Peslier, Anne H.</p> <p>2013-01-01</p> <p>Estimating the amount of water in the interior of terrestrial planets has tremendous implications on our understanding of solar nebula evolution, planet formation and geological history, and extraterrestrial volcanism. Mars has been a recent focus of such enquiry with complementary datasets from spacecrafts, rovers and martian meteorite studies. In planetary interiors, water can be dissolved in fluids or melts and hydrous phases, but can also be locked as protons attached to structural oxygen in lattice defects in nominally anhydrous minerals (NAM) such as olivine, pyroxene, or feldspar [1-3]. Measuring water in Martian meteorite NAM is challenging because the minerals are fragile and riddled with fractures from impact processes that makes them break apart during sample processing. Moreover, curing the sample in epoxy causes problems for the two main water analysis techniques, Fourier transform infrared spectrometry (FTIR) and secondary ionization mass spectrometry (SIMS). Measurements to date have resulted in a heated debate on how much water the mantle of Mars contains. SIMS studies of NAM [4], amphiboles [5], and apatites [6-8] from Martian meteorites report finding enough water in these phases to infer that the martian mantle is as hydrous as that of the Earth. On the other hand, a SIMS study of glass in olivine melt inclusions from <span class="hlt">shergottites</span> concludes that the Martian mantle is much drier [9]. The latter interpretation is also supported by the fact that most martian hydrous minerals generally have the relevant sites filled with Cl and F instead of H [10,11]. As for experimental results, martian basalt compositions can be reproduced using water as well as Cl in the parent melts [12,13]. Here FTIR is used to measure water in martian meteorite minerals in order to constrain the origin of the distribution of water in martian meteorite phases.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/1982PolRe..25..131A','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/1982PolRe..25..131A"><span>High resolution electron microscopic characterization of phyllosilicates and finding of a new type with 11A structure in <span class="hlt">Yamato</span>-74662</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Akai, J.</p> <p>1982-12-01</p> <p>Matrix materials in <span class="hlt">Yamato</span>-74662 have been examined by HREM and AEM. Under microscopic observations, phyllosilicates in <span class="hlt">Yamato</span>-74662 were found: (1) as matrix materials, (2) in irregular cavities, and (3) replacing pyroxene and olivine grains. Five types of phyllosilicates in the matrix were observed by HREM; (1) 7A platy phyllosilicate, (2) 7A poorly organized tubular phyllosilicate, (3) 17A platy phyllosilicate, (4) poorly organized 7A layer structures with interlayering of 5A layer structure and (5) 11A platy phyllosilicate. Parallel intergrowth of the 11A mineral and 7A berthierine, and characteristic HREM suggest that the 11A mineral is a new phyllosilicate with an interstratified structure of serpentine-like and brucite-like layers. Mineralogy and texture of the matrix suggest that the phyllosilicates were derived by alteration from such precursor materials as CV chondrites, and experienced some mixing or brecciation process after (or during) alteration.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/19058996','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/19058996"><span>First finding of burkeite in melt inclusions in olivine from sheared <span class="hlt">lherzolite</span> xenoliths.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Korsakov, Andrey V; Golovin, Alexander V; De Gussem, Kris; Sharygin, Igor S; Vandenabeele, Peter</p> <p>2009-08-01</p> <p>For the first time burkeite was observed as a daughter phase in the melt inclusions in olivine by Raman spectroscopy. The olivine comes from sheared <span class="hlt">lherzolite</span> xenoliths from the Udachnaya-East kimberlite pipe (Yakutia, Russia). This anhydrous sulfate-carbonate mineral (Na(6)(CO(3))(SO(4))(2)) is generally considered to be a characteristic mineral in saline soils or in continental lacustrine evaporite deposits. Recently, however, this mineral was identified in hydrothermal fluids. Our observations indicate that burkeite can also be formed from a mantle-derived melt.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/20100026405','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/20100026405"><span>Argon Analyses of Lherzolic <span class="hlt">Shergottites</span> Y984028 and Y000097</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Park, J.; Nyquist, L. E.; Bogard, D. D.; Garrison, D. H.; Shih, C.-Y.; Mikouchi, T.; Misawa, K.</p> <p>2010-01-01</p> <p>Antarctic Martian meteorites <span class="hlt">Yamato</span> (Y) 984028 and Y000027/47/97 have similar textures, mineralogy, chemistry, and isotopic composition and are possibly paired. We analyzed the argon isotopic composition of Y984028 whole rock (WR) and pyroxene mineral separates (Px) in order to evaluate their trapped Ar components and compare with Y000097 Ar data. WR and Px yield an apparent Ar-39-Ar-40 age spectra of roughly 2 Ga, much older than the crystallization age determined by other isotopic techniques. Sm-Nd and Rb-Sr ages for Y984028 are approximately 170 Ma. This discrepancy is likely the byproduct of several coexisting Ar components, such as radiogenic 40Ar*, cosmogenic Ar, and trapped Ar from the multiple minerals, as well as multiple source origins. Similarly, the reported Ar-39-Ar-40 age of Y000097 is approximately 260 Ma with a Rb-Sr age of 147+/- 28 Ma and a Sm-Nd age of 152 +/- 13 Ma [4]. Apparently Ar-Ar ages of both Y984028 and Y000097 show trapped Ar components. Stepwise temperature extractions of Ar from Y984028 Px show several Arcomponents released at different temperatures. For example, intermediate temperature data (800-1100 C) are nominally consistent with the Sm-Nd and Rb-Sr radiometric ages (approximately 170 Ma) with an approximately Martian atmosphere trapped Ar composition with a Ar-40-Ar-36 ratio of approximately 1800. Based on K/Ca distribution, we know that Ar-39 at both lower and intermediate temperatures is primarily derived from plagioclase and olivine. Argon released during higher temperature extractions (1200-1500 C), however, differs significantly. The thermal profile of argon released from Martian meteorites is complicated by multiple sources, such as Martian atmosphere, Martian mantle, inherited Ar, terrestrial atmosphere, cosmogenic Ar. Obviously, Ar release at higher temperatures from Px should contain little terrestrial atmospheric component. Likewise, Xe-129/Xe-132 from high temperature extractions (1200-1800 C) gives a value above that</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/20110007848','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/20110007848"><span>Rb-Sr And Sm-Nd Ages, and Petrogenesis of Depleted <span class="hlt">Shergottite</span> Northwest Africa 5990</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Shih, C. Y.; Nyquist, L. E.; Reese, Y.; Irving, A. J.</p> <p>2011-01-01</p> <p>Northwest Africa (NWA) 5990 is a very fresh Martian meteorite recently found on Hamada du Draa, Morocco and was classified as an olivine-bearing diabasic igneous rock related to depleted <span class="hlt">shergottites</span> [1]. The study of [1] also showed that NWA 5990 resembles QUE 94201 in chemical, textural and isotopic aspects, except QUE 94201 contains no olivine. The depleted <span class="hlt">shergottites</span> are characterized by REE patterns that are highly depleted in LREE, older Sm-Nd ages of 327-575 Ma and highly LREE-depleted sources with Nd= +35+48 [2-7]. Age-dating these samples by Sm-Nd and Rb-Sr methods is very challenging because they have been strongly shocked and contain very low abundances of light rare earth elements (Sm and Nd), Rb and Sr. In addition, terrestrial contaminants which are commonly present in desert meteorites will compromise the equilibrium of isotopic systems. Since NWA 5990 is a very fresh meteorite, it probably has not been subject to significant desert weathering and thus is a good sample for isotopic studies. In this report, we present Rb-Sr and Sm-Nd isotopic results for NWA 5990, discuss the correlation of the determined ages with those of other depleted <span class="hlt">shergottites</span>, especially QUE 94201, and discuss the petrogenesis of depleted <span class="hlt">shergottites</span>.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/20100003465','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/20100003465"><span>Sulfur Isotopes in Gas-rich Impact-Melt Glasses in <span class="hlt">Shergottites</span></span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Rao, M. N.; Hoppe, P.; Sutton, S. R.; Nyquist, Laurence E.; Huth, J.</p> <p>2010-01-01</p> <p>Large impact melt glasses in some <span class="hlt">shergottites</span> contain huge amounts of Martian atmospheric gases and they are known as gas-rich impact-melt (GRIM) glasses. By studying the neutron-induced isotopic deficits and excesses in Sm-149 and Sm-150 isotopes resulting from Sm-149 (n,gamma) 150Sm reaction and 80Kr excesses produced by Br-79 (n,gamma) Kr-80 reaction in the GRIM glasses using mass-spectrometric techniques, it was shown that these glasses in <span class="hlt">shergottites</span> EET79001 and Shergotty contain regolith materials irradiated by a thermal neutron fluence of approx.10(exp 15) n/sq cm near Martian surface. Also, it was shown that these glasses contain varying amounts of sulfates and sulfides based on the release patterns of SO2 (sulfate) and H2S (sulfide) using stepwise-heating mass-spectrometric techniques. Furthermore, EMPA and FE-SEM studies in basaltic-<span class="hlt">shergottite</span> GRIM glasses EET79001, LithB (,507& ,69), Shergotty (DBS I &II), Zagami (,992 & ,994) showed positive correlation between FeO and "SO3" (sulfide + sulfate), whereas those belonging to olivine-phyric <span class="hlt">shergottites</span> EET79001, LithA (,506, & ,77) showed positive correlation between CaO/Al2O3 and "SO3".</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015M%26PS...50.2024H','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015M%26PS...50.2024H"><span>Petrography and geochemistry of the enriched basaltic <span class="hlt">shergottite</span> Northwest Africa 2975</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>He, Qi; Xiao, Long; Balta, J. Brian; Baziotis, Ioannis P.; Hsu, Weibiao; Guan, Yunbin</p> <p>2015-12-01</p> <p>We present a study of the petrology and geochemistry of basaltic <span class="hlt">shergottite</span> Northwest Africa 2975 (NWA 2975). NWA 2975 is a medium-grained basalt with subophitic to granular texture. Electron microprobe (EMP) analyses show two distinct pyroxene compositional trends and patchy compositional zoning patterns distinct from those observed in other meteorites such as Shergotty or QUE 94201. As no bulk sample was available to us for whole rock measurements, we characterized the fusion crust and its variability by secondary ion mass spectrometer (SIMS) measurements and laser ablation inductively coupled plasma spectroscopy (LA-ICP-MS) analyses as a best-available proxy for the bulk rock composition. The fusion crust major element composition is comparable to the bulk composition of other enriched basaltic <span class="hlt">shergottites</span>, placing NWA 2975 within that sample group. The CI-normalized REE (rare earth element) patterns are flat and also parallel to those of other enriched basaltic <span class="hlt">shergottites</span>. Merrillite is the major REE carrier and has a flat REE pattern with slight depletion of Eu, parallel to REE patterns of merrillites from other basaltic <span class="hlt">shergottites</span>. The oxidation state of NWA 2975 calculated from Fe-Ti oxide pairs is NNO-1.86, close to the QFM buffer. NWA 2975 represents a sample from the oxidized and enriched <span class="hlt">shergottite</span> group, and our measurements and constraints on its origin are consistent with the hypothesis of two distinct Martian mantle reservoirs: a reduced, LREE-depleted reservoir and an oxidized, LREE-enriched reservoir. Stishovite, possibly seifertite, and dense SiO2 glass were also identified in the meteorite, allowing us to infer that NWA 2975 experienced a realistic shock pressure of ~30 GPa.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=20030111635&hterms=nD&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D50%26Ntt%3D%253FnD','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=20030111635&hterms=nD&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D50%26Ntt%3D%253FnD"><span>Age and Petrogenesis of Picritic <span class="hlt">Shergottite</span> NWA1068: Sm-Nd and Rb-Sr Isotopic Studies</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Shih, C.-Y.; Nyquist, L. E.; Wiesmann, H.; Barrat, J. A.</p> <p>2003-01-01</p> <p>NWA 1068 is a 577g picritic <span class="hlt">shergottite</span> found in the Moroccan Sahara in 2001. The meteorite resembles several other picritic <span class="hlt">shergottites</span>, e.g. EETA79001B, DaG476, SaU005 and Dho019, in major-element chemistry and mineralogy, but it differs significantly from these meteorites in REE distribution pattern. It has a slightly LREE-depleted pattern commonly shared by some olivine-free basaltic <span class="hlt">shergottites</span>, e.g. Shergotty, Zagami and Los Angeles, but not QUE94201. Detailed geochemical and mineral-petrological studies were given in. We performed Rb-Sr and Sm-Nd isotopic analyses on this rock to determine its crystallization age and to study the petrogenetic relationship between this meteorite and other basaltic and pricritic <span class="hlt">shergottites</span>.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015LPICo1879.1017W','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015LPICo1879.1017W"><span>An Exploration Zone in Cerberus Containing Young and Old Terrains, Including Fossae/Faults and <span class="hlt">Shergottite</span> Distal Ejecta</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Wright, S. P.; Niles, P. B.; Bell, M. S.; Milbury, C.; Rice, J. W.; Burton, A. S.; Archer, P. D.; Rampe, E. B.; Piqueux, S.</p> <p>2015-10-01</p> <p>Cerberus contains Amazonian lava flows embaying a range of photogeologic units: ridged plains, heavily cratered terrain, highland knobs, and perhaps the Medusa Fossae Fm. Zunil Crater distal ejecta produced secondary crater fields (of <span class="hlt">shergottites</span>?).</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=20030111635&hterms=Age+Anger&qs=N%3D0%26Ntk%3DAll%26Ntx%3Dmode%2Bmatchall%26Ntt%3DAge%2BAnger','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=20030111635&hterms=Age+Anger&qs=N%3D0%26Ntk%3DAll%26Ntx%3Dmode%2Bmatchall%26Ntt%3DAge%2BAnger"><span>Age and Petrogenesis of Picritic <span class="hlt">Shergottite</span> NWA1068: Sm-Nd and Rb-Sr Isotopic Studies</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Shih, C.-Y.; Nyquist, L. E.; Wiesmann, H.; Barrat, J. A.</p> <p>2003-01-01</p> <p>NWA 1068 is a 577g picritic <span class="hlt">shergottite</span> found in the Moroccan Sahara in 2001. The meteorite resembles several other picritic <span class="hlt">shergottites</span>, e.g. EETA79001B, DaG476, SaU005 and Dho019, in major-element chemistry and mineralogy, but it differs significantly from these meteorites in REE distribution pattern. It has a slightly LREE-depleted pattern commonly shared by some olivine-free basaltic <span class="hlt">shergottites</span>, e.g. Shergotty, Zagami and Los Angeles, but not QUE94201. Detailed geochemical and mineral-petrological studies were given in. We performed Rb-Sr and Sm-Nd isotopic analyses on this rock to determine its crystallization age and to study the petrogenetic relationship between this meteorite and other basaltic and pricritic <span class="hlt">shergottites</span>.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/20090022115','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/20090022115"><span>Sm-Nd, Rb-Sr, and Mn-Cr Ages of <span class="hlt">Yamato</span> 74013</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Nyquist, L. E.; Shih, C.- Y.; Reese, Y.D.</p> <p>2009-01-01</p> <p><span class="hlt">Yamato</span> 74013 is one of 29 paired diogenites having granoblastic textures. The Ar-39 - Ar-40 age of Y-74097 is approximately 1100 Ma. Rb-Sr and Sm-Nd analyses of Y-74013, -74037, -74097, and -74136 suggested that multiple young metamorphic events disturbed their isotopic systems. Masuda et al. reported that REE abundances were heterogeneous even within the same sample (Y-74010) for sample sizes less than approximately 2 g. Both they and Nyquist et al. reported data for some samples showing significant LREE enrichment. In addition to its granoblastic texture, Y-74013 is characterized by large, isolated clots of chromite up to 5 mm in diameter. Takeda et al. suggested that these diogenites originally represented a single or very small number of coarse orthopyroxene crystals that were recrystallized by shock processes. They further suggested that initial crystallization may have occurred very early within the deep crust of the HED parent body. Here we report the chronology of Y-74013 as recorded in chronometers based on long-lived Rb-87 and Sm-147, intermediate- lived Sm-146, and short-lived Mn-53.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/20110015619','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/20110015619"><span>The Formation of Wassonite: A New Titanium Monosulfide Mineral in the <span class="hlt">Yamato</span> 691 Enstatite Chondrite</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Nakamura-Messenger, K.; Keller, L. P.; Messenger, S.; Rubin, A. E.; Choi, B.-G.; Petaev, M. I.; Clemett, S. J.; Zhang, S.; Rahman, Z.; Oikawa, K.</p> <p>2011-01-01</p> <p>Wassonite, ideally stoichiometric TiS, is a titanium monosulfide not previously observed in nature, that was discovered within the <span class="hlt">Yamato</span> 691 EH3 enstatite chondrite [1]. Because of the submicrometer size of the wassonite grains, it was not possible to determine conventional macroscopic properties. However, the chemical composition and crystal structure were well constrained by extensive quantitative energy dispersive x-ray analysis and electron diffraction using transmission electron microscopy (TEM). The crystal system for wassonite is rhombohedral (a = 3.42 plus or minus 0.07, c = 26.50 plus or minus 0.53 Angstroms) with space group: R(sup 3 raised bar) m (R9 type), cell volume: 268.4 plus or minus 0.53 Angstroms(sup 3), Z=9, density (calculated): 4.452 grams per cubic centimeter, empirical formula: (Ti(sub 0.93), Fe(sub 0.06), Cr(sub 0.01))S. In this study, we discuss possible formation mechanisms of wassonite and its associated minerals based on the petrology, mineralogy, crystallography, thermodynamic calculations, Al/Mg isotopic systematics and the O-isotopic composition of the wassonite-bearing BO chondrule.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://pubs.er.usgs.gov/publication/70026675','USGSPUBS'); return false;" href="http://pubs.er.usgs.gov/publication/70026675"><span>Garnet <span class="hlt">lherzolites</span> from Louwrensia, Namibia: Bulk composition and P/T relations</span></a></p> <p><a target="_blank" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Boyd, F.R.; Pearson, D.G.; Hoal, Karin O.; Hoal, B.G.; Nixon, P.H.; Kingston, M.J.; Mertzman, S.A.</p> <p>2004-01-01</p> <p>Bulk, mineral and trace element analyses of garnet <span class="hlt">lherzolite</span> xenoliths from the Louwrensia kimberlite pipe, south-central Namibia, together with previously published Re-Os isotopic data [Chem. Geol. (2004)], form the most extensive set of chemical data for off-craton suites from southern Africa. The Louwrensia suite is similar to those from the Kaapvaal craton in that it includes both predominantly coarse-grained, equant-textured peridotites characterised by equilibration temperatures 1200 ??C. Redepletion ages range back to 2.1 Gy, concordant with the age of the crustal basement and about 1 Gy younger than the older peridotites of the adjacent Kaapvaal craton root. The coarse, low-temperature Louwrensia peridotites have an average Mg number for olivine of 91.6 in comparison to 92.6 for low-temperature peridotites from the craton. Orthopyroxene content averages 24 wt.% with a range of 11-40 wt.% for Louwrensia low-temperature peridotites, in comparison to a mean of 31.5 wt.% and a range of 11-44 wt.% for low-temperature peridotites from the Kaapvaal craton. Other major, minor and trace element concentrations in minerals forming Louwrensia <span class="hlt">lherzolites</span> are more similar to values in corresponding Kaapvaal peridotite minerals than to those in lithospheric peridotites of Phanerozoic age as represented by off-craton basalt-hosted xenoliths and orogenic peridotites. Proportions of clinopyroxene and garnet in both the Louwrensia and Kaapvaal <span class="hlt">lherzolites</span> overlap in the range up to 10 wt.% forming a trend extending towards pyrolite composition. Disequilibrium element partitioning between clinopyroxene and garnet for some incompatible trace elements is evidence that some of the trend is caused by enrichment following depletion. The disequilibrium is interpreted to have been caused by relatively recent growth of diopside, as previously suggested for cratonic peridotites. Attempts to constrain the depth of melting required to produce the Louwrensia peridotites suggests</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2004AGUFM.V24A..05M','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2004AGUFM.V24A..05M"><span>Compositional variations across a dunite - harzburgite - <span class="hlt">lherzolite</span> - plagioclase <span class="hlt">lherzolite</span> sequence at the Trinity ophiolite: Evidence for multiple episodes of melt flow and melt-rock reaction in the mantle.</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Morgan, Z. T.; Liang, Y.; Kelemen, P.</p> <p>2004-12-01</p> <p>In the preceding report we showed experimentally that the dunite-harzburgite-<span class="hlt">lherzolite</span> (DHL) sequence found in the mantle sections of ophiolite could be formed by reactive dissolution of <span class="hlt">lherzolite</span> in a basaltic liquid. The most striking results of our <span class="hlt">lherzolite</span> dissolution experiments are the sharp mineralogical boundaries between adjacent lithologies and simple monotonic composition variations in minerals across the DHL sequence. Here we present a detailed compositional traverse across a dunite (3.64 m wide) - harzburgite-<span class="hlt">lherzolite</span> (5.64 m) - plagioclase <span class="hlt">lherzolite</span> (> 10 m) sequence (referred to as DHL-PL) at the Trinity ophiolite that shows complicated composition trends and melt flow history. With the exception of a small (1 m wide) anomalous region within the dunite, less than 1 m away from the dunite-harzburgite contact, the Mg#s of olivine (90), cpx (92.8), opx (90.4 in harzburgite) and spinel (40), as well as Al2O3 and TiO2 abundance in cpx, opx and spinel are essentially constant from dunite to <span class="hlt">lherzolite</span>. The CaO content in olivine (0.02%), opx (1%) and cpx (23.5%) are also uniform throughout the harzburgite-plagioclase <span class="hlt">lherzolite</span> sequence. However, the Mg# of olivine and opx, Al2O3, TiO2 and Cr2O3 in cpx and opx, as well as Na2O in cpx increase 2 meters into the plagioclase <span class="hlt">lherzolite</span>. In addition, asymmetric concentration gradients are observed for CaO in olivine and Cr2O3, Al2O3, MgO, and FeO in spinel. These asymmetric concentration gradients are mostly in the dunite-side of the dunite-harzburgite contact. And finally, the 1 m wide anomalous region within the dunite is characterized by elevated Mg# and NiO in olivine, Al2O3, TiO2, Cr2O3, and REE in cpx, and very distinct elemental abundance in spinel. The composition variations reported here are substantially different from those of Quick (1981) who measured a smaller (1 m) DHL-PL sequence at the Trinity ophiolite. Together these two Trinity data sets show a large variation in DHL-PL chemistry</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/20090020654','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/20090020654"><span>Sulfur Speciation in the Martian Regolith Component in <span class="hlt">Shergottite</span> Glasses</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Rao, M. N.; Nyquist, Laurence E.; Sutton, S.; Huth, J.</p> <p>2009-01-01</p> <p>We have shown that Gas-Rich Impact-Melt (GRIM) glasses in Shergotty, Zagami, and EET79001 (Lith A and Lith B) contain Martian regolith components that were molten during impact and quenched into glasses in voids of host rock materials based on neutron-capture isotopes, i.e., Sm-150 excesses and Sm-149 deficits in Sm, and Kr-80 excesses produced from Br [1, 2]. These GRIM glasses are rich in S-bearing secondary minerals [3.4]. Evidence for the occurrence of CaSO4 and S-rich aluminosilicates in these glasses is provided by CaO-SO3 and Al2O3-SO3 correlations, which are consistent with the finding of gypsum laths protruding from the molten glass in EET79001 (Lith A) [5]. However, in the case of GRIM glasses from EET79001 (Lith B), Shergotty and Zagami, we find a different set of secondary minerals that show a FeO-SO3 correlation (but no MgOSO3 correlation), instead of CaO-SO3 and Al2O3-SO3 correlations observed in Lith A. These results might indicate different fluidrock interactions near the <span class="hlt">shergottite</span> source region on Mars. The speciation of sulfur in these salt assemblages was earlier studied by us using XANES techniques [6], where we found that Lith B predominantly contains Fe-sulfide globules (with some sulfate). On the other hand, Lith A showed predominantly Casulfite/ sulfate with some FeS. Furthermore, we found Fe to be present as Fe2+ indicating little oxidation, if any, in these glasses. To examine the sulfide-sulfate association in these glasses, we studied their Fe/Ni ratios with a view to find diagnostic clues for the source fluid. The Fe-sulfide mineral (Fe(0.93)Ni(0.3)S) in EET79001, Lith A is pyrrhotite [7, 8]. It yields an Fe/Ni ratio of 31. In Shergotty, pyrrhotite occurs with a molar ratio of Fe:S of 0.94 and a Ni abundance of 0.12% yielding a Fe/Ni ratio of approx.500 [8]. In this study, we determined a NiO content of approx.0.1% and FeO/NiO ratio of approx.420 in S-rich globules in #507 (EET79001, Lith B) sample using FE-SEM. In the same sample</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/1999Litho..48..287M','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/1999Litho..48..287M"><span>Growth of subcontinental lithosphere: evidence from repeated dike injections in the Balmuccia <span class="hlt">lherzolite</span> massif, Italian Alps</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Mukasa, Samuel B.; Shervais, John W.</p> <p>1999-09-01</p> <p>The Balmuccia alpine <span class="hlt">lherzolite</span> massif is a fragment of subcontinental lithospheric mantle emplaced into the lower crust 251 Ma ago during the final, extensional phase of the Hercynian orogeny. The Balmuccia massif consists largely of <span class="hlt">lherzolite</span>, with subordinate harzburgite and dunite, and an array of dike rocks formed in the mantle before crustal emplacement. Dike rocks include websterite and bronzitite of the Cr-diopside suite, spinel clinopyroxenite and spinel-poor websterite of the Al-augite suite, gabbro and gabbronorite of the late gabbro suite, and hornblendite of the hydrous vein suite. The dike rocks display consistent intrusive relationships with one another, such that Cr-diopside suite dikes are always older than dikes and veins of the Al-augite suite, followed by dikes of the late gabbro suite and veins of the hydrous vein suite. Phlogopite (phl) veinlets that formed during interaction with the adjacent crust are the youngest event. There are at least three generations of Cr-diopside suite dikes, as shown by crosscutting relations. Dikes of the Al-augite suite form a polybaric fractionation series from spinel clinopyroxenite to websterite and feldspathic websterite, which crystallized from aluminous alkaline magmas at relatively high pressures. The late gabbro suite of dikes intruded at lower pressures, where plagioclase saturation occurred before significant mafic phase fractionation. Hornblendite veins have distinct compositional and isotopic characteristics, which show that they are not related to either the Al-augite suite or to the late gabbro dike suite. Cr-diopside suite dikes have Nd and Sr isotopic compositions similar to those of the host <span class="hlt">lherzolite</span> and within the range of compositions defined by ocean-island basalts. The Al-augite dikes and the hornblendite veins have Sr and Nd isotopic compositions similar to those of Cr-diopside suite <span class="hlt">lherzolite</span> and websterite. The late gabbro dikes have Nd and Sr isotopic compositions similar to mid</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2005AGUFMMR13A0078S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2005AGUFMMR13A0078S"><span>Melting Interval of Natural Carbonated <span class="hlt">Lherzolite</span> at 3 GPa and Genesis of Alkalic OIBs</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Smith, N. D.; Dasgupta, R.; Hirschmann, M. M.</p> <p>2005-12-01</p> <p>Alkalic lavas are characteristic of many intraplate magmatic provinces, both on continents and on many oceanic islands. Such lavas are generally thought to originate from small degrees of partial melting of fertile peridotite±CO21. However, natural alkalic lavas have lower Al2O3, CaO and higher FeO* and TiO2 than liquids likely to be descended from partial melts generated in previous experiments on peridotite+CO22. We performed experiments at 3 GPa to investigate silicate melt compositions generated near the transition from near-solidus carbonate-rich to high temperature silicate-rich melts in the melting interval of carbonated <span class="hlt">lherzolite</span>. Experiments were conducted in Pt/C capsules with a fertile carbonated <span class="hlt">lherzolite</span> (MixKLB-1+2.5 wt.% CO2) at 3 GPa from 1075 to 1600 °C. Below the solidus, CO2 is stored in dolomitess, which disappears between 1075-1105 °C, generating ~6 wt.% carbonate-rich melt. Carbonatitic melt coexists with the four-phase <span class="hlt">lherzolite</span> residue up to 1325 °C. Carbonated silicate melt is observed beginning 1350 °C. Cpx, garnet and opx disappear at 1350-1375 °C, 1425-1450 °C and 1550-1575 °C respectively. Melt compositions analysed with a defocused microprobe beam increase sharply in SiO2 (~7 to 21 wt.%) and Al2O3 (~3 to 7 wt.%) between 1325 and 1350 °C, reflecting a transition from carbonatite to melilitite. From 1350 to 1600 °C (9 to 51 % melt), melts (on a CO2-free basis) increase in SiO2 (~29 to 46 wt.%), MgO (~20 to 29 wt.%), and decrease in TiO2 (1.6 to 0.5 wt.%), CaO (~26 to 7 wt.%), and Na2O (~2 to 0.6 wt.%). Al2O3 increases from ~9 to 12 wt.% from 1350 to 1450 °C and then decreases to ~7 wt.% at 1600 °C and FeO* varies between 12-10 wt.%. Experimental melt fraction versus composition trends suggest that small-degree partial melts of carbonated peridotite could evolve to match the TiO2, FeO*, and Al2O3 of natural alkalic lavas, but these low-degree melts will have much higher CaO and CaO/Al2O3 ratios than those found in alkalic</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=19940016396&hterms=Elephants&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D90%26Ntt%3DElephants','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=19940016396&hterms=Elephants&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D90%26Ntt%3DElephants"><span>Weathering features and secondary minerals in Antarctic <span class="hlt">Shergottites</span> ALHA77005 and LEW88516</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Wentworth, Susan J.; Gooding, James L.</p> <p>1993-01-01</p> <p>Previous work has shown that all three sub-groups of the <span class="hlt">shergottite</span>, nakhlite, and chassignite (SNC) clan of meteorites contain aqueous precipitates of probable pre-terrestrial origin. In the context of secondary minerals, the most thoroughly studied <span class="hlt">shergottite</span> has been Elephant Moraine, Antarctica A79001 (EETA79001). The recognition of LEW88516 as the latest SNC specimen, and its close similarity with ALHA77005, invite a comparative study of the latter two meteorites, and with EETA79001, from the perspective of aqueous alteration. The fusion crusts of the two meteorites are quite similar except that ALHA77005 is more vesicular (possibly indicating a higher indigenous volatile content). Secondary aluminosilicates (and salts on LEW88516) of definite Antarctic origin partially fill vesicles and fractures on both fusion crusts. Interior samples of the two meteorites are grossly similar in that traces of secondary minerals are present in both.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/1984GeCoA..48.1723B','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/1984GeCoA..48.1723B"><span>Noble gas contents of <span class="hlt">shergottites</span> and implications for the Martian origin of SNC meteorites</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Bogard, D. D.; Nyquist, L. E.; Johnson, P.</p> <p>1984-09-01</p> <p>Three meteorites belonging to the rare group of SNC achondrites, which may have originated in the planet Mars, have been subjected to noble gas isotopic concentration measurements. The elemental and isotopic ratios obtained are unlike those for any other noble gas components except those obtained in analyses of the Martian atmosphere by Viking spacecraft. It is hypothesized that the Kr and Xe gases represent a portion of the Martian atmosphere which was shock-implanted in the case of Elephant Moraine A79001, and that they constitute direct evidence of a Martian origin for the <span class="hlt">shergottite</span> meteorites. If the SNC meteorites were ejected from Mars at the <span class="hlt">shergottite</span> shock age of about 180 My ago, they must have been objects more than 6 m in diameter which experienced at least three space collisions to initiate cosmic ray exposure.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=19850029870&hterms=elephant+evolution&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D30%26Ntt%3Delephant%2Bevolution','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=19850029870&hterms=elephant+evolution&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D30%26Ntt%3Delephant%2Bevolution"><span>Noble gas contents of <span class="hlt">shergottites</span> and implications for the Martian origin of SNC meteorites</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Bogard, D. D.; Nyquist, L. E.; Johnson, P.</p> <p>1984-01-01</p> <p>Three meteorites belonging to the rare group of SNC achondrites, which may have originated in the planet Mars, have been subjected to noble gas isotopic concentration measurements. The elemental and isotopic ratios obtained are unlike those for any other noble gas components except those obtained in analyses of the Martian atmosphere by Viking spacecraft. It is hypothesized that the Kr and Xe gases represent a portion of the Martian atmosphere which was shock-implanted in the case of Elephant Moraine A79001, and that they constitute direct evidence of a Martian origin for the <span class="hlt">shergottite</span> meteorites. If the SNC meteorites were ejected from Mars at the <span class="hlt">shergottite</span> shock age of about 180 My ago, they must have been objects more than 6 m in diameter which experienced at least three space collisions to initiate cosmic ray exposure.</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_5");'>5</a></li> <li><a href="#" onclick='return showDiv("page_6");'>6</a></li> <li class="active"><span>7</span></li> <li><a href="#" onclick='return showDiv("page_8");'>8</a></li> <li><a href="#" onclick='return showDiv("page_9");'>9</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_7 --> <div id="page_8" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_6");'>6</a></li> <li><a href="#" onclick='return showDiv("page_7");'>7</a></li> <li class="active"><span>8</span></li> <li><a href="#" onclick='return showDiv("page_9");'>9</a></li> <li><a href="#" onclick='return showDiv("page_10");'>10</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="141"> <li> <p><a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=19860063607&hterms=Earth+core&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D40%26Ntt%3DEarth%2Bcore','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=19860063607&hterms=Earth+core&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D40%26Ntt%3DEarth%2Bcore"><span>Core formation in the earth and <span class="hlt">shergottite</span> parent body (SPB) - Chemical evidence from basalts</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Treiman, A. H.; Drake, M. J.; Janssens, M.-J.; Wolf, R.; Ebihara, M.</p> <p>1986-01-01</p> <p>Abundances of siderophile and chalcophile elements in the <span class="hlt">shergottite</span> parental body (SPB) have been compared with those of the earth. To this end, new INAA and RNAA analyses of non-Antarctic meteorites have been performed, and the composition of the <span class="hlt">shergottite</span> SPB mantle has been inferred from the compositions of the SNC meteorites. The composition of the earth's mantle has been inferred from the compositions of terrestrial basalt. Finally, the effects of volatile depletion, core formation, and mineral/melt fractionation on the abundances of siderophile and chalcophile elements in the SPB and the earth have been taken into consideration. Compared to the earth, the SPB mantle is richer in moderately siderophile elements and more depleted with respect to chalcophile elements. The observed relative abundances of siderophile and chalcophile elements in the SPB and the earth mantles indicate that the SPB underwent accretion and/or differentiation processes which differ from those in the earth.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/20150002847','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/20150002847"><span>Correlations Between Surficial Sulfur and a REE Crustal Assimilation Signature in Martian <span class="hlt">Shergottites</span></span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Jones, J. H.; Franz, H. B.</p> <p>2015-01-01</p> <p>Compared to terrestrial basalts, the Martian <span class="hlt">shergottite</span> meteorites have an extraordinary range of Sr and Nd isotopic signatures. In addition, the S isotopic compositions of many <span class="hlt">shergottites</span> show evidence of interaction with the Martian surface/ atmosphere through mass-independent isotopic fractionations (MIF, positive, non-zero delta(exp 33)S) that must have originated in the Martian atmosphere, yet ultimately were incorporated into igneous sulfides (AVS - acid-volatile sulfur). These positive delta(exp 33)S signatures are thought to be governed by solar UV photochemical processes. And to the extent that S is bound to Mars and not lost to space from the upper atmosphere, a positive delta(exp 33)S reservoir must be mass balanced by a complementary negative reservoir.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/20120017925','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/20120017925"><span>Rb-Sr Isotopic Systematics of Alkali-Rich Fragments in the <span class="hlt">Yamato</span>-74442 LL-Chondritic Breccia</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Yokoyama, T.; Misawa, K.; Okano, O.; Shih, C.-Y.; Nyquist, L. E.; Simo, J. I.; Tappa, M. J.; Yoneda, S.</p> <p>2012-01-01</p> <p>Alkali-rich igneous fragments were identified in the brecciated LL-chondrites, Kr henberg (LL5)], Bhola (LL3-6) and <span class="hlt">Yamato</span> (Y)-74442 (LL4), and show characteristic fractionation patterns of alkaline elements. The K-Rb-Cs-rich fragments in Kr henberg, Bhola, and Y-74442 are very similar in mineralogy and petrography (olivine + pyroxene + glass), suggesting that they could have come from related precursor materials. We have undertaken Rb-Sr isotopic studies on alkali-rich fragments in Y-74442 to precisely determine their crystallization ages and the isotopic signatures of their precursor material(s).</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017GeCoA.201..303N','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017GeCoA.201..303N"><span>26Al-26Mg systematics in chondrules from Kaba and <span class="hlt">Yamato</span> 980145 CV3 carbonaceous chondrites</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Nagashima, Kazuhide; Krot, Alexander N.; Komatsu, Mutsumi</p> <p>2017-03-01</p> <p>We report the mineralogy, petrography, and in situ measured 26Al-26Mg systematics in chondrules from the least metamorphosed CV3 (Vigarano-type) chondrites, Kaba and <span class="hlt">Yamato</span> (Y) 980145. Two Y 980145 chondrules measured show no resolvable excesses in 26Mg (26Mg∗), a decay product of a short-lived (t1/2 ∼0.7 Ma) radionuclide 26Al. Plagioclase in one of the chondrules is replaced by nepheline, indicative of thermal metamorphism. The lack of 26Mg∗ in the Y 980145 chondrules is most likely due to disturbance of their 26Al-26Mg systematics during the metamorphism. Although Kaba experienced extensive metasomatic alteration (<300 °C), it largely avoided subsequent thermal metamorphism, and the 26Al-26Mg systematics of its chondrules appear to be undisturbed. All eight Kaba chondrules measured show 26Mg∗, corresponding to the initial 26Al/27Al ratios [(26Al/27Al)0] ranging from (2.9 ± 1.7) × 10-6 to (6.3 ± 2.7) × 10-6. If CV parent asteroid accreted rapidly after chondrule formation, the inferred (26Al/27Al)0 ratios in Kaba chondrules provide an upper limit on 26Al available in this asteroid at the time of its accretion. The estimated initial abundance of 26Al in the CV asteroid is too low to melt it and contradicts the existence of a molten core in this body suggested from the paleomagnetic records of Allende [Carporzen et al. (2011) Magnetic evidence for a partially differentiated carbonaceous chondrite parent body. Proc. Natl. Acad. Sci. USA108, 6386-6389] and Kaba [Gattacceca et al. (2013) More evidence for a partially differentiated CV parent body from the meteorite Kaba. Lunar Planet. Sci.44, abstract#1721].</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2013M%26PS...48.1780R','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2013M%26PS...48.1780R"><span>Anhydrous liquid line of descent of <span class="hlt">Yamato</span>-980459 and evolution of Martian parental magmas</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Rapp, Jennifer F.; Draper, David S.; Mercer, Cameron M.</p> <p>2013-10-01</p> <p>We report the results of nominally anhydrous equilibrium and fractional crystallization experiments on a synthetic <span class="hlt">Yamato</span>-980459 (Y98) bulk composition at 0.5 GPa. These experiments allow us to test a suggested fractional crystallization model, calculated using MELTS by Symes et al. (<link href="#maps12197-bib-0059"/>), in which a Y98-like initial liquid yielded a magma closely resembling the bulk composition of QUE 94201. Although the two meteorites cannot be cogenetic owing to their age difference, they are thought to represent bona fide magmatic liquids rather than products of crystal accumulation, as are most Martian basaltic meteorites. Hence, understanding possible petrogenetic links between these types of liquids could be revealing about processes of melting and crystallization that formed the range of Martian basalts. We find that Y98 can, in fact, generate a residual liquid closely resembling QUE, but only after a very different crystallization process, and different degree of crystallization, than that modeled using MELTS. In addition, both the identity and sequence of crystallizing phases are very different between model and experiments. Our fractional crystallization experiments do not produce a QUE-like liquid, and the crystallizing phases are an even poorer match to the MELTS-calculated compositions than in the equilibrium runs. However, residual liquids from our experiments define a liquid line of descent that encompasses bulk compositions of parental melts calculated for several Martian basaltic meteorites, suggesting that the known Martian basaltic meteorites had their ultimate origin from the same or very similar source lithologies. These are, in turn, similar to source rocks modeled by previous studies as products of extensive crystallization of an initial Martian magma ocean.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2012M%26PS...47.2251J','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2012M%26PS...47.2251J"><span>Heavily metamorphosed clasts from the CV chondrite breccias Mokoia and <span class="hlt">Yamato</span>-86009</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Jogo, Kaori; Nagashima, Kazuhide; Hutcheon, Ian D.; Krot, Alexander N.; Nakamura, Tomoki</p> <p>2012-12-01</p> <p>Abstract- Metamorphosed clasts in the CV carbonaceous chondrite breccias Mokoia and <span class="hlt">Yamato</span>-86009 (Y-86009) are coarse-grained, granular, polymineralic rocks composed of Ca-bearing (up to 0.6 wt% CaO) ferroan olivine (Fa34-39), ferroan Al-diopside (Fs9-13Wo47-50, approximately 2-7 wt% Al2O3), plagioclase (An37-84Ab63-17), Cr-spinel (Cr/(Cr + Al) = 0.19-0.45, Fe/(Fe + Mg) = 0.60-0.79), nepheline, pyrrhotite, pentlandite, Ca-phosphate, and rare grains of Ni-rich taenite; low-Ca pyroxene is absent. Most clasts have triple junctions between silicate grains, indicative of prolonged thermal annealing. Based on the olivine-spinel and pyroxene thermometry, the estimated metamorphic temperature recorded by the clasts is approximately 1100 K. Few clasts experienced thermal metamorphism to a lower degree and preserved chondrule-like textures. The Mokoia and Y-86009 clasts are mineralogically unique and different from metamorphosed chondrites of known groups (H, L, LL, R, EH, EL, CO, CK) and primitive achondrites (acapulcoites, brachinites, lodranites). On a three-isotope oxygen diagram, compositions of olivine in the clasts plot along carbonaceous chondrite anhydrous mineral line and the Allende mass-fractionation line, and overlap with those of the CV chondrule olivines; the Δ17O values of the clasts range from about -4.3‰ to -3.0‰. We suggest that the clasts represent fragments of the CV-like material that experienced metasomatic alteration, high-temperature metamorphism, and possibly melting in the interior of the CV parent asteroid. The lack of low-Ca pyroxene in the clasts could be due to its replacement by ferroan olivine during iron-alkali metasomatic alteration or by high-Ca ferroan pyroxene during melting under oxidizing conditions.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.osti.gov/scitech/biblio/618157','SCIGOV-STC'); return false;" href="https://www.osti.gov/scitech/biblio/618157"><span>Sulfide isotopic compositions in <span class="hlt">shergottites</span> and ALH84001, and possible implications for life on Mars</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Greenwood, J.P.; McSween, H.Y. Jr.; Riciputi, L.R.</p> <p>1997-10-01</p> <p>The <span class="hlt">shergottite</span> and ALH84001 meteorites hold keys for understanding geologic and possibly biologic processes on Mars. Recently, it has been proposed that carbonates in ALH84001, and the Fe-sulfides they contain, are products of extraterrestrial biogenic activity. Here we report ion microprobe analyses of sulfides in <span class="hlt">shergottites</span> and ALH84001. The sulfur isotope ratios of igneous pyrrhotites in <span class="hlt">shergottites</span> (mean {delta}{sup 34}S{sub CDT}: Shergotty = -0.4{per_thousand}, Zagami = +2.7{per_thousand}, EETA79001A = 1.9{per_thousand}, EETA79001B = -1.7{per_thousand}, LEW88516 = -1.9{per_thousand}, QUE94201 = +0.8{per_thousand}) are similar to those of terrestrial ocean-floor basalts, suggesting that the sulfur isotopic composition of the Martian mantle may be similar to that of the mantle of the Earth. The sulfur isotopic systematics of ALH84001 sulfides are distinct from the <span class="hlt">shergottites</span>. Measured sulfur isotope ratios of eight pyrite grains ({delta}{sup 34}S{sub CDT} = +2.0 to +7.3{per_thousand}) in crushed zones confirm previously reported analyses of isotopically heavy sulfides and are indistinguishable from an Fe-sulfide zone within a carbonate globule ({delta}{sup 34}S{sub CDT} = +6.0{per_thousand}). Analyses of synthesized, fine-grained mixtures of sulfide, carbonate, and magnetite indicate than the measured sulfur isotope ratio is independent of the presence of carbonate and magnetite in the sputtered volume, confirming the accuracy of the analysis of the fine-grained sulfide in the carbonate globule. Terrestrial biogenic sulfate reduction typically results in light isotopic enrichments. The similarity of {delta}{sup 34}S values of the sulfides in ALH84001 imply that the Fe-sulfide zones within ALH84001 carbonates are probably not the result of bacterial reduction of sulfate. 38 refs., 3 figs., 1 tab.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/20110012697','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/20110012697"><span>Stabile Chlorine Isotope Study of Martian <span class="hlt">Shergottites</span> and Nakhlites; Whole Rock and Acid Leachates and Residues</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Nakamura, N.; Nyquist, L. E.; Reese, Y.; Shih, C-Y; Fujitani, T.; Okano, O.</p> <p>2011-01-01</p> <p>We have established a precise analytical technique for stable chlorine isotope measurements of tiny planetary materials by TIMS (Thermal Ionization Mass Spectrometry) [1], for which the results are basically consistent with the IRMS tech-nique (gas source mass spectrometry) [2,3,4]. We present here results for Martian <span class="hlt">shergottites</span> and nakhlites; whole rocks, HNO3-leachates and residues, and discuss the chlorine isotope evolution of planetary Mars.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/20130004220','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/20130004220"><span>Chemical Composition of Four <span class="hlt">Shergottites</span> from Northwest Africa (NWA 2800, NWA, 5214, NWA 5990, NWA 6342)</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Yang, S.; Humayun, M.; Jefferson, G.; Fields, D.; Righter, K.; Irving, A. J.</p> <p>2013-01-01</p> <p><span class="hlt">Shergottites</span> represent the majority of recovered Martian meteorites. As basic igneous rocks, they formed from magmas that were emplaced in the Martian crust [1]. Due to the low ambient pressure of the Martian atmosphere, subaerial lavas and shallow magma chambers are expected to outgas volatile metals (e.g., Cd, Te, Re, Bi) [2]. The planetary abundances of the volatile siderophile and chalcophile elements are important at establishing the depth of core formation for Mars, and must be known as a baseline for understanding volcanic outgassing on Mars, particularly the large enrichments of S and Cl observed in modern Martian soils [3]. There is little data on volatile siderophile and chalcophile elements from Martian meteorites, excluding a few well-analyzed samples [2]. Further, a large number of <span class="hlt">shergottites</span> being recovered from North West Africa are in need of chemical analysis. All of the <span class="hlt">shergottites</span> are in need of state-of-the art analysis for such ratios as Ge/Si and Ga/Al, which can now be accomplished by LA-ICP-MS [2].</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/20070021571','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/20070021571"><span>Excess Ar-40 in the Zagami <span class="hlt">Shergottite</span>: Does It Reveal Crystallization History?</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Bogard, Donald D.; Park, Jisun</p> <p>2007-01-01</p> <p>The Zagami basaltic <span class="hlt">shergottite</span> has fine- and coarse-grained (FG & CG) areas, which may reflect partial crystallization in a deep, slowly cooled magma chamber to form Mg-rich pyroxene cores, followed by entrainment of these crystals into a magma that rose and crystallized near the surface. Late-stage melt pockets formed mesostasis and feldspar (maskelynite) having a range of compositions, but low water abundance. Higher I(sub Sr) in the FG portion may result from the second stage having incorporated old crustal rocks that failed to reach isotopic equilibrium. Zagami, like other <span class="hlt">shergottites</span>, contains excess Ar-40(sub xs) beyond that expected from internal decay of K-40 during its Sm-Nd age of 177 Myr. We suggest that at least a portion of this Ar-40(sub xs) in Zagami and some other <span class="hlt">shergottites</span> was inherited from the magma, much as is the case of MORBs on Earth. We made Ar-39-Ar-40 age determinations on feldspar and pyroxene separates from both the FG and CG portions of Zagami. If Zagami experienced an evolving fractional crystallization history, including possible crustal contamination of the magma, that might be indicated in differing amounts of Ar-40(sub xs) between mineral phases and between FG and CG portions.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2011M%26PS...46....1Z','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2011M%26PS...46....1Z"><span>Bounce Rock - A <span class="hlt">shergottite</span>-like basalt encountered at Meridiani Planum, Mars</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Zipfel, Jutta; Schräder, Christian; Jolliff, Bradley L.; Gellert, Ralf; Herkenhoff, Kenneth E.; Rieder, Rudolf; Anderson, Robert; Bell, James F., III; Brückner, Johannes; Crisp, Joy A.; Christensen, Philip R.; Clark, Benton C.; de Souza, Paulo A., Jr.; Dreibus, Gerlind; D'Uston, Claude; Economou, Thanasis; Gorevan, Steven P.; Hahn, Brian C.; Klingelhäfer, Göstar; McCoy, Timothy J.; McSween, Harry Y., Jr.; Ming, Douglas W.; Morris, Richard V.; Rodionov, Daniel S.; Squyres, Steven W.; Wńnke, Heinrich; Wright, Shawn P.; Wyatt, Michael B.; Yen, Albert S.</p> <p>2011-01-01</p> <p>Abstract- The Opportunity rover of the Mars Exploration Rover mission encountered an isolated rock fragment with textural, mineralogical, and chemical properties similar to basaltic <span class="hlt">shergottites</span>. This finding was confirmed by all rover instruments, and a comprehensive study of these results is reported here. Spectra from the miniature thermal emission spectrometer and the Panoramic Camera reveal a pyroxene-rich mineralogy, which is also evident in Mössbauer spectra and in normative mineralogy derived from bulk chemistry measured by the alpha particle X-ray spectrometer. The correspondence of Bounce Rock’s chemical composition with the composition of certain basaltic <span class="hlt">shergottites</span>, especially Elephant Moraine (EET) 79001 lithology B and Queen Alexandra Range (QUE) 94201, is very close, with only Cl, Fe, and Ti exhibiting deviations. Chemical analyses further demonstrate characteristics typical of Mars such as the Fe/Mn ratio and P concentrations. Possible shock features support the idea that Bounce Rock was ejected from an impact crater, most likely in the Meridiani Planum region. Bopolu crater, 19.3 km in diameter, located 75 km to the southwest could be the source crater. To date, no other rocks of this composition have been encountered by any of the rovers on Mars. The finding of Bounce Rock by the Opportunity rover provides further direct evidence for an origin of basaltic <span class="hlt">shergottite</span> meteorites from Mars.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://pubs.er.usgs.gov/publication/70033801','USGSPUBS'); return false;" href="http://pubs.er.usgs.gov/publication/70033801"><span>Bounce Rock-A <span class="hlt">shergottite</span>-like basalt encountered at Meridiani Planum, Mars</span></a></p> <p><a target="_blank" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Zipfel, J.; Schroder, C.; Jolliff, B.L.; Gellert, Ralf; Herkenhoff, K. E.; Rieder, R.; Anderson, R.; Bell, J.F.; Brückner, J.; Crisp, J.A.; Christensen, P.R.; Clark, B. C.; de Souza, P.A.; Dreibus, G.; D'uston, C.; Economou, T.; Gorevan, S.P.; Hahn, B.C.; Klingelhofer, G.; McCoy, T.J.; McSween, H.Y.; Ming, D. W.; Morris, R.V.; Rodionov, D.S.; Squyres, S. W.; Wanke, H.; Wright, S.P.; Wyatt, M.B.; Yen, A. S.</p> <p>2011-01-01</p> <p>The Opportunity rover of the Mars Exploration Rover mission encountered an isolated rock fragment with textural, mineralogical, and chemical properties similar to basaltic <span class="hlt">shergottites</span>. This finding was confirmed by all rover instruments, and a comprehensive study of these results is reported here. Spectra from the miniature thermal emission spectrometer and the Panoramic Camera reveal a pyroxene-rich mineralogy, which is also evident in M??ssbauer spectra and in normative mineralogy derived from bulk chemistry measured by the alpha particle X-ray spectrometer. The correspondence of Bounce Rock's chemical composition with the composition of certain basaltic <span class="hlt">shergottites</span>, especially Elephant Moraine (EET) 79001 lithology B and Queen Alexandra Range (QUE) 94201, is very close, with only Cl, Fe, and Ti exhibiting deviations. Chemical analyses further demonstrate characteristics typical of Mars such as the Fe/Mn ratio and P concentrations. Possible shock features support the idea that Bounce Rock was ejected from an impact crater, most likely in the Meridiani Planum region. Bopolu crater, 19.3km in diameter, located 75km to the southwest could be the source crater. To date, no other rocks of this composition have been encountered by any of the rovers on Mars. The finding of Bounce Rock by the Opportunity rover provides further direct evidence for an origin of basaltic <span class="hlt">shergottite</span> meteorites from Mars. ?? The Meteoritical Society, 2011.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2010AGUFM.V21A2320G','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2010AGUFM.V21A2320G"><span>Plate Tectonics Constrained by Evidence-Based Magmatic Temperatures and Phase Relations of Fertile <span class="hlt">Lherzolite</span> (Invited)</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Green, D. H.; Falloon, T.</p> <p>2010-12-01</p> <p>In order to understand Earth’s plate tectonics we must interpret the most direct probes for mantle composition and temperature distribution i.e. the primitive basaltic magmas and peridotites representing partial melts and mantle residues. An evidence-based approach to identification of parental magmas and determination of their temperatures requires glass and phenocryst compositions and experimentally calibrated Fe/Mg partitioning between olivine and melt. We have compared magmatic crystallization temperatures between ‘hot-spot’(proposed to be plume-related) and normal mid-ocean ridge basalt (MORB) parental liquids, by examining three representative magmatic suites from both ocean island (Hawaii, Iceland, and Réunion) and mid-ocean ridge settings (Cocos-Nazca, East Pacific Rise, and Mid-Atlantic Ridge). We have glass and olivine phenocryst compositions, including volatile (H2O) contents, and have calculated parental liquid compositions at 0.2GPa by incrementally adding olivine back into the glass compositions until a liquid in equilibrium with the most-magnesian olivine phenocryst composition is obtained. The results of these calculations demonstrate that there is very little difference (maximum of ~20°C) between the ranges of crystallization temperatures of the parental liquids (MORB:1243-1351°C versus OIB:1286-1372°C) when volatile contents are taken into account. However while lacking temperature contrast, the source regions for ‘hot-spot’ parental magmas contain geochemical signatures of old subducted crust/lithosphere. The mantle depths of origin determined for both the MORB and OIB suites are similar (MORB:1-2 GPa; OIB:1-2.5 GPa). Calculations of mantle potential temperatures (Tp) are model dependent, particularly to melt fraction from an inferred source. Assuming similar fertile <span class="hlt">lherzolite</span> sources, the differences in Tp values between the hottest MORB and the hottest ocean island tholeiite sources are ~80°C. These differences disappear if the</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014AGUFM.V52B..05G','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014AGUFM.V52B..05G"><span>The Behavior of Fe3+/∑Fe During Partial Melting of Spinel <span class="hlt">Lherzolite</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Gaetani, G. A.</p> <p>2014-12-01</p> <p>The use of wet chemistry and X-ray absorption near edge structure (XANES) spectroscopy to determine the oxidation state of Fe in submarine glasses and olivine-hosted melt inclusions has provided important new insights into the global systematics of Fe3+/∑Fe in mid-ocean ridge basalts (MORB) [1, 2]. Because MORB are aggregates of near-fractional partial melts formed by decompression melting of variably depleted peridotite, it is difficult to judge the extent to which they directly reflect the oxidation state of the oceanic upper mantle. To provide a theoretical framework within which to interpret Fe3+/∑Fe in MORB, I have developed a model that describes the behavior of Fe3+/∑Fe during spinel <span class="hlt">lherzolite</span> partial melting in a system closed to oxygen. Modeling is carried out by calculating the Fe3+/∑Fe of olivine using the point defect model of [3], and determining Fe3+/∑Fe of the bulk peridotite from mineral-mineral partitioning. The inter-mineral Fe3+/Fe2+ exchange coefficients are derived from Mössbauer data on natural spinel peridotites, and are parameterized in terms of oxygen fugacity, temperature, and the Fe content of the olivine. The Fe3+/∑Fe of the melt is determined by combining mass-balance with an equation relating the Fe3+/∑Fe of the melt to the fugacity of oxygen [4]. Spinel <span class="hlt">lherzolite</span> partial melting is modeled after [5]. Modeling results indicate that oxygen fugacity does not follow the fayalite-magnetite-quartz (FMQ) buffer during partial melting. For isobaric partial melting, the system becomes reduced relative to FMQ with increasing extent of melting. This results from an increase in the FMQ buffer with increasing temperature, whereas oxygen fugacity in the peridotite remains nearly constant. Conversely, during polybaric partial melting the oxidation state of the residual peridotite increases relative to FMQ. The effective partition coefficient for Fe3+is larger than previously thought, so that a redox couple with S is not required to</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015P%26SS..117...24M','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015P%26SS..117...24M"><span>Lunar meteorite <span class="hlt">Yamato</span>-983885: Noble gases, nitrogen and cosmic ray exposure history</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Mahajan, Ramakant R.</p> <p>2015-11-01</p> <p>Noble gases and nitrogen have been in lunar meteorite from antartcica: the polymict regolith breccias, <span class="hlt">Yamato</span>-983885 (hereafter Y-983885). Y-983885 has highest concentration of trapped noble gases (Ar, Kr, and Xe) among all the lunar meteorites and returned lunar samples. Noble gases and nitrogen abundances measured in two samples of the lunar meteorite Y-983885. The concentration of trapped noble gases in Y-983885 (A) are, 20Ne=3.69×10-3, 36Ar=12.6×10-4, 84kr=8.57×10-7 and 132Xe=1.63×10-7 ccSTP/g. The cosmic-ray exposure ages for Y-983885 are thus calculated to be T21 (A)=1592±232 Ma and T21 (B)=574±85 Ma for 2π geometry (using production rates as per Hohenberg et al., 1978 and bulk composition). The exposure ages of samples A and B differ, indicating that they have undergone different exposure scenarios on the lunar surface. The different irradiation ages (T21 (A)=1592±232 Ma and T21 (B)=574±85 Ma) indicates that the regolith material which constitutes the meteorite Y-983885 resided at different shielding depths on lunar surface before agglomeration into the final meteorite. Exposure ages calculated using end member compositon like norite, basalt, tractolite (1947 to 1365 and 711 to 455 for A and B respectively) indicates clearly that the two samples A and B has undergone different exposure on Moon. The 20Ne/22Ne ratio of 13.60±0.01 in temperature step 400 °C of Y-983885 (A) demonstrate a clear retention of solar wind signature in this meteorite. The presence of high contents of trapped solar wind gases indicates that Y-983885 consists of mature lunar regolith material. Variable amounts of solar gases as well as cosmogenic noble gases indicate that Y-983885 (A and B) is compacted from several fragments that were exposed at the surface and/or at various depths in the regolith, before becoming part of Y-983885.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2013GeCoA.101..233E','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2013GeCoA.101..233E"><span>Shock-induced deformation of <span class="hlt">Shergottites</span>: Shock-pressures and perturbations of magmatic ages on Mars</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>El Goresy, Ahmed; Gillet, Ph.; Miyahara, M.; Ohtani, E.; Ozawa, S.; Beck, P.; Montagnac, G.</p> <p>2013-01-01</p> <p><span class="hlt">Shergottites</span> and Chassignites practiced major deformation effects whose nature, magnitude and relevance were controversially evaluated and disputatively debated. Our studies of many shocked <span class="hlt">shergottites</span> present, contrary to numerous previous reports, ample evidence for pervasive shock-induced melting amounting of at least 23 vol.% of the <span class="hlt">shergottite</span> consisting of maskelynite and pyrrhotite, partial melting of pyroxene, titanomagnetite, ilmenite and finding of several high-pressure polymorphs and pressure-induced dissociation reactions. Our results cast considerable doubt on using the refractive index (RI) or cathodoluminescence (CL) spectra of maskelynite, in estimating the magnitudes of peak-shock pressure in both <span class="hlt">shergottites</span> and ordinary chondrites. RI of maskelynite was set after quenching of the feldspar liquid before decompression to maskelynite glass followed by glass relaxation after decompression at the closure temperature of relaxation. The RI procedure widely practiced in the past 38 years revealed unrealistic very high-pressure estimates discrepant with the high-pressure mineral inventory in shocked <span class="hlt">shergottites</span> and ordinary chondrites and with results obtained by robust laboratory static experiments. <span class="hlt">Shergottites</span> contain the silica high-pressure polymorphs: the scrutinyite-structured polymorph seifertite, a monoclinic ultra dense polymorph of silica with ZrO2-structure, stishovite, a dense liquidus assemblage consisting of stishovite + Na-hexa-aluminosilicate (Na-CAS) and both K-lingunite and Ca-lingunite. Applying individual high-pressure silica polymorphs alone like stishovite, to estimate the equilibrium shock pressure, is inadequate due to the considerable shift of their nominal upper pressure bounds intrinsically induced by spatially variable absorptions of minor oxides like Al2O3, Na2O, FeO, MgO and TiO2. This practice revealed variable pressure estimates even within the same <span class="hlt">shergottite</span> subjected to the same peak-shock pressure. Occurrence of Na</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=19990020865&hterms=Lafayette&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D50%26Ntt%3DLafayette','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=19990020865&hterms=Lafayette&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D50%26Ntt%3DLafayette"><span>What Were the Major Factors That Controlled Mineralogical Similarities and Differences of Basaltic, <span class="hlt">Lherzolitic</span> and Clinopyroxentic Martian Meteorites Within Each Group</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Mikouchi, T.; Miyamoto, M.; McKay, G. A.</p> <p>1998-01-01</p> <p>Twelve martian meteorites that have been re- covered so far are classified into five groups (basalt, <span class="hlt">lherzolite</span>, clinopyroxenite, dunite, and orthopyroxenite) mainly from petrology and chemistry. Among them, the dunite and orthopyroxenite groups consist of only one meteorite each (dunite: Chassigny, orthopyroxenite: ALH 84001). The basalt group is the largest group and consists of four meteorites (Shergotty, Zagani, EETA 79001, and QUE 94201). The <span class="hlt">lherzolitic</span> and clinopyroxenitic groups include three meteorites each (<span class="hlt">Lherzolite</span>: ALH 77005, LEW 88516, and Y793605, clinopyroxenite: Nakhla, Governador Valadares, and Lafayette). These meteorites within each group are generally similar to the others, but none of them is paired with the others. In this abstract, we discuss the major factors that controlled mineralogical similarities and differences of basaltic, <span class="hlt">lherzolitic</span>, and clinopyroxenitic meteorites within each group. This may help in understanding their petrogenesis and original locations on Mars in general.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://pubs.er.usgs.gov/publication/70018247','USGSPUBS'); return false;" href="http://pubs.er.usgs.gov/publication/70018247"><span>A study of REE and Pb, Sr and Nd isotopes in garnet-<span class="hlt">lherzolite</span> xenoliths from Mingxi, Fujian Province</span></a></p> <p><a target="_blank" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Wankang, H.; Junwen, W.; Basu, A.R.; Tatsumoto, M.</p> <p>1993-01-01</p> <p>The REE and Pb, Sr, Nd isotopes in three xenoliths from limburgite and scoria-breccias, including spinel-<span class="hlt">lherzolite</span>, spinel-garnet-<span class="hlt">lherzolite</span> and phlogopite-gamet-<span class="hlt">lherzolite</span>, were analysed. The REE contents of the xenoliths are 1.3 to 3.3 times those of the chondrites with their REE patterns characterized by weak LREE depletion. The143Nd/144Nd values of whole rocks and minerals range from 0.51306 to 0.51345 with ??Nd=+ 8.2- +15.8,206Pb/204 Pb < 18.673, and207Pb/204Pb < 15.574. All this goes to show that the upper mantle in Mingxi at the depth of 67-82 km is a depleted mantle of MORB type, with87Sr/86 Sr ratios 0.70237-0.70390. In Nd-Sr diagram the data points of whole rocks are all out of the mantle array, implying that the xenoliths from Mingxi have more radiogenic Sr isotopes than those of the mantle array. ?? 1993 Institute of Geochemistry, Chinese Academy of Sciences.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.osti.gov/scitech/biblio/5065224','SCIGOV-STC'); return false;" href="https://www.osti.gov/scitech/biblio/5065224"><span>Mantle metasomatism beneath western Victoria, Australia. II. Isotopic geochemistry of Cr-diopside <span class="hlt">lherzolites</span> and Al-augite pyroxenites</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Griffin, W.L.; O'Reilly, S.Y.; Stabel, A.</p> <p>1988-02-01</p> <p>Cr-diopside spinel <span class="hlt">lherzolite</span> xenoliths from Victoria show metasomatic introduction of amphibole +- mica +- apatite, accompanied by enrichments in Sr, LREE and other incompatible elements. The metasomatism can be related to fluids emanating from crystallizing basaltic magmas now represented by dykes of pyroxenite. Abundant garnet and spinel metapyroxenites are products of an older magmatic episode; igneous-textured wehrlite series xenoliths represent a younger (Recent.) episode. Sr-Nd isotopic compositions of the <span class="hlt">lherzolites</span> spread into the enriched mantle field (epsilon/sub Nd/ < O, epsilon /sub Sr/ > O). Nd isotopic systematics suggest a maximum age for LREE enrichment of <700 Ma at 300-500 Ma, the metapyroxenites define a mixing hyperbola with the <span class="hlt">lherzolites</span>, most of which have epsilon/sub Sr/ > O at this time. More detailed mixing models require a third (apatite-rich component with present-day epsilon/sub Sr/ and epsilon/sub Nd/ approx. O). The least-modified metapyroxenites have very unradiogenic Nd and unsupported radiogenic Sr, suggesting a large component of older recycled crustal material. The origin of the apatite component is uncertain.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017M%26PS...52..391H','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017M%26PS...52..391H"><span>Trace elements in olivine and the petrogenesis of the intermediate, olivine-phyric <span class="hlt">shergottite</span> NWA 10170</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Howarth, Geoffrey H.; Udry, Arya</p> <p>2017-02-01</p> <p>Olivine-phyric <span class="hlt">shergottites</span> represent primitive basaltic to picritic rocks, spanning a large range of Mg# and olivine abundances. As primitive olivine-bearing magmas are commonly representative of their mantle source on Earth, understanding the petrology and evolution of olivine-phyric <span class="hlt">shergottites</span> is critical in our understanding of Martian mantle compositions. We present data for the olivine-phyric <span class="hlt">shergottite</span> Northwest Africa (NWA) 10170 to constrain the petrology with specific implications for magma plumbing-system dynamics. The calculated oxygen fugacity and bulk-rock REE concentrations (based on modal abundance) are consistent with a geochemically intermediate classification for NWA 10170, and overall similarity with NWA 6234. In addition, we present trace element data using laser ablation ICP-MS for coarse-grained olivine cores, and compare these data with terrestrial and Martian data sets. The olivines in NWA 10170 contain cores with compositions of Fo77 that evolve to rims with composition of Fo58, and are characterized by cores with low Ni contents (400-600 ppm). Nickel is compatible in olivine and such low Ni content for olivine cores in NWA 10170 suggests either early-stage fractionation and loss of olivine from the magma in a staging chamber at depth, or that Martian magmas have lower Ni than terrestrial magmas. We suggest that both are true in this case. Therefore, the magma does not represent a primary mantle melt, but rather has undergone 10-15% fractionation in a staging chamber prior to extrusion/intrusion at the surface of Mars. This further implies that careful evaluation of not only the Mg# but also the trace element concentrations of olivine needs to be conducted to evaluate pristine mantle melts versus those that have fractionated olivine (±pyroxene and oxide minerals) in staging chambers.</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_6");'>6</a></li> <li><a href="#" onclick='return showDiv("page_7");'>7</a></li> <li class="active"><span>8</span></li> <li><a href="#" onclick='return showDiv("page_9");'>9</a></li> <li><a href="#" onclick='return showDiv("page_10");'>10</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_8 --> <div id="page_9" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_7");'>7</a></li> <li><a href="#" onclick='return showDiv("page_8");'>8</a></li> <li class="active"><span>9</span></li> <li><a href="#" onclick='return showDiv("page_10");'>10</a></li> <li><a href="#" onclick='return showDiv("page_11");'>11</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="161"> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/20110007857','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/20110007857"><span>Acid-Sulfate-Weathering Activity in <span class="hlt">Shergottite</span> Sites on Mars Recorded in Grim Glasses</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Rao, M. N.; Nyquist, L. E.; Ross, K.; Sutton, S. R.; Schwandt, C. S.</p> <p>2011-01-01</p> <p>Based on mass spectrometric studies of sulfur species in Shergotty and EET79001, [1] and [2] showed that sulfates and sulfides occur in different proportions in <span class="hlt">shergottites</span>. Sulfur speciation studies in gas-rich impact-melt (GRIM) glasses in EET79001 by the XANES method [3] showed that S K-XANES spectra in GRIM glasses from Lith A indicate that S is associated with Ca and Al presumably as sulfides/sulfates whereas the XANES spectra of amorphous sulfide globules in GRIM glasses from Lith B indicate that S is associated with Fe as FeS. In these amorphous iron sulfide globules, [4] found no Ni using FE-SEM and suggested that the globules resulting from immiscible sulfide melt may not be related to the igneous iron sulfides having approximately 1-3% Ni. Furthermore, in the amorphous iron sulfides from 507 GRIM glass, [5] determined delta(sup 34)S values ranging from +3.5%o to -3.1%o using Nano-SIMS. These values plot between the delta(sup 34)S value of +5.25%o determined in the sulfate fraction in Shergotty [6] at one extreme and the value of -1.7%o obtained for igneous sulfides in EET79001 and Shergotty [7] at the other. These results suggest that the amorphous Fe-S globules likely originated by shock reduction of secondary iron sulfate phases occurring in the regolith precursor materials during impact [7]. Sulfates in the regolith materials near the basaltic <span class="hlt">shergottite</span> sites on Mars owe their origin to surficial acid-sulfate interactions. We examine the nature of these reactions by studying the composition of the end products in altered regolith materials. For the parent material composition, we use that of the host <span class="hlt">shergottite</span> material in which the impact glasses are situated.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2002M%26PS...37..487B','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2002M%26PS...37..487B"><span>Petrology and chemistry of the basaltic <span class="hlt">shergottite</span> North West Africa 480</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Barrat, J. A.; Gillet, Ph.; Sautter, V.; Jambon, A.; Javoy, M.; Göpel, C.; Lesourd, M.; Keller, F.; Petit, E.</p> <p>2002-04-01</p> <p>North West Africa (NWA) 480 is a new martian meteorite of 28 g found in the Moroccan Sahara in November 2000. It consists mainly of large gray pyroxene crystals (the largest grains are up to 5 mm in length) and plagioclase converted to maskelynite. Excluding the melt pocket areas, modal analyses indicate the following mineral proportions: 72 vol% pyroxenes extensively zoned, 25% maskelynite, 1% phosphates (merrillite and chlorapatite), 1% opaque oxides (ilmenite, ulvospinel and chromite) and sulfides, and 1% others such as silica and fayalite. The compositional trend of NWA 480 pyroxenes is similar to that of Queen Alexandra Range (QUE) 94201 but in NWA 480 the pyroxene cores are more Mg-rich (En77-En65). Maskelynites display a limited zoning (An42-50Ab54-48Or2-4). Our observations suggest that NWA 480 formed from a melt with a low nuclei density at a slow cooling rate. The texture was achieved via a single-stage cooling where pyroxenes grew continuously. A similar model was previously proposed for QUE 94201 by McSween et al. (1996). NWA 480 is an Al-poor ferroan basaltic rock and resembles Zagami or Shergotty for major elements and compatible trace element abundances. The bulk rock analysis for oxygen isotopes yields V17O = +0.42%o, a value in agreement at the high margin, with those measured on other <span class="hlt">shergottites</span> (Clayton and Mayeda, 1996; Romanek et al., 1998; Franchi et al., 1999). Its CI-normalized rare earth element pattern is similar to those of peridotitic <span class="hlt">shergottites</span> such as Allan Hills (ALH)A77005, suggesting that these <span class="hlt">shergottites</span> shared a similar parent liquid, or at least the same mantle source.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017GeCoA.204....1U','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017GeCoA.204....1U"><span>Petrogenesis of the NWA 7320 enriched martian gabbroic <span class="hlt">shergottite</span>: Insight into the martian crust</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Udry, Arya; Howarth, Geoffrey H.; Lapen, Thomas J.; Righter, Minako</p> <p>2017-05-01</p> <p>Northwest Africa (NWA) 7320 is classified as a gabbroic <span class="hlt">shergottite</span>, the second to be recognized in the martian meteorite record. This interpretation is based on: (1) the calculated bulk-rock rare earth element (REE) concentrations, which show the highest Eu positive anomaly (Eu/Eu∗ = 2.2) of all the <span class="hlt">shergottites</span>, reflecting accumulation of plagioclase; and (2) the highest modal abundance of maskelynitized plagioclase (50 mod.%) compared to the other <span class="hlt">shergottites</span>. The three-phase symplectite (fayalite + hedenbergite + silica) is present in NWA 7320 and formed as a result of the breakdown of metastable pyroxene/pyroxenoid margins on coarse-grained pyroxenes. The latter is indicative of metastable overgrowths on pyroxene cores during the final stages of crystallization, followed by relatively slow cooling at subsolidus conditions. The NWA 7320 parental melt originated from an incompatible trace element enriched and oxidized (∼FMQ) source as indicated by Sm-Nd, Lu-Hf isotope systematics, ilmenite-titanomagnetite pairs, the partition coefficient of Cr in pyroxene, and merrillite REE compositions. The Ti/Al ratio of pyroxene in NWA 7320 indicates an initial crystallization depth of 30-70 km (P = 4-9 kbar). However, the largest impact craters on Mars are <8 km in depth, indicating that NWA 7320 could not have been ejected from this depth and must have had a polybaric formation history. We suggest that the pyroxene phenocrysts began to crystallize at depth, but were entrained as antecrysts in a basaltic magma ascending to shallower levels in the martian crust. In addition, plagioclase likely crystallized during magma ascent, followed by subsequent accumulation in a shallow magma intrusion or sill, resulting in the gabbroic texture. Furthermore, the similarity in the radiogenic isotope composition of NWA 7320 to that of Los Angeles and NWA 856 suggest that these meteorites were linked to common volcanic system on Mars.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017EGUGA..19.4894L','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017EGUGA..19.4894L"><span>Atypical geochemistry of the <span class="hlt">lherzolite</span> enclave in the Paleoarchean Bug Granulite complex - participation of the chondrite material?</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Lobach-Zhuchenko, Svetlana; Egorova, Yuliya</p> <p>2017-04-01</p> <p>An enclave of a small ( 30 * 300 sm) lens-like body [N56°30`, E13°50`] of spinel <span class="hlt">lherzolite</span> occurs in the Paleoarchean orthogneiss of the Bug complex of the Ukrainian Shield which experienced multistage metamorphism and deformation [Claesson et al., 2006; Lobach-Zhuchenko et al., 2016]. The spinel <span class="hlt">lherzolite</span> lens is mantled by a thin rim of a phlogopite websterite at the contact with the host orthogneiss. The spinel <span class="hlt">lherzolite</span> consists of Ol (Fo 85), Opx (#Mg 0.86), Cpx (#Mg 0.92), minor Phl (#Mg 0.92), Cr- Spl, Srp, Pn (Fe 4.3 Ni 4.6 S 8), Mel, Ccp, Crb, Mag, Ap. A mineral assemblage of the websterite is the same except for the minor or absence of Ol and more concentration of Phl. While the mineral composition of the <span class="hlt">lherzolite</span> is usial for the mantle ultramafic rocks its geochemistry is atypical (SiO2 - 41.04 wt%, TiO2 - 0.26, Al2O3 - 1.62, Fe2O3 - 3.88, FeO - 7.75, MnO - 0.18, MgO - 38.90, CaO - 0.61, Na2O - 0.09, K2O - 1.12, P2O5 - 0.02, LOI - 3.37, CO2 - 0.85, S - 0.08 wt%). The main distinctions of this rock include (1) low # Mg (0.86) relative to PM and mantle xenoliths [Pearson et al., 2003], (2) high abundance of Ni - average 3737 ppm versus 1960 ppm in PM [Palme & O`Neil, 2003] and as a consequence olivine enriched in Ni relative to its Mg-number [Mysen, 2006; Herzberg et al., 2016], (3) high Ni/Cr = 4.76 and Ni/Co = 21.56 versus PM with Ni/Cr = 0.74; Ni/Co = 18.20 [Palme & O`Neil, 2003] and as compared with other terrestrial ultramafics, for instance, relative to orogenic lehrzolite (Ni = 2024; Ni/Cr = 0.78; Ni/Co = 18.4) [Lorand et al., 2000]. It is known that such high ratios are typical for all types of chondrites, e.g., the ratios in C1, C2, C3, L, E chondrites are: Ni/Cr = 2.9-5.3, Ni/Co = 21-29 [Mason, 1971; Sobotovich, 1986]. Probably, the geochemistry of the studied <span class="hlt">lherzolite</span> inclusion assumes participation of the chondrite material in its formation during some impact event in the past.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/20080009608','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/20080009608"><span>Petrology and Mineral Chemistry of New Olivine-Phyric <span class="hlt">Shergottite</span> RBT04262</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Dalton, H. A.; Peslier, A. H.; Brandon, A. D.; Lee, C.-T. A.; Lapen, T. J.</p> <p>2008-01-01</p> <p>RBT04262 was found by the 2004-2005 ANSMET team at the Roberts Massif in Antarctica. It is paired with RBT04261 and is classified as an olivine-phyric <span class="hlt">shergottite</span>. RBT04261 is 4.0 x 3.5 x 2.5 cm and 78.8 g, and RBT04262 is 6.5 x 5.5 x 3.5 cm and 204.6 g. Both were partially covered by a fusion crust [1]. Chemical analysis and mapping of this meteorite was performed using the Cameca SX100 electron microprobe at NASA Johnson Space Center.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=20040062072&hterms=nD&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D40%26Ntt%3D%253FnD','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=20040062072&hterms=nD&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D40%26Ntt%3D%253FnD"><span>Sm-Nd Age and Initial Sr-87/Sr-86 for <span class="hlt">Yamato</span> 980318: An Old Cumulate Eucrite</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Nyquist, L. E.; Takeda, H.; Shih, C.-Y.; Wiesmann, H.</p> <p>2004-01-01</p> <p>The complex pyroxene exsolution texture of the Moore County cumulate eucrite was interpreted by Miyamoto and Takeda as indicating initial cooling at 160 C/Ma followed by a sudden temperature rise and final cooling at 0.35 C/yr. They suggested initial cooling at a depth of approx. 8 km near the base of Vesta s crust, followed by impact excavation to its surface. Young Sm-Nd ages of approx. 4456, 4460, and 4410 Ma, respectively, for the Moore County, Moama, and Serra de Mag cumulate eucrites are puzzling because closure to Nd isotopic exchange would occur in only a few Ma at the above initial cooling rate. The exception to young ages among the cumulate eucrites is EET87520, with a 147Sm-147 - Nd-143 age of 4547-4598 Ma. We report here initial results of a combined mineralogical/chronological study of the <span class="hlt">Yamato</span> 980318 feldspar-cumulate eucrite.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=19920060800&hterms=drilling&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D50%26Ntt%3Ddrilling','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=19920060800&hterms=drilling&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D50%26Ntt%3Ddrilling"><span>Petrology of basaltic sills from ocean drilling program sites 794 and 797 in the <span class="hlt">Yamato</span> Basin of the Japan Sea</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Thy, P.</p> <p>1992-01-01</p> <p>The basaltic sills from ocean drilling program sites 794 and 797 in the <span class="hlt">Yamato</span> Basin of the Japan Sea are characterized petrographically on the basis of a detailed study of the composition of relict phenocryst and groundmass phases. The systematic variation in the rock compositions is discussed. Results of 1-atm melting experiments on a relatively primitive basalt from site 797 are reported. The sills are found to constitute two distinct groups of suites: primitive, olivine-bearing suites with low potassium and primitive olivine-bearing to evolved, olivine-free suites with relatively high potassium. A pseudoinvariant reaction relationship between olivine and augite and magnetite is inferred. Complex magmatic and tectonic evolutions in the region, perhaps reflecting a transitional stage between subduction zone activity and back arc spreading, are suggested.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2012JGRB..117.6206T','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2012JGRB..117.6206T"><span>A melting model for variably depleted and enriched <span class="hlt">lherzolite</span> in the plagioclase and spinel stability fields</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Till, Christy B.; Grove, Timothy L.; Krawczynski, Michael J.</p> <p>2012-06-01</p> <p>Here we develop a <span class="hlt">lherzolite</span> melting model and explore the effects of variations in mantle composition, pressure, temperature, and H2O content on melt composition. New experiments and a compilation of experimental liquids saturated with all of the mantle minerals (olivine, orthopyroxene, clinopyroxene, plagioclase and/or spinel) are used to calibrate a model that predicts the temperature and major element composition of a broad spectrum of primary basalt types produced under anhydrous to low H2O-content conditions at upper mantle pressures. The model can also be used to calculate the temperature and pressure at which primary magmas were produced in the mantle, as well as to model both near-fractional adiabatic decompression and batch melting. Our experimental compilation locates the pressure interval of the plagioclase to spinel transition on the solidus and shows that it is narrow (˜0.1 GPa) for melting of natural peridotite compositions. The multiple saturation boundaries determined by our model provide a method for assessing the appropriate mineral assemblage, as well as the extent of the fractional crystallization correction required to return a relatively primitive liquid to equilibrium with the mantle source. We demonstrate that an inaccurate fractionation correction can overestimate temperature and depths of melting by hundreds of degrees and tens of kilometers, respectively. This model is particularly well suited to examining the temperature and pressure of origin for intraplate basaltic volcanism and is used to examine the petrogenesis of a suite of Holocene basaltic lavas from Diamond Crater in Oregon's High Lava Plains (HLP).</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=19860063602&hterms=thermoluminescence&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D30%26Ntt%3Dthermoluminescence','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=19860063602&hterms=thermoluminescence&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D30%26Ntt%3Dthermoluminescence"><span>Thermoluminescence and the shock and reheating history of meteorites. III - The <span class="hlt">shergottites</span></span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Hasan, F. A.; Haq, M.; Sears, D. W. G.</p> <p>1986-01-01</p> <p>Thermoluminescence (TL) measurements on Shergotty, ALHA 77005, Zagami, and EETA 79001 (lithology A) have been used to obtain further information on the shock history of these meteorites. The level of TL sensitivity in the <span class="hlt">shergottites</span> varied by a factor of 10, but was always low, probably reflecting the amount of crystalline material in the maskelynite. There are trends in the TL peak temperature, peak width, and TL sensitivity which are believed to be associated with different proportions of feldspar in high- and low-temperature forms. This interpretation is consistent with the observed changes induced in the TL properties by annealing <span class="hlt">shergottites</span> at 400-900 C. It is suggested that the observed trends were produced during postshock crystallization at a variety of cooling rates, the increasing order of cooling rate being EETA 79001, Zagami, ALHA 77005, and Shergotty, and that there is high-temperature feldspar present in all the samples. This implies a postshock temperature above 600 C, and a small (less than 10 m) size of the ejecta. Current theories are well able to explain how objects of this size could have been ejected from Mars.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=19870046806&hterms=single+parent&qs=N%3D0%26Ntk%3DAll%26Ntx%3Dmode%2Bmatchall%26Ntt%3Dsingle%2Bparent','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=19870046806&hterms=single+parent&qs=N%3D0%26Ntk%3DAll%26Ntx%3Dmode%2Bmatchall%26Ntt%3Dsingle%2Bparent"><span>Core formation in the <span class="hlt">shergottite</span> parent body and comparison with the earth</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Treiman, Allan H.; Jones, John H.; Drake, Michael J.</p> <p>1987-01-01</p> <p>Abundances of elements in <span class="hlt">shergottite</span>, nakhlite, and Chassigny meteorites which originated on a single planet, the <span class="hlt">shergottite</span> parent body (SPB), were examined with the aim of elucidating the chemical conditions of metal separation and core formation in the SPB and of testing present models of planetary core formation. Using partition coefficients and the SPB mantle composition determined in earlier studies, the abundances of Ag, Au, Co, Ga, Mo, Ni, P, Re, S, and W were modeled, with free parameters being oxygen fugacity, proportion of solid metal formed, proportion of metallic liquid formed, and proportion of silicate that is molten. It is shown that the abundances of all elements (except Mo) could be reproduced using models with these four free parameters. In contrast to the SPB, an equivalent model used to predict element abundances in the earth's mantle was shown by Jones and Drake (1986) to be inadequate; there is at present no hypothesis capable of quantitatively reproducing the elemental abundances of the earth's mantle. The contrast suggests that these two terrestrial planets (assuming that the SPB is Mars) may have accreted or differentiated differently.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=19860063603&hterms=Elephants&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D50%26Ntt%3DElephants','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=19860063603&hterms=Elephants&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D50%26Ntt%3DElephants"><span>Nuclear tracks, Sm isotopes and neutron capture effects in the Elephant Morraine <span class="hlt">shergottite</span></span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Rajan, R. S.; Lugmair, G.; Tamhane, A. S.; Poupeau, G.</p> <p>1986-01-01</p> <p>Nuclear track studies, uranium concentration measurements and Sm-isotope studies have been performed on both lithologies A and B of the Elephant Morraine <span class="hlt">shergottite</span>, EETA 79001. Track studies show that EETA 79001 was a rather small object in space with a preatmospheric radius of 12 + or - 2 cm, corresponding to a preatmospheric mass of 28 + or - 13 kg. Phosphates have U concentrations ranging from 0.3 to 1.3 ppm. There are occasional phosphates with excess fission tracks, possibly produced from neutron-induced fission of U and Th, during the regolith exposure in the <span class="hlt">shergottite</span> parent body (SPB). Sm-isotope studies, while not showing any clear-cut excess in Sm-150, make it possible to derive meaningful upper limits to thermal neutron fluences of 2 to 3 x 10 to the 15th n/sq cm, during a possible regolith irradiation. These limits are consistent with the track data and also make it possible to derive an upper limit to the neutron exposure age of EETA 79001 of 55 Myr in the SPB regolith.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=19860063602&hterms=history+theory&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D20%26Ntt%3Dhistory%2Btheory','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=19860063602&hterms=history+theory&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D20%26Ntt%3Dhistory%2Btheory"><span>Thermoluminescence and the shock and reheating history of meteorites. III - The <span class="hlt">shergottites</span></span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Hasan, F. A.; Haq, M.; Sears, D. W. G.</p> <p>1986-01-01</p> <p>Thermoluminescence (TL) measurements on Shergotty, ALHA 77005, Zagami, and EETA 79001 (lithology A) have been used to obtain further information on the shock history of these meteorites. The level of TL sensitivity in the <span class="hlt">shergottites</span> varied by a factor of 10, but was always low, probably reflecting the amount of crystalline material in the maskelynite. There are trends in the TL peak temperature, peak width, and TL sensitivity which are believed to be associated with different proportions of feldspar in high- and low-temperature forms. This interpretation is consistent with the observed changes induced in the TL properties by annealing <span class="hlt">shergottites</span> at 400-900 C. It is suggested that the observed trends were produced during postshock crystallization at a variety of cooling rates, the increasing order of cooling rate being EETA 79001, Zagami, ALHA 77005, and Shergotty, and that there is high-temperature feldspar present in all the samples. This implies a postshock temperature above 600 C, and a small (less than 10 m) size of the ejecta. Current theories are well able to explain how objects of this size could have been ejected from Mars.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/20150002923','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/20150002923"><span>Formation and Preservation of the Depleted and Enriched <span class="hlt">Shergottite</span> Isotopic Reservoirs in a Convecting Martian Mantle</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Kiefer, Walter S.; Jones, John H.</p> <p>2015-01-01</p> <p>There is compelling isotopic and crater density evidence for geologically recent volcanism on Mars, in the last 100-200 million years and possibly in the last 50 million years. This volcanism is due to adiabatic decompression melting and thus requires some type of present-day convective upwelling in the martian mantle. On the other hand, martian meteorites preserve evidence for at least 3 distinct radiogenic isotopic reservoirs. Anomalies in short-lived isotopic systems (Sm-146, Nd-142, Hf-182, W-182) require that these reservoirs must have developed in the first 50 to 100 million years of Solar System history. The long-term preservation of chemically distinct reservoirs has sometimes been interpreted as evidence for the absence of mantle convection and convective mixing on Mars for most of martian history, a conclusion which is at odds with the evidence for young volcanism. This apparent paradox can be resolved by recognizing that a variety of processes, including both inefficient mantle mixing and geographic separation of isotopic reservoirs, may preserve isotopic heterogeneity on Mars in an actively convecting mantle. Here, we focus on the formation and preservation of the depleted and enriched isotopic and trace element reservoirs in the <span class="hlt">shergottites</span>. In particular, we explore the possible roles of processes such as chemical diffusion and metasomatism in dikes and magma chambers for creating the isotopically enriched <span class="hlt">shergottites</span>. We also consider processes that may preserve the enriched reservoir against convective mixing for most of martian history.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/1996LPI....27..425G','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/1996LPI....27..425G"><span>The Role of Garnet in Martian Mantle Evolution: Further Evidence from <span class="hlt">Shergottite</span> Rare Earth Patterns</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Gleason, J. D.; Kring, D. A.; Boynton, W. V.</p> <p>1996-03-01</p> <p>REE fractionation and isotopic decoupling effects in SNC meteorites have been attributed in the past to the presence of garnet in their mantle source regions. Quantifying the garnet effect is now possible using the parent melt REE compositions determined by for the <span class="hlt">shergottites</span>, a group of SNC meteorites characterized by complex rare earth element (REE) patterns and 180 Ma isotopic ages. Below, we develop a multi-stage REE evolution model for a <span class="hlt">shergottite</span> source which underwent fractional fusion at earlier stages with garnet present. Similar processes may account for (1) the decoupling of the Sm-Nd isotopic system from the Rb-Sr and U-Th-Pb isotopic systems in SNC meteorites, and (2) non-chondritic abundance ratios for certain refractory lithophile elements (e.g., high Th/La, U/La, and low Al/Ti) in SNC's. If this model is generally correct, it then requires a planet large enough to have crystallized substantial garnet in its mantle source regions, consistent with a martian origin for the SNC's.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/1986GeCoA..50.1039R','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/1986GeCoA..50.1039R"><span>Nuclear tracks, SM isotopes and neutron capture effects in the Elephant Morraine <span class="hlt">shergottite</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Rajan, R. S.; Lugmair, G.; Tamhane, A. S.; Poupeau, G.</p> <p>1986-06-01</p> <p>Nuclear track studies, uranium concentration measurements and Sm-isotope studies have been performed on both lithologies A and B of the Elephant Morraine <span class="hlt">shergottite</span>, EETA 79001. Track studies show that EETA 79001 was a rather small object in space with a preatmospheric radius of 12 + or - 2 cm, corresponding to a preatmospheric mass of 28 + or - 13 kg. Phosphates have U concentrations ranging from 0.3 to 1.3 ppm. There are occasional phosphates with excess fission tracks, possibly produced from neutron-induced fission of U and Th, during the regolith exposure in the <span class="hlt">shergottite</span> parent body (SPB). Sm-isotope studies, while not showing any clear-cut excess in Sm-150, make it possible to derive meaningful upper limits to thermal neutron fluences of 2 to 3 x 10 to the 15th n/sq cm, during a possible regolith irradiation. These limits are consistent with the track data and also make it possible to derive an upper limit to the neutron exposure age of EETA 79001 of 55 Myr in the SPB regolith.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=19860063603&hterms=elephant+evolution&qs=N%3D0%26Ntk%3DAll%26Ntx%3Dmode%2Bmatchall%26Ntt%3Delephant%2Bevolution','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=19860063603&hterms=elephant+evolution&qs=N%3D0%26Ntk%3DAll%26Ntx%3Dmode%2Bmatchall%26Ntt%3Delephant%2Bevolution"><span>Nuclear tracks, Sm isotopes and neutron capture effects in the Elephant Morraine <span class="hlt">shergottite</span></span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Rajan, R. S.; Lugmair, G.; Tamhane, A. S.; Poupeau, G.</p> <p>1986-01-01</p> <p>Nuclear track studies, uranium concentration measurements and Sm-isotope studies have been performed on both lithologies A and B of the Elephant Morraine <span class="hlt">shergottite</span>, EETA 79001. Track studies show that EETA 79001 was a rather small object in space with a preatmospheric radius of 12 + or - 2 cm, corresponding to a preatmospheric mass of 28 + or - 13 kg. Phosphates have U concentrations ranging from 0.3 to 1.3 ppm. There are occasional phosphates with excess fission tracks, possibly produced from neutron-induced fission of U and Th, during the regolith exposure in the <span class="hlt">shergottite</span> parent body (SPB). Sm-isotope studies, while not showing any clear-cut excess in Sm-150, make it possible to derive meaningful upper limits to thermal neutron fluences of 2 to 3 x 10 to the 15th n/sq cm, during a possible regolith irradiation. These limits are consistent with the track data and also make it possible to derive an upper limit to the neutron exposure age of EETA 79001 of 55 Myr in the SPB regolith.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=19840065510&hterms=noble+gases&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D80%26Ntt%3Dnoble%2Bgases','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=19840065510&hterms=noble+gases&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D80%26Ntt%3Dnoble%2Bgases"><span>The case for a Martian origin of the <span class="hlt">shergottites</span> - Nitrogen and noble gases in EETA 79001</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Becker, R. H.; Pepin, R. O.</p> <p>1984-01-01</p> <p>Nitrogen and noble gases have been measured in samples of a glass inclusion and its surrounding basaltic matrix in an Antarctic <span class="hlt">shergottite</span> meteorite (EETA 79001). The nitrogen component was found trapped in the glass, but not the matrix, having a value of delta 15-N = +190 per mil. Ratios between abundances of Ar-40 and N-14, N-15 and N-14 in the glass are consistent with the dilution of a Martian atmospheric component. The trapped noble gases in the glass are similar to elemental and isotopic compositions measured in Mars atmosphere by the Viking lander, and are in general agreement with previous measurements. It is suggested that a sample of Martian atmosphere has been caught in the EETA 79001 glass, and that other <span class="hlt">shergottite</span>, nakhilite, and chassignite meteorites with similar features probably also originated on Mars. A table is presented which lists the abundances of nitrogen and the noble gases found in the non-glassy matrix and in the EETA 79001 glass.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/servlets/purl/803430','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/servlets/purl/803430"><span>Exposure History of <span class="hlt">Shergottites</span> Dar Al Gani 476/489/670/735 and Sayh Al Uhaymir 005</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Nishiizumi, N.; Caffee, M.; Jull, A.J.T.; Klandrud, S.E.</p> <p>2001-04-01</p> <p>Four basaltic <span class="hlt">shergottites</span>, Dar al Gani (DaG) 476, 489, 670, and 735 were found in the Libyan Sahara [1-3]; two basaltic <span class="hlt">shergottites</span>, Sayh al Uhaymir (SaU) 005 and 008 were found in Oman [4]. Recently SaU 051 was also recognized as a possible pair of SaU 005/008. Although the collection sites were different, the texture, bulk chemical compositions, and noble gas compositions of these <span class="hlt">shergottites</span> are similar [e.g. 4]. However, cosmic-ray-produced noble gases alone cannot unambiguously constrain the irradiation history for these objects. From a combination of cosmogenic stable- and radionuclides, exposure histories, and ejection conditions from the hypothesized Martian parent body, and genetic relationships between the Martian meteorites can be determined. In addition to those nuclides produced by galactic cosmic rays (GCR) are those produced by solar cosmic rays (SCR). Radionuclides produced by SCRs reside in the uppermost few centimeters of extraterrestrial bodies and their presence in meteorites indicates the degree to which a meteorite has been ablated. Previous work shows ablation is less than 1-2 cm in at least three <span class="hlt">shergottites</span>, ALH 77005, Shergotty, and EETA79001 [e.g. 5] and so it is possible some SCR signal may be observed in these meteorites. This suggests that the atmospheric entry velocity and/or entry angle of these <span class="hlt">shergottites</span> is much lower than the velocity and/or entry angle of most ordinary chondrites. We report here preliminary results of cosmogenic nuclides, {sup 14}C (half-life = 5,730 yr), {sup 36}Cl (3.01 x 10{sup 5} yr), {sup 26}Al (7.05 x 10{sup 5} yr), and {sup 10}Be(1.5 x 10{sup 6} yr).</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.osti.gov/scitech/biblio/6322645','SCIGOV-STC'); return false;" href="https://www.osti.gov/scitech/biblio/6322645"><span>Magmatic/metasomatic amphibole in the mantle: evidence from the Balmuccia <span class="hlt">lherzolite</span> massif, Ivrea zone, western Italian Alps</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Shervais, J.W.</p> <p>1985-01-01</p> <p>Amphibole and mica are the most important alkali-rich phases stable under mantle P-T conditions, and constitute the primary source of the alkalis needed to form basaltic magmas. Yet, the origin and distribution of these phases in the upper mantle is poorly understood. The Balmuccia <span class="hlt">lherzolite</span> massif is a small slice of subcontinental mantle in the western Alps that intruded granulite facies lower crust 250 m.y. ago, and was exposed during the Alpine orogeny. Amphibole (HB) ranging in composition from Ti-pargasite to kaersutite in a minor but widespread accessory phase in the <span class="hlt">lherzolite</span>, in websterite and bronzite dikes of the Cr-Di suite, and in pyroxenite and gabbro dikes of the Al-Aug suite. Textural and compositional relations show that HB in the Cr-Di and Al-Aug suite dikes formed by crystallization of residual magma, or by reaction between this magma and earlier formed phases (primarily spinel). Hb also occurs in thin (1-2 cm) veins of hornblendite and pyroxene hornblendite, and in the HB-enriched wallrock adjacent to these veins. Similar Hb veins in the Lherz massif have been shown to form from an alkali and water-enriched residual magma derived by filter pressing of Al-Aug pyroxenites. This origin is not possible at Balmuccia because the Hb veins have higher Ti, Cr, K/Na and Mgnumbers than any accessory Hb in Al-Aug suite dikes. Fractionation trends in the veins are controlled by HB. This requires that the HB veins formed from a separate and distinct parent magma that metasomatically enriched the <span class="hlt">lherzolite</span> on a local scale. However, remelting of the widespread pyroxenite dikes may constitute a more important source of alkalis than the rare HB-rich veins.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016GeCoA.185...64G','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016GeCoA.185...64G"><span>The behavior of Fe3+/∑Fe during partial melting of spinel <span class="hlt">lherzolite</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Gaetani, Glenn A.</p> <p>2016-07-01</p> <p>This study presents an internally consistent model for the behavior of Fe3+/∑Fe during partial melting of spinel <span class="hlt">lherzolite</span>. The Fe3+/∑Fe ratio for olivine is calculated on the basis of point defect thermodynamics, and the oxidation states of iron in the other solid phases are calculated using Fe3+/Fe2+ distribution between olivine and orthopyroxene, clinopyroxene, or spinel. Conservation of mass is used to relate the Fe3+/Fe2+ ratio of partial melt to the concentrations of Fe3+ and Fe2+ in the initial and residual solids as a function of pressure, temperature, and oxygen fugacity. Results from isobaric batch melting calculations demonstrate that the Fe3+/∑Fe ratio of the partial melt decreases with increasing melt fraction. Conversely, the Fe3+/∑Fe ratio of the partial melt increases with increasing melt fraction during decompression batch melting. The relative oxygen fugacity of the upper mantle depends on both the oxidation state of iron and mantle potential temperature. Results from incremental decompression melting calculations in which 1% melt is produced for each 100 MPa of decompression and then removed from the residual solid indicate that relative oxygen fugacity calculated from the oxidation state of iron in basaltic glass does not represent a unique value for the oceanic upper mantle but, rather, reflects conditions in the lower portion of the melting regime. A 100 °C change in mantle potential temperature produces a change in relative oxygen fugacity of ∼0.8 log units, similar to the global range inferred from mid-ocean ridge basalt glasses. It is necessary, therefore, to compare relative oxygen fugacity calculated from basaltic glass with proxies for potential temperature before drawing conclusions on heterogeneity of the oxidation state of iron in the oceanic upper mantle. Results from model calculations also suggest that the sub-arc mantle is intrinsically more oxidizing than the oceanic mantle because it is cooler. The global correlation</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_7");'>7</a></li> <li><a href="#" onclick='return showDiv("page_8");'>8</a></li> <li class="active"><span>9</span></li> <li><a href="#" onclick='return showDiv("page_10");'>10</a></li> <li><a href="#" onclick='return showDiv("page_11");'>11</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_9 --> <div id="page_10" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_8");'>8</a></li> <li><a href="#" onclick='return showDiv("page_9");'>9</a></li> <li class="active"><span>10</span></li> <li><a href="#" onclick='return showDiv("page_11");'>11</a></li> <li><a href="#" onclick='return showDiv("page_12");'>12</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="181"> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2000E%26PSL.178..269L','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2000E%26PSL.178..269L"><span>Generation of Hawaiian post-erosional lavas by melting of a mixed <span class="hlt">lherzolite</span>/pyroxenite source</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Lassiter, J. C.; Hauri, E. H.; Reiners, P. W.; Garcia, M. O.</p> <p>2000-05-01</p> <p>Melting of mafic veins in a marble-cake mantle may play an important role in generating isotopic and chemical heterogeneities in mid-ocean ridge and ocean island basalts. Mafic veins have lower solidi than mantle peridotite and will be preferentially sampled during partial melting, particularly at low melt fractions. However, the abundance of mafic components in the mantle or their role during melt generation has been difficult to quantify because most isotopic systems (e.g. Rb-Sr, Sm-Nd, U-Th-Pb) are not diagnostic of the presence or absence of mafic components. The compatible behavior of Os during mantle melting combined with the incompatible behavior of Re makes the Re-Os isotopic system uniquely well suited for distinguishing mafic and ultramafic contributions to melt generation. Almost all peridotites have low 187Os/ 188Os (e.g. chondritic to subchondritic). In contrast, mafic rocks have much higher Re/Os than peridotites, which results in the rapid ingrowth of 187Os and the development of large isotopic contrasts between mafic and ultramafic components within the mantle. In this paper, we show that Os-isotopes in Hawaiian post-erosional lavas extend to more radiogenic values than are found in Hawaiian <span class="hlt">lherzolites</span>, abyssal peridotites or most other ultramafic samples. Os-isotopes are not correlated with other isotopic tracers, in contrast with plume-derived Hawaiian shield-stage lavas. The lack of correlation between Os-isotopes and Sr-, Nd- or Pb-isotopes and the more 'depleted' or MORB-like Sr-Nd isotopic signature of the post-erosional lavas relative to other Hawaiian lavas precludes significant melt input from the Hawaiian plume. However, Os-isotopes are correlated with major and trace elements. Lavas with more radiogenic Os-isotope compositions have higher silica and alumina and lower calcium and incompatible trace element abundances than lavas with less radiogenic Os-isotopes. These correlations result from mixing of pyroxenite- and peridotite</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017GeCoA.207..277C','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017GeCoA.207..277C"><span>Crystallization history of enriched <span class="hlt">shergottites</span> from Fe and Mg isotope fractionation in olivine megacrysts</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Collinet, Max; Charlier, Bernard; Namur, Olivier; Oeser, Martin; Médard, Etienne; Weyer, Stefan</p> <p>2017-06-01</p> <p>Martian meteorites are the only samples available from the surface of Mars. Among them, olivine-phyric <span class="hlt">shergottites</span> are basalts containing large zoned olivine crystals with highly magnesian cores (Fo 70-85) and rims richer in Fe (Fo 45-60). The Northwest Africa 1068 meteorite is one of the most primitive ;enriched; <span class="hlt">shergottites</span> (high initial 87Sr/86Sr and low initial ε143Nd). It contains olivine crystals as magnesian as Fo 77 and is a major source of information to constrain the composition of the parental melt, the composition and depth of the mantle source, and the cooling and crystallization history of one of the younger magmatic events on Mars (∼180 Ma). In this study, Fe-Mg isotope profiles analyzed in situ by femtosecond-laser ablation MC-ICP-MS are combined with compositional profiles of major and trace elements in olivine megacrysts. The cores of olivine megacrysts are enriched in light Fe isotopes (δ56FeIRMM-14 = -0.6 to -0.9‰) and heavy Mg isotopes (δ26MgDSM-3 = 0-0.2‰) relative to megacryst rims and to the bulk martian isotopic composition (δ56Fe = 0 ± 0.05‰, δ26Mg = -0.27 ± 0.04‰). The flat forsterite profiles of megacryst cores associated with anti-correlated fractionation of Fe-Mg isotopes indicate that these elements have been rehomogenized by diffusion at high temperature. We present a 1-D model of simultaneous diffusion and crystal growth that reproduces the observed element and isotope profiles. The simulation results suggest that the cooling rate during megacryst core crystallization was slow (43 ± 21 °C/year), and consistent with pooling in a deep crustal magma chamber. The megacryst rims then crystallized 1-2 orders of magnitude faster during magma transport toward the shallower site of final emplacement. Megacryst cores had a forsterite content 3.2 ± 1.5 mol% higher than their current composition and some were in equilibrium with the whole-rock composition of NWA 1068 (Fo 80 ± 1.5). NWA 1068 composition is thus close to a</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/20140000409','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/20140000409"><span>Ar-Ar and Rb-Sr Ages of the Tissint Olivine-phyric Martian <span class="hlt">Shergottite</span></span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Park, J.; Herzog, G. F.; Nyquist, L. E.; Shih, C.-Y.; Turin, B.; Lindsay, F. N.; Delaney, J. S.; Swisher, C. C., III; Agee, C.</p> <p>2013-01-01</p> <p>The fifth martian meteorite fall, Tissint, is an olivine-phyric <span class="hlt">shergottite</span> that contains olivine macrocrysts (approximately 1.5 mm) [1]. [2] reported the Sm-Nd age of Tissint as 596 plus or minus 23 Ma along with Rb-Sr data that defined no isochron. [3] reported Lu-Hf and Sm-Nd ages of 583 plus or minus 86 Ma and 616 plus or minus 67 Ma, respectively. The cosmic-ray exposure ages of Tissint are 1.10 plus or minus 0.15 Ma based on 10Be [4], and 1.0-1.1 Ma, based on 3He, 21Ne, and 38Ar [5,6].We report Ar-Ar ages and Rb-Sr data.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/20395507','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/20395507"><span>A younger age for ALH84001 and its geochemical link to <span class="hlt">shergottite</span> sources in Mars.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Lapen, T J; Righter, M; Brandon, A D; Debaille, V; Beard, B L; Shafer, J T; Peslier, A H</p> <p>2010-04-16</p> <p>Martian meteorite ALH84001 (ALH) is the oldest known igneous rock from Mars and has been used to constrain its early history. Lutetium-hafnium (Lu-Hf) isotope data for ALH indicate an igneous age of 4.091 +/- 0.030 billion years, nearly coeval with an interval of heavy bombardment and cessation of the martian core dynamo and magnetic field. The calculated Lu/Hf and Sm/Nd (samarium/neodymium) ratios of the ALH parental magma source indicate that it must have undergone extensive igneous processing associated with the crystallization of a deep magma ocean. This same mantle source region also produced the <span class="hlt">shergottite</span> magmas (dated 150 to 570 million years ago), possibly indicating uniform igneous processes in Mars for nearly 4 billion years.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2013EGUGA..15.5855B','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2013EGUGA..15.5855B"><span>Low temperature fertile spinel <span class="hlt">lherzolites</span> from Sikhote-Alin, Far East Russia</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Bluemel, Andrea; Ntaflos, Theo; Ashchepkov, Igor; Prikhodko, Vladimir; Gregoire, Michél</p> <p>2013-04-01</p> <p>The Pacific margin of East and NE Asia is part of the circum-Pacific orogenic system and could be considered as a tectonic collage of nappes, displaced terrenes, accreted island arcs and accretionary complexes. This tectonic environment is the consequence of the convergence between the Palaeo-Pacific plate and the eastern Eurasian continent. It could be divided into three main units; the Koryak-Kamachatka fold belt, the Sikhote-Alin fold belt and the Okhotsk volcanic belt. The broadly defined Sikhote-Alin fold belt here refers to a nearly N-S belt extending north from the southern shoreline of the Okhotsk Sea south to the northern margin of the Japan Sea. The Mantle xenoliths come from Tuttochi, a locality close to Khabarovsk, Sikhote-Alin. The xenoliths are spinel peridotites, their sizes vary from 3 to 8 cm in diameter and they are exceptional fresh. The majority of the samples are coarse grained with protogranular texture. However a number of xenoliths have transitional textures from relatively coarse grained protogranular to fine grained equigranular textures. Hydrous phases such as phlogopite and/or amphibole were not found so far. The most striking feature is the fact that part of the xenoliths show heavy infiltration of melts. These melts circulate intergranular and react with the neighbor minerals creating veinlets with variable thickness that consists of glass and new forming minerals. Especially, their interaction with orthopyroxene results often to its almost entirely consumption, indicating that the invaded melt was silica undersaturated but rich in alkalies. According to their modal composition the xenoliths are fertile spinel <span class="hlt">lherzolites</span> as also can be inferred from the compositions of the constituent minerals. Olivine is forsteritic with Fo varying from 89.3 to 90.1 and the average NiO content is 0.37 wt%. The mg# of orthopyroxene and clinopyroxene vary from 0.895-0.904 and 0.904-0.915, respectively and the spinel is Al2O3-rich with an average of cr</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/20140012799','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/20140012799"><span>Preliminary Report on U-Th-Pb Isotope Systematics of the Olivine-Phyric <span class="hlt">Shergottite</span> Tissint</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Moriwaki, R.; Usui, T.; Yokoyama, T.; Simon, J. I.; Jones, J. H.</p> <p>2014-01-01</p> <p>Geochemical studies of <span class="hlt">shergottites</span> suggest that their parental magmas reflect mixtures between at least two distinct geochemical source reservoirs, producing correlations between radiogenic isotope compositions, and trace element abundances.. These correlations have been interpreted as indicating the presence of a reduced, incompatible-element- depleted reservoir and an oxidized, incompatible-element-rich reservoir. The former is clearly a depleted mantle source, but there has been a long debate regarding the origin of the enriched reservoir. Two contrasting models have been proposed regarding the location and mixing process of the two geochemical source reservoirs: (1) assimilation of oxidized crust by mantle derived, reduced magmas, or (2) mixing of two distinct mantle reservoirs during melting. The former clearly requires the ancient martian crust to be the enriched source (crustal assimilation), whereas the latter requires a long-lived enriched mantle domain that probably originated from residual melts formed during solidification of a magma ocean (heterogeneous mantle model). This study conducts Pb isotope and U-Th-Pb concentration analyses of the olivine-phyric <span class="hlt">shergottite</span> Tissint because U-Th-Pb isotope systematics have been intensively used as a powerful radiogenic tracer to characterize old crust/sediment components in mantle- derived, terrestrial oceanic island basalts. The U-Th-Pb analyses are applied to sequential acid leaching fractions obtained from Tissint whole-rock powder in order to search for Pb isotopic source components in Tissint magma. Here we report preliminary results of the U-Th-Pb analyses of acid leachates and a residue, and propose the possibility that Tissint would have experienced minor assimilation of old martian crust.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=19940016361&hterms=leached&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D20%26Ntt%3Dleached','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=19940016361&hterms=leached&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D20%26Ntt%3Dleached"><span>The U-Th-Pb, Sm-Nd, and Ar-Ar isotopic systematics of lunar meteorite <span class="hlt">Yamato</span>-793169</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Torigoye, Noriko; Misawa, Keji; Dalrymple, G. Brent; Tatsumoto, Mitsunobu</p> <p>1993-01-01</p> <p>U-Th-Pb, Sm-Nd, and (Ar-40)-(Ar-39) isotopic studies were performed on <span class="hlt">Yamato</span> (Y)-793169, an unbrecciated diabasic lunar meteorite whose chemical composition is close to low Ti(LT) and very low-Ti (VLT) mare basalts. The isotopic data indicate that the meteorite was formed earlier than 3.9 Ga from a source with low U/Pb and high Sm/Nd and was distributed by a thermal event at 751 Ma. due to the small sample size (104 mg), a plagioclase crystal and glass grains were handpicked for Ar analysis, leaving four fractions for the U-Th-Pb and Sm-Nd studies; a fine-grained fraction (less than 63 microns; Fine) and three medium-grained fractions (63-150 microns). Medium-grained fractions were divided by density; a heavy fraction (rho greater than 3.3) consisting mainly of pyroxene (PX1), a lighter fraction (rho less than 2.8) consisting of plagioclase (PL), and a middle density fraction (predominantly pyroxene; PX2). The fractions were washed with acetone and alcohol, and then leached in 0.01 HBr and 0.1N HBr in order to remove any terrestrial Pb contamination. Analysis of the HBr leaches revealed that this meteorite was heavily contaminated with terrestrial Pb during its residence in Antarctic ice.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/1984LPSC...14..612S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/1984LPSC...14..612S"><span>Petrogenesis of the SNC (<span class="hlt">shergottites</span>, nakhlites, chassignites) meteorites - Implications for their origin from a large dynamic planet, possibly Mars</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Smith, M. R.; Laul, J. C.; Ma, M.-S.; Huston, T.; Verkouteren, R. M.; Lipschutz, M. E.; Schmitt, R. A.</p> <p>1984-02-01</p> <p>Comprehensive chemical data are presented on the <span class="hlt">shergottites</span> Shergotty, Zagami, Allan Hills (ALHA) 77005, and the new member Elephant Moraine (EETA) 79001 using results of sequential instrumental and radiochemical neutron activation analysis. The close relationship of the Antarctic shergotites indicates that ALHA 77005 is a residual source produced by incongruent melting of a source similar in bulk composition to EETA 79001A and that EETA 79001B and the interstitial phases in EETA 79001A are the melts produced by such melting episodes. The large ion lithophile LIL) trace element abundanced of the <span class="hlt">shergottites</span> require variable but extensive degrees of nomodal melting of isotopically constrained parent sources. The SNG sources are consistent with their derivation by extensive fractionation of a primitive magma initially produced from a source having chondritic refractory LIL trace element abundances. Petrogenetic and age relationships among SNC meteorites suggest a single complex-provenance on a dynamic planet not unlike earth, probably Mars.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=19840043311&hterms=elephant+evolution&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D30%26Ntt%3Delephant%2Bevolution','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=19840043311&hterms=elephant+evolution&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D30%26Ntt%3Delephant%2Bevolution"><span>Petrogenesis of the SNC (<span class="hlt">shergottites</span>, nakhlites, chassignites) meteorites - Implications for their origin from a large dynamic planet, possibly Mars</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Smith, M. R.; Laul, J. C.; Ma, M. S.; Huston, T.; Verkouteren, R. M.; Lipschutz, M. E.; Schmitt, R. A.</p> <p>1984-01-01</p> <p>Comprehensive chemical data are presented on the <span class="hlt">shergottites</span> Shergotty, Zagami, Allan Hills (ALHA) 77005, and the new member Elephant Moraine (EETA) 79001 using results of sequential instrumental and radiochemical neutron activation analysis. The close relationship of the Antarctic shergotites indicates that ALHA 77005 is a residual source produced by incongruent melting of a source similar in bulk composition to EETA 79001A and that EETA 79001B and the interstitial phases in EETA 79001A are the melts produced by such melting episodes. The large ion lithophile LIL) trace element abundanced of the <span class="hlt">shergottites</span> require variable but extensive degrees of nomodal melting of isotopically constrained parent sources. The SNG sources are consistent with their derivation by extensive fractionation of a primitive magma initially produced from a source having chondritic refractory LIL trace element abundances. Petrogenetic and age relationships among SNC meteorites suggest a single complex-provenance on a dynamic planet not unlike earth, probably Mars.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014AGUFMDI21A4258B','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014AGUFMDI21A4258B"><span>Partial Melting of Garnet <span class="hlt">Lherzolite</span> with H2o and CO2 at 3 GPa: Implications for Intraplate Magmatism.</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Baasner, A.; Medard, E.; Laporte, D.</p> <p>2014-12-01</p> <p>The origin and source rock of alkali-rich and SiO2-undersatured magmas in the Earth`s upper mantle have been under debate for a long time. The garnet signature in rare earth element patterns of such magmas suggest a garnet-bearing source rock, which could be garnet <span class="hlt">lherzolite</span> or garnet pyroxenite. Partial melting experiments were performed at 3 GPa and 1345-1445 °C in a piston-cylinder apparatus using mixtures of natural <span class="hlt">lherzolite</span> with 0.4-0.7 wt% H2O and 0.4-0.7 wt% CO2 as starting materials. Different designs of AuPd capsules were used for melt extraction. Mineral and melt phases were analysed with electron microprobe and laser ablation inductively coupled plasma mass spectrometry. The degree of partial melting in the experiments ranges from ~20% to ~4% and decreases with decreasing temperature and decreasing volatile content in the starting material. All samples contain olivine and orthopyroxene. Garnet is present in experiments performed below 1420 °C. The amount of clinopyroxene decreases with increasing degree of partial melting and volatile concentration in the starting material. Depending on the capsule design the melts quenched to glasses or to a mixture of quench crystals and residual glass. The composition of the partial melts ranges from basalts through picrobasalts to foidites. The alkali concentration increases and the SiO2 concentration decreases with decreasing degree of partial melting and increasing volatile concentration in the starting material. The partial melts are similar in many aspects to alkali intraplate magmas (basanites to melilitites), although they are richer in MgO. Compositions closer to natural basanites could be obtained either at lower degree of melting (and lower volatile contents) or through olivine fractionation. Our results strongly suggests that. SiO2-undersaturated intraplate magmas can be generated by mantle melting of garnet-<span class="hlt">lherzolite</span> in the presence of H2O and CO2 in the Earth`s upper mantle at 3 GPa (~100 km depth).</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/20140012817','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/20140012817"><span>Identification of Martian Regolith Sulfur Components in <span class="hlt">Shergottites</span> Using Sulfur K Xanes and Fe/S Ratios</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Sutton, S. R.; Ross, D. K.; Rao, M. N.; Nyquist, L. E.</p> <p>2014-01-01</p> <p>Based on isotopic anomalies in Kr and Sm, Sr-isotopes, S-isotopes, XANES results on S-speciation, Fe/S ratios in sulfide immiscible melts [5], and major element correlations with S determined in impact glasses in EET79001 Lith A & Lith B and Tissint, we have provided very strong evidence for the occurrence of a Martian regolith component in some impact melt glasses in <span class="hlt">shergottites</span>. Using REE measurements by LA-ICP-MS in <span class="hlt">shergottite</span> impact glasses, Barrat and co-workers have recently reported conflicting conclusions about the occurrence of Martian regolith components: (a) Positive evidence was reported for a Tissint impact melt, but (b) Negative evidence for impact melt in EET79001 and another impact melt in Tissint. Here, we address some specific issues related to sulfur speciation and their relevance to identifying Martian regolith components in impact glasses in EET79001 and Tissint using sulfur K XANES and Fe/S ratios in sulfide immiscible melts. XANES and FE-SEM measurements in approx. 5 micron size individual sulfur blebs in EET79001 and Tissint glasses are carried out by us using sub-micron size beams, whereas Barrat and coworkers used approx. 90 micron size laser spots for LA- ICP-MS to determine REE abundances in bulk samples of the impact melt glasses. We contend that Martian regolith components in some <span class="hlt">shergottite</span> impact glasses are present locally, and that studying impact melts in various <span class="hlt">shergottites</span> can give evidence both for and against regolith components because of sample heterogeneity.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/20150001926','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/20150001926"><span>Mineralogical Comparison of Olivine in <span class="hlt">Shergottites</span> and A Shocked L Chondrite: Implications for Shock Histories of Brown Olivine</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Takenouchi, A.; Mikouchi, T.; Yamaguchi, A.; Zolensky, M. E.</p> <p>2015-01-01</p> <p>Most Martian meteorites are heavily shocked, exhibiting numerous shock features, for example undulatory extinction of olivine and pyroxene, the presence of diaplectic glass ("maskelynite") and the formation of shock melt. Among these shock features, olivine darkening ("brown" olivine) is unique in Martian meteorites because no other meteorite group shows such a feature. Although the presence of brown olivine in <span class="hlt">shergottites</span> was reported thirty years ago, detailed observation by TEM has not been performed until the NWA 2737 chassignite was discovered, whose olivine is darkened, being completely black in hand specimen. Fe metal nano-particles were found in NWA 2737 olivine which are considered to have been formed by olivine reduction during heavy shock. Subsequently, magnetite nano-particles were also found in other Martian meteorites and the coexistence of Fe metal and magnetite nano-particles was reported in the NWA 1950 <span class="hlt">shergottite</span> and some Fe metal nano-particles were mantled by magnetite. Therefore, the formation process of nano-particles seems to be complex. Because "brown" olivine is unique to Martian meteorites, they have a potential to constrain their shock conditions. In order to better understand the shock history of Martian meteorites, we compared olivine in several <span class="hlt">shergottites</span> with that in a highly-shocked L chondrite which contains ringwoodite.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2012EGUGA..14.5667G','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2012EGUGA..14.5667G"><span>Phase relationships of a <span class="hlt">lherzolite</span> from the Roberts Victor Mine, South Africa: A study of chemical and physical parameters in the Kaapvaal Craton.</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Globig, J.; Sommer, H.</p> <p>2012-04-01</p> <p>The Roberts Victor kimberlite pipe-dike system is well known as type locality for intensively studied eclogitic xenoliths. Since more than 95% of the Roberts Victor xenoliths are rather of eclogitic than of peridotitic type, mineralogical data of <span class="hlt">lherzolitic</span> peridotites from the mine is extremely rare. In fact, there is no detailed petrological study of peridotitic mantle xenoliths from the Roberts Victor Mine up to the present day. As the <span class="hlt">lherzolitic</span> xenolith nodules from the Roberts Victor Mine are strongly altered, due to contact with the aqueous fluid of the ascending kimberlitic melt bulk chemistry analyses result in too low SiO2 and too high MgO concentrations. Thus, Roberts Victor <span class="hlt">lherzolites</span> provide a distorted image of the sampled mantle regions. To avoid inaccuracies in composition, we used mineral analyses of the rock forming minerals from lherzolithes from the Roberts Victor Mine and implemented a planimetric method to recalculate a proper bulk rock composition that is free of volatiles and representative of a garnet <span class="hlt">lherzolite</span> from the Kaapvaal Craton. The recalculated bulk chemistry for the four-phase <span class="hlt">lherzolite</span> composition Ol-Opx-Cpx-Gt is; SiO2≈45.83 wt.%, TiO2≈0.04 wt.%, Cr2O3≈0.51 wt.%, Al2O3≈1.84 wt.%, FeO≈6.27 wt.%, MnO≈0.07 wt.%, MgO≈43.51 wt.%, CaO≈0.53 wt.%, Na2O≈0.10 wt.%. As our bulk composition fits accurately the composition range of <span class="hlt">lherzolites</span> from the Kaapvaal Craton, analysed by Carswell and Dawson (1970), it is seen to represent the chemistry of the upper mantle beneath South Africa. By the use of the Gibbs minimization software PerpleX (Connolly, 2005) we created a petrological p-T phase diagram for a water saturated <span class="hlt">lherzolite</span> from 473-2073 K and 10-100 kbar, based on the recalculated bulk composition, to estimate the proportion of <span class="hlt">lherzolite</span> in the lithospheric-asthenospheric mantle of the Kaapvaal Craton. Furthermore and more importantly, we used PerpleX to model the modal distribution of the phases Atg, Br, Chl</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2010AGUFM.P51B1423S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2010AGUFM.P51B1423S"><span>Martian Pyroxenes in the <span class="hlt">Shergottite</span> Meteorites; Zagami, SAU005, DAG476 and EETA79001</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Stephen, N.; Benedix, G. K.; Bland, P.; Hamilton, V. E.</p> <p>2010-12-01</p> <p>The geology and surface mineralogy of Mars is characterised using remote sensing techniques such as thermal emission spectroscopy (TES) from instruments on a number of spacecraft currently orbiting Mars or gathered from roving missions on the Martian surface. However, the study of Martian meteorites is also important in efforts to further understand the geological history of Mars or to interpret mission data as they are believed to be the only available samples that give us direct clues as to Martian igneous processes [1]. We have recently demonstrated that the spectra of Martian-specific minerals can be determined using micro-spectroscopy [2] and that these spectra can be reliably obtained from thin sections of Martian meteorites [3]. Accurate modal mineralogy of these meteorites is also important [4]. In this study we are using a variety of techniques to build upon previous studies of these particular samples in order to fully characterise the nature of the 2 common pyroxenes found in Martian <span class="hlt">Shergottites</span>; pigeonite and augite [5], [6]. Previous studies have shown that the <span class="hlt">Shergottite</span> meteorites are dominated by pyroxene (pigeonite and augite in varying quantities) [4], [5], commonly but not always olivine, plagioclase or maskelynite/glass and also hydrous minerals, which separate the Martian meteorites from other achondrites [7]. Our microprobe study of meteorites Zagami, EETA79001, SAU005 and DAG476 in thin-section at the Natural History Museum, London shows a chemical variability within both the pigeonite and augite composition across individual grains in all thin sections; variation within either Mg or Ca concentration varies from core to rim within the grains. This variation can also be seen in modal mineralogy maps using SEM-derived element maps and the Photoshop® technique previously described [4], and in new micro-spectroscopy data, particularly within the Zagami meteorite. New mineral spectra have been gathered from the <span class="hlt">Shergottite</span> thin-sections by</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017GeCoA.211..280F','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017GeCoA.211..280F"><span>Evaluating crustal contributions to enriched <span class="hlt">shergottites</span> from the petrology, trace elements, and Rb-Sr and Sm-Nd isotope systematics of Northwest Africa 856</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Ferdous, J.; Brandon, A. D.; Peslier, A. H.; Pirotte, Z.</p> <p>2017-08-01</p> <p>The origin of the incompatible trace element (ITE) characteristics of enriched <span class="hlt">shergottites</span> has been critical for examining two contradicting scenarios to explain how these Martian meteorites form. The first scenario is that it reflects ITE enrichment in an early-formed mantle reservoir whereas the second scenario attributes it to assimilation of ancient Martian crust (∼4-4.5 Ga) by ITE-depleted magmas. Strongly differentiated <span class="hlt">shergottite</span> magmas may yield added constraints for determining which scenario can best explain this signature in enriched <span class="hlt">shergottites</span>. The meteorite Northwest Africa (NWA) 856 is a basaltic <span class="hlt">shergottite</span> that, unlike many enriched <span class="hlt">shergottites</span>, lacks olivine and has undergone extensive differentiation from more primitive parent magma. In similarity to other basaltic <span class="hlt">shergottites</span>, NWA 856 is comprised primarily of compositionally zoned clinopyroxenes (45% pigeonite and 23% augite), maskelynite (23%) and accessory minerals such as ulvöspinel, merrillite, Cl-apatite, ilmenite, pyrrhotite, baddeleyite and silica polymorph. The CI-chondrite normalized rare earth element (REE) abundance patterns for its maskelynite, phosphates, and its whole rock are flat with corresponding light-REE depletions in clinopyroxenes. The 87Rb-87Sr and 147Sm-143Nd internal isochron ages are 162 ± 14 (all errors are ±2σ) Ma and 162.7 ± 5.5 Ma, respectively, with an initial εNdI = -6.6 ± 0.2. The Rb-Sr isotope systematics are affected by terrestrial alteration resulting in larger scatter and a less precise internal isochron age. The whole rock composition is used in MELTS simulations to model equilibrium and fractional crystallization sequences to compare with the crystallization sequence from textural observations and to the mineral compositions. These models constrain the depth of initial crystallization to a pressure range of 0.4-0.5 GPa (equivalent to 34-42 km) in anhydrous conditions at the Fayalite-Magnetite-Quartz buffer, and consistently reproduce the</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/1995GeCoA..59.1363Z','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/1995GeCoA..59.1363Z"><span>Geochemical and isotopic studies of syenites from the <span class="hlt">Yamato</span> Mountains, East Antarctica: Implications for the origin of syenitic magmas</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Zhao, J.-X.; Shiraishi, K.; Ellis, D. J.; Sheraton, J. W.</p> <p>1995-04-01</p> <p>Voluminous syenites were intruded during the waning stage of the granulite facies metamorphism in the <span class="hlt">Yamato</span> Mountains of East Antarctica. The area has been interpreted as part of a Cambrian continental collision zone with regional upper amphibolite to granulite facies metamorphism occurring during ca. 500-660 Ma period. Regardless of minor geochemical variations between different groups, all syenites are characterised by high K 20 + Na 20 (8-12%), K 20/Na 20 (˜2), Sr (800-3500 ppm), Ba (2000-8500 ppm), and comparatively high TiO 2, P 20 5, Zr, and light REES relative to I-type granites. They are significantly higher in Mg number (50-75) compared with typical calc-alkaline suites, igneous charnockites, or A-type granites and define a distinctive trend on an AFM (alkali-FeO tot-MgO) diagram. Their trace element distribution diagrams are characterised by pronounced enrichment in LIL and REES, large negative Nb and Ti anomalies, and no depletion in Sr or Ba relative to the neighbouring elements. In this regard, they closely resemble the ˜500 Ma post-tectonic mela-syenite to alkali basalt dikes widely occurring in East Antarctica. Such geochemical features are distinct from rift- or hotspot-related syenites, which are usually characterised by low K/Na ratios, negative Ba and Sr anomalies, and a lack of negative Nb anomalies. Initial isotopic compositions of the syenites are characterised by relatively low initial ɛNd values (-2.6 to -5.5) and high Sri ratios (0.7057-0.7088). Since the syenites are extremely enriched in Sr and Nd, such isotopic signatures are interpreted as reflecting the nature of the mantle source, rather than significant crystal contamination. Such isotopic signatures are also distinct from those of the rift- or hotspot-related syenites which are thought to be derived from depleted asthenospheric mantle. Considering the distinctive geochemical signatures of the <span class="hlt">Yamato</span> syenites and their analogy to posttectonic alkaline mafic dikes in Antarctica</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/20080026094','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/20080026094"><span>Feldspathic Clasts in <span class="hlt">Yamato</span> 86032: Remnants of the Lunar Crust with Implications for its Formation and Impact History</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Nyquist, L.; Bogard, D.; Yamaguchi, A.; Shih, C.-Y.; Ebihara, M.; Reese, Y.; Garrison, D.; Takeda, H.</p> <p>2006-01-01</p> <p><span class="hlt">Yamato</span> (Y)-86032 is a relatively large, feldspathic lunar highlands meteorite composed of a variety of highland lithologies. Low bulk contents of Th and Fe indicated that it came from a region of the moon far distant from the Procellarum KREEP Terrain (PKT) and the Apollo landing sites, perhaps from the farside. A large (5.2 x 3.6 cm) slab was cut from Y-86032 . We report results from coordinated textural, mineralogical-petrological, chemical, and isotopic studies of lithologies identified in the slab, emphasizing the results of Ar-39/Ar-40, Rb-Sr, and Sm-Nd chronological studies as well as Sm-isotopic studies. These studies characterize the history of Y-86032 and its precursors in the farside mega-regolith, leading to inferences about the formation and evolution of the lunar crust. Textural studies establish that the Y-86032 breccia is composed of a variety of highland components including feldspathic breccias, and other components, such as possible VLT mare basalts. Impact melt veins smoothly abut the other lithologies. Thus, Y-86032 experienced at least two impact events. These impacts occurred on a predominantly feldspathic protolith, which formed 4.43+/-0.03 Ga ago as determined from a Sm-Nd isochron for mineral clasts separated from the two dominant lithologies. Initial Nd-143/Nd-144 in the protolith at that time was -0.64+/-0.13 epsilon-units below Nd-143/Nd-144 in reservoirs having chondritic Sm/Nd ratios, consistent with prior fractionation of mafic cumulates from the LMO. Although the mineral chemistry of these clasts differs in detail from that of minerals in Apollo 16 Ferroan Anorthosites (FANs), the Rb-Sr studies establish that the initial Sr-87/Sr-86 in them was the same as in the FANs.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2010M%26PS...45.1108I','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2010M%26PS...45.1108I"><span>Dhofar 225 and Dhofar 735: Relationship to CM2 chondrites and metamorphosed carbonaceous chondrites, Belgica-7904 and <span class="hlt">Yamato</span>-86720</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Ivanova, Marina A.; Lorenz, Cyrill A.; Nazarov, Mikhail A.; Brandstaetter, Franz; Franchi, Ian A.; Moroz, Lyuba V.; Clayton, Robert N.; Bychkov, Andrew Yu.</p> <p>2010-07-01</p> <p>Dhofar (Dho) 225 and Dho 735 are carbonaceous chondrites found in a hot desert and having affinities to Belgica-like Antarctic chondrites (Belgica [B-] 7904 and <span class="hlt">Yamato</span> [Y-] 86720). Texturally they resemble CM2 chondrites, but differ in mineralogy, bulk chemistry and oxygen isotopic compositions. The texture and main mineralogy of Dho 225 and Dho 735 are similar to the CM2 chondrites, but unlike CM2 chondrites they do not contain any (P, Cr)-sulfides, nor tochilinite 6Fe0.9S*5(Fe,Mg)(OH)2. H2O-contents of Dho 225 and Dho 735 (1.76 and 1.06 wt%) are lower than those of CM2 chondrites (2-18 wt%), but similar to those in the metamorphosed carbonaceous chondrites of the Belgica-like group. Bulk compositions of Dho 225 and Dho 735, as well as their matrices, have low Fe and S and low Fe/Si ratios relative to CM2 chondrites. X-ray powder diffraction patterns of the Dho 225 and Dho 735 matrices showed similarities to laboratory-heated Murchison CM2 chondrite and the transformation of serpentine to olivine. Dho 225 and 735's oxygen isotopic compositions are in the high 18O range on the oxygen diagram, close to the Belgica-like meteorites. This differs from the oxygen isotopic compositions of typical CM2 chondrites. Experimental results showed that the oxygen isotopic compositions of Dho 225 and Dhofar 725, could not be derived from those of typical CM2 chondrites via dehydration caused by thermal metamorphism. Dho 225 and Dho 735 may represent a group of chondrites whose primary material was different from typical CM2 chondrites and the Belgica-like meteorites, but they formed in an oxygen reservoir similar to that of the Belgica-like meteorites.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=19920074085&hterms=united+kingdom+history&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D60%26Ntt%3Dunited%2Bkingdom%2Bhistory','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=19920074085&hterms=united+kingdom+history&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D60%26Ntt%3Dunited%2Bkingdom%2Bhistory"><span>Zagami - Product of a two-stage magmatic history. [of <span class="hlt">shergottite</span> meteorite</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Mccoy, Timothy J.; Taylor, G. J.; Keil, Klaus</p> <p>1992-01-01</p> <p>Results of petrologic studies of new large samples of the Zagami <span class="hlt">shergottite</span> are presented. Pyroxene crystals have homogeneous Mg-rich pigeonite and augite cores, overgrown by Fe-rich zoned pyroxene rims. Amphibole-bearing magmatic inclusions occur exclusively in the cores. It is concluded that Zagami experienced a two-stage crystallization history. The first stage occurred in a deep-seated, slowly cooling magma chamber. There, the homogeneous Mg-rich cores of the pyroxenes crystallized during relatively slow cooling. During the second stage, the Mg-rich pyroxenes were entrained into a magma that either intruded to the near-surface and cooled in a relatively thin dike or sill, or extruded to the surface and crystallized in a lava flow greater than 10 m thick, again without indications of crystal settling. The estimated depth of the magma chamber for Zagami of greater than 7.5 km and thickness of the putative lava flow of greater than 10 m are consistent with calculations and observations of volcanic constructs and flows in the Tharsis region of Mars.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.osti.gov/scitech/biblio/21344499','SCIGOV-STC'); return false;" href="https://www.osti.gov/scitech/biblio/21344499"><span>Cathodoluminescence Characterization of Maskelynite and Alkali Feldspar in <span class="hlt">Shergottite</span> (Dhofar 019)</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Kayama, M.; Nakazato, T.; Nishido, H.; Ninagawa, K.; Gucsik, A.</p> <p>2009-08-17</p> <p>Dhofar 019 is classified as an olivine-bearing basaltic <span class="hlt">shergottite</span> and consists of subhedral grains of pyroxene, olivine, feldspar mostly converted to maskelynite and minor alkali feldspar. The CL spectrum of its maskelynite exhibits an emission band at around 380 nm. Similar UV-blue emission has been observed in the plagioclase experimentally shocked at 30 and 40 GPa, but not in terrestrial plagioclase. This UV-blue emission is a notable characteristic of maskelynite. CL spectrum of alkali feldspar in Dhofar 019 has an emission bands at around 420 nm with no red emission. Terrestrial alkali feldspar actually consists of blue and red emission at 420 and 710 nm assigned to Al-O{sup -}-Al and Fe{sup 3+} centers, respectively. Maskelynite shows weak and broad Raman spectral peaks at around 500 and 580 cm{sup -1}. The Raman spectrum of alkali feldspar has a weak peak at 520 cm{sup -1}, whereas terrestrial counterpart shows the emission bands at 280, 400, 470, 520 and 1120 cm{sup -1}. Shock pressure on this meteorite transformed plagioclase and alkali feldspar into maskelynite and almost glass phase, respectively. It eliminates their luminescence centers, responsible for disappearance of yellow and/or red emission in CL of maskelynite and alkali feldspar. The absence of the red emission band in alkali feldspar can also be due to the lack of Fe{sup 3+} in the feldspar as it was reported for some lunar feldspars.</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_8");'>8</a></li> <li><a href="#" onclick='return showDiv("page_9");'>9</a></li> <li class="active"><span>10</span></li> <li><a href="#" onclick='return showDiv("page_11");'>11</a></li> <li><a href="#" onclick='return showDiv("page_12");'>12</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_10 --> <div id="page_11" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_9");'>9</a></li> <li><a href="#" onclick='return showDiv("page_10");'>10</a></li> <li class="active"><span>11</span></li> <li><a href="#" onclick='return showDiv("page_12");'>12</a></li> <li><a href="#" onclick='return showDiv("page_13");'>13</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="201"> <li> <p><a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=19950047179&hterms=noble+gases&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D20%26Ntt%3Dnoble%2Bgases','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=19950047179&hterms=noble+gases&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D20%26Ntt%3Dnoble%2Bgases"><span>Nitrogen and noble gases in a glass sample from the LEW88516 <span class="hlt">shergottite</span></span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Becker, Richard H.; Pepin, Robert O.</p> <p>1993-01-01</p> <p>A glass separate from the LEW88516 <span class="hlt">shergottite</span> was analyzed by step-wise combustion for N and noble gases to determine whether it contained trapped gas similar in composition to the martian atmosphere-like component previously observed in lithology C of EETA79001. Excesses of Ar-40 and Xe-129 were in fact observed in this glass, although the amounts of these excesses less than or = to 20% of those seen in the latter meteorite, and are comparable to the amounts seen in whole-rock analyses of LEW88516. The isotopic composition of N in LEW88516 does not show an enrichment in delta N-15 commensurate with the amount of isotopically-heavy N expected from the noble gases excesses. One must posit some extreme assumptions about the nature of the N components present in LEW88516 in order to allow the presence of the trapped nitrogen component. Alternatively, the N has somehow been decoupled from the noble gases, and was either never present of has been lost.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2010M%26PS...45.1359C','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2010M%26PS...45.1359C"><span>Terrestrial and Martian weathering signatures of xenon components in <span class="hlt">shergottite</span> mineral separates</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Cartwright, J. A.; Ocker, K. D.; Crowther, S. A.; Burgess, R.; Gilmour, J. D.</p> <p>2010-08-01</p> <p>Xenon-isotopic ratios, step-heating release patterns, and gas concentrations of mineral separates from Martian <span class="hlt">shergottites</span> Roberts Massif (RBT) 04262, Dar al Gani (DaG) 489, Shergotty, and Elephant Moraine (EET) 79001 lithology B are reported. Concentrations of Martian atmospheric xenon are similar in mineral separates from all meteorites, but more weathered samples contain more terrestrial atmospheric xenon. The distributions of xenon from the Martian and terrestrial atmospheres among minerals in any one sample are similar, suggesting similarities in the processes by which they were acquired. However, in opaque and maskelynite fractions, Martian atmospheric xenon is released at higher temperatures than terrestrial atmospheric xenon. It is suggested that both Martian and terrestrial atmospheric xenon were initially introduced by weathering (low temperature alteration processes). However, the Martian component was redistributed by shock, accounting for its current residence in more retentive sites. The presence or absence of detectable 129Xe from the Martian atmosphere in mafic minerals may correspond to the extent of crustal contamination of the rock's parent melt. Variable contents of excess 129Xe contrast with previously reported consistent concentrations of excess 40Ar, suggesting distinct sources contributed these gases to the parent magma.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016M%26PS...51.2061H','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016M%26PS...51.2061H"><span>Postcrystallization metasomatism in <span class="hlt">shergottites</span>: Evidence from the paired meteorites LAR 06319 and LAR 12011</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Howarth, Geoffrey H.; Liu, Yang; Chen, Yang; Pernet-Fisher, John F.; Taylor, Lawrence A.</p> <p>2016-11-01</p> <p>Apatite is the major volatile-bearing phase in Martian meteorites, containing structurally bound fluorine, chlorine, and hydroxyl ions. In apatite, F is more compatible than Cl, which in turn is more compatible than OH. During degassing, Cl strongly partitions into the exsolved phase, whereas F remains in the melt. For these reasons, the volatile concentrations within apatite are predictable during magmatic differentiation and degassing. Here, we present compositional data for apatite and merrillite in the paired enriched, olivine-phyric <span class="hlt">shergottites</span> LAR 12011 and LAR 06319. In addition, we calculate the relative volatile fugacities of the parental melts at the time of apatite formation. The apatites are dominantly OH-rich (calculated by stoichiometry) with variable yet high Cl contents. Although several other studies have found evidence for degassing in the late-stage mineral assemblage of LAR 06319, the apatite evolutionary trends cannot be reconciled with this interpretation. The variable Cl contents and high OH contents measured in apatites are not consistent with fractionation either. Volatile fugacity calculations indicate that water and fluorine activities remain relatively constant, whereas there is a large variation in the chlorine activity. The Martian crust is Cl-rich indicating that changes in Cl contents in the apatites may be related to an external crustal source. We suggest that the high and variable Cl contents and high OH contents of the apatite are the results of postcrystallization interaction with Cl-rich, and possibly water-rich, crustal fluids circulating in the Martian crust.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/1996GeCoA..60.4241C','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/1996GeCoA..60.4241C"><span>On the recent enrichment of subcontinental lithosphere: A detailed UPb study of spinel <span class="hlt">lherzolite</span> xenoliths, Yukon, Canada</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Carignan, Jean; Ludden, John; Francis, Don</p> <p>1996-11-01</p> <p>Lead strontium, and osmium isotopic data have been obtained for whole rocks and mineral separates (olivine, orthopyroxene, clinopyroxene, and spinel) for spinel <span class="hlt">lherzolite</span> xenoliths hosted by lavas of the Quaternary Alligator Lake volcanic centre, southern Yukon. Whole-rock xenolith samples display a large variation of lead concentrations, from 16 ppb for a harzburgite to up to 400 ppb for a <span class="hlt">lherzolite</span>. However, their lead isotope ratios are relatively homogeneous with 206Pb /204Pb of 19.07 ± 0.08, 207Pb /204Pb of 15.65 ± 0.07, and 208Pb /204Pb of 38.67 ± 0.17 ( n = 7). However, the 238U /204Pb ratios display a large variation, from 12.2 to 46.5, and do not correlate with indices of fertility such as calcium or aluminum content. Mineral separates yield even larger variations in lead isotopic composition and lead and uranium concentrations. Some olivine fractions have both the lowest radiogenic compositions ( 206Pb /204Pb = 18.75 ) and the lowest 238U /204Pb ratios (˜3.1). Clinopyroxenes (cpx) display the highest lead and uranium concentrations (up to 1277 ppb and 195 ppb, respectivelly) and generally similar or more radiogenic lead isotopic composition and higher 238U /204Pb ratios than their whole-rock compositions. Orthopyroxene and spinel fractions yield intermediate compositions between olivine and cpx. Although whole rocks and cpx for individual samples yield almost identical 87Sr /86Sr , the xenoliths ( n = 5) display a large variation of strontium isotopic compositions ( 87Sr /86Sr from 0.07033 to 0.7050), lead and strontium isotope ratios of cpx and the distribution of the data in a UPb isochron diagram suggest that the subcontinental lithosphere under the Yukon was affected by a recent (< ˜30 Ma) enrichment in uranium, lead, and strontium. The metasomatic fluid/magma might have had an isotopic composition close to that of some sediments in the northern Pacific Ocean. When compared to K d values reported in the literature, olivine is enriched in</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/20110016359','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/20110016359"><span>Sm-Nd and Initial Sr-87/Sr-86 Isotopic Systematics of Asuka 881394 and Cumulate Eucrites <span class="hlt">Yamato</span> 980318/433 Compared</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Nyquist, L. E.; Shih, C-Y; Young, Y. D.; Takeda, H.</p> <p>2011-01-01</p> <p>The Asuka 881394 achondrite contains fossil Al-26 and Mn-53 and has a Pb-206/Pb-207 age of 4566.5 +/- 0.2 Ma, the oldest for an achondrite. Recent re-investigation of A881394 yielded revised initial Sm-146/Sm-144 = (9.1 +/- 1.4) x 10(exp -3), a Sm-147-Nd-143 age of 4525 +/- 58 Ma, a Rb-87-Sr-87 age of 4490 +/- 130 Ma, and initial Sr-87/Sr-86 = 0.698991 +/- 19, respectively. The relatively large uncertainties in the Sm-Nd and Rb-Sr ages are due to disturbances of the isotopic systematics of tridymite and other minor phases. A preliminary value for the Sm-147-Nd-143 age of the <span class="hlt">Yamato</span> 980318 cumulate eucrite of 4560 +/- 150 Ma was refined in later work to 4567 +/- 24 Ma as reported orally at LPSC 35. Similarly, a preliminary value for Sm-146/Sm-144 = (7.7 +/- 1.2) x 10 (exp -3) was refined to (6.0 +/- 0.3) x 10(exp -3). For <span class="hlt">Yamato</span> 980433, a Sm-147-Nd-143 age of 4542 +/-42 Ma and Sm-146/Sm-144 = (5.7 +/- 0.5) x 10(exp -3) has been reported. Because these two cumulate eucrites are paired, we consider them to represent one igneous rock and present their combined isotopic data here.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/11361350','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/11361350"><span>Two novel Pao-like retrotransposons (Kamikaze and <span class="hlt">Yamato</span>) from the silkworm species Bombyx mori and B. mandarina: common structural features of Pao-like elements.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Abe, H; Ohbayashi, F; Sugasaki, T; Kanehara, M; Terada, T; Shimada, T; Kawai, S; Mita, K; Kanamori, Y; Yamamoto, M T; Oshiki, T</p> <p>2001-04-01</p> <p>To characterize the structural features common to Pao-like retrotransposons, we analyzed two lambda phage clones which contain the Pao-like elements from the silkworm species Bombyx mori and B. mandarinia, and copies of Pao itself and ninja of Drosophila simulans, amplified by PCR. We previously identified two randomly amplified polymorphic DNAs (RAPDs), W-Kamikaze and W-<span class="hlt">Yamato</span>, from B. mori and B. mandarina, which are part of two novel Pao-like retrotransposons, Kamikaze and <span class="hlt">Yamato</span>, respectively. Complete characterization of these and other elements of this group reported here shows that Pao-like elements have common features that distinguish them from the other groups of LTR-retrotransposons. While the elements of the Ty1-copia group encode only one cysteine and histidine (Cys) motif in their gag-like region, the Pao-like elements specify three Cys motifs. The highly conserved D(35)E motif in the integrase domain of the retrotransposon polyprotein seems to be conserved in Pao-like elements, but the number of amino acid residues between D and E varies and is greater than 35. A comparison of the deduced amino acid sequences of the reverse transcriptase domain revealed the Pao-like elements are members of neither the Ty1-copia nor the gypsy-Ty3 groups. Therefore, we confirmed that the long-terminal-repeat (LTR) retrotransposons should be divided into three major groups (or families), namely the Ty1-copia, gypsy-Ty3, and Pao-like groups.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016M%26PS...51...80U','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016M%26PS...51...80U"><span>Lithium isotopes and light lithophile element abundances in <span class="hlt">shergottites</span>: Evidence for both magmatic degassing and subsolidus diffusion</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Udry, Arya; McSween, Harry Y.; Hervig, Richard L.; Taylor, Lawrence A.</p> <p>2016-01-01</p> <p>Degassed magmatic water was potentially the major source of surficial water on Mars. We measured Li, B, and Be abundances and Li isotope profiles in pyroxenes, olivines, and maskelynite from four compositionally different shergottites—Shergotty, QUE 94201, LAR 06319, and Tissint—using secondary ion mass spectrometry (SIMS). All three light lithophile elements (LLE) are incompatible: Li and B are soluble in H2O-rich fluids, whereas Be is insoluble. In the analyzed <span class="hlt">shergottites</span>, Li concentration decreases and Be concentration increases from cores to rims in pyroxenes. However, B concentrations do not vary consistently with Li and Be abundances, except in QUE 94201 pyroxenes. Additionally, abundances of these three elements in olivines show a normal igneous-fractionation trend consistent with the crystallization of olivine before magma ascent and degassing. We expect that kinetic effects would lead to fractionation of 6Li in the vapor phase compared to 7Li during degassing. The Li isotope profiles, with increasing δ7Li from cores to rims, as well as Li and B profiles indicate possible degassing of hydrous fluids only for the depleted <span class="hlt">shergottite</span> QUE 94201, as also supported by degassing models. Conversely, Shergotty, LAR 06319, and Tissint appear to have been affected by postcrystallization diffusion, based on their LLE and Li isotope profiles, accompanied by diffusion models. This process may represent an overlay on a degassing pattern. The LLE profiles and isotope profiles in QUE 94201 support the hypothesis that degassing of some basaltic <span class="hlt">shergottite</span> magmas provided water to the Martian surface, although evidence may be obscured by subsolidus diffusion processes.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014EGUGA..16.5060C','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014EGUGA..16.5060C"><span>Experimental quantification of P-T conditions of mantle refertilisation at shallow depth under spreading ridges and formation of plagioclase + spinel <span class="hlt">lherzolite</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Chalot-Prat, Françoise; Falloon, Trevor J.; Green, David H.</p> <p>2014-05-01</p> <p>We studied the first-order melting process of differentiation in the Earth, and the major process of rejuvenation of the upper mantle after melting related to plate spreading (Chalot-Prat et al, 2010; 2013). We conducted experiments at High Pressure (0.75 and 0.5 GPa) and High Temperature (1260-1100°C) to obtain magma compositions in equilibrium with the mineral assemblages of a plagioclase + spinel <span class="hlt">lherzolite</span>. These PT conditions prevail at 17-30km below axial oceanic spreading ridges. We used a "trial and error" approach in a system involving nine elements (Cr-Na-Fe-Ca-Mg-Al-Si-Ti-Ni). This approaches as closely as possible a natural mantle composition, Cr being a key element in the system. Our objectives were : • to determine experimentally the compositions of melts in equilibrium with plagioclase + spinel <span class="hlt">lherzolite</span>, with emphasis on the role of plagioclase composition in controlling melt compositions; • to test the hypothesis that MORB are produced at shallow depth (17-30kms) • to quantify liquid- and mantle residue compositional paths at decreasing T and low P to understand magma differentiation by "percolation-reaction" at shallow depth in the mantle; • to compare experimental mantle mineral compositions to those of re-fertilised oceanic mantle lithosphere outcropping at the axis of oceanic spreading ridges, enabling quantification of the pressure (i.e. depth) and temperature of the re-fertilisation process that leads to formation of plagioclase and indicates the minimum thickness of the lithosphere at ridge axes. In the normative basalt tetrahedron, liquids plot on two parallel cotectic lines from silica-oversaturated (basaltic andesite at 0.75 GPa or andesite at 0.5 GPa) at the calcic end to silica-undersaturated compositions (trachyte) at the sodic end. The lower the pressure, the greater the silica oversaturation. Besides the plagioclase solid solution has a dominant role in determining the solidus temperature of plagioclase + spinel <span class="hlt">lherzolites</span></p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016CoMP..171...45B','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016CoMP..171...45B"><span>Partial melting of garnet <span class="hlt">lherzolite</span> with water and carbon dioxide at 3 GPa using a new melt extraction technique: implications for intraplate magmatism</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Baasner, Amrei; Médard, Etienne; Laporte, Didier; Hoffer, Géraldine</p> <p>2016-05-01</p> <p>The origin and source rocks of alkali-rich and SiO2-undersatured magmas in the Earth's upper mantle are still under debate. The garnet signature in rare earth element patterns of such magmas suggests a garnet-bearing source rock, which could be garnet <span class="hlt">lherzolite</span> or garnet pyroxenite. Partial melting experiments were performed at 2.8 GPa and 1345-1445 °C in a piston-cylinder using mixtures of natural <span class="hlt">lherzolite</span> with either 0.4 wt% H2O and 0.4 wt% CO2 or 0.7 wt% H2O and 0.7 wt% CO2. Different designs of AuPd capsules were used for melt extraction. The most successful design included a pentagonally shaped disc placed in the top part of the capsule for sufficient melt extraction. The degrees of partial melting range from 0.2 to 0.04 and decrease with decreasing temperature and volatile content. All samples contain olivine and orthopyroxene. The amounts of garnet and clinopyroxene decrease with increasing degree of partial melting until both minerals disappear from the residue. Depending on the capsule design, the melts quenched to a mixture of quench crystals and residual glass or to glass, allowing measurement of the volatile concentrations by Raman spectroscopy. The compositions of the partial melts range from basalts through picrobasalts to foidites. Compared to literature data for melting of dry <span class="hlt">lherzolites</span>, the presence of H2O and CO2 reduces the SiO2 concentration and increases the MgO concentration of partial melts, but it has no observable effect on the enrichment of Na2O in the partial melts. The partial melts have compositions similar to natural melilitites from intraplate settings, which shows that SiO2-undersaturated intraplate magmas can be generated by melting of garnet <span class="hlt">lherzolite</span> in the Earth's upper mantle in the presence of H2O and CO2.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/20110007805','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/20110007805"><span>Recognizing the Effects of Terrestrial Contamination on D/H Ratios in <span class="hlt">Shergottite</span> Phosphates</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Ross, D. K.; Ito, M.; Hervig, R.; Rao, M. N.; Nyquist, L. E.</p> <p>2011-01-01</p> <p>Hydrogen isotope ratios in <span class="hlt">shergottite</span> phosphate minerals have been investigated by SIMS in the meteorites Queen Alexandra Range (QUE) 94201 and Los Angeles. We have also collected electron probe data on these phosphates in order to characterize the phosphate minerals and attempt to document any potential hydrogen isotopic differences between chlor-apatite and whitlockite. In the section of Los Angeles we studied (748), we found both chlor-apatite and whitlockite, but in the section of QUE 94201,38 studied, we found only whitlockite. In both meteorites, D/H ratios (expressed in units of delta D (sub SMOW) vary, from terrestrial values up to approximately 5400%o in QUE 94201, and to approximately 3800%o in Los Angeles. We have carefully examined the ion probed pits with high-resolution FE-SEM. In most cases where the D/H ratios are low, we have iden-tified cracks that instersect the ion probe pit. These cracks are not visible in the optical microscope attached to the SIMS instument, making them impossible to avoid during SIMS data collection. We contend that the low ratios are a function of substantial terrestrial contamination, and that similar contamination is a likely factor in previously published studies on D/H ratios in martian phosphates. Here we highlight the difficulty of attempts to constrain the martian mantle D/H ratio using phosphate data, given that both terrestrial contamination and martian mantle hydrogen will move phosphate D/H ratios in the same direction, toward lower values. We note that our data include some of the most deuterium-rich values ever reported for martian phosphates. It is clear that some of our measurements are only minimally or totally uncontaminated, but the question arises, are intermediate values diminished because of true martian variability, or do they reflect contamination?</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=20020046467&hterms=Rutherford&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D10%26Ntt%3DRutherford','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=20020046467&hterms=Rutherford&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D10%26Ntt%3DRutherford"><span>An Experimental Study of Eu/Gd Partitioning Between a <span class="hlt">Shergottite</span> Melt and Pigeonite: Implications for the Oxygen Fugacity of the Martian Interior</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>McCanta, M. C.; Rutherford, M. J.; Jones, J. H.</p> <p>2002-01-01</p> <p>We experimentally investigated the partitioning behavior of Eu/Gd between a synthetic <span class="hlt">shergottite</span> melt and pigeonite as a function of oxygen fugacity. This has implications for the oxidation state of the source region of the martian meteorites. Additional information is contained in the original extended abstract.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2013AGUFM.V33A2721H','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2013AGUFM.V33A2721H"><span>Chalcophile and Siderophile Element Abundances in Kilbourne Hole <span class="hlt">Lherzolites</span>: Distinguishing the Signature of Melt Depleted Primitive Mantle from Metasomatic Overprints</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Harvey, J.; König, S.; Luguet, A.</p> <p>2013-12-01</p> <p>Selenium, tellurium and the highly siderophile elements in peridotites have the potential to illustrate planetary scale processes that are opaque to lithophile elements. However, the interpretation of chalcophile and siderophile element abundances relies heavily on the selection of representative mantle material and the determination of what processes have affected these elements since melt depletion. Whole rock and in-situ sulfide data demonstrate that chalcophile and HSE systematics of the upper mantle could be significantly modified through sulfide-metasomatism, particularly by C-O-H-S × Cl fluids[1] or sulfide melts[2] i.e., chalcophile and siderophile element abundances result from a complex interplay between sulfide addition and alteration of pre-existing sulfide. Here we present new bulk-rock S-Se-Te-PGE abundances on a suite (n = 17) of <span class="hlt">lherzolite</span> and harzburgite xenoliths from Kilbourne Hole, USA[3, 4]. Mineral modal abundances, major element contents and LREE/HREE ratios for 10 of these xenoliths are consistent with varying degrees of melt depletion (≤ 20 %) whereas the remainder appear to have been affected by cryptic metasomatism, refertilization, or melt-rock interaction which affected lithophile element abundances [4]. While sulfur, Se and PGE budgets are primarily controlled by sulfides, 50 × 30% of Te in peridotite may be accounted for by Pt-Pd tellurides[5]. Although most Kilbourne Hole peridotite xenoliths have PGE characteristics consistent with varying degrees of melt depletion and somewhat scattered Se/Te ratios, KH96-24 has Pt-Pd-Te abundances consistent with Pt-Pd-telluride precipitation, in addition to petrographic evidence for alteration by secondary processes[4]. S/Se are well correlated within the suite. However, <span class="hlt">lherzolites</span> that retain a strong melt-depletion signature have distinctly lower abundances of both S and Se (<65 ppm and <31 ppm respectively) compared to peridotites that have had their lithophile element budgets perturbed</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2004AGUFM.V41C1406L','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2004AGUFM.V41C1406L"><span>The Behavior of Pyroxenes During Partial Melting of Pyroxenite and <span class="hlt">Lherzolite</span> in the Mantle: An Experimental and Numerical Study</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Lo Cascio, M.; Liang, Y.</p> <p>2004-12-01</p> <p> cpx within the RBL, and production of Na2O-Al2O3-SiO2-rich melts in that region. This dissolution and reprecipitation process, due to two very different time-scales of crystal-melt interaction in partially molten systems, is reproduced in our numerical simulations of partial melting of bio-mineralic rocks in binary and ternary systems, and is likely to occur during <span class="hlt">lherzolite</span> and pyroxenite partial melting in the laboratory and nature. One of the important consequences of cpx reprecipitation during peridotite and pyroxenite partial melting is the significant reduction in diffusive reequilibration time between the cpx and the surrounding melt, since diffusion coefficients of trace elements such as REE, U, and Th in cpx are much smaller than those of major elements in cpx and melt. The rate of cpx reprecipitation is dominated by the rate of chemical diffusion of the major components in cpx. This dissolution and reprecipitation process may help to explain the apparent equilibrium melting trends observed in some slab derived magmas that were produced at relatively low temperatures. The mechanisms outlined above can also be used to better understand the melting process of <span class="hlt">lherzolite</span> and pyroxene-rich lithologies in the upper mantle and could partially explain the petrogenesis of high Na2O-Al2O3-SiO2 magmas, without the involvement of an eclogite component in the source region. [1] Lo Cascio et al., GRL, 31, L16605, doi: 10.1029/2004GL020602</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2010GeCoA..74.2231A','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2010GeCoA..74.2231A"><span>Antarctic lunar meteorites <span class="hlt">Yamato</span>-793169, Asuka-881757, MIL 05035, and MET 01210 (YAMM): Launch pairing and possible cryptomare origin</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Arai, Tomoko; Ray Hawke, B.; Giguere, Thomas A.; Misawa, Keiji; Miyamoto, Masamichi; Kojima, Hideyasu</p> <p>2010-04-01</p> <p>The Antarctic lunar meteorite Meteorite Hills (MET) 01210 is a polymict regolith breccia, dominantly composed of mare basalt components. One relatively large (2.7 × 4.7 mm) basalt clast in MET 01210 (MET basalt) shows remarkable mineralogical similarities to the lunar-meteorite crystalline mare basalts <span class="hlt">Yamato</span> (Y)-793169, Asuka (A)-881757, and Miller Range (MIL) 05035. All four basalts have similar rock texture, mineral assemblage, mineral composition, pyroxene crystallization trend, and pyroxene exsolution lamellae. The estimated TiO 2 contents (˜2.0 wt%) of the MET basalt and MIL 05035 are close to the bulk-rock TiO 2 contents of Y-793169 and A-881757. These similarities suggest that Y-793169, A-881757, MIL 05035, and the MET basalt came from the same basalt flow, which we designate the YAMM basalt. The source-basalt pairing of the YAMM is also supported by their similar REE abundances, crystallization ages (approx. 3.8-3.9 Ga), and isotopic compositions (low U/Pb, low Rb/Sr, and high Sm/Nd). The pyroxene exsolution lamellae, which are unusually coarse (up to a few microns) by mare standards, imply a relatively slow cooling in an unusually thick lava and/or subsequent annealing within a cryptomare. Reported noble gas and CRE data with close launch ages (˜1 Ma) and ejection depths (deeper than several meters) among the four meteorites further indicate their simultaneous ejection from the moon. Despite the marginally close terrestrial ages, pairing in the conventional Earth-entry sense seems unlikely because of the remote recovery sites among the YAMM meteorites. The high abundance (68%) of mare components in MET 01210 estimated from a two-component mixing model calculation could have resulted from either lateral mixing at a mare-highland boundary or vertical mixing in a cryptomare. The proportion of mare materials in MET 01210 is greater than in Apollo core samples at the mare-highland boundary. The burial depth (>several meters deep) inferred from the lack of</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/20150002838','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/20150002838"><span>Gusev-Meridiani-Type Soil Component Dissolved in Some Shock Glasses in <span class="hlt">Shergottites</span></span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Ross, D. K.; Rao, M. N.; Nyquist, L. E.; Shi, C. Y.; Sutton, S.; Harrison, D. H.</p> <p>2015-01-01</p> <p>Modal analysis, based on APXS, MiniTES and Mossbauer results obtained at Gusev and Meridiani sites on Mars, indicates that Martian soils consist predominantly of igneous minerals such as olivine, pyroxene and feldspar (approximately70 - 80%), with the balance consisting of alteration minerals such as sulfates, silica and chlorides]. These studies also showed that soil alteration did not occur in-situ and igneous and alteration components are derived from different sources. Below, we analyse the chemical abundance data obtained from shock glasses in <span class="hlt">shergottites</span> using mass balance mixing models. In these models, the two main end members used are (a) host rock chemical composition and (b) the GM soils average composition as the second component. Here, we consider the S-bearing phases as indicators of added alteration phases in the shock glasses and GM soils. Although the S-bearing phase in shock glasses occurs as micron sized sulfide blebs, we showed in earlier abstracts that sulfur was originally present as sulfate in impact glass-precursor materials and was subsequently reduced to sulfide during shock melting. This conclusion is based on results obtained from S-K XANES studies, Fe/S atomic ratios in sulfide blebs and 34S/32S isotopic measurements in these sulfide blebs. Additionally, sulfur in several EET79001 Lith. A glasses is found to correlate positively with Al2O3 and CaO (and negatively with FeO and MgO), suggesting the presence of Al- and Ca- sul-fate-bearing phases. The distribution of the 87Sr/86Sr iso-topic ratios determined in Lith. A glasses (,27 &,188 and,54) indicate that Martian soil gypsum and host rock material were mixed with each other in the glass precursors. In some vugs in Lith A glass,27 detected gypsum laths. Furthermore, the Martian regolith-de-rived component (where sulfur typically occurs as sul-fate) is identified in these glasses by determining neutron produced isotopic excesses/deficits in 80Kr and 149Sm isotopes. Moreover, the</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2010EGUGA..1212550B','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2010EGUGA..1212550B"><span>Mantle metasomatism by melts of HIMU piclogite components: new insights from Fe-<span class="hlt">lherzolite</span> xenoliths (Calatrava Volcanic District, Central Spain)</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Bianchini, Gianluca; Beccaluva, Luigi; Bonadiman, Costanza; Nowell, Geoff M.; Pearson, D. Graham; Siena, Franca; Wilson, Marjorie</p> <p>2010-05-01</p> <p>Mantle xenoliths from the Calatrava Volcanic District (CLV), central Spain, are characterized by a wide compositional range, which includes <span class="hlt">lherzolites</span> (prevalent) as well as minor amounts of wehrlite, ol-websterite and rare dunites. They generally have bulk-rock Mg#s <89, lower than any primordial mantle estimates. Intra-suite variations in modal proportions are inconsistent with those predicted by melting models irrespective of the starting composition; mineral and bulk-rock variation diagrams show inconsistencies between the CLV compositions (anomalously enriched in Fe-Ti) and those predicted from partial melting of primordial mantle material. Processes other than pure melt extraction are confirmed by the whole-rock REE budget, typically characterized by LREE enrichments, with LaN/YbN (up to 6.7), probably related to pervasive metasomatism. CLV mantle clinopyroxenes (cpx) generally display fractionated REE patterns with upward convex shapes, characterized by low HREE (Tm-Lu) concentrations (typically <6 x chondrite) and enrichments in Middle/Light REE (NdN/YbN up to 7, LaN/YbN up to 5). These "enriched" cpx compositions either result from re-equilibration of primary mantle cpx with an incoming melt, or represent cpx crystallization directly from the metasomatic agent. The latter was plausibly generated at greater depths in the presence of residual garnet (from peridotite or eclogite starting materials). Separated cpx have homogeneous 87Sr/86Sr compositions between 0.7031 and 0.7032; 143Nd/144Nd ranges from 0.51288 to 0.51295 and 176Hf/177Hf is in the range 0.28302-0.28265. Unlike mantle xenoliths and alpine-type peridotites from other Iberian occurrences, which range in composition from the Depleted Mantle (DM) to the Enriched Mantle (EM), the CLV mantle cpxs approach the composition of the HIMU mantle end-member, the genesis of which is generally interpreted as the result of long-term recycling of oceanic basalts/gabbros (or their eclogitic equivalent) via</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2003EAEJA.....8111L','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2003EAEJA.....8111L"><span>The effects of small amounts of H2O on partial melting of model spinel <span class="hlt">lherzolite</span> in the system CMAS</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Liu, X.; St. C. Oneill, H.</p> <p>2003-04-01</p> <p>Water (H_2O) is so effective at lowering the solidus temperatures of silicate systems that even small amounts of H_2O are suspected to be important in the genesis of basaltic magmas. The realization that petrologically significant amounts of H_2O can be stored in nominally anhydrous mantle minerals (olivine and pyroxenes) has fundamental implications for the understanding of partial melting in the mantle, for it implies that the role that H_2O plays in mantle melting may not be appropriately described by models in which the melting is controlled by hydrous phases such as amphibole. Although the effect of water in suppressing the liquidus during crystallization is quite well understood, such observations do not provide direct quantitative information on the solidus. This is because liquidus crystallization occurs at constant major-element composition of the system, but at unbuffered component activities (high thermodynamic variance). By contrast, for partial melting at the solidus the major-element component activities are buffered by the coexisting crystalline phases (low variance), but the major-element composition of the melt can change as a function of added H_2O. Accordingly we have determined both the solidus temperature and the melt composition in the system CMAS with small additions of H_2O, to 4 wt%, in equilibrium with the four-phase <span class="hlt">lherzolite</span> assemblage of fo+opx+cpx+sp. Experiments were conducted at 1.1 GPa and temperatures from 1473 K to the dry solidus at 1593 K in a piston-cylinder apparatus. Starting materials were pre-synthesised assemblage of fo+opx+cpx+sp, plus an oxide/hydroxide mix of approximately the anticipated melt composition. H_2O was added as either Mg(OH)_2 or Al(OH)_3. The crystalline assemblage and melt starting mix were added as separate layers inside sealed Pt capsules, to ensure large volumes of crystal-free melt. After the run doubly polished sections were prepared in order to analyse the quenched melt by FTIR spectroscopy, to</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=19910025973&hterms=united+kingdom+history&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D70%26Ntt%3Dunited%2Bkingdom%2Bhistory','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=19910025973&hterms=united+kingdom+history&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D70%26Ntt%3Dunited%2Bkingdom%2Bhistory"><span>Rare earth elements in minerals of the ALHA77005 <span class="hlt">shergottite</span> and implications for its parent magma and crystallization history</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Lundberg, Laura L.; Crozaz, Ghislaine; Mcsween, Harry Y., Jr.</p> <p>1990-01-01</p> <p>Analyses of mineral REE and selected minor and trace elements were carried out on individual grains of pyroxenes, whitlockite, maskelynite, and olivine of the Antarctic <span class="hlt">shergottite</span> ALHA77005, and the results are used to interpret its parent magma and crystallization history. The results of mineral compositions and textural observations suggest that ALHA77005 is a cumulate with about half cumulus material (olivine + chromite) and half postcumulus phases. Most of the REEs in ALHA77005 reside in whitlockite whose modal concentration is about 1 percent. Mineral REE data support previous suggestions that plagioclase and whitlockite crystallized late, and that low-Ca pyroxene initiated crystallization before high-Ca pyroxene. The REE patterns for the intercumulus liquid, calculated from distribution coefficients for ALHA77005 pyroxene, plagioclase, and whitlockite, are in very good agreement and are similar to that of Shergotty.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=19860047526&hterms=indigenous&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D30%26Ntt%3Dindigenous','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=19860047526&hterms=indigenous&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D30%26Ntt%3Dindigenous"><span>The case for a Martian origin of the <span class="hlt">shergottites</span>. II - Trapped and indigenous gas components in EETA 79001 glass</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Wiens, R. C.; Becker, R. H.; Pepin, R. O.</p> <p>1986-01-01</p> <p>The isotopic composition of N, Ar, Ne, and He, trapped in an uncrushed sample of the antarctic <span class="hlt">shergottite</span> EETA 79001, was analyzed by subjecting the evacuated sample to stepped heating in the presence of 100 mtorr of oxygen. The isotopic composition of nitrogen (with the delta-N-15 value of greater than 300 percent) and the elemental ratios Ar-36/N-14 and Ar-40/N-14 were covariant along mixing lines passing through the Martian atmospheric composition. The results of this and previous analyses are consistent with a two-component nitrogen system in which about 84 ppb of trapped Martian atmospheric N is mixed in variable proportions with another, more thermally labile N component during stepped heating. The isotopic Ar-36/Ar-38 ratio of the EETA 79001 is different from that of the earth atmosphere by about 25 percent.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=19910025973&hterms=Cerium&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D70%26Ntt%3DCerium','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=19910025973&hterms=Cerium&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D70%26Ntt%3DCerium"><span>Rare earth elements in minerals of the ALHA77005 <span class="hlt">shergottite</span> and implications for its parent magma and crystallization history</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Lundberg, Laura L.; Crozaz, Ghislaine; Mcsween, Harry Y., Jr.</p> <p>1990-01-01</p> <p>Analyses of mineral REE and selected minor and trace elements were carried out on individual grains of pyroxenes, whitlockite, maskelynite, and olivine of the Antarctic <span class="hlt">shergottite</span> ALHA77005, and the results are used to interpret its parent magma and crystallization history. The results of mineral compositions and textural observations suggest that ALHA77005 is a cumulate with about half cumulus material (olivine + chromite) and half postcumulus phases. Most of the REEs in ALHA77005 reside in whitlockite whose modal concentration is about 1 percent. Mineral REE data support previous suggestions that plagioclase and whitlockite crystallized late, and that low-Ca pyroxene initiated crystallization before high-Ca pyroxene. The REE patterns for the intercumulus liquid, calculated from distribution coefficients for ALHA77005 pyroxene, plagioclase, and whitlockite, are in very good agreement and are similar to that of Shergotty.</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_9");'>9</a></li> <li><a href="#" onclick='return showDiv("page_10");'>10</a></li> <li class="active"><span>11</span></li> <li><a href="#" onclick='return showDiv("page_12");'>12</a></li> <li><a href="#" onclick='return showDiv("page_13");'>13</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_11 --> <div id="page_12" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_10");'>10</a></li> <li><a href="#" onclick='return showDiv("page_11");'>11</a></li> <li class="active"><span>12</span></li> <li><a href="#" onclick='return showDiv("page_13");'>13</a></li> <li><a href="#" onclick='return showDiv("page_14");'>14</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="221"> <li> <p><a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=19860047526&hterms=INDIGENOUS&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D40%26Ntt%3DINDIGENOUS','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=19860047526&hterms=INDIGENOUS&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D40%26Ntt%3DINDIGENOUS"><span>The case for a Martian origin of the <span class="hlt">shergottites</span>. II - Trapped and indigenous gas components in EETA 79001 glass</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Wiens, R. C.; Becker, R. H.; Pepin, R. O.</p> <p>1986-01-01</p> <p>The isotopic composition of N, Ar, Ne, and He, trapped in an uncrushed sample of the antarctic <span class="hlt">shergottite</span> EETA 79001, was analyzed by subjecting the evacuated sample to stepped heating in the presence of 100 mtorr of oxygen. The isotopic composition of nitrogen (with the delta-N-15 value of greater than 300 percent) and the elemental ratios Ar-36/N-14 and Ar-40/N-14 were covariant along mixing lines passing through the Martian atmospheric composition. The results of this and previous analyses are consistent with a two-component nitrogen system in which about 84 ppb of trapped Martian atmospheric N is mixed in variable proportions with another, more thermally labile N component during stepped heating. The isotopic Ar-36/Ar-38 ratio of the EETA 79001 is different from that of the earth atmosphere by about 25 percent.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2012E%26PSL.341..195N','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2012E%26PSL.341..195N"><span>U-Pb isotopic systematics of shock-loaded and annealed baddeleyite: Implications for crystallization ages of Martian meteorite <span class="hlt">shergottites</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Niihara, Takafumi; Kaiden, Hiroshi; Misawa, Keiji; Sekine, Toshimori; Mikouchi, Takashi</p> <p>2012-08-01</p> <p>Shock-recovery and annealing experiments on basalt-baddeleyite mixtures were undertaken to evaluate shock effects on U-Pb isotopic systematics of baddeleyite. Shock pressures up to 57 GPa caused fracturing of constituent phases, mosaicism of olivine, maskelynitization of plagioclase, and melting, but the phase transition from monoclinic baddeleyite structure to high-pressure/temperature polymorphs of ZrO2 was not confirmed. The U-Pb isotopic systems of the shock-loaded baddeleyite did not show a large-scale isotopic disturbance. The samples shock-recovered from 47 GPa were then employed for annealing experiments at 1000 or 1300 °C, indicating that the basalt-baddeleyite mixture was almost totally melted except olivine and baddeleyite. Fine-grained euhedral zircon crystallized from the melt was observed around the relict baddeleyite in the sample annealed at 1300 °C for 1 h. The U-Pb isotopic systems of baddeleyite showed isotopic disturbances: many data points for the samples annealed at 1000 °C plotted above the concordia. Both radiogenic lead loss/uranium gain and radiogenic lead gain/uranium loss were observed in the baddeleyite annealed at 1300 °C. Complete radiogenic lead loss due to shock metamorphism and subsequent annealing was not observed in the shock-loaded/annealed baddeleyites studied here. These results confirm that the U-Pb isotopic systematics of baddeleyite are durable for shock metamorphism. Since <span class="hlt">shergottites</span> still preserve Fe-Mg and/or Ca zonings in major constituent phases (i.e. pyroxene and olivine), the shock effects observed in Martian baddeleyites seem to be less intense compared to that under the present experimental conditions. An implication is that the U-Pb systems of baddeleyite in <span class="hlt">shergottites</span> will provide crystallization ages of Martian magmatic rocks.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016DokES.467..303K','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016DokES.467..303K"><span>Composition of a carbonatitic melt in equilibrium with <span class="hlt">lherzolite</span> at 5.5-6.3 GPa and 1350°C</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Kruk, A. N.; Sokol, A. G.; Chebotarev, D. A.; Palyanov, Yu. A.; Sobolev, N. V.</p> <p>2016-03-01</p> <p>Generation of ultra-alkaline melts by the interaction of <span class="hlt">lherzolite</span> with cardonatites of various genesis was simulated at the P- T parameters typical of the base of the subcratonic lithosphere. Experiments with a duration of 150 h were performed at 5.5 and 6.3 GPa and 1350°C. The concentrations of CaO and MgO in melts are buffered by the phases of peridotite, and the concentrations of alkalis and FeO depend on the composition of the starting carbonatite. Melts are characterized by a low (<7 wt %) concentration of SiO2 and Ca# from 0.40 to 0.47. It is demonstrated that only high-Mg groups of carbonatitic inclusions in fibrous diamonds have a composition close to that of carbonatitic melts in equilibrium with <span class="hlt">lherzolite</span>. Most likely, the formation of kimberlite-like melts relatively enriched in SiO2 requires an additional source of heat from mantle plumes and probably H2O fluid.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=19860063595&hterms=Igneous+petrology&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D50%26Ntt%3DIgneous%2Bpetrology','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=19860063595&hterms=Igneous+petrology&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D50%26Ntt%3DIgneous%2Bpetrology"><span>A discussion of isotopic systematics and mineral zoning in the <span class="hlt">shergottites</span> - Evidence for a 180 m.y. igneous crystallization age</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Jones, J. H.</p> <p>1986-01-01</p> <p>The chronologies of the Shergotty, Zagami, ALHA 77005, and EETA 79001 meteorites were reexamined on the basis of <span class="hlt">shergottites</span>' petrography and mineral chemistry data. Among the various isochrons, the concordant Rb-Sr (about 180 Myr) and U-Th-Pb (about 190 Myr) internal isochrons are interpreted as representing the time of igneous crystallization, while the Rb-Sr, Sm-Nd, and Pb-Pb whole-rock isochrons are interpreted as mixing lines, and are reasonably attributed to igneous processes such as wall-rock assimilation and magma mixing. If the approximated age of less than 200 Myr is correct, the <span class="hlt">shergottites</span> represent the youngest known extraterrestrial basalts. This conclusion supports the hypothesis that the SNC meteorites are samples of Mars.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2013EGUGA..15.5463B','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2013EGUGA..15.5463B"><span>Detailed Raman Spectroscopic Study of the Tissint Meteorite: Extraordinary Occurrence of High Pressure Polymorphs in a Single Fresh Piece of Martian <span class="hlt">Shergottite</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Baziotis, Ioannis; Liu, Yang; Taylor, Lawrence</p> <p>2013-04-01</p> <p>A recent (July 2011) witnessed fall of a Martian <span class="hlt">Shergottite</span>, Tissint, has generated great excitement for its pristine nature and its great scientific potential owing to its minimum terrestrial contamination. In recent work, using detailed petrography, electron microprobe method, micro-Raman Spectroscopy on serial sections, we investigated the presence of high-pressure (Hi-P) polymorphs occurring in impact-melt pockets throughout our 10 gm sample. Based upon the static and dynamic phase experimentation, we reconstructed the P-T-t conditions for the formation of these many polymorphs (Baziotis et al., 2012, Nature Comm.). Tissint is an olivine-phyric <span class="hlt">shergottite</span>, with large olivine grains (2000 ° C. Furthermore, the large size of ringwoodite in Tissint likely reflects prolonged shock durations. After heating, rapid cooling was achieved in ~50 ms for the center of the melt pocket and ~20 ms for the rim of the pocket, rendering conditions capable of preserving the high-P minerals observed.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=19860063595&hterms=Igneous+rocks&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D90%26Ntt%3DIgneous%2Brocks','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=19860063595&hterms=Igneous+rocks&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D90%26Ntt%3DIgneous%2Brocks"><span>A discussion of isotopic systematics and mineral zoning in the <span class="hlt">shergottites</span> - Evidence for a 180 m.y. igneous crystallization age</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Jones, J. H.</p> <p>1986-01-01</p> <p>The chronologies of the Shergotty, Zagami, ALHA 77005, and EETA 79001 meteorites were reexamined on the basis of <span class="hlt">shergottites</span>' petrography and mineral chemistry data. Among the various isochrons, the concordant Rb-Sr (about 180 Myr) and U-Th-Pb (about 190 Myr) internal isochrons are interpreted as representing the time of igneous crystallization, while the Rb-Sr, Sm-Nd, and Pb-Pb whole-rock isochrons are interpreted as mixing lines, and are reasonably attributed to igneous processes such as wall-rock assimilation and magma mixing. If the approximated age of less than 200 Myr is correct, the <span class="hlt">shergottites</span> represent the youngest known extraterrestrial basalts. This conclusion supports the hypothesis that the SNC meteorites are samples of Mars.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/20140011731','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/20140011731"><span>Sm-Nd and Rb-Sr Isotopic Systematics of a Heavily Shocked Martian Meteorite Tissint and Petrogenesis of Depleted <span class="hlt">Shergottites</span></span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Shih, C.-Y.; Nyquist, L. E.; Park, J.; Agee, Carl B.</p> <p>2014-01-01</p> <p>Tissint is a very fresh Martian meteorite that fell near the town of Tissint in Morocco on July 18, 2011. It contains abundant olivine megacrysts (23%) in a fine-grained matrix of pyroxene (55%), maskelynitized plagioclase (15%), opaques (4%) and melt pockets (3%) and is petrographically similar to lithologies A and C of picritic <span class="hlt">shergottite</span> EETA 79001 [1,2]. The presence of 2 types of shock-induced glasses and all 7 high-pressure mineral phases that were ever found in melt pockets of Martian meteorites suggests it underwent an intensive shock metamorphism of 25 GPa and 2000 C localized in melt pockets [2]. Mineral textures suggest that olivines, pyroxenes and plagioclases probably did not experience such hightemperature. Earlier determinations of its age yielded 596+/-23 Ma [3] and 616+/-67 Ma [4], respectively, for the Sm-Nd system and 583+/-86 Ma for the Lu-Hf system [4], in agreement with the 575+/-18 Ma age of the oldest olivine-phyric depleted <span class="hlt">shergottite</span> Dho 019 [5]. However, the exposure ages of Tissint (1 Ma [1, 6, 7]) and Dho 019 (20 Ma [8]) are very different requiring two separate ejection events. These previously determined Sm-Nd and Lu-Hf ages are older than the Ar-Ar maskelynite plateau age of 524+/-15 Ma [9], reversing the pattern usually observed for Martian meteorites. In order to clarify these age issues and place models for Tissint's petrogenesis on a firm basis, we present new Rb-Sr and Sm- Nd isotopic results for Tissint, and discuss (a) the shock effects on them and the Ar-Ar chronometer, (b) correlation of the determined ages with those of other depleted <span class="hlt">shergottites</span>, and (c) the petrogenesis of depleted <span class="hlt">shergottites</span>. Since the meteorite is a recent fall, terrestrial contamination is expected to be minimal, but, the strong shock metamorphism might be expected to compromise the equilibrium of the isotopic systems.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=19940016384&hterms=consortium&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D70%26Ntt%3Dconsortium','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=19940016384&hterms=consortium&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D70%26Ntt%3Dconsortium"><span>Consortium study of lunar meteorites <span class="hlt">Yamato</span>-793169 and Asuka-881757: Geochemical evidence of mutual similarity, and dissimilarity versus other mare basalts</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Warren, Paul H.; Lindstrom, Marilyn M.</p> <p>1993-01-01</p> <p>Compositions of bulk powders and separated minerals from two meteorites derived from the mare lava plains of the Earth's Moon, <span class="hlt">Yamato</span>-793169 and Asuka-881757, indicate a remarkable degree of similarity to one another, and clearly favor lunar origin. However, these meteorites are unlike any previously studied lunar rock. In both cases, the bulk-rock TiO2 content is slightly greater than the level separating VLT from low-Ti mare basalt, yet the Sc content is much higher than previously observed except among high-Ti mare basalts. Conceivably, the Sc enrichment in A881757 reflects origin of this rock as a cumulate from a mare magma of 'normal' Sc content, but this seems unlikely. Mineral-separate data suggest that most of the Sc is in pyroxene, and a variety of evidence weighs against the cumulus hypothesis as a major cause for the high Sc. The remarkable similarity between Y793169 and A881757 suggests the possibility that they were derived from a single source crater on the Moon.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016AGUFM.T31D2933S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016AGUFM.T31D2933S"><span>Mantle wedge structure beneath the <span class="hlt">Yamato</span> Basin, southern part of the Japan Sea, revealed by long-term seafloor seismic observations</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Shinohara, M.; Nakahigashi, K.; Yamashita, Y.; Yamada, T.; Mochizuki, K.; Shiobara, H.</p> <p>2016-12-01</p> <p>The Japanese Islands are located at subduction zones where Philippine Sea (PHS) plate subducts from the southeast beneath the Eurasian plate and the Pacific plate descends from the east beneath the PHS and Eurasian plates and have a high density of seismic stations. Many seismic tomography studies using land seismic station data were conducted to reveal the seismic structure. These studies discussed the relationship between heterogeneous structures and the release of fluids from the subducting slab, magma generation and movement in the subduction zone. However, regional tomography using the land station data did not have a sufficient resolution to image a deep structure beneath the Japan Sea.To obtain the deep structure, observations of natural earthquakes within the Japan Sea are essential. Therefore, we started the repeating long-term seismic observations using ocean bottom seismometers(OBSs) in the <span class="hlt">Yamato</span> Basin from 2013 to 2016. We apply travel-time tomography method to the regional earthquake and teleseismic arrival-data recorded by OBSs and land stations. In this presentation, we will report the P and S wave tomographic images down to a depth of 300 km beneath the southern part of the Japan Sea. This study was supported by "Integrated Research Project on Seismic and Tsunami Hazards around the Sea of Japan" conducted by the Ministry of Education, Culture, Sports, Science, and Technology (MEXT) of Japan.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2006AGUFM.P23C0070W','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2006AGUFM.P23C0070W"><span>A Search for <span class="hlt">Shergottite</span>-like Outliers in Orbital TES Data Using the Mini-TES Spectrum of Bounce Rock</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Wright, S. P.; Wyatt, M. B.; Christensen, P. R.</p> <p>2006-12-01</p> <p>Bounce Rock was found by the MER Opportunity rover and is interpreted as an anomalous distal impact ejecta deposited on the windblown sands of the Meridiani plains [Squyres et al., Science, 2004]. X-Ray, Moessbauer, and thermal infrared (TIR) spectra of Bounce Rock are distinct from any measured at either Rover landing site and are best matched by various basaltic <span class="hlt">shergottites</span> such as Shergotty and Zagami. Recent work on the TIR spectra of experimentally shocked plagioclases and basalts [Johnson et al., JGR, 2002; 2006] and shocked terrestrial basalt [Wright et al., LPSC, 2006] suggest that the Mini-TES spectrum of Bounce Rock appears to be an unshocked version of Zagami or perhaps Shergotty. Spectral observations of unshocked martian lithologies similar in composition to martian meteorites are important for constraining the extent of SNC-like lithologies in orbital data as all meteorite samples display some degree of shock effect and may not be representative of the bulk of martian surface compositions. The Mini-TES spectrum of Bounce Rock thus represents a rare unshocked pigeonite-augite-plagioclase basalt spectrum that would never be available in meteorite collections or spectral libraries. This fact and the difficulties of both producing an artificial pigeonite spectrum and finding pigeonite-rich regions on Mars make the Bounce Rock spectrum an excellent end-member in the search for potential <span class="hlt">shergottite</span> source regions with global TIR data. Previous work locating Thermal Emission Spectrometer (TES) pixels high in olivine, orthopyroxene [Hamilton et al., MaPS, 2003], and quartzofeldspathic minerals [Bandfield et al., JGR, 2004] have shown the utility of using lithologic end-members rather than large mineral spectral libraries. However, minerals with higher polymerization than feldspar such as olivines and pyroxenes do not show changes in TIR spectra at the shock level all <span class="hlt">shergottites</span> have been subjected to [Johnson et al., JGR, 2002]. In this work, global TES</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016CoMP..171...19K','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016CoMP..171...19K"><span><span class="hlt">Lherzolitic</span> versus harzburgitic garnet trends: sampling of extended depth versus extended composition. Reply to the comment by Ivanic et al. 2015</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Kopylova, M.; Hill, P. J. A.; Russell, J. K.; Cookenboo, H.</p> <p>2016-02-01</p> <p>Using the Hill et al. (Contrib Mineral Petrol 169:13, 2015. doi: 10.1007/s00410-014-1102-7) modeling technique, we have tested the idea of Ivanic et al. (Contrib Mineral Petrol 164:505-520, 2012) that decompression and metamorphic re-equilibration of garnet with spinel causes garnet zoning perpendicular to the Cr-Ca harzburgitic trend in garnet composition. The modeling confirms that garnet zoning across the harzburgitic trend cannot form without spinel buffering. The harzburgitic trend is very rare because it results from extreme compositional heterogeneity of the mantle at the same depth. In contrast, the common <span class="hlt">lherzolitic</span> trend requires less diversity in the bulk composition of the mantle, as it can be established with only a few samples of metamorphically re-equilibrated mantle peridotite deriving from a variety of depths.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2011AGUFM.V31D2557D','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2011AGUFM.V31D2557D"><span>Trace element abundances in pyroxenes from a dunite-harzburgite-<span class="hlt">lherzolite</span> sequence at the Trinity ophiolite: Evidence for multiple episodes of melt migration and melt-rock reaction</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Dygert, N. J.; Liang, Y.; Kelemen, P. B.</p> <p>2011-12-01</p> <p>Dunite, harzburgite, <span class="hlt">lherzolite</span>, and plagioclase <span class="hlt">lherzolite</span> (DHL-PL) sequences have been observed in the mantle sections of the Trinity ophiolite [1]. In an earlier study, detailed microprobe analyses of olivine, orthopyroxene (opx), clinopyroxene (cpx), and spinel were conducted on a densely sampled traverse across a 20-meter DHL-PL sequence [2]. Systematic outcrop-scale compositional gradients in major elements such as Ni in olivine and Ti in cpx suggest basaltic melt migration from the dunite into adjacent plagioclase <span class="hlt">lherzolite</span>, causing melt-rock reactions that dissolved plagioclase, opx, and cpx and precipitated olivine. Analogous geochemical gradients and lithological sequences have been produced in reactive dissolution experiments involving melt-bearing peridotite and basalt [3]. In an effort to further improve our understanding of melt migration and melt-rock reaction processes at Trinity, we analyzed pyroxene grains in all four lithologies for transition metals and rare earth elements (REE) using LA-ICPMS. Generally, REE patterns fall into two distinct groups, those within and near (<4m from) the dunite body will be referred to as group 1, while those farther from the dunite body (9-17.5m from the dunite-harzburgite contact) will be referred to as group 2. Group 1 cpx are extremely depleted in LREE with (Ce)C1 = 0.08-0.3, (Sm/Ce)C1 = 3-10, and (Sm/Yb)C1 = 0.3 to 0.8. Group 2 cpx have higher REE abundances but a similar extent of LREE depletion with (Ce)C1 = 0.5-1.5, (Sm/Ce)C1 = 5-16, and (Sm/Yb)C1 = 0.7-1.0. In general, REE concentrations in cpx cores and rims are similar across the transect, but two group 2 samples farthest from the dunite-harzburgite contact (15.4m and 17.5m) have lower mean rim concentrations than core concentrations, trending toward the more depleted REE abundances in group 1 cpx. Among the four group 1 samples in which opx was measured, cpx/opx REE partitioning is similar and suggests equilibration at near-magmatic temperatures (~1200</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/1986JVGR...29..355T','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/1986JVGR...29..355T"><span>Genesis of calc-alkali andesite magma in a hydrous mantle-crust boundary: Petrology of <span class="hlt">lherzolite</span> xenoliths from the Ichinomegata crater, Oga peninsula, northeast Japan, part II</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Takahashi, Eiichi</p> <p>1986-09-01</p> <p>The Ichinomegata volcano, northwestern Honshu, Japan, consisting of three explosion craters, is characterized by the presence of contemporaneous basalt (high-alkali tholeiite) and calc-alkali andesite and a variety of mafic and ultramafic xenoliths of deep-seated origin. The population of the rock types decreases exponentially as a function of increasing depth of their origin. Based on the Ichinomegata xenolith mineralogy, it is inferred that the lower crust and uppermost mantle beneath this area is partially hydrated, consisting dominantly of hornblende gabbro and hornblende-bearing spinel <span class="hlt">lherzolite</span>, respectively. Chemical analysis on spinel-pyroxene symplectite (so called garnet pseudomorph) in some Ichinomegata <span class="hlt">lherzolites</span> suggests a calcic-plagioclase primary chemistry rather than garnet. In <span class="hlt">lherzolite</span> xenoliths which have undergone a preheating event, primary partial melting textures are observed. The composition of the glass formed along the grain boundaries of the partially melted <span class="hlt">lherzolites</span> are similar to those produced in hydrous melting experiments on natural peridotite at about 10 kbar between 1000 and 1100°C. The high-alkali tholeiite and calc-alkali andesite of the Ichinomegata volcano are considered to have been formed by the following two-stage melting processes; (1) derivation of the basalt magma from partial melting of a peridotite diapir in the upper mantle at 40-50 km depth; (2) derivation of the calc-alkali andesite magma at 25-30 km depth by wet partial melting of the rocks at the mantle/crust boundary caused by emplacement of hot basaltic magma body. It is proposed that similar wet partial melting takes place more extensively beneath major island-arc volcanoes in the world, because the lower crust and the upper mantle beneath them may be hydrated due to continuous water supply from the subducting plate, and the amount of heat energy liberated at the mantle/crust boundary would be much larger in major stratovolcanoes than in the</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.osti.gov/scitech/biblio/6643130','SCIGOV-STC'); return false;" href="https://www.osti.gov/scitech/biblio/6643130"><span>Isotope and trace element systematics in a spinel-<span class="hlt">lherzolite</span>-bearing suite of basanitic volcanic rocks from San Luis Potosi, Mexico</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Pier, J.E.G.</p> <p>1989-01-01</p> <p><span class="hlt">Lherzolite</span>-bearing basanitic magmas of Quaternary age have erupted to form maars, lava/cinder cones and lava flows in two volcanic fields (Ventura and Santo Domingo) in the central Mexican state of San Luis Potosi. The systematics of the radiogenic isotopes of Sr, Nd, and Pb and the relationship between these parameters and elemental compositions are used to investigate the petrogenesis of the volcanic rocks and the nature of their mantle sources. Sr and Nd isotopic data are presented for 19 basanitic rocks, 5 kaersutites, and 6 <span class="hlt">lherzolitic</span> xenoliths; Pb data presented for the same 19 volcanic rocks and 4 of the 5 kaersutites. The isotopic compositions for all of these samples fall within the mantle range defined by MORBs and OIBs. The basanites generally plot within the OIB field on isotopic diagrams; most of the kaersutites are displaced to slightly more-depleted (i.e. MORB-like) values than the volcanic samples and the xenoliths, with one exception, are significantly more-depleted than either of these sample-types. As crustal contamination is considered unlikely for most of the volcanic samples, these trends are thought to arise from mixing multiple mantle components. The absence of similar isotopic elemental relationships for Epsilon Nd and the lack of correlation between {sup 206}Pb/{sup 204}Pb and the other Pb isotopes require a mixture of at least three mantle reservoirs: a depleted reservoir analogous to that of the MORBs, a St. Helena-type component, and a third component, which primarily affects Sr and {sup 208}Pb/{sup 204}Pb composition. This third component carries relatively radiogenic Sr and {sup 208}Pb/{sup 204}Pb and appears to be correlated with the degree of melting.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/20080013380','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/20080013380"><span>Sulfur and Iron Speciation in Gas-rich Impact-melt Glasses from Basaltic <span class="hlt">Shergottites</span> Determined by Microxanes</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Sutton, S. R.; Rao, M. N.; Nyquist, L. E.</p> <p>2008-01-01</p> <p>Sulfur is abundantly present as sulfate near Martian surface based on chemical and mineralogical investigations on soils and rocks in Viking, Pathfinder and MER missions. Jarosite is identified by Mossbauer studies on rocks at Meridian and Gusev, whereas MgSO4 is deduced from MgO - SO3 correlations in Pathfinder MER and Viking soils. Other sulfate minerals such as gypsum and alunogen/ S-rich aluminosilicates and halides are detected only in martian meteorites such as <span class="hlt">shergottites</span> and nakhlites using SEM/FE-SEM and EMPA techniques. Because sulfur has the capacity to occur in multiple valence states, determination of sulfur speciation (sulfide/ sulfate) in secondary mineral assemblages in soils and rocks near Mars surface may help us understand whether the fluid-rock interactions occurred under oxidizing or reducing conditions. To understand the implications of these observations for the formation of the Gas-rich Impact-melt (GRIM) glasses, we determined the oxidation state of Fe in the GRIM glasses using Fe K micro-XANES techniques.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017E%26PSL.474..180M','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017E%26PSL.474..180M"><span>Coupled Pb isotopic and trace element systematics of the Tissint meteorite: Geochemical signatures of the depleted <span class="hlt">shergottite</span> source mantle</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Moriwaki, Ryota; Usui, Tomohiro; Simon, Justin I.; Jones, John H.; Yokoyama, Tetsuya; Tobita, Minato</p> <p>2017-09-01</p> <p>The application of Martian meteorite U-Th-Pb isotope systematics to track the geochemical evolution of the Martian mantle has had limited success because of the difficulty in discriminating an indigenous magmatic Pb component from secondary near-surface components that have additionally been overprinted by terrestrial contamination. To mitigate this challenge, a successive acid-leaching experiment was conducted on the Tissint meteorite, the freshest, witnessed fall of a primitive, olivine-bearing Martian basalt. Trace element concentration analyses of acid leachates and residues indicate that secondary terrestrial contaminants were effectively removed by the early steps in the leaching experiments and that the acid residues contain pristine Pb from Tissint. The acid residue, which shows the most depleted REE signature, also has the least radiogenic Pb isotopic composition (206Pb/204Pb = 10.948, 207Pb/204Pb = 11.187, 208Pb/204Pb = 30.228). A two-stage mantle evolution model based on this composition indicates that the Tissint mantle has the lowest μ-value (238U/204Pb = 1.62 ± 0.09) among the <span class="hlt">shergottite</span> sources.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=19820048232&hterms=rare+earths&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D90%26Ntt%3D%2527%2527rare%2Bearths%2527%2527','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=19820048232&hterms=rare+earths&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D90%26Ntt%3D%2527%2527rare%2Bearths%2527%2527"><span>Complementary rare earth element patterns in unique achondrites, such as ALHA 77005 and <span class="hlt">shergottites</span>, and in the earth</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Ma, M.-S.; Schmitt, R. A.; Laul, J. C.</p> <p>1982-01-01</p> <p>Abundances of major, minor, and trace elements are determined in the Antarctic achondrite Allan Hills (ALHA) 77005 via sequential instrumental and radiochemical neutron activation analysis. The rare earth element (REE) abundances of ALHA 77005 reveal a unique chondritic normalized pattern; that is, the REEs are nearly unfractionated from La to Pr at approximately 1.0X chondrites, monotonically increased from Pr to Gd at approximately 3.4X with no Eu anomaly, nearly unfractionated from Gd and Ho and monotonically decreased from Ho to Lu at approximately 2.2X. It is noted that this unique REE pattern of ALHA 77005 can be modeled by a melting process involving a continuous melting and progressive partial removal of melt from a light REE enriched source material. In a model of this type, ALHA 77005 could represent either a crystallized cumulate from such a melt or the residual source material. Calculations show that the parent liquids for the <span class="hlt">shergottites</span> could also be derived from a light REE enriched source material similar to that for ALHA 77005.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2006JGRD..11116302M','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2006JGRD..11116302M"><span>Interpreting ancient ice in a shallow ice core from the South <span class="hlt">Yamato</span> (Antarctica) blue ice area using flow modeling and compositional matching to deep ice cores</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Moore, John C.; Nishio, Fumihiko; Fujita, Shuji; Narita, Hideki; Pasteur, Elizabeth; Grinsted, Aslak; Sinisalo, Anna; Maeno, Norikazu</p> <p>2006-08-01</p> <p>We explore methods of dating a 101 m ice core from a bare ice ablation area in the <span class="hlt">Yamato</span> Mountains, Dronning Maud Land, East Antarctica. There are two unknowns, the age of the ice at the surface and the age spanned by the core. The ice crystal growth rate was used to estimate the age span of the core at about 5 kyr. CO2, CH4 and N2O data on the core were compared with well-dated records from deep cores, leading to two plausible matches, both within isotope stage C. Detailed comparison of high-resolution DEP records from this core and the Dome Fuji core support the 55-61 kyr BP fit best. Oxygen isotope values in the core were then used to constrain the source elevation of the snow in the core, and hence the velocities in a simple flow line model. We inverted the ice core surface age, age span and origin site and their confidence intervals in a sensitivity study of flow model parameter space. The flow line model predicts good matches to the core by reducing glacial flow rates to 70% of present-day, accumulation rates by 45% with 10% confidence intervals. The modeled surface age for the whole meteorite field yields maximum surface ages of about 90 kyr, which is consistent with known, but poorly constrained, tephra dating, meteorite terrestrial ages and the frequency of meteorite discoveries. This approach can be used quite generally to link deep ice cores to surface outcrops on blue ice fields.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2013AGUFM.T11B2447Q','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2013AGUFM.T11B2447Q"><span>Probing the structure of the sub-Salinia mantle lithosphere using spinel <span class="hlt">lherzolite</span> xenoliths from Crystal Knob, Santa Lucia Range, California</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Quinn, D. P.; Saleeby, J.; Ducea, M. N.; Luffi, P. I.</p> <p>2013-12-01</p> <p>We present the first petrogenetic analysis of a suite of peridotite xenoliths from the Crystal Knob volcanic neck in the Santa Lucia Range, California. The neck was erupted during the Plio-Pleistocene through the Salinia terrane, a fragment of the Late Cretaceous southern Sierra-northwest Mojave supra-subduction core complex that was displaced ~310 km in the late Cenozoic along the dextral San Andreas fault. The marginal tectonic setting makes these xenoliths ideal for testing different models of upper-mantle evolution along the western North American plate boundary. Possible scenarios include the early Cenozoic underplating of Farallon-plate mantle lithosphere nappes (Luffi et al., 2009), Neogene slab window opening (Atwater and Stock, 1998), and the partial subduction and stalling of the Monterey microplate (Pisker et al., 2012). The xenoliths from Crystal Knob are spinel <span class="hlt">lherzolites</span>, which sample the mantle lithosphere underlying Salinia, and dunite cumulates apparently related to the olivine-basalt host. Initial study is focused on the spinel <span class="hlt">lherzolites</span>: these display an allotriomorphic granular texture with anisotropy largely absent. However, several samples exhibit a weak shape-preferred orientation in elongate spinels. Within each xenolith, the silicate phases are in Fe-Mg equilibrium; between samples, Mg# [molar Mg/(Mg+Fe)*100] ranges from 87 to 91. Spinels have Cr# [molar Cr/(Cr+Al)*100] ranging from 10 to 27. Clinopyroxene Rb-Sr and Sm-Nd radiogenic isotope data show that the <span class="hlt">lherzolites</span> are depleted in large-ion lithophile (LIL) elements, with uniform enrichment in 143Nd (ɛNd from +10.3 to +11.0) and depletion in 87Sr (87/86Sr of .702). This data rules out origin in the continental lithosphere, such as that observed in xenoliths from above the relict subduction interface found at at Dish Hill and Cima Dome in the Mojave (Luffi et al., 2009). The Mesozoic mantle wedge, which is sampled by xenoliths from beneath the southern Sierra Nevada batholith</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.osti.gov/scitech/biblio/1009042','SCIGOV-STC'); return false;" href="https://www.osti.gov/scitech/biblio/1009042"><span>Sulfur and iron speciation in gas-rich impact-melt glasses from basaltic <span class="hlt">shergottites</span> determined by microXANES</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Sutton, S.R.; Rao, M.N.; Nyquist, L.E.</p> <p>2008-04-28</p> <p>Sulfur and iron K XANES measurements were made on GRIM glasses from EET 79001. Iron is in the ferrous state. Sulfur speciation is predominately sulfide coordination but is Fe coordinated in Lith B and, most likely, Ca coordinated in Lith A. Sulfur is abundantly present as sulfate near Martian surface based on chemical and mineralogical investigations on soils and rocks in Viking, Pathfinder and MER missions. Jarosite is identified by Moessbauer studies on rocks at Meridian and Gusev, whereas MgSO{sub 4} is deduced from MgO-SO{sub 3} correlations in Pathfinder MER and Viking soils. Other sulfate minerals such as gypsum and alunogen/S-rich aluminosilicates and halides are detected only in martian meteorites such as <span class="hlt">shergottites</span> and nakhlites using SEM/FE-SEM and EMPA techniques. Because sulfur has the capacity to occur in multiple valence states, determination of sulfur speciation (sulfide/sulfate) in secondary mineral assemblages in soils and rocks near Mars surface may help us understand whether the fluid-rock interactions occurred under oxidizing or reducing conditions. On Earth, volcanic rocks contain measurable quantities of sulfur present as both sulfide and sulfate. Carroll and Rutherford showed that oxidized forms of sulfur may comprise a significant fraction of total dissolved sulfur, if the oxidation state is higher than {approx}2 log fO{sub 2} units relative to the QFM buffer. Terrestrial samples containing sulfates up to {approx}25% in fresh basalts from the Galapagos Rift on one hand and high sulfide contents present in oceanic basalts on the other indicate that the relative abundance of sulfide and sulfate varies depending on the oxygen fugacity of the system. Basaltic <span class="hlt">shergottites</span> (bulk) such as Shergotty, EET79001 and Zagami usually contain small amounts of sulfur ({approx}0.5%) as pyrrhotite. But, in isolated glass pockets containing secondary salts (known as GRIM glasses) in these meteorites, sulfur is present in high abundance ({approx}1-12%). To</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_10");'>10</a></li> <li><a href="#" onclick='return showDiv("page_11");'>11</a></li> <li class="active"><span>12</span></li> <li><a href="#" onclick='return showDiv("page_13");'>13</a></li> <li><a href="#" onclick='return showDiv("page_14");'>14</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_12 --> <div id="page_13" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_11");'>11</a></li> <li><a href="#" onclick='return showDiv("page_12");'>12</a></li> <li class="active"><span>13</span></li> <li><a href="#" onclick='return showDiv("page_14");'>14</a></li> <li><a href="#" onclick='return showDiv("page_15");'>15</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="241"> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/20160003470','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/20160003470"><span>The Mineralogy, Geochemistry, and Redox State of Multivalent Cations During the Crystallization of Primitive <span class="hlt">Shergottitic</span> Liquids at Various (f)O2. Insights into the (f)O2 Fugacity of the Martian Mantle and Crustal Influences on Redox Conditions of Martian Magmas.</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Shearer, C. K.; Bell, A. S.; Burger, P. V.; Papike, J. J.; Jones, J.; Le, L.; Muttik, N.</p> <p>2016-01-01</p> <p>The (f)O2 [oxygen fugacity] of crystallization for martian basalts has been estimated in various studies to range from IW-1 to QFM+4 [1-3]. A striking geochemical feature of the <span class="hlt">shergottites</span> is the large range in initial Sr isotopic ratios and initial epsilon(sup Nd) values. Studies by observed that within the <span class="hlt">shergottite</span> group the (f)O2 [oxygen fugacity] of crystallization is highly correlated with these chemical and isotopic characteristics with depleted <span class="hlt">shergottites</span> generally crystallizing at reduced conditions and enriched <span class="hlt">shergottites</span> crystallizing under more oxidizing conditions. More recent work has shown that (f)O2 [oxygen fugacity] changed during the crystallization of these magmas from one order of magnitude in Y980459 (Y98) to several orders of magnitude in Larkman Nunatak 06319. These real or apparent variations within single <span class="hlt">shergottitic</span> magmas have been attributed to mixing of a xenocrystic olivine component, volatile loss-water disassociation, auto-oxidation during crystallization of mafic phases, and assimilation of an oxidizing crustal component (e.g. sulfate). In contrast to the <span class="hlt">shergottites</span>, augite basalts such as NWA 8159 are highly depleted yet appear to be highly oxidized (e.g. QFM+4). As a first step in attempting to unravel petrologic complexities that influence (f)O2 [oxygen fugacity] in martian magmas, this study explores the effect of (f)O2 [oxygen fugacity] on the liquid line of descent (LLD) for a primitive <span class="hlt">shergottite</span> liquid composition (Y98). The results of this study will provide a fundamental basis for reconstructing the record of (f)O2 [oxygen fugacity] in <span class="hlt">shergottites</span> and other martian basalts, its effect on both mineral chemistries and valence state partitioning, and a means for examining the role of crystallization (and other more complex processes) on the petrologic linkages between olivine-phyric and pyroxene-plagioclase <span class="hlt">shergottites</span>.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=20040062419&hterms=location&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D90%26Ntt%3Dlocation','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=20040062419&hterms=location&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D90%26Ntt%3Dlocation"><span>In Situ Location and Characterization of Carbon-bearing Phases in Carbonaceous Chondrites: Insights from <span class="hlt">Yamato</span> 791198, a Weakly-altered CM2 Chondrite</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Brearley, Adrian J.</p> <p>2004-01-01</p> <p>Intense studies of carbonaceous chondrites have provided remarkable insights into the behavior of carbon during the earliest stages of our solar system. This research has demonstrated that carbonaceous meteorites contain a diverse array of organic compounds, whose origins are probably the result of multiple processes that occurred in different locations including interstellar space, the solar nebula and asteroidal parent bodies [1-3]. The most abundant organic carbon component in CI1 and CM2 carbonaceous chondrites is so-called macromolecular carbon, a high molecular weight material that has some affinities to terrestrial kerogen and constitutes approximately 60-70% of the organic material in these meteorites. Although recent studies e.g. [3] have radically improved our understanding of the structural and compositional characteristics of this material, a number of key questions remain to be addressed. In particular, our knowledge of where this macromolecular material is distributed at the fine-scale within carbonaceous chondrites is scant. [4] have shown that organic material is associated with phyllosilicate-rich matrix in CM chondrites, but the detailed mineralogical associations are not well-known. Over the past 2 years, we have begun to address this question by using energy filtered transmission electron microscopy (EFTEM) to locate carbon-bearing materials in situ, focusing specifically on the CM2s. To date we have reported data on the Murchison CM2 chondrite [5], a meteorite that has experienced a modest degree of aqueous alteration. To extend our observations to other CM2 chondrites, we have examined the occurrence of carbon-bearing phases in <span class="hlt">Yamato</span> 791198. Our recent studies [5] have shown that Y-791198 is among the most weakly-altered CM chondrite currently known and hence is likely to preserve a quite primitive distribution of carbonaceous material. In this study, we present initial observations on the distribution of these materials in one fine</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2011JHyd..400..465T','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2011JHyd..400..465T"><span>Pollutant runoff yields in the <span class="hlt">Yamato</span>-gawa River, Japan, to be applied for EAH books of municipal wastewater intending pollutant discharge reduction</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Tsuzuki, Yoshiaki; Yoneda, Minoru</p> <p>2011-04-01</p> <p>SummaryA Social Experiment Program to decrease municipal wastewater pollutant discharge by "soft interventions" in households and to improve river water quality was conducted in the <span class="hlt">Yamato</span>-gawa River Basin, Japan. Environmental accounting housekeeping (EAH) books of municipal wastewater were prepared mainly for dissemination purpose to be applied during the Social Experiment Program. The EAH books are table format spreadsheets to estimate pollutant discharges. Pollutant load per capita flowing into water body (PLC wb) and pollutant runoff yields from sub-river basins to the river mouth are indispensable parameters for their preparation. In order to estimate the pollutant runoff yields of the pollutants, BOD, TN and TP, a concept of pollutant runoff yield from upper monitoring point, MP n, to lower monitoring point, MP n+1 ( Rm n(n+1)), and that from corresponding sub-river basin ( Rd(n+1)(n+1)) was introduced in this paper. When proportion of the pollutant runoff yields, p n (= Rm n(n+1)/ Rd(n+1)(n+1)), was equal to 1.0 in all the river sections, which was determined based on the simulation results of Rm and Rd, pollutant runoff yield from sub-river basin n to the monitoring point nearest to the river mouth, Ry n7, were estimated to be 0.3-66.8% for BOD, 25.8-75.8% for TN and 18.9-78.5% for TP. The EAH books of municipal wastewater were prepared by adopting the estimated pollutant runoff yields, Ry n7. The EAH books were thought to be distributed widely, however, they did not seem to be used by many ordinary citizens in the Social Experiment Program in February, 2010, judging from the small number of website visitor counter and less responses from people. Possible reasons for less usage than expected were considered to be unsuccessful negotiation with the official organizations of the Social Experiment Program on the EAH books utilization as official tools and some difficulties in using the EAH books for ordinary people.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017M%26PS...52..268T','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017M%26PS...52..268T"><span>Oxygen isotope characteristics of chondrules from the <span class="hlt">Yamato</span>-82094 ungrouped carbonaceous chondrite: Further evidence for common O-isotope environments sampled among carbonaceous chondrites</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Tenner, T. J.; Kimura, M.; Kita, N. T.</p> <p>2017-02-01</p> <p>High-precision secondary ion mass spectrometry (SIMS) was employed to investigate oxygen three isotopes of phenocrysts in 35 chondrules from the <span class="hlt">Yamato</span> (Y) 82094 ungrouped 3.2 carbonaceous chondrite. Twenty-one of 21 chondrules have multiple homogeneous pyroxene data (∆17O 3SD analytical uncertainty: 0.7‰); 17 of 17 chondrules have multiple homogeneous pyroxene and plagioclase data. Twenty-one of 25 chondrules have one or more olivine data matching coexisting pyroxene data. Such homogeneous phenocrysts (1) are interpreted to have crystallized from the final chondrule melt, defining host O-isotope ratios; and (2) suggest efficient O-isotope exchange between ambient gas and chondrule melt during formation. Host values plot within 0.7‰ of the primitive chondrule mineral (PCM) line. Seventeen chondrules have relict olivine and/or spinel, with some δ17O and δ18O values approaching -40‰, similar to CAI or AOA-like precursors. Regarding host chondrule data, 22 of 34 have Mg#s of 98.8-99.5 and ∆17O of -3.9‰ to -6.1‰, consistent with most Acfer 094, CO, CR, and CV chondrite chondrules, and suggesting a common reduced O-isotope reservoir devoid of 16O-poor H2O. Six Y-82094 chondrules have ∆17O near -2.5‰, with Mg#s of 64-97, consistent with lower Mg# chondrules from Acfer 094, CO, CR, and CV chondrites; their signatures suggest precursors consisting of those forming Mg# 99, ∆17O: -5‰ ± 1‰ chondrules plus 16O-poor H2O, at high dust enrichments. Three type II chondrules plot slightly above the PCM line, near the terrestrial fractionation line (∆17O: +0.1‰). Their O-isotopes and olivine chemistry are like LL3 type II chondrules, suggesting they sampled ordinary chondrite-like chondrule precursors. Finally, three Mg# >99 chondrules have ∆17O of -6.7‰ to -8.1‰, potentially due to 16O-rich refractory precursor components. The predominance of Mg# 99, ∆17O: -5‰ ± 1‰ chondrules and a high chondrule-to-matrix ratio suggests bulk Y-82094</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016GeoOD..58....1M','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016GeoOD..58....1M"><span>Chemical composition and osmium-isotope systematics of primary and secondary PGM assemblages from high-Mg chromitite of the Nurali <span class="hlt">lherzolite</span> massif, the South Urals, Russia</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Malitch, K. N.; Anikina, E. V.; Badanina, I. Yu.; Belousova, E. A.; Pushkarev, E. V.; Khiller, V. V.</p> <p>2016-01-01</p> <p>The isotopic and geochemical characteristics of PGE mineralization in high-Mg chromitite from the banded dunite-wehrlite-clinopyroxenite complex of the Nurali <span class="hlt">lherzolite</span> massif, the South Urals, Russia is characterized for the first time. Electron microprobe analysis and LA MC-ICP-MS mass spectrometry are used for studying Cr-spinel and platinum-group minerals (PGM). Two processes synchronously develop in high-Mg chromitite subject to metamorphism: (1) the replacement of Mg-Al-rich Cr-spinel, orthopyroxene, and diopside by chromite, Cr-amphibole, chlorite, and garnet; (2) the formation of a secondary mineral assemblage consisting of finely dispersed ruthenium or Ru-hexaferrum aggregate and silicate-oxide or silicate matter on the location of primary Ru-Os-sulfides of the laurite-erlichmanite solid solution series. Similar variations of Os-isotopic composition in both primary and secondary PGM assemblages are evidence for the high stability of the Os isotope system in PGM and for the possibility of using model 187Os/188Os ages in geodynamic reconstructions.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016M%26PS...51..407W','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016M%26PS...51..407W"><span>Noble gases in 18 Martian meteorites and angrite Northwest Africa 7812—Exposure ages, trapped gases, and a re-evaluation of the evidence for solar cosmic ray-produced neon in <span class="hlt">shergottites</span> and other achondrites</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Wieler, R.; Huber, L.; Busemann, H.; Seiler, S.; Leya, I.; Maden, C.; Masarik, J.; Meier, M. M. M.; Nagao, K.; Trappitsch, R.; Irving, A. J.</p> <p>2016-02-01</p> <p>We present noble gas data for 16 <span class="hlt">shergottites</span>, 2 nakhlites (NWA 5790, NWA 10153), and 1 angrite (NWA 7812). Noble gas exposure ages of the <span class="hlt">shergottites</span> fall in the 1-6 Ma range found in previous studies. Three depleted olivine-phyric <span class="hlt">shergottites</span> (Tissint, NWA 6162, NWA 7635) have exposure ages of ~1 Ma, in agreement with published data for similar specimens. The exposure age of NWA 10153 (~12.2 Ma) falls in the range of 9-13 Ma reported for other nakhlites. Our preferred age of ~7.3 Ma for NWA 5790 is lower than this range, and it is possible that NWA 5790 represents a distinct ejection event. A Tissint glass sample contains Xe from the Martian atmosphere. Several samples show a remarkably low (21Ne/22Ne)cos ratio < 0.80, as previously observed in a many <span class="hlt">shergottites</span> and in various other rare achondrites. This was explained by solar cosmic ray-produced Ne (SCR Ne) in addition to the commonly found galactic cosmic ray-produced Ne, implying very low preatmospheric shielding and ablation loss. We revisit this by comparing measured (21Ne/22Ne)cos ratios with predictions by cosmogenic nuclide production models. Indeed, several <span class="hlt">shergottites</span>, acalpulcoites/lodranites, angrites (including NWA 7812), and the Brachina-like meteorite LEW 88763 likely contain SCR Ne, as previously postulated for many of them. The SCR contribution may influence the calculation of exposure ages. One likely reason that SCR nuclides are predominantly detected in meteorites from rare classes is because they usually are analyzed for cosmogenic nuclides even if they had a very small (preatmospheric) mass and hence low ablation loss.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2005AGUFM.P51A0902D','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2005AGUFM.P51A0902D"><span>Assimilation of High 18O/16O Crust by <span class="hlt">Shergottite</span>-Nakhlite-Chassigny (SNC) Magmas on Mars</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Day, J. M.; Taylor, L. A.; Valley, J. W.; Spicuzza, M. J.</p> <p>2005-12-01</p> <p>There is significant geochemical evidence for assimilation of crustal material into sub-aerial, mantle-derived, terrestrial basaltic magmas. Some of the most powerful constraints on crustal assimilation come from oxygen isotope studies, because supracrustal rocks often have distinct 18O/16O ratios resulting from interaction with Earth's hydrosphere. From a planetary perspective, studies of carbonate concretions from meteorite ALH84001 have yielded evidence for low-temperature crustal interaction at or near the surface of its putative parent body, Mars. This finding raises the possibility that crustal assimilation processes may be tracked using oxygen isotopes in combination with geochemical data of other reputed martian (SNC) meteorites. The whole-rock oxygen isotope ratios (Laser fluorination δ18O = +4.21 to +5.85‰ VSMOW) of SNC meteorites, correlate with aspects of their incompatible element chemistry. Some of the oxygen isotope variability may be explained by post-magmatic alteration on Mars or Earth; however, it appears, based on petrographic and geochemical observations, that a number of SNC meteorites, especially <span class="hlt">Shergottites</span>, retain the original whole-rock oxygen isotope values of their magmas prior to crystallisation. Correlations between oxygen isotopes and incompatible element geochemistry are consistent with assimilation of a high-18O/16O, incompatible-element rich, oxidizing crustal component by hot, mantle-derived magmas (δ18O = ~~4.2‰). A crustal component has previously been recognized from Sr-Nd-Os isotope systematics and oxygen fugacity measurements of SNC meteorites. Oxygen isotope evidence from SNC meteorites suggests high-18O/16O crustal contaminants on Mars result from low temperature (< 300°C) interaction with martian hydrosphere. The extent of apparent crustal contamination tracked by oxygen isotopes in SNC meteorites implies that the majority of martian crust may have undergone such interactions. Evidence for assimilation of</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2010EGUGA..12.8448H','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2010EGUGA..12.8448H"><span>Melt localization and its relation to deformation in the subcontinental mantle: a case study from layered dunite-harzburgite-<span class="hlt">lherzolite</span> bodies of the Ronda peridotite massif, Spain</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Hidas, Karoly; Garrido, Carlos J.; Bodinier, Jean-Louis; Tommasi, Andrea; Booth-Rea, Guillermo; Gervilla, Fernando; Marchesi, Claudio</p> <p>2010-05-01</p> <p>; Vauchez & Garrido, 2001). In the vicinity of the recrystallization front, coarse granular peridotites pass into layered granular peridotites with a typical layered structure composed of plagioclase <span class="hlt">lherzolites</span>, harzburgites and dunites. The main scientific goals of this study are to test new mechanism(s) for the formation of dunites and dunite-harzburgite-<span class="hlt">lherzolite</span> layered bodies in the subcontinental lithospheric mantle on the example of Ronda peridotite massif (Spain), and to introduce new processes that are expected to lead the evolution of the subcontinental lithospheric mantle in extensional settings. References Kelemen, P.B. & Dick, H.J.B. (1995). Focused melt flow and localized deformation in the upper-mantle — juxtaposition of replacive dunite and ductile shear zones in the Josephine peridotite, SW Oregon. J. Geophys. Res. 100 (B1): 423-438. Kelemen, P.B., Hirth, G., Shimizu, N., Spiegelman, M. & Dick, H.J.B. (1997). A review of melt migration processes in the adiabatically upwelling mantle beneath oceanic spreading ridges. Philosophical Transactions of the Royal Society a-Mathematical Physical and Engineering Sciences 355(1723): 283-318. Lenoir, X., Garrido, C.J., Bodinier, J.L., Dautria, J.M. & Gervilla, F. (2001). The recrystallization front of the Ronda peridotite: Evidence for melting and thermal erosion of subcontinental lithospheric mantle beneath the Alboran basin. pp. 141-158. Savelieva, G.N., Sobolev, A.V., Batanova, V.G., Suslov, P.V. & Bruhmann, G. (2008). The structure of melt transport mantle channels. Geotectonics 42 (6): 430--447. Van Der Wal, D. & Bodinier, J.L. (1996). Origin of the recrystallisation front in the Ronda peridotite by km-scale pervasive porous melt flow. Contributions to Mineralogy and Petrology, 122(4): 387-405. Vauchez, A. & Garrido, C.J. (2001). Seismic properties of an asthenospherized lithospheric mantle: constraints from lattice preferred orientations in peridotite from the Ronda massif. Earth and Planetary Science Letters</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015GCarp..66...41N','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015GCarp..66...41N"><span>Orthopyroxene-enrichment in the <span class="hlt">lherzolite</span>-websterite xenolith suite from Paleogene alkali basalts of the Poiana Ruscă Mountains (Romania)</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Nédli, Zsuzsanna; Szabó, Csaba; Dégi, Júlia</p> <p>2015-12-01</p> <p>In this paper we present the petrography and geochemistry of a recently collected <span class="hlt">lherzolite</span>-websterite xenolith series and of clinopyroxene xenocrysts, hosted in Upper Cretaceous-Paleogene basanites of Poiana Ruscă (Romania), whose xenoliths show notable orthopyroxene-enrichment. In the series a slightly deformed porphyroclastic-equigranular textured series could represent the early mantle characteristics, and in many cases notable orthopyroxene growth and poikilitic texture formation was observed. The most abundant mantle lithology, Type A xenoliths have high Al and Na-contents but low mg# of the pyroxenes and low cr# of spinel suggesting a low degree (< 10 %) of mafic melt removal. They are also generally poor in overall REE-s (rare earth elements) and have flat REY (rare earth elements+ Y) patterns with slight LREE-depletion. The geochemistry of the Type A xenoliths and calculated melt composition in equilibrium with the xenolith clinopyroxenes suggests that the percolating melt causing the poikilitization can be linked to a mafic, Al-Na-rich, volatile-poor melt and show similarity with the Late Cretaceous-Paleogene (66-72 Ma) subduction-related andesitic magmatism of Poiana Ruscă. Type B xenoliths, with their slightly different chemistry, suggest that, after the ancient depletion, the mantle went through a slight metasomatic event. A subsequent passage of mafic melts in the mantle, with similar compositions to the older andesitic magmatism of Poiana Ruscă, is recorded in the pyroxenites (Fe-rich xenoliths), whereas the megacrysts seem to be cogenetic with the host basanite. The Poiana Ruscă xenoliths differ from the orthopyroxene-enriched mantle xenoliths described previously from the Carpathian-Pannonian Region and from the Dacia block.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014AGUFM.V23D4822B','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014AGUFM.V23D4822B"><span>Lithophile Trace Element Mass Balance in Spinel <span class="hlt">Lherzolites</span> from Borée, Massif Central, France: the Effects of Melt Impregnation on Variably Depleted Peridotites</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Barnett, C. J.; Harvey, J.; Morgan, D. J.; Hammond, S.; Walshaw, R.</p> <p>2014-12-01</p> <p>Isotopic and elemental investigations of peridotite xenoliths can be used to model the timing and degree of melt extraction in the mantle. However, the primary melt depletion signature preserved in these xenoliths can be overprinted by subsequent metasomatism and melt-rock interactions, which tend to obscure the degree of original melt depletion either through the crystallisation of secondary phases or through the pervasive addition of lithophile element-rich basalt or its derivatives. Anhydrous spinel <span class="hlt">lherzolite</span> xenoliths from the volcanic Maar de Borée in the French Massif Central have textures that vary from equigranular to protogranular. There is clear evidence of melt infiltration of up to several modal per cent in an anastomosing network of veins and stringers. Bulk-rock major elements and compatible trace element concentrations suggest that the Borée peridotites are genetically related by differing degrees of melt extraction, but the influence of melt infiltration, clearly visible at the thin section scale, and likely comprising several modal percent of the rock, makes this melt depletion difficult to quantify accurately. Some incompatible trace element concentrations in clinopyroxenes are consistent with melt depletion, while elevated (La/Yb)Nratios in others are clearly indicative of cryptic metasomatism and suggest yet another style of metasomatism. Furthermore, infiltrated melt along grain boundaries and in interstitial pockets disturbs the incompatible element mass balance, further obscuring the true nature of the prior melt depletion event(s). Quantitative lithophile element mass balance calculations will allow the effects of melt infiltration to be determined and stripped away from bulk-rock xenolith compositions, permitting a more realistic appraisal of the original melt depletion event.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2006CoMP..152....1A','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2006CoMP..152....1A"><span>Trace element partitioning between mica- and amphibole-bearing garnet <span class="hlt">lherzolite</span> and hydrous basanitic melt: 1. Experimental results and the investigation of controls on partitioning behaviour</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Adam, John; Green, Trevor</p> <p>2006-07-01</p> <p>Thirty five minor and trace elements (Li, Be, B, Sc, Cu, Zn, Ga, Ge, As, Rb, Nb, Mo, Ag, Cd, In, Sn, Sb, Cs, Ba, La, Ce, Nd, Sm, Tb, Ho, Tm, Lu, Hf, Ta, W, Tl, Pb, Bi, Th and U) in experimentally produced near-liquidus phases, from a primitive nelpheline basanite from Bow Hill in Tasmania (Australia), were analysed by LAM ICP-MS. A number of halogens (F, Cl and I) were also analysed by electron microprobe. The analyses were used to determine mineral/melt partition coefficients for mica, amphibole, garnet, clinopyroxene, orthopyroxene and olivine for conditions close to multiple saturation of the basanite liquidus with garnet <span class="hlt">lherzolite</span> (approximately 2.6 GPa and 1,200°C with 7.5 wt% of added H2O). A broader range of conditions was also investigated from 1.0 GPa and 1,025°C to 3.5 GPa and 1,190°C with 5-10 wt% of added H2O. The scope and comprehensiveness of the data allow them to be used for two purposes, these include the following: an investigation of some of the controlling influences on partition coefficients; and the compilation of a set partition coefficients that are directly relevant to the formation of the Bow Hill basanite magma by partial melting of mantle peridotite. Considering clinopyroxene, the mineral phase for which the most data were obtained, systematic correlations were found between pressure and temperature, mineral composition, cation radius and valence, and Δ G coulb (the coulombic potential energy produced by substituting a cation of mismatched valence into a crystallographic site). Δ G coulb is distinctly different for different crystallographic sites, including the M2 and M1 sites in clinopyroxene. These differences can be modelled as a function of variations in optimum valence (expressed as 1 sigma standard deviations) within individual M1 and M2 site populations.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/servlets/purl/10154294','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/servlets/purl/10154294"><span>Ga, Ca, and 3d transition element (Cr through Zn) partitioning among spinel-<span class="hlt">lherzolite</span> phases from the Lanzo massif, Italy: Analytical results and crystal chemistry</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Wogelius, R.A.; Fraser, D.G.</p> <p>1994-06-01</p> <p>Ultramafic rocks exposed in Lanzo massif, Italy is a record of mantle geochemistry, melting, sub-solidus re-equilibration. Plagioclase(+ spinel)-<span class="hlt">lherzolite</span> samples were analyzed by Scanning Proton Microscopy, other techniques. Previous work postulated partial melting events and a two-stage sub-solidus cooling history; this paper notes Ga enrichment on spinel-clinopyroxene grain boundaries, high Ga and transition element content of spinel, and pyroxene zonation in Ca and Al. Trace element levels in olivine and orthopyroxene are also presented. Zoning trends are interpreted as due to diffusion during cooling. Olivine-clinopyroxene Cr and Ca exchange as well as clinopyroxene and spinel zonation trends indicate that the massif experienced at least two sub-solidus cooling episodes, one at 20 kbar to 1000 C and one at 8 kbar <750C. Ga levels in cores of Lanzo high-Cr spinels are high (82-66 ppM) relative to other mantle spinels (66-40 ppM), indicating enrichment. Ga content of ultramafic spinels apparently increases with Cr content; this may be due to: increased Ga solubility stemming from crystal chemical effects and/or higher Ga activities in associated silicate melts. Thus, during melting, high-Cr residual spinel may tend to buffer solid-phase Ga level. These spinels are not only rich in Ga and Cr (max 26.37 el. wt %), but also in Fe (max 21.07 el. wt %), Mn (max 3400 ppM), and Zn (max 2430 ppM). These enrichments are again due to melt extraction and partitioning into spinel structure. Low Ni (min 1050 ppM) levels are due to unsuccessful competition of Ni with Cr for octahedral structural sites caused by crystal field. Comparisons of change in partitioning vs Cr content among several 3d transition elements for spinels from Lanzo, other localities allow us to separate crystal field effects from bulk chemical effects and to show that in typical assemblages, inversion of olivine-spinel partition coefficient for Ni from <1 to >1 should occur at 11% el. wt. Cr in spinel.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016E%26PSL.444....1D','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016E%26PSL.444....1D"><span>Variable microstructural response of baddeleyite to shock metamorphism in young basaltic <span class="hlt">shergottite</span> NWA 5298 and improved U-Pb dating of Solar System events</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Darling, James R.; Moser, Desmond E.; Barker, Ivan R.; Tait, Kim T.; Chamberlain, Kevin R.; Schmitt, Axel K.; Hyde, Brendt C.</p> <p>2016-06-01</p> <p>The accurate dating of igneous and impact events is vital for the understanding of Solar System evolution, but has been hampered by limited knowledge of how shock metamorphism affects mineral and whole-rock isotopic systems used for geochronology. Baddeleyite (monoclinic ZrO2) is a refractory mineral chronometer of great potential to date these processes due to its widespread occurrence in achondrites and robust U-Pb isotopic systematics, but there is little understanding of shock-effects on this phase. Here we present new nano-structural measurements of baddeleyite grains in a thin-section of the highly-shocked basaltic <span class="hlt">shergottite</span> Northwest Africa (NWA) 5298, using high-resolution electron backscattered diffraction (EBSD) and scanning transmission electron microscopy (STEM) techniques, to investigate shock-effects and their linkage with U-Pb isotopic disturbance that has previously been documented by in-situ U-Pb isotopic analyses. The shock-altered state of originally igneous baddeleyite grains is highly variable across the thin-section and often within single grains. Analyzed grains range from those that preserve primary (magmatic) twinning and trace-element zonation (baddeleyite shock Group 1), to quasi-amorphous ZrO2 (Group 2) and to recrystallized micro-granular domains of baddeleyite (Group 3). These groups correlate closely with measured U-Pb isotope compositions. Primary igneous features in Group 1 baddeleyites (n = 5) are retained in high shock impedance grain environments, and an average of these grains yields a revised late-Amazonian magmatic crystallization age of 175 ± 30 Ma for this <span class="hlt">shergottite</span>. The youngest U-Pb dates occur from Group 3 recrystallized nano- to micro-granular baddeleyite grains, indicating that it is post-shock heating and new mineral growth that drives much of the isotopic disturbance, rather than just shock deformation and phase transitions. Our data demonstrate that a systematic multi-stage microstructural evolution in</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2011AGUFM.P31B1709S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2011AGUFM.P31B1709S"><span>EBSD analysis of the <span class="hlt">Shergottite</span> Meteorites: New developments within the technique and their implication on what we know about the preferred orientation of Martian minerals</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Stephen, N.; Benedix, G. K.; Bland, P.; Berlin, J.; Salge, T.; Goran, D.</p> <p>2011-12-01</p> <p>What we know about the geology and mineralogy of the Martian surface has been characterised by both the use of remote sensing techniques and the analysis of Martian meteorites. Various techniques are employed to conduct these analyses including crystallographic, geochemical and spectral measurements, all of which enable us to infer a geological history for these rocks. Several references have been made to the potential for preferred orientation of crystals within the <span class="hlt">Shergottites</span> [1] and their implication for the cooling history of the respective magmas on Mars [2]. We have already shown that a preferred orientation of the two pyroxenes, augite and pigeonite, can be seen in the Zagami meteorite using electron back-scatter diffraction (EBSD) analysis [3]. However, when compared to previous modal studies of the same meteorites [4], it becomes apparent that the current EBSD datasets for Martian meteorites are incomplete. Indexing of some minerals can be hampered by the lack of available matches within library databases for EBSD, or become difficult to resolve between minerals where crystallographic differences between similar minerals fall below the technical limitations of the instrument [3]. Recent advances in EBSD technologies combined with the simultaneous acquisition of energy-dispersive spectra (EDS) however now allow us to determine a more comprehensive set of analyses in a much shorter period of time, fully resolving even similar minerals where areas have been left with no indexing previously [5]. Preliminary investigations suggest that the new technology can successfully index >90% of the sample. The most recent EBSD analyses potentially reveals previously unseen fabrics in the meteorites alongside the EDS hyper-spectral imaging helping to resolve any unknown or questionable phases within them. In this study we will present new data from an investigation using EDS alongside EBSD analysis on 2 <span class="hlt">Shergottite</span> meteorites, SAU 005 and Zagami, to further resolve</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2004GeCoA..68.2925B','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2004GeCoA..68.2925B"><span>Li isotopic variations in single pyroxenes from the Northwest Africa 480 <span class="hlt">shergottite</span> (NWA 480): a record of degassing of Martian magmas?</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Beck, P.; Barrat, J. A.; Chaussidon, M.; Gillet, Ph; Bohn, M.</p> <p>2004-07-01</p> <p> of <span class="hlt">shergottites</span> like Zagami and Shergotty, but also during the crystallization of the other types of basaltic <span class="hlt">shergottites</span>.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/19970019937','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/19970019937"><span>Constraints on Martian Differentiation Processes from Rb-Sr and Sm-Nd Isotopic Analyses of the Basaltic <span class="hlt">Shergottite</span> QUE 94201</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Borg, Lars E.; Nyquist, Larry E.; Taylor, Larry A.; Wiesmann, Henry; Shih, Chi-Y.</p> <p>1997-01-01</p> <p>Isotopic analyses of mineral, leachate, and whole rock fractions from the Martian <span class="hlt">shergottite</span> meteorite QUE 94201 yield Rb-Sr and Sm-Nd crystallization ages of 327 +/- 12 and 327 +/- 19 Ma, respectively. These ages are concordant, although the isochrons are defined by different fractions within the meteorite. Comparison of isotope dilution Sm and Nd data for the various QUE 94201 fractions with in situ ion microprobe data for QUE 94201 minerals from the literature demonstrate the presence of a leachable crustal component in the meteorite. This component is likely to have been added to QUE 94201 by secondary alteration processes on Mars, and can affect the isochrons by selectively altering the isotopic systematics of the leachates and some of the mineral fractions. The absence of crustal recycling processes on Mars may preserve the geochemical evidence for early differentiation and the decoupling of the Rb-Sr and Sm-Nd isotopic systems, underscoring one of the fundamental differences between geologic processes on Mars and the Earth.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2013M%26PS...48.1359B','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2013M%26PS...48.1359B"><span>Magmatic history and parental melt composition of olivine-phyric <span class="hlt">shergottite</span> LAR 06319: Importance of magmatic degassing and olivine antecrysts in Martian magmatism</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Balta, J. Brian; Sanborn, Matthew; McSween, Harry Y.; Wadhwa, Meenakshi</p> <p>2013-08-01</p> <p>Several olivine-phyric <span class="hlt">shergottites</span> contain enough olivine that they could conceivably represent the products of closed-system crystallization of primary melts derived from partial melting of the Martian mantle. Larkman Nunatak (LAR) 06319 has been suggested to represent a close approach to a Martian primary liquid composition based on approximate equilibrium between its olivine and groundmass. To better understand the olivine-melt relationship and the evolution of this meteorite, we report the results of new petrographic and chemical analyses. We find that olivine megacryst cores are generally not in equilibrium with the groundmass, but rather have been homogenized by diffusion to Mg# 72. We have identified two unique grain types: an olivine glomerocryst and an olivine grain preserving a primary magmatic boundary that constrains the time scale of eruption to be on the order of hours. We also report the presence of trace oxide phases and phosphate compositions that suggest that the melt contained approximately 1.1% H2O and lost volatiles during cooling, also associated with an increase in oxygen fugacity upon degassing. We additionally report in situ rare earth element measurements of the various mineral phases in LAR 06319. Based on these reported trace element abundances, we estimate the oxygen fugacity in the LAR 06319 parent melt early in its crystallization sequence (i.e., at the time of crystallization of the low-Ca and high-Ca pyroxenes), the rare earth element composition of the parent melt, and those of melts in equilibrium with later formed phases. We suggest that LAR 06319 represents the product of closed-system crystallization within a shallow magma chamber, with additional olivine accumulated from a cumulate pile. We infer that the olivine megacrysts are antecrysts, derived from a single magma chamber, but not directly related to the host magma, and suggest that mixing of antecrysts within magma chambers may be a common process in Martian magmatic</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016M%26PS...51.2011F','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016M%26PS...51.2011F"><span>Effect of chlorine on near-liquidus crystallization of olivine-phyric <span class="hlt">shergottite</span> NWA 6234 at 1 GPa: Implication for volatile-induced melting of the Martian mantle</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Farcy, Benjamin J.; Gross, Juliane; Carpenter, Paul; Hicks, Jacob; Filiberto, Justin</p> <p>2016-11-01</p> <p>Martian magmas are thought to be rich in chlorine compared with their terrestrial counterparts. Here, we experimentally investigate the effect of chlorine on liquidus depression and near-liquidus crystallization of olivine-phyric <span class="hlt">shergottite</span> NWA 6234 and compare these results with previous experimental results on the effect of chlorine on near-liquidus crystallization of the surface basalts Humphrey and Fastball. Previous experimental results showed that the change in liquidus temperature is dependent on the bulk composition of the basalt. The effect of chlorine on liquidus depression is greater for lower SiO2 and higher Al2O3 magmas than for higher SiO2 and lower Al2O3 magmas. The bulk composition for this study has lower Al2O3 and higher FeO contents than previous work; therefore, we provide additional constraints on the effect of the bulk composition on the influence of chlorine on near-liquidus crystallization. High pressure and temperature crystallization experiments were performed at 1 GPa on a synthetic basalt, of the bulk composition of NWA 6234, with 0-4 wt% Cl added to the sample as AgCl. The results are consistent with previous notions that with increasing wt% Cl in the melt, the crystallization temperature decreases. Importantly, our results have a liquidus depression ∆T (°C) from added chlorine that is consistent with the difference in bulk composition and suggest a dependence on both the bulk Al2O3 and FeO content. Our results suggest that the addition of chlorine to the Martian mantle may lower magma genesis temperatures and potentially aid in the petrogenesis of Martian magmas.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/20120001831','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/20120001831"><span>Laboratory Shock Experiments on Basalt - Iron Sulfate Mixes at Approximately 40-50 GPa and Their Relevance to the Martian Regolith Component Present in <span class="hlt">Shergottites</span></span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Rao, M. N.; Nyquist, L. E.; Ross, D. K.; Asimow, P. D.; See, T.; Sutton, S.; Cardernas, F.; Montes, R.; Cintala, M.</p> <p>2012-01-01</p> <p>Basaltic <span class="hlt">shergottites</span> such as Shergotty, Zagami and EET79001 contain impact melt glass pockets that are rich in Martian atmospheric gases [1] and are known as gas-rich impact-melt (GRIM) glasses. These glasses show evidence for the presence of a Martian regolith component based on Sm and Kr isotopic studies [2]. The GRIM glasses are sometimes embedded with clusters of innumerable micron-sized iron-sulfide blebs associated with minor amounts of iron sulfate particles [3, 4]. These sulfide blebs are secondary in origin and are not related to the primary igneous sulfides occurring in Martian meteorites. The material comprising these glasses arises from the highly oxidizing Martian surface and sulfur is unlikely to occur as sulfide in the Martian regoilith. Instead, sulfur is shown to occur as sulfate based on APXS and Mossbauer results obtained by the Opportunity and Spirit rovers at Meridiani and Gusev [5]. We have earlier suggested that the micron-sized iron sulfide globules in GRIM glasses were likely produced by shock-reduction of iron sulfate occurring in the regolith at the time when the GRIM glasses were produced by the meteoroid impact that launched the Martian meteorites into space [6]. As a result of high energy deposition by shock (approx. 40-60 GPa), the iron sulfate bearing phases are likely to melt along with other regolith components and will get reduced to immiscible sulfide fluid under reducing conditions. On quenching, this generates a dispersion of micron-scale sulfide blebs. The reducing agents in our case are likely to be H2 and CO which were shock-implanted from the Martian atmosphere into these glasses along with the noble gases. We conducted lab simulation experiments in the Lindhurst Laboratory of Experimental Geophysics at Caltech and the Experimental Impact Laboratory at JSC to test whether iron sulfide globules can be produced by impact-driven reduction of iron sulfate by subjecting Columbia River Basalt (CRB) and ferric sulfate mixtures to</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2009M%26PS...44..805F','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2009M%26PS...44..805F"><span>40Ar-39Ar age determinations of lunar basalt meteorites Asuka 881757, <span class="hlt">Yamato</span> 793169, Miller Range 05035, La Paz Icefield 02205, Northwest Africa 479, and basaltic breccia Elephant Moraine 96008</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Fernandes, Vera A.; Burgess, Ray; Morris, Adam</p> <p>2009-06-01</p> <p>40Ar-39Ar data are presented for the unbrecciated lunar basaltic meteorites Asuka (A-) 881757, <span class="hlt">Yamato</span> (Y-) 793169, Miller Range (MIL) 05035, LaPaz Icefield (LAP) 02205, Northwest Africa (NWA) 479 (paired with NWA 032), and basaltic fragmental breccia Elephant Moraine (EET) 96008. Stepped heating 40Ar-39Ar analyses of several bulk fragments of related meteorites A-881757, Y-793169 and MIL 05035 give crystallization ages of 3.763 ± 0.046 Ga, 3.811 ± 0.098 Ga and 3.845 ± 0.014 Ga, which are comparable with previous age determinations by Sm-Nd, U-Pb Th-Pb, Pb-Pb, and Rb-Sr methods. These three meteorites differ in the degree of secondary 40Ar loss with Y-793169 showing relatively high Ar loss probably during an impact event ˜200 Ma ago, lower Ar loss in MIL 05035 and no loss in A-881757. Bulk and impact melt glass-bearing samples of LAP 02205 gave similar ages (2.985 ± 0.016 Ga and 2.874 ± 0.056 Ga) and are consistent with ages previously determined using other isotope pairs. The basaltic portion of EET 96008 gives an age of 2.650 ± 0.086 Ga which is considered to be the crystallization age of the basalt in this meteorite. The Ar release for fragmental basaltic breccia EET 96008 shows evidence of an impact event at 631 ± 20 Ma. The crystallization age of 2.721 ± 0.040 Ga determined for NWA 479 is indistinguishable from the weighted mean age obtained from three samples of NWA 032 supporting the proposal that these meteorites are paired. The similarity of 40Ar-39Ar ages with ages determined by other isotopic systems for multiple meteorites suggests that the K-Ar isotopic system is robust for meteorites that have experienced a significant shock event and not a prolonged heating regime.</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_11");'>11</a></li> <li><a href="#" onclick='return showDiv("page_12");'>12</a></li> <li class="active"><span>13</span></li> <li><a href="#" onclick='return showDiv("page_14");'>14</a></li> <li><a href="#" onclick='return showDiv("page_15");'>15</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_13 --> <div id="page_14" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_12");'>12</a></li> <li><a href="#" onclick='return showDiv("page_13");'>13</a></li> <li class="active"><span>14</span></li> <li><a href="#" onclick='return showDiv("page_15");'>15</a></li> <li><a href="#" onclick='return showDiv("page_16");'>16</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="261"> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016M%26PS...51..390S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016M%26PS...51..390S"><span>Determination of volatile concentrations in fluorapatite of Martian <span class="hlt">shergottite</span> NWA 2975 by combining synchrotron FTIR, Raman spectroscopy, EMPA, and TEM, and inferences on the volatile budget of the apatite host-magma</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>SłAby, Ewa; Koch-Müller, Monika; FöRster, Hans-Jürgen; Wirth, Richard; Rhede, Dieter; Schreiber, Anja; Schade, Ulrich</p> <p>2016-02-01</p> <p>We combined the focused ion beam sample preparation technique with polarized synchrotron-based FTIR (Fourier transform infrared) spectroscopy, laser-Raman spectroscopy, electron microprobe analysis (EMPA), and transmission electron microscope (TEM) analysis to identify and quantify structurally bound OH, F, Cl, and CO3 groups in fluorapatite from the Northwest Africa 2975 (NWA 2975) <span class="hlt">shergottite</span>. In this study, the first FTIR spectra of the OH-stretching region from a Martian apatite are presented that show characteristic OH-bands of a F-rich, hydroxyl-bearing apatite. Depending on the method of apatite-formula calculation and whether charge balance is assumed or not, the FTIR-based quantification of the incorporated OH, expressed as wt% H2O, is in variably good agreement with the H2O concentration calculated from electron microprobe data. EMP analyses yielded between 0.35 and 0.54 wt% H2O, and IR data yielded an average H2O content of 0.31 ± 0.03 wt%, consistent with the lower range determined from EMP analyses. The TEM observations implied that the volatiles budget of fluorapatite is magmatic. The water content and the relative volatile ratios calculated for the NWA 2975 magma are similar to those established for other enriched or intermediate <span class="hlt">shergottites</span>. It is difficult to define the source of enrichment: either Martian wet mantle or crustal assimilation. Comparing the environment of parental magma generation for NWA 2975 with the terrestrial mantle in terms of water content, it displays a composition intermediate between enriched and depleted MORB.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/1996LPI....27..705K','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/1996LPI....27..705K"><span>QUE94201, a New Martian Meteorite that May Represent a Bulk Melt Rather than a Cumulate Fraction</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Kring, D. A.; Gleason, J. D.; Hill, D. H.; Jull, A. J. T.; Boynton, W. V.</p> <p>1996-03-01</p> <p>QUE94201 is a new mafic achondrite dominated by pyroxene and plagioclase. Petrologic and geochemical analyses of a bulk chip (,16) and thin-section (,7) indicate the sample is a basaltic gabbro that is related to previously described basaltic and <span class="hlt">lherzolitic</span> <span class="hlt">shergottites</span> of suspected martian origin. However, unlike the cumulate fractions represented by other <span class="hlt">shergottites</span>, QUE94201 is a plutonic rock that fractionally crystallized in what appears (petrographically) to be a closed system. QUE94201 contains more Fe-rich pyroxene and more bulk Al, Ti, and P than other <span class="hlt">shergottites</span>, including lithology B of EETA79001, and thus appears to be more evolved. However, QUE94201 is also more LREE-depleted than other <span class="hlt">shergottites</span> which suggests it has not assimilated as much of the LREE-enriched mantle component thought to have affected the compositions of other <span class="hlt">shergottites</span>.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=19860063599&hterms=noble+gases&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D60%26Ntt%3Dnoble%2Bgases','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=19860063599&hterms=noble+gases&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D60%26Ntt%3Dnoble%2Bgases"><span>Xenon and other noble gases in <span class="hlt">shergottites</span></span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Swindle, T. D.; Caffee, M. W.; Hohenberg, C. M.</p> <p>1986-01-01</p> <p>The isotopic composition of the xenon component trapped in EETA 79001's lithologies B and C has been determined, and other noble gases were measured in some samples. The Xe component was found to have light isotope ratios indistinguishable from those of the terrestrial atmosphere. The trapped component has a Xe-129/Xe-132 ratio of about 2.4, and is enhanced in Xe-134 and Xe-136 relative to the terrestrial atmosphere or the average carbonaceous chondrite. Similarities between values for Ar-40/Ar-36, Xe-129/Xe-132, and N-15/N-14 and the corresponding Martian atmospheric values suggest Martian origin of the trapped gases.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2011LPI....42.1897S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2011LPI....42.1897S"><span>40Ar-39Ar Studies of the Shocked L6 Chondrites Allan Hills 78003, <span class="hlt">Yamato</span> 74445, and <span class="hlt">Yamato</span> 791384</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Swindle, T. D.; Isachsen, C. E.; Weirich, J. R.; Kimura, M.</p> <p>2011-03-01</p> <p>Three heavily shocked L6 chondrites clearly record resetting of their K-Ar systems in the last ~1000 Ma. However, their Ar systematics are complicated enough that it is not obvious whether they were involved in the 475 Ma L-chondrite event.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.osti.gov/scitech/biblio/6716326','SCIGOV-STC'); return false;" href="https://www.osti.gov/scitech/biblio/6716326"><span>Compositional evolution of high-temperature sheared <span class="hlt">lherzolite</span> PHN 1611</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Smith, D. ); Griffin, W.L.; Ryan, C.G. )</p> <p>1993-02-01</p> <p>The evolution of fertile' mantle has been studied by proton microprobe (PIXE) analysis of minerals of a high-temperature sheared xenolith from the Thaba Putsoa kimerlite in Lesotho, southern Africa. Analyzed elements include Ni, Cu, Zn, Ga, Sr, Y, and Zr. Garnets are homogeneous in Ni and Zn but have rims enriched relative to cores in Zr and Y. Compositions of olivine neoblasts define intergranular gradients of Fe, Zn, and Ni; Fe-rich olivine is relatively Zn-rich but Ni-poore. Although individual clinopyroxene grains are nearly homogeneous, clinopyroxene associated with Fe-rich olivine is relatively Fe- and Zn-rich but Sr- and Cr-poor. The trace-element abundances and compositional gradients constrain the processes of periodotite enrichment and the thermal history. Enrichment of Zr, Y, and Fe in garnet rims documents infiltration of a silica-undersaturated melt. The Fe-rich olivine compositions and the Zn and Fe gradients establish that the xenolith was sampled from near a melt conduit. Mechanical mixing of inhomogeneous peridotite and melt infiltration may have been concurrent. Because garnets appear homogeneous in Ni, mantle temperature changes affecting PHN 1611 occurred before or over a longer period than the melt infiltration. Measured and calculated abundances of many incompatible trace elements in the rock are similar to those proposed for primitive mantle. Calculated chondrite-normalized abundances of Sr, Ti, Zr, and Y are like those of appropriate REE. Enrichment processes in PHN 1611 proceeded at unusually high recorded temperature and in the apparent absence of minor phases common in lower-temperature metasomatized rocks, but similar processes may be common. In particular, mechanical mixing near mantle dikes may frequently occur. These enrichment mechanisms may produce xenolith compositions that resemble some proposed for primitive mantle but that have different implications for mantle evolution. 61 refs., 7 figs., 2 tabs.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/20120007400','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/20120007400"><span>Iron Redox Systematics of <span class="hlt">Shergottites</span> and Martian Magmas</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Righter, Kevin; Danielson, L. R.; Martin, A. M.; Newville, M.; Choi, Y.</p> <p>2010-01-01</p> <p>Martian meteorites record a range of oxygen fugacities from near the IW buffer to above FMQ buffer [1]. In terrestrial magmas, Fe(3+)/ SigmaFe for this fO2 range are between 0 and 0.25 [2]. Such variation will affect the stability of oxides, pyroxenes, and how the melt equilibrates with volatile species. An understanding of the variation of Fe(3+)/SigmaFe for martian magmas is lacking, and previous work has been on FeO-poor and Al2O3-rich terrestrial basalts. We have initiated a study of the iron redox systematics of martian magmas to better understand FeO and Fe2O3 stability, the stability of magnetite, and the low Ca/high Ca pyroxene [3] ratios observed at the surface.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/20100036694','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/20100036694"><span>Crystallization of the Zagami <span class="hlt">Shergottite</span>: An Experimental Study</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Lofgren, Gary E.; McCoy, Timothy J.</p> <p>2000-01-01</p> <p>Spherulites are usually rounded or spherical objects found in rhyolitic obsidian. They usually comprise acicular crystals of alkali feldspar that radiate from a single point. The radiating array of crystalline fibers typically have a similar crystallographic orientation such that a branch fiber departs slightly but appreciably from that of its parent fiber. Individual fibers range from 1 to several micrometers in diameter. The spherulites most likely form by heterogeneous nucleation on microscopic seed crystals, bubbles, or some other surface at high degrees of supercooling. They grow very rapidly stabilizing their fibrous habit and typically range in size from microscopic to a few cm in diameter.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2003EAEJA....10642D','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2003EAEJA....10642D"><span>Chemical Alterations in Martian Meteorites from Cold and Hot Deserts</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Dreibus, G.; Huisl, W.; Spettel, B.; Haubold, R.; Jagoutz, E.</p> <p>2003-04-01</p> <p>Martian meteorites (SNC) provide evidence of the magmatic fractionation processes of their parent body. As 23 of the total of 27 meteorites are finds, the influence of chemical alterations during their residence time on Earth must be considered, when interpreting the mineralogical, chemical, or isotopic features. Many basaltic <span class="hlt">shergottites</span> and nakhlites were collected both in the cold desert, Antarctica, and in hot deserts of North Africa and Asia. To detect alteration processes in the finds we have to compare their analytical data with those obtained from the very scarce falls. In this way, we find an overabundance of iodine in meteorites from Antarctica. The iodine contamination is caused by aerosols adhering to the ice. Therefore, iodine can penetrate into the meteorite during its residence in Antarctica. The iodine content measured in the Antarctic <span class="hlt">shergottites</span> varies from 0.060 to 4.6 ppm and seems to depend on their residence time on ice. The paired <span class="hlt">Yamato</span> nakhlites Y-000593 and Y-000749 recently discovered in Antarctica also reveal an iodine overabundance compared to Nakhla, which is the only fall among the nakhlites. However, in Nakhla we have another problem of alteration. Nakhla has unusually high Br and Cl concentrations which could originate from terrestrial or parent body alterations. As Cl and Br are readily extracted during water leaching experiments we favor a terrestrial contamination. A Br overabundance was also found in many olivine-rich <span class="hlt">shergottite</span> finds from hot deserts, DaG 476, Dhofar 019, and SaU 005. However, in the basaltic <span class="hlt">shergottite</span> Dhofar 378 and in the nakhlite NWA 817 [1] no Br contamination was observed. The olivine phases of the <span class="hlt">shergottites</span> seem to be preferably attacked by weathering reactions in the hot deserts. In the <span class="hlt">shergottites</span> from hot deserts, the subchondritic La/U ratios are remarkable, indicating a U contamination. All these meteorites are covered with an evaporation product, caliche. Caliche has a high content of</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2012LPI....43.2108R','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2012LPI....43.2108R"><span>Crystallization of <span class="hlt">Yamato</span> 980459 at 0.5 GPa: Are Residual Liquids like QUE 94201</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Rapp, J. F.; Draper, D. S.; Mercer, C. M. M.</p> <p>2012-03-01</p> <p>We have experimentally crystallized the Y-980459 composition, and find that the liquid evolves to a very similar composition to that of QUE 94201. This implies that these two meteorites sample geochemically similar source regions.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/20120002806','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/20120002806"><span>Crystallization of <span class="hlt">Yamato</span> 980459 at 0.5 GPA: Are Residual Liquids Like QUE 94201?</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Rapp, J. F.; Draper, D. S.; Mercer, C.</p> <p>2012-01-01</p> <p>The Martian basaltic meteorites Y980459 and QUE94201 (henceforth referred to as Y98 and QUE respectively) are thought to represent magmatic liquid compositions, rather than being products of protracted crystallization and accumulation like the majority of other martian meteorites. Both meteorite compositions have been experimentally crystallized at 1 bar, and liquidus phases were found to match corresponding mineral core compositions in the meteorites, consistent with the notion that these meteorites represent bona fide melts. They also represent the most primitive and most evolved basaltic martian samples, respectively. Y98 has Mg# (molar Mg/Mg+Fe) approximates 65, and lacks plagioclase; whereas QUE has Mg# approximates 40, and lacks olivine. However they share important geochemical characteristics (e.g. superchondritic CaO/Al2O3, very high epsilon(sub Nd) and low Sr-87/Sr-87) that suggest they sample a similar highly depleted mantle reservoir. As such, they represent likely endmembers of martian magmatic liquid compositions, and it is natural to seek petrogenetic linkages between the two. We make no claim that the actual meteorites themselves share a genetic link (the respective ages rule that out); we are exploring only in general whether primitive martian liquids like Y98 could evolve to liquids resembling QUE. Both experimental and computational efforts have been made to determine if there is indeed such a link. Recent petrological models at 1 bar generated using MELTS suggest that a QUE-like melt can be derived from a parental melt with a Y98 composition. However, experimental studies at 1 bar have been less successful at replicating this progression. Previous experimental crystallization studies of Y98 by our group at 0.5 GPa have produced melt compositions approaching that of QUE, although these results were complicated by the presence of small, variable amounts of H2O in some of the runs owing to the use of talc/pyrex experimental assemblies. Therefore we have repeated the four experiments, augmented with additional runs, all using BaCO3 cell assemblies, which are devoid of water, and these new experiments supersede those reported earlier. Here we report results of experiments simulating equilibrium crystallization; fractional crystallization experiments are currently underway.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=20010045199&hterms=dolomite&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D90%26Ntt%3Ddolomite','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=20010045199&hterms=dolomite&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D90%26Ntt%3Ddolomite"><span>Mineralogy and Petrology of <span class="hlt">Yamato</span> 86029: A New Type of Carbonaceous Chondrite</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Tonui, E.; Zolensky, M. E.</p> <p>2001-01-01</p> <p>Y-86029 resembles CI chondrites. Its matrix is very fine-grained. Olivine shows evidence of shock, which has rarely been observed in carbonaceous chondrites. Y-86029 experienced aqueous and thermal alteration during or after accretion in parent body. Additional information is contained in the original extended abstract.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://pubs.er.usgs.gov/publication/70012220','USGSPUBS'); return false;" href="http://pubs.er.usgs.gov/publication/70012220"><span>Samarium-neodymium systematics in kimberlites and in the minerals of garnet <span class="hlt">lherzolite</span> inclusions</span></a></p> <p><a target="_blank" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Basu, A.R.; Tatsumoto, M.</p> <p>1979-01-01</p> <p>The initial ratios of neodymium-143 to neodymium-144 in kimberlites ranging in age between 90 ?? 106 to 1300 ?? 106 years from South Africa, India, and the United States are different from the corresponding ratios in the minerals of peridotite inclusions in the kimberlites but are identical to the ratios in the basaltic achondrite Juvinas at the times of emplacement of the respective kimberlite pipes. This correlation between the kimberlites and Juvinas, which represents the bulk chondritic earth in rare-earth elements, strongly indicates that the kimberlite's source in the mantle is chondritic in rare-earth elements and relatively primeval in composition. Copyright ?? 1979 AAAS.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/17790851','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/17790851"><span>Samarium-neodymium systematics in kimberlites and in the minerals of garnet <span class="hlt">lherzolite</span> inclusions.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Basu, A R; Tatsumoto, M</p> <p>1979-07-27</p> <p>The initial ratios of neodymium-143 to neodymium-144 in kimberlites ranging in age between 90 x 10(6) to 1300 x 10(6) years from South Africa, India, and the United States are different from the corresponding ratios in the minerals of peridotite inclusions in the kimberlites but are identical to the ratios in the basaltic achondrite Juvinas at the times of emplacement of the respective kimberlite pipes. This correlation between the kimberlites and Juvinas, which represents the bulk chondritic earth in rare-earth elements, strongly indicates that the kimberlite's source in the mantle is chondritic in rare-earth elements and relatively primeval in composition.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2001AGUFM.T11B0858S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2001AGUFM.T11B0858S"><span>Mantle Partial Melting Beneath Gakkel Ridge Reflected in the Petrography of Spinel <span class="hlt">Lherzolites</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Snow, J. E.; Dick, H.; Buechl, A.; Michael, P.; Hellebrand, E.; Ship Sc Parties HEALY 102-POLARSTERN 59,; Ship Sc Parties HEALY 102-POLARSTERN 59,; Ship Sc Parties HEALY 102-POLARSTERN 59,</p> <p>2001-12-01</p> <p>One of the main aims of the AMORE expedition to Gakkel Ridge was to investigate the nature of mantle residues of low-degree partial melting. Previous results from a single sample of highly serpentinized Gakkel peridotite were unable to conclusively resolve many of the issues of mantle melting and mantle veining involved (1). We have made a preliminary examination of 46 thin sections and hundreds of hand samples of mantle peridotites made on board PFS POLARSTERN and HEALY in the course of the expedition. Most of these peridotites are altered 60-90%, like most abyssal peridotites. Some however are stunningly fresh, containing no detectable serpentine in thin section. The distribution of mantle rock types is similar to that from other mid-ocean ridges. Dunites are present but rare, in contrast to the SW Indian Ridge oblique spreading center at 12° E, as are plagioclase peridotites, in contrast to their abundance at Molloy Ridge further south on the arctic ridge system. There are two differences between this sample set and those commonly observed on mid-ocean ridges that are of particular note. First is the relative abundance of clinopyroxene. The mean clinopyroxene content and size observed in thin section are both qualitatively greater than is commonly observed in abyssal peridotites. Second, the spinels are more nearly euhedral, more abundant and commonly very pale in color. The pale color is well known to be a sign of low Cr content (and thus high activity of Al) in the residual system. All of these observations suggest a low degree of partial melting in the Gakkel Ridge mantle, in accordance with theoretical predictions. What has not been observed to date in even the largest and freshest samples is any evidence of significant mantle veining. It may be that mantle veins have sufficiently low solidi that they melt out completely without a trace even at the lowest degrees of partial melting. The petrographic evidence however suggests that there never was significant veining. Plagioclase is present in a few of the fresh samples, forming haloes around embayed spinels, and in contact with clinopyroxene forming spectacular symplectic haloes around the spinel. This suggests that in this case, the low pressure phase transformation cpx + spinel to plagioclase + olivine is responsible for the observed textures rather than impregnation by a basaltic melt (2). 1) E. Hellebrand et al, Chemical Geology in press 2001. 2) H. Dick (1989) in: Magmatism in the Ocean Basins</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/20060010509','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/20060010509"><span>Ar-Ar Ages of Nakhlites Y000593, NWA998, and Nakhla and CRE Age of NWA998.</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Garrison, D. H.; Bogard, D. D.</p> <p>2006-01-01</p> <p>The seven known Martian nakhlites are Nakhla, Lafayette, Governador Valadares, and four recent finds from hot and cold deserts: MIL03346 from the Transantarctic Mountains, a paired group from the <span class="hlt">Yamato</span> Mountains (Y000593, Y000749, and Y000802; 1), and two from Morocco (NWA998 and NWA817; 2). Radiometric ages (Sm-Nd, Rb-Sr, U-Pb, and Ar-Ar) for the first three nakhlites, along with Chassigny, fall in the range of 1.19-1.37 Gyr and may suggest a common formation age (e.g., 3). These meteorites also show very similar cosmic-ray (space) exposure ages, which suggests a single ejection event from Mars (3). The ages for nakhlites are different from those of Martian <span class="hlt">shergottites</span>, whose radiometric ages vary by nearly a factor of three (approximately 165-475 Myr) and whose space exposure ages vary over a factor of approximately 20 (3). <span class="hlt">Shergottite</span> ages suggest that multiple locations on the Martian surface have been sampled, whereas nakhlite data imply that only one Mars surface location has been sampled. Because older Martian surfaces are expected to be more abundant, it seems surprising that all nakhlites would represent only one Martian impact event. To address this issue, we are measuring the Ar-39-Ar-40 ages of Y-000593, NWA-998, Nakhla, and MIL-03346, and the space (CRE) exposure age of NWA998.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/20050169505','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/20050169505"><span>Ar-Ar Ages of Nakhlites Y000593, NWA998, and Nakhla and CRE Ages of NWA998</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Garrison, D. H.; Bogard, D. D.</p> <p>2005-01-01</p> <p>The seven known Martian nakhlites are Nakhla, Lafayette, Governador Valadares, and four recent finds from hot and cold deserts: MIL03346 from the Transantarctic Mountains, a paired group from the <span class="hlt">Yamato</span> Mountains (Y000593, Y000749, and Y000802, and two from Morocco (NWA998 and NWA817. Radiometric ages (Sm-Nd, Rb-Sr, U-Pb, and Ar-Ar) for the first three nakhlites, along with Chassigny, fall in the range of 1.19-1.37 Gyr and may suggest a common formation age. These meteorites also show very similar cosmic-ray (space) exposure ages, suggesting a single ejection event from Mars. The ages for nakhlites are different from those of Martian <span class="hlt">shergottites</span>, whose radiometric ages vary by nearly a factor of three (approx. 165-475 Myr) and whose space exposure ages vary over a factor of approx. 20. <span class="hlt">Shergottite</span> ages suggest that multiple locations on the Martian surface have been sampled, whereas nakhlite data imply sampling of only one Mars surface location. Because older Martian surfaces are expected to be more abundant, it seems surprising that all nakhlites would represent only one Martian impact event. To address this issue, we are measuring the (39)Ar-(40)Ar ages of Y-000593, NWA-998, Nakhla, and MIL-03346, and the space (CRE) exposure age of NWA998. Additional information is included in the original extended abstract.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015MsT..........1T','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015MsT..........1T"><span>Hydrogen Isotopic Systematics of Nominally Anhydrous Phases in Martian Meteorites</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Tucker, Kera</p> <p></p> <p>Hydrogen isotope compositions of the martian atmosphere and crustal materials can provide unique insights into the hydrological and geological evolution of Mars. While the present-day deuterium-to-hydrogen ratio (D/H) of the Mars atmosphere is well constrained (~6 times that of terrestrial ocean water), that of its deep silicate interior (specifically, the mantle) is less so. In fact, the hydrogen isotope composition of the primordial martian mantle is of great interest since it has implications for the origin and abundance of water on that planet. Martian meteorites could provide key constraints in this regard, since they crystallized from melts originating from the martian mantle and contain phases that potentially record the evolution of the H 2O content and isotopic composition of the interior of the planet over time. Examined here are the hydrogen isotopic compositions of Nominally Anhydrous Phases (NAPs) in eight martian meteorites (five <span class="hlt">shergottites</span> and three nakhlites) using Secondary Ion Mass Spectrometry (SIMS). This study presents a total of 113 individual analyses of H2O contents and hydrogen isotopic compositions of NAPs in the <span class="hlt">shergottites</span> Zagami, Los Angeles, QUE 94201, SaU 005, and Tissint, and the nakhlites Nakhla, Lafayette, and <span class="hlt">Yamato</span> 000593. The hydrogen isotopic variation between and within meteorites may be due to one or more processes including: interaction with the martian atmosphere, magmatic degassing, subsolidus alteration (including shock), and/or terrestrial contamination. Taking into consideration the effects of these processes, the hydrogen isotope composition of the martian mantle may be similar to that of the Earth. Additionally, this study calculated upper limits on the H2O contents of the <span class="hlt">shergottite</span> and nakhlite parent melts based on the measured minimum H2O abundances in their maskelynites and pyroxenes, respectively. These calculations, along with some petrogenetic assumptions based on previous studies, were subsequently used</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/20150001940','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/20150001940"><span>Early Solar System Alkali Fractionation Events Recorded by K-Ca Isotopes in the <span class="hlt">Yamato</span>-74442 LL-Chondritic Breccia</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Tatsunori, T.; Misawa, K.; Okano, O.; Shih, C.-Y.; Nyquist, L. E.; Simon, J. I.; Tappa, M. J.; Yoneda, S.</p> <p>2015-01-01</p> <p>Radiogenic ingrowth of Ca-40 due to decay of K-40 occurred early in the solar system history causing the Ca-40 abundance to vary within different early-former reservoirs. Marshall and DePaolo ] demonstrated that the K-40/Ca-40 decay system could be a useful radiogenic tracer for studies of terrestrial rocks. Shih et al. [3,4] determined 40K/40Ca ages of lunar granitic rock fragments and discussed the chemical characteristics of their source materials. Recently, Yokoyama et al. [5] showed the application of the K-40/Ca-40 chronometer for high K/Ca materials in ordinary chondrites (OCs). High-precision calcium isotopic data are needed to constrain mixing processes among early solar system materials and the time of planetesimal formation. To better constrain the solar system calcium isotopic compositions among astromaterials, we have determined the calcium isotopic compositions of OCs and an angrite. We further estimated a source K/Ca ratio for alkali-rich fragments in a chondritic breccia using the estimated solar system initial Ca-40/Ca-44.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2010GeCoA..74.4507Y','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2010GeCoA..74.4507Y"><span>The variety of lithologies in the <span class="hlt">Yamato</span>-86032 lunar meteorite: Implications for formation processes of the lunar crust</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Yamaguchi, A.; Karouji, Y.; Takeda, H.; Nyquist, L.; Bogard, D.; Ebihara, M.; Shih, C.-Y.; Reese, Y.; Garrison, D.; Park, J.; McKay, G.</p> <p>2010-08-01</p> <p>We performed a petrologic, mineralogical, geochemical, and isotopic study of several lithologies in the Y-86032 feldspathic breccia. This study leads us to conclude that Y-86032 likely originated on the lunar farside. Y-86032 is composed of several types of feldspathic clasts, granulitic breccias, and minor basaltic clasts set in a clastic matrix. We identify an "An97 anorthosite" that has An contents similar to those of nearside FANs. Mg' (= molar Mg/(Mg + Fe) × 100) values vary significantly from ˜45 to ˜80 covering the ranges of both nearside FANs and the Mg' gap between FANs and the Mg-suite. A light-gray feldspathic (LG) breccia making up ˜20% of the investigated slab (5.2 × 3.6 cm 2) mainly consists of fragments of anorthosites ("An93 anorthosite") more sodic than nearside FANs. LG also contains an augite-plagioclase clast which either could be genetically related to the An93 anorthosite or to slowly-cooled basaltic magma intruded into the precursor rock. The Na-rich nature of both An93 anorthosite and this clast indicates that the LG breccia was derived from a relatively Na-rich but incompatible-element-poor source. The Mg' variation indicates that the "An97 anorthosite" is a genomict breccia of several types of primary anorthosites. Granulitic breccias in Y-86032 have relatively high Mg' in mafic minerals. The highest Mg' values in mafic minerals for the "An97 anorthosite" and granulitic breccias are similar to those of Mg-rich lithologies recently described in Dhofar 489. Basaltic clasts in the dark-gray matrix are aluminous, and the zoning trends of pyroxene are similar to those of VLT or LT basalts. The crystallization of these basaltic clasts pre-date the lithification age of the clastic matrix at ˜3.8 Ga. The low K contents of plagioclase in both the anorthositic and basaltic clasts and generally low incompatible element abundances in all the lithologies in Y-86032 indicate that KREEP was not involved during the formation of the precursor lithologies. This observation further suggests that urKREEP did not exist in the source regions of these igneous lithologies. All these facts support the idea that Y-86032 was derived from a region far distant from the PKT and that the lithic clasts and fragments are indigenous to that region. An An97 anorthositic clast studied here has distinct Sm-Nd isotopic systematics from those previously found for another An97 anorthositic clast and "An93 anorthosite", and suggests either that An97 anorthosites come from isotopically diverse sources, or that the Sm-Nd isotopic systematics of this clast were reset ˜4.3 Ga ago. These lines of geochemical, isotopic, and petrologic evidence suggest that the lunar crust is geochemically more heterogeneous than previously thought.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/20120013688','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/20120013688"><span>Martian Igneous Geochemistry: The Nature of the Martian Mantle</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Mittlefehldt, D. W.; Elkins-Tanton, L. T.; Peng, Z. X.; Herrin, J. S.</p> <p>2012-01-01</p> <p>Mafic igneous rocks probe the interiors of their parent objects, reflecting the compositions and mineralogies of their source regions, and the magmatic processes that engendered them. Incompatible trace element contents of mafic igneous rocks are widely used to constrain the petrologic evolution of planets. We focus on incompatible element ratios of martian meteorites to constrain the petrologic evolution of Mars in the context of magma ocean/cumulate overturn models [1]. Most martian meteorites contain some cumulus grains, but regardless, their incompatible element ratios are close to those of their parent magmas. Martian meteorites form two main petrologic/ age groupings; a 1.3 Ga group composed of clinopyroxenites (nakhlites) and dunites (chassignites), and a <1 Ga group composed of basalts and <span class="hlt">lherzolites</span> (<span class="hlt">shergottites</span>).</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_12");'>12</a></li> <li><a href="#" onclick='return showDiv("page_13");'>13</a></li> <li class="active"><span>14</span></li> <li><a href="#" onclick='return showDiv("page_15");'>15</a></li> <li><a href="#" onclick='return showDiv("page_16");'>16</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_14 --> <div id="page_15" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_13");'>13</a></li> <li><a href="#" onclick='return showDiv("page_14");'>14</a></li> <li class="active"><span>15</span></li> <li><a href="#" onclick='return showDiv("page_16");'>16</a></li> <li><a href="#" onclick='return showDiv("page_17");'>17</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="281"> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016EGUGA..1810005O','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016EGUGA..1810005O"><span>Petrologic Evolution of Karayazı Basaltic Plateau: Mixture of melts-derived from both spinel and garnet <span class="hlt">lherzolite</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Oyan, Vural; Özdemir, Yavuz; Jourdan, Fred</p> <p>2016-04-01</p> <p>Collision-related volcanism in Eastern Anatolia spreads in a wide zone from the Erzurum-Kars Plateau in the northeast to the Karacadaǧ in the south. Volcanic activity in the region started 15 Ma ago (Middle Miocene) in the south of region following the continent-continent collision between Arabian and Eurasia plates, and continued up to historical times. Voluminous basaltic lava plateaus and basaltic lavas from local eruption centers occurred as a result of high production level of volcanism during the Pliocene time interval. Karayazı basatic lava area located in the Northeast of Turkey is one of the most important and largest basaltic plateau in the East Anatolia. This area which is named to be Karayazı basaltic plateau has covered an area of approximately 200 km2. Lavas of the Karayazı basaltic plateau are characterized with alkali and subalkali basalt erupted from different centers up to from Miocene to Quaternary times. Lavas of the Karayazı basaltic plateau is characterized by alkali olivine basalts and subalkali basalts. These lavas are composed of olivine, plagioclase, augite and titanoaugite crystals and display porphyritic to aphyric textures. Sr, Nd and Hf isotopic compositions of the basaltic plateau vary between 0.703396-0.704976, 0.512730-0.512918 ve 0.282002-0.283029, respectively. MORB pattern of the lavas and isotopic composition imply that alkali and subalkali basalts erupted from Karayazı plateau could have been derived from a mantle source that had previously been enriched by a distinct subduction component. A partial melting model was conducted to evaluate partial melting processes in mantle source of the alkali and subalkali basalts. Results of this model suggest the presence of both strongly spinel and slightly garnet peridotite in the source, a partial melting degree of 2-10 % and mixing of the derivative melts from them in the genesis of the Karayazı basaltic volcanism. All these findings indicate that the source region of the Karayazı basaltic volcanism might have been a mixture of melts derived from both astenospheric and lithospheric mantles, containing a distinct subduction signature. Key Words: East Anatolia, Karayazı basalt plateau, Melting, Spinel, Garnet</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/servlets/purl/936965','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/servlets/purl/936965"><span>Uranium-lead isotope systematics of Mars inferred from the basaltic <span class="hlt">shergottite</span> QUE 94201</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Gaffney, A M; Borg, L E; Connelly, J N</p> <p>2006-12-22</p> <p>Uranium-lead ratios (commonly represented as {sup 238}U/{sup 204}Pb = {mu}) calculated for the sources of martian basalts preserve a record of petrogenetic processes that operated during early planetary differentiation and formation of martian geochemical reservoirs. To better define the range of {mu} values represented by the source regions of martian basalts, we completed U-Pb elemental and isotopic analyses on whole rock, mineral and leachate fractions from the martian meteorite Queen Alexandra Range 94201 (QUE 94201). The whole rock and silicate mineral fractions have unradiogenic Pb isotopic compositions that define a narrow range ({sup 206}Pb/{sup 204}Pb = 11.16-11.61). In contrast, the Pb isotopic compositions of weak HCl leachates are more variable and radiogenic. The intersection of the QUE 94201 data array with terrestrial Pb in {sup 206}Pb/{sup 204}Pb-{sup 207}Pb/{sup 204}Pb-{sup 208}Pb/{sup 204}Pb compositional space is consistent with varying amounts of terrestrial contamination in these fractions. We calculate that only 1-7% contamination is present in the purified silicate mineral and whole rock fractions, whereas the HCl leachates contain up to 86% terrestrial contamination. Despite the contamination, we are able to use the U-Pb data to determine the initial {sup 206}Pb/{sup 204}Pb of QUE 94201 (11.086 {+-} 0.008) and calculate the {mu} value of the QUE 94201 mantle source to be 1.823 {+-} 0.008. This is the lowest {mu} value calculated for any martian basalt source, and, when compared to the highest values determined for martian basalt sources, indicates that {mu} values in martian source reservoirs vary by at least 100%. The range of source {mu} values further indicates that the {mu} value of bulk silicate Mars is approximately three. The amount of variation in the {mu} values of the mantle sources ({mu} {approx} 2-4) is greater than can be explained by igneous processes involving silicate phases alone. We suggest the possibility that a small amount of sulfide crystallization may generate large extents of U-Pb fractionation during formation of the mantle sources of martian basalts.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/20120001842','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/20120001842"><span>Volatile Siderophile Elements in <span class="hlt">Shergottites</span>: Constraints on Core Formation and Magmatic Degassing</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Righter, Kevin; Humayun, M.</p> <p>2012-01-01</p> <p>Volatile siderophile elements (e.g., As, Sb, Ge, Ga, In, Bi, Zn, Cd, Sn, Cu, Pb) can place constraints both on early differentiation as well as the origin of volatiles. This large group of elements has been used to constrain Earth accretion [1,2], and Earth-Moon geochemistry [3]. Application to Earth has been fostered by new experimental studies of these elements such as Ge, In, and Ga [4,5,6]. Application to Mars has been limited by the lack of data for many of these elements on martian meteorites. Many volatile elements are considered in the pioneering work by [7] but for only the small number of martian samples then available. We have made new measurements on a variety of martian meteorites in order to obtain more substantial datasets for these elements using the analytical approach of [8]. We use the new dataset, together with published data from the literature, to define martian mantle abundances of volatile siderophile elements. Then, we evaluate the possibility that these abundances could have been set by mid-mantle (14 GPa, 2100 C) metal-silicate equilibrium, as suggested by the moderately and slightly siderophile elements [9]. Finally, we examine the possibility that some elements were affected by volatility and magmatic degassing.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=19830067592&hterms=Elephants&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D60%26Ntt%3DElephants','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=19830067592&hterms=Elephants&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D60%26Ntt%3DElephants"><span>Petrogenesis of the Elephant Moraine A79001 meteorite Multiple magma pulses on the <span class="hlt">shergottite</span> parent body</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Mcsween, H. Y., Jr.; Jarosewich, E.</p> <p>1983-01-01</p> <p>The EETA 79001 achondrite consists of two distinct igneous lithologies joined along a planar, non-brecciated contact. Both are basaltic rocks composed primarily of pigeonite, augite, and maskelynite, but one contains zoned megacrysts of olivine, orthopyroxene, and chromite that represent disaggregated xenoliths of harzburzite. Both lithologies probably formed from successive volcanic flows or multiple injections of magma into a small, shallow chamber. Many similarities between the two virtually synchronous magmas suggest that they are related. Possible mechanisms to explain their differences involve varying degrees of assimilation, fractionation from similar parental magmas, or partial melting of a similar source peridotite; of these, assimilation of the observed megacryst assemblage seems most plausible. However, some isotopic contamination may be required in any of these petrogenetic models. The meteorite has suffered extensive shock metamorphism and localized melting during a large impact event that probably excavated and liberated it from its parent body.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/servlets/purl/1019058','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/servlets/purl/1019058"><span>Disturbance of isotope systematics in meteorites during shock and thermal metamorphism and implications for <span class="hlt">shergottite</span> chronology</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Gaffney, A M; Borg, L E; Asmerom, Y</p> <p>2008-12-10</p> <p>Shock and thermal metamorphism of meteorites from differentiated bodies such as the Moon and Mars have the potential to disturb chronometric information contained in these meteorites. In order to understand the impact-related mechanisms and extent of disturbance to isochrons, we undertook experiments to shock and heat samples of 10017, a 3.6 billion year old lunar basalt. One sub-sample was shocked to 55 GPa, a second subsample was heated to 1000 C for one week, and a third sub-sample was maintained as a control sample. Of the isotope systems analyzed, the Sm-Nd system was the least disturbed by shock or heat, followed by the Rb-Sr system. Ages represented by the {sup 238}U-{sup 206}Pb isotope system were degraded by shock and destroyed with heating. In no case did either shock or heating alone result in rotated or reset isochrons that represent a spurious age. In some cases the true crystallization age of the sample was preserved, and in other cases age information was degraded or destroyed. Although our results show that neither shock nor thermal metamorphism alone can account for the discordant ages represented by different isotope systems in martian meteorites, we postulate that shock metamorphism may render a meteorite more susceptible than unshocked material to subsequent disturbance during impact-related heating or aqueous alteration on Mars or Earth. The combination of these processes may result in the disparate chronometric information preserved in some meteorites.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=19830067592&hterms=Peridotite&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D70%26Ntt%3DPeridotite','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=19830067592&hterms=Peridotite&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D70%26Ntt%3DPeridotite"><span>Petrogenesis of the Elephant Moraine A79001 meteorite Multiple magma pulses on the <span class="hlt">shergottite</span> parent body</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Mcsween, H. Y., Jr.; Jarosewich, E.</p> <p>1983-01-01</p> <p>The EETA 79001 achondrite consists of two distinct igneous lithologies joined along a planar, non-brecciated contact. Both are basaltic rocks composed primarily of pigeonite, augite, and maskelynite, but one contains zoned megacrysts of olivine, orthopyroxene, and chromite that represent disaggregated xenoliths of harzburzite. Both lithologies probably formed from successive volcanic flows or multiple injections of magma into a small, shallow chamber. Many similarities between the two virtually synchronous magmas suggest that they are related. Possible mechanisms to explain their differences involve varying degrees of assimilation, fractionation from similar parental magmas, or partial melting of a similar source peridotite; of these, assimilation of the observed megacryst assemblage seems most plausible. However, some isotopic contamination may be required in any of these petrogenetic models. The meteorite has suffered extensive shock metamorphism and localized melting during a large impact event that probably excavated and liberated it from its parent body.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2009AGUFMMR12A..04B','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2009AGUFMMR12A..04B"><span>Martian Meteorite Chronology and Effects of Impact Metamorphism (Invited)</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Bouvier, A.; Blichert-Toft, J.; Albarede, F.</p> <p>2009-12-01</p> <p>Martian (SNC) meteorites provide important clues to processes of alteration or shock at the surface of the planet as many of them contain secondary phases and/or high-pressure assemblages, which are the products of aqueous alteration and impact events, respectively. They include gabbros (<span class="hlt">shergottites</span>), pyroxenites (nakhlites), and dunites (chassignites), and a single orthopyroxenite, ALH 84001. Pb-Pb isotope systematics of Martian meteorites favor three groups of formation ages: 4.3 Ga for depleted <span class="hlt">shergottites</span>, 4.1 Ga for ALH 84001 and intermediate and enriched <span class="hlt">shergottites</span>, and 1.3 Ga for nakhlites and Chassigny [1]. This contrasts with the young mineral isochron ages obtained by Ar-Ar dating or phosphate-based chronometers (e.g., U-Pb, Sm-Nd). In addition to Pb-Pb isotope systematics [1], we have obtained preliminary Sm-Nd and Lu-Hf mineral isochron data for the <span class="hlt">shergottite</span> NWA 480 and find an age of ~345 Ma in contrast to its ~4.1 Ga Pb-Pb age. For the nakhlites MIL 03346 and <span class="hlt">Yamato</span>-000593, we find Sm-Nd and Lu-Hf ages at ~1335 Ma, consistent with their ~1.3 Ga Pb-Pb age. Hence, all <span class="hlt">shergottites</span> unambiguously show evidence of resetting events, which is not the case for nakhlites. We interpret the young ages indicated by <span class="hlt">shergottite</span> Rb-Sr, Sm-Nd, Lu-Hf, and U-Pb internal isochrons as recent resetting by fluids, impacts, or both. Internal isochrons date the last closure, whether initial cooling or late resetting, of the chronometric system in coexisting minerals. Problems arise in part because the carriers of the parent and daughter nuclides have been wrongly assigned to major rather than accessory minerals, and in part because, with the exception of the Pb-Pb chronometer, the rock samples have been strongly leached and, hence, the parent and daughter nuclides became fractionated in the process. The Rb-Sr, U-Pb, Sm-Nd, and Lu-Hf mineral isochrons of <span class="hlt">shergottites</span> show young age clusters around 180, 350, 475, and 575 Ma. Each cluster of young mineral isochron ages</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015Icar..258..366O','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015Icar..258..366O"><span>Candidates source regions of martian meteorites as identified by OMEGA/MEx</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Ody, A.; Poulet, F.; Quantin, C.; Bibring, J.-P.; Bishop, J. L.; Dyar, M. D.</p> <p>2015-09-01</p> <p>The objective of this study is to identify and map spectral analogues of some key martian meteorites (basaltic <span class="hlt">shergottites</span> Los Angeles, Shergotty, QUE 94201, <span class="hlt">lherzolitic</span> <span class="hlt">shergottite</span> ALH A77005, Nakhla, Chassigny and the orthopyroxenite ALH 84001) in order to localize terrain candidates for their source regions. We develop a best fit procedure to reproduce the near-infrared (NIR) spectral properties of the martian surface as seen by the hyperspectral imaging spectrometer OMEGA/MEx from the NIR spectra of the martian meteorites. The fitting process is tested and validated, and Root Mean Square (RMS) global maps for each meteorite are obtained. It is found that basaltic <span class="hlt">shergottites</span> have NIR spectral properties the most representative of the martian surface with the best spectral analogues found in early Hesperian volcanic provinces. Sites with spectral properties similar to those of ALH A77005 are scarce. They are mainly localized in olivine-bearing regions such as Nili Fossae and small Noachian/early Hesperian terrains. The only plausible source region candidate for Chassigny is the Nili Patera caldera dated to 1.6 Ga. Widespread spectral analogues for the ALH 84001 meteorite are found northeast of Syrtis Major and northwest of the Hellas basin. While this distribution is in agreement with the low-calcium-pyroxene-rich composition and old age (4.1 Ga) of this meteorite, the modal mineralogy of these candidates is not consistent with that of this meteorite. No convincing spectral analogue is found for the Amazonian-aged Nakhla meteorite suggesting that its olivine/high-calcium-pyroxene-rich composition could be representative of the Amazonian terrains buried under dust. Finally, some young rayed craters are proposed as possible candidates for source craters of the studied martian meteorites.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/20150019423','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/20150019423"><span>Evidence from Hydrogen Isotopes in Meteorites for a Subsurface Hydrogen Reservoir on Mars</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Usui, Tomohiro; Alexander, Conel M. O'D.; Wang, Jianhua; Simon, Justin I.; Jones, John H.</p> <p>2015-01-01</p> <p>The surface geology and geomorphology of Mars indicates that it was once warm enough to maintain a large body of liquid water on its surface, though such a warm environment might have been transient. The transition to the present cold and dry Mars is closely linked to the history of surface water, yet the evolution of surficial water is poorly constrained. We have conducted in situ hydrogen isotope (D/H) analyses of quenched and impact glasses in three Martian meteorites (<span class="hlt">Yamato</span> 980459, EETA79001, LAR 06319) by Cameca ims-6f at Digital Terrain Models (DTM) following the methods of [1]. The hydrogen isotope analyses provide evidence for the existence of a distinct but ubiquitous water/ice reservoir (D/H = 2-3 times Earth's ocean water: Standard Mean Ocean Water (SMOW)) that lasted from at least the time when the meteorites crystallized (173-472 Ma) to the time they were ejected by impacts (0.7-3.3 Ma), but possibly much longer [2]. The origin of this reservoir appears to predate the current Martian atmospheric water (D/H equals approximately 5-6 times SMOW) and is unlikely to be a simple mixture of atmospheric and primordial water retained in the Martian mantle (D/H is approximately equal to SMOW [1]). Given the fact that this intermediate-D/H reservoir (2-3 times SMOW) is observed in a diverse range of Martian materials with different ages (e.g., SNC (<span class="hlt">Shergottites</span>, Nakhlites, Chassignites) meteorites, including <span class="hlt">shergottites</span> such as ALH 84001; and Curiosity surface data [3]), we conclude that this intermediate-D/H reservoir is likely a global surficial feature that has remained relatively intact over geologic time. We propose that this reservoir represents either hydrated crust and/or ground ice interbedded within sediments. Our results corroborate the hypothesis that a buried cryosphere accounts for a large part of the initial water budget of Mars.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015M%26PS...50.1703B','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015M%26PS...50.1703B"><span>Influence of redox conditions on the intensity of Mars crustal magnetic anomalies</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Brachfeld, Stefanie; Shah, Deepa; First, Emily; Hammer, Julia; Bowles, Julie</p> <p>2015-10-01</p> <p>We evaluate the relationship between the intensity of remanent magnetization and fO2 in natural and synthetic Mars meteorites. The olivine-phyric <span class="hlt">shergottite</span> meteorite <span class="hlt">Yamato</span> 980459 (Y-980459) and a sulfur-free synthetic analog (Y-98*) of identical major element composition were analyzed to explore the rock magnetic and remanence properties of a basalt crystallized from a primitive melt, and to explore the role of magmatic and alteration environment fO2 on Mars crustal anomalies. The reducing conditions under which Y-980459 is estimated to have formed (QFM-2.5; Shearer et al. 2006) were replicated during the synthesis of Y-98*. Y-980459 contains pyrrhotite and chromite. Chromite is the only magnetic phase in Y-98*. The remanence-carrying capacity of Y-980459 is comparable to other <span class="hlt">shergottites</span> that formed in the fO2 range of QFM-3 to QFM-1. The remanence-carrying capacity of these low fO2 basalts is 1-2 orders of magnitude too weak to account for the intense crustal anomalies observed in Mars's southern cratered highlands. Moderately oxidizing conditions of >QFM-1, which are more commonly observed in nakhlites and Noachian breccias, are key to generating either a primary igneous assemblage or secondary alteration assemblage capable of acquiring an intense remanent magnetization, regardless of the basalt character or thermal history. This suggests that if igneous rocks are responsible for the intensely magnetized crust, these oxidizing conditions must have existed in the magmatic plumbing systems of early Mars or must have existed in the crust during secondary processes that led to acquisition of a chemical remanent magnetization.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/20170008925','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/20170008925"><span>40 Years of Collecting Martian Meteorites</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Funk, R. C.; Sattershite, C. E.; Righter, K.; Harrington, R.</p> <p>2017-01-01</p> <p>This year marks the 40th anniversary of the first Martian meteorite found in Antarctica by ANSMET, ALH 77005. Since then, an additional 14 Martian meteorites have been found by the ANSMET team making for a total of 15 Martian meteorites in the Antarctic collection at Johnson Space Center. Of the 15 meteorites, some have been paired so the 15 meteorites actually represent a total of approximately 9 separate meteorites. The first Martian meteorite found by ANSMET was ALH 77005 (482.500 g), a <span class="hlt">lherzolitic</span> <span class="hlt">shergottite</span>. When collected, this meteorite was split as a part of the joint expedition with the National Institute of Polar Research (NIPR) Japan. Originally classified as an "achondrite-unique", it was re-classified as a Martian <span class="hlt">lherzolitic</span> <span class="hlt">shergottites</span> in 1982 [1]. This meteorite has been allocated to 125 scientists for research and there are 181.964 g remaining at Johnson Space Center (JSC). Two years later, one of the most significant Martian meteorites of the collection at JSC was found at Elephant Moraine, EET 79001 (7942.000 g), a <span class="hlt">shergottite</span>. This meteorite is the largest in the Martian collection at JSC and was the largest stony meteorite sample collected during the 1979 season. In addition to its size, this meteorite is of particular interest because it contains a linear contact separating two different igneous lithologies, basaltic and olivine-phyric. EET 79001 has glass inclusions that contain chemical compositions that are proportionally identical to the Martian atmosphere, as measured by the Viking spacecraft [2]. This discovery helped scientists to identify where the "SNC" meteorite suite had originated, and that we actually possessed Martian samples. This meteorite has been allocated to 195 scientists for research and there are 5304.770 g of sample is available. Five years later, ANSMET found ALH 84001 (1930.900 g), the only Martian orthopyroxenite. This meteorite was initially classified as a diogenite but was reclassified as being a Martian</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2010M%26PS...45...21S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2010M%26PS...45...21S"><span>High oxidation state during formation of Martian nakhlites</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Szymanski, Anja; Brenker, Frank E.; Palme, Herbert; El Goresy, Ahmed</p> <p>2010-01-01</p> <p>The oxygen fugacities recorded in the nakhlites Nakhla, <span class="hlt">Yamato</span>-000593 (Y-000593), Lafayette, and NWA998 were studied by applying the Fe,Ti-oxide oxybarometer. Oxygen fugacities obtained cluster closely around the FMQ (Fayalite-Magnetite-Quartz) buffer (NWA998=FMQ-0.8 Y-000593=FMQ-0.7 Nakhla=FMQ Lafayette=FMQ+ 0.1). The corresponding equilibration temperatures are 810°C for Nakhla and Y-000593, 780°C for Lafayette and 710°C for NWA998. All nakhlites record oxygen fugacities significantly higher and with a tighter range than those determined for Martian basalts, i.e., <span class="hlt">shergottites</span> whose oxygen fugacities vary from FMQ-1 to FMQ-4. It has been known for some time that nakhlites are different from other Martian meteorites in chemistry, mineralogy, and crystallization age. The present study adds oxygen fugacity to this list of differences. The comparatively large variation in fO2 recorded by <span class="hlt">shergottites</span> was interpreted by Herd et al. (2002) as reflecting variable degrees of contamination with crustal fluids that would also carry a light rare earth element (REE)-enriched component. The high oxygen fugacities and the large light REE enrichment of nakhlites fit qualitatively in this model. In detail, however, it is found that the inferred contaminating phase in nakhlites must have been different from those in <span class="hlt">shergottites</span>. This is supported by unique 182W/184W and 142Nd/144Nd ratios in nakhlites, which are distinct from other Martian meteorites. It is likely that the differences in fO2 between nakhlites and other Martian meteorites were established very early in the history of Mars. Parental trace element rich and trace element poor regions (reservoirs) of Mars mantle (Brandon et al. 2000) must have been kept isolated throughout Martian history. Our results further show significant differences in closure temperature among the different nakhlites. The observed range in equilibration temperatures together with similar fO2 values is attributable to crystallization of</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2006E%26PSL.246...90M','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2006E%26PSL.246...90M"><span>Rb Sr, Sm Nd and Ar Ar isotopic systematics of Martian dunite Chassigny</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Misawa, K.; Shih, C.-Y.; Reese, Y.; Bogard, D. D.; Nyquist, L. E.</p> <p>2006-06-01</p> <p>Isotopic analysis of the Martian meteorite Chassigny yields a Rb-Sr age of 1406 ± 14 Ma with an initial 87Sr/ 86Sr ratio of 0.702251 ± 0.000034, a Sm-Nd age of 1386 ± 28 Ma with an initial ɛ143Nd-value of + 16.9 ± 0.3 and an 39Ar- 40Ar age of 1360 + 40 - 20 Ma. The concordance of these ages and the Rb-Sr and Sm-Nd initial isotopic signatures suggest that Chassigny crystallized from low Rb/Sr, light rare earth element depleted source materials ˜ 1390 Ma ago. The ages and ɛ143Nd-values of Chassigny and the nakhlites Governador Valadares and Lafayette overlap, suggesting that they could have come from very similar mantle sources. Nakhla, Northwest Africa 998 and <span class="hlt">Yamato</span> 000593 appear to be from similar but distinct sources. Chassigny and all nakhlites so far studied have undergone similar evolution histories. That is, chassignites/nakhlites were derived from a region where volcanism lasted at least 50 Ma and crystallized from different lava flows or subsurface sills. They probably were launched from Mars by a single impact event. The trapped Martian atmospheric 40Ar/ 36Ar ratios in Chassigny, nakhlites and <span class="hlt">shergottite</span> impact glass are similar and possibly indicate minimal change in this ratio over the past ≥ 600 Ma.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/20100008620','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/20100008620"><span>SM-ND Age and REE Systematics of Larkman Nunatek 06319: Closed System Fractional Crystallization of a <span class="hlt">Shergottite</span> Magma</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Shafer, J. T.; Brandon, A. D.; Lapen T. J.; Righter, M.; Peslier, A. H.</p> <p>2010-01-01</p> <p>Sm-Nd isotopic data were collected on mineral separates and bulk rock powders of LAR 06319, yielding an age of 180+/-13 Ma (2(sigma)). This age is concordant with the Lu-Hf age (197+/-29 Ma, [1]) determined in conjunction with these data and the Sm-Nd age (190+/-26 Ma) of Shih et al., 2009 [2]. The Sm-Nd data form at statistically significant isochron (Fig. 1) that is controlled largely by leachate-residue pairs (samples with the R suffix are residues after leaching in cold 2N HCl for 10 minutes).</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=19870038381&hterms=noble+gases&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D60%26Ntt%3Dnoble%2Bgases','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=19870038381&hterms=noble+gases&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D60%26Ntt%3Dnoble%2Bgases"><span>Shock-implanted noble gases - An experimental study with implications for the origin of Martian gases in <span class="hlt">shergottite</span> meteorites</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Bogard, Donald D.; Horz, Friedrich; Johnson, Pratt H.</p> <p>1986-01-01</p> <p>The shock-implantation of gases is studied by artificially shocking whole rock and power samples of terrestrial basalt to pressures of 2-40 GPa. Ar, Kr, Xe, and Ne were implanted into the silicate. It is observed that the amount of implanted gas is linearly proportional to its partial pressure over a pressure range of 0.0001 to 0.1 atmosphere. The fractionation effect in the implanted gas and the gas diffusion properties are examined. The amounts of gas that would have been implanted with 100 percent efficiency are calculated from the measured porosities of the power samples and are compared to observed abundances. It is determined that the implantation efficiencies are approximately 0.5 percent at 2 GPa, 7 percent at 5 GPa, and greater than 50 percent at both 20 and 35 GPa. The experimental data correlate with the shock implantation of Martian gases without mass fractionation into the shock-melted phase of meteorite EETA 79001.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017GeCoA.210..228K','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017GeCoA.210..228K"><span>Martian low-temperature alteration materials in shock-melt pockets in Tissint: Constraints on their preservation in <span class="hlt">shergottite</span> meteorites</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Kuchka, C. R.; Herd, C. D. K.; Walton, E. L.; Guan, Y.; Liu, Y.</p> <p>2017-08-01</p> <p>We apply an array of in situ analytical techniques, including electron and Raman microscopy, electron and ion probe microanalysis, and laser ablation mass spectrometry to the Tissint martian meteorite in order to find and elucidate a geochemical signature characteristic of low-temperature alteration at or near the martian surface. Tissint contains abundant shock-produced quench-crystallized melt pockets containing water in concentrations ranging from 73 to 1730 ppm; water content is positively correlated with Cl content. The isotopic composition of hydrogen in the shock-produced glass ranges from δD = 2559 to 4422‰. Water is derived from two distinct hydrogen reservoirs: the martian near-surface (>500‰) and the martian mantle (-100‰). In one shock melt pocket comprising texturally homogeneous vesiculated glass, the concentration of H in the shock melt decreases while simultaneously becoming enriched in D, attributable to the preferential loss of H over D to the vesicle while the pocket was still molten. While igneous sulfides are pyrrhotite in composition (Fe0.88-0.90S), the iron to sulfur ratios of spherules in shock melt pockets are elevated, up to Fe1.70S, which we attribute to shock-oxidation of igneous pyrrhotite and the formation of hematite at high temperature. The D- and Cl-enrichment, and higher oxidation of the pockets (as indicated by hematite) support a scenario in which alteration products formed within fractures or void spaces within the rock; the signature of these alteration products is preserved within shock melt (now glass) which formed upon collapse of these fractures and voids during impact shock. Thermal modeling of Tissint shock melt pockets using the HEAT program demonstrates that the shock melt pockets with the greatest potential to preserve a signature of aqueous alteration are small, isolated from other regions of shock melt, vesicle-free, and glassy.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/20090011793','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/20090011793"><span>Noble Gas Analysis for Mars Robotic Missions: Evaluating K-Ar Age Dating for Mars Rock Analogs and Martian <span class="hlt">Shergottites</span></span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Park, J.; Ming, D. W.; Garrison, D. H.; Jones, J. H.; Bogard, D. D.; Nagao, K.</p> <p>2009-01-01</p> <p>The purpose of this noble gas investigation was to evaluate the possibility of measuring noble gases in martian rocks and air by future robotic missions such as the Mars Science Laboratory (MSL). The MSL mission has, as part of its payload, the Sample Analysis at Mars (SAM) instrument, which consists of a pyrolysis oven integrated with a GCMS. The MSL SAM instrument has the capability to measure noble gas compositions of martian rocks and atmosphere. Here we suggest the possibility of K-Ar age dating based on noble gas release of martian rocks by conducting laboratory simulation experiments on terrestrial basalts and martian meteorites. We provide requirements for the SAM instrument to obtain adequate noble gas abundances and compositions within the current SAM instrumental operating conditions, especially, a power limit that prevents heating the furnace above approx.1100 C. In addition, Martian meteorite analyses from NASA-JSC will be used as ground truth to evaluate the feasibility of robotic experiments to constrain the ages of martian surface rocks.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=19870038381&hterms=shocking&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D30%26Ntt%3Dshocking','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=19870038381&hterms=shocking&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D30%26Ntt%3Dshocking"><span>Shock-implanted noble gases - An experimental study with implications for the origin of Martian gases in <span class="hlt">shergottite</span> meteorites</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Bogard, Donald D.; Horz, Friedrich; Johnson, Pratt H.</p> <p>1986-01-01</p> <p>The shock-implantation of gases is studied by artificially shocking whole rock and power samples of terrestrial basalt to pressures of 2-40 GPa. Ar, Kr, Xe, and Ne were implanted into the silicate. It is observed that the amount of implanted gas is linearly proportional to its partial pressure over a pressure range of 0.0001 to 0.1 atmosphere. The fractionation effect in the implanted gas and the gas diffusion properties are examined. The amounts of gas that would have been implanted with 100 percent efficiency are calculated from the measured porosities of the power samples and are compared to observed abundances. It is determined that the implantation efficiencies are approximately 0.5 percent at 2 GPa, 7 percent at 5 GPa, and greater than 50 percent at both 20 and 35 GPa. The experimental data correlate with the shock implantation of Martian gases without mass fractionation into the shock-melted phase of meteorite EETA 79001.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2012LPI....43.2644V','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2012LPI....43.2644V"><span>Anomalous Enstatite Meteorites Queen Alexandra Range 94204 and Pairs: The Perplexing Question of Impact Melts or Partial Melt Residues, Either way, Unrelated to <span class="hlt">Yamato</span> 793225</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>van Niekerk, D.; Keil, K.</p> <p>2012-03-01</p> <p>QUE 94204 and its seven pairs are anomalous enstatite meteorites that may either be impact melt products, or partial melt residues. We explore the petrology of these meteorites and present new findings.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=19890049155&hterms=Allan&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D30%26Ntt%3DAllan','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=19890049155&hterms=Allan&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D30%26Ntt%3DAllan"><span>Allan Hills 84025 - The second brachinite, far more differentiated than brachina, and an ultramafic achondritic clast from L chondrite <span class="hlt">Yamato</span> 75097</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Warren, P. H.; Kallemeyn, G. W.</p> <p>1989-01-01</p> <p>New bulk-compositional and petrographic data tend to confirm that dunitic-wehrlitic meteorite ALH84025 is a second brachinite. It is suggested here that ALH84025 originated as an olivine heteradcumulate, whereas Brachina, or ALH84025, originated as an olivine orthocumulate. The tendency for pyroxenes among brachinites to be high-Ca may be a consequence of a relatively low MgO/FeO ratio, and/or high Na/Ca and K/Ca ratios in the bulk parent body. New data for a 2.5-cm dunite-melatroctolite clast from L6 chondrite Y75097 are reported. This clast has experience depletion of middle REE, except for a large (+) Eu anomaly. The clast as a whole is enriched in phosphates, but almost exclusively in its least-metamorphosed 'core' portion, whereas the analyzed samples represent phosphate-poor portions. It is suggested that this bizarre assemblage probably originated as an achondrite containing cumulus olivine, plagioclase, and phosphate, not necessarily all from a single igneous source rock.</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_13");'>13</a></li> <li><a href="#" onclick='return showDiv("page_14");'>14</a></li> <li class="active"><span>15</span></li> <li><a href="#" onclick='return showDiv("page_16");'>16</a></li> <li><a href="#" onclick='return showDiv("page_17");'>17</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_15 --> <div id="page_16" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_14");'>14</a></li> <li><a href="#" onclick='return showDiv("page_15");'>15</a></li> <li class="active"><span>16</span></li> <li><a href="#" onclick='return showDiv("page_17");'>17</a></li> <li><a href="#" onclick='return showDiv("page_18");'>18</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="301"> <li> <p><a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=20030111022&hterms=nebular+hypothesis&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D20%26Ntt%3Dnebular%2Bhypothesis','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=20030111022&hterms=nebular+hypothesis&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D20%26Ntt%3Dnebular%2Bhypothesis"><span>Mineralogy and Textural Characteristics of Fine-grained Rims in the <span class="hlt">Yamato</span> 791198 CM2 Carbonaceous Chondrite: Constraints on the Location of Aqueous Alteration</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Chizmadia, Lysa J.; Brearley, Adrian J.</p> <p>2003-01-01</p> <p>Carbonaceous chondrites provide important clues into the nature of physical and chemical processes in the early solar system. A question of key importance concerns the role of water in solar nebular and asteroidal processes. The effects of water on primary mineral assemblages have been widely recognized in chondritic meteorites, especially the CI and CM carbonaceous chondrites. These meteorites have undergone extensive aqueous alteration that occurred prior to their arrival on Earth. In the case of the CM chondrites, this alteration has resulted in the partial to complete replacement of the primary nebular phases with secondary alteration phases. Considerable controversy exists as to the exact location where the alteration of the CM chondrites occurred. Several textural lines of evidence have been cited in support of aqueous alteration prior to the accretion of the final parent asteroid. An important line of evidence to support this hypothesis is the dis-equilibrium nature of fine-grained rims and matrix materials. [2] also noted the juxtaposition of micron-sized Fe-Ni metal grains and apparently unaltered chondrule glass against hydrated rim silicates. Conversely, there is a large body of evidence in favor of parent body alteration such as the occurrence of undisturbed Fe-rich aureoles and the systematic redistribution of elemental components over millimeters, e.g., Mg(+2) into the matrix and Fe(+2) into chondrules etc.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014GGG....15.1533M','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014GGG....15.1533M"><span>Effect of variable CO2 on eclogite-derived andesite and <span class="hlt">lherzolite</span> reaction at 3 GPa—Implications for mantle source characteristics of alkalic ocean island basalts</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Mallik, Ananya; Dasgupta, Rajdeep</p> <p>2014-04-01</p> <p>We have performed reaction experiments between 1, 4, and 5 wt % CO2-bearing MORB-eclogite (recycled oceanic crust)-derived low-degree andesitic partial melt and fertile peridotite at 1375°C, 3 GPa for infiltrating melt fractions of 25% and 33% by weight. We observe that the reacted melts are alkalic with degree of alkalinity or Si undersaturation increasing with increasing CO2 content in reacting melt. Consequently, an andesite evolves through basanite to nephelinite owing to greater drawdown of SiO2 from melt and enhanced precipitation of orthopyroxene in residue. We have developed an empirical model to predict reacted melt composition as a function of reacting andesite fraction and source CO2 concentration. Using our model, we have quantified the mutual proportions of equilibrated melt from andesite-peridotite (+ CO2) hybridization and subsequent peridotite (± CO2)-derived melt required to produce the major element composition of various ocean island basalts. Our model can thus be applied to characterize the source of ocean islands from primary alkalic lava composition. Accordingly, we determined that average HIMU source requires 24 wt % of MORB-eclogite-derived melt relative to peridotite containing 2 wt % CO2 and subsequent contribution of 45% of volatile-free peridotite partial melt. We demonstrate that mantle hybridization by eclogite melt-peridotite (± CO2) reaction in the system can produce high MgO (>15 wt %) basaltic melts at mantle potential temperature (TP) of 1350°C. Therefore, currently used thermometers to estimate TP using MgO content of primary alkalic melts need to be revised, with corrections for melt-rock reaction in a heterogeneous mantle as well as presence of CO2.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/1990JGR....9515859L','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/1990JGR....9515859L"><span>Geochemistry and petrology of spinel <span class="hlt">lherzolite</span> xenoliths from Xalapasco de La Joya, San Luis Potosi, Mexico: Partial melting and mantle metasomatism</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Liang, Yan; Elthon, Don</p> <p>1990-09-01</p> <p>Spinel Iherzolite xenoliths from Xalapasco de La Joya, San Luis Potosi, Mexico, are divided into two distinct groups according to their major element and trace element characteristics. Group Ia xenoliths are characterized by light rare earth element (LREE) depletion ((La/Lu)N = 0.10-0.77 in clinopyroxene) and linear major and compatible trace element relationships. Group Ib xenoliths are characterized by FeO and Na2O enrichment and higher (La/Lu)N ratios (0.80-4.1 in clinopyroxene) and complex major element relationships. These samples, which have a range of equilibrium temperatures of 910°-1070°C, exhibit protogranular textures and typical orthopyroxene+clinopyroxene+spinel clusters. Modal abundances and chemical compositions of the group Ia xenoliths vary from primitive (15.2% clinopyroxene, 38.5% MgO, 1824 ppm Ni) to moderately depleted (6.4-8.7% clinopyroxene, 43.8-44.1% MgO, 2192 ppm Ni). Systematic variations of major elements and compatible trace elements in the group Ia xenoliths are interpreted to result from various degrees (<25%) of partial melting and melt extraction, followed by subsolidus equilibration and annealing. The extracted melts have a range of compositions similar to picritic basalts. Abundances of moderately incompatible trace elements, Sc and Cr, in the group Ia minerals have been substantially redistributed during subsolidus equilibration. In a few of these xenoliths there appears to be vestiges of incipient metasomatism, but metasomatism has not substantially influenced the group as a whole. Group Ib xenoliths have been substantially influenced by metasomatic processes. The ∑FeO and Na2O contents of the cores of clinopyroxenes in group Ib xenoliths are higher than clinopyroxenes in group Ia samples. The higher La contents and La/Lu ratios in group Ib clinopyroxenes (compared to group Ia), together with this FeO and Na2O enrichment, suggest that equilibration of basanites with residual mantle has been a major process in the evolution of group Ib peridotites. Clinopyroxenes in the group Ib xenoliths are reversely zoned with higher Mg # (100×Mg/(Mg+∑Fe)), CaO, and TiO2 and with lower Na2O and Al2O3 in their rims than in their cores. Bulk rock Al2O3 and SiO2 contents of the group Ib xenoliths tend to be lower than those of group Ia at the same MgO contents. The Al2O3 and SiO4 depletion in bulk rocks and Al2O3 and Na2O depletion in the rims of the group Ib minerals result from reaction with an alkaline-element-enriched, H2O dominated fluid. The history of group Ib xenoliths appear to be dominated by an early phase of melt extraction followed by interaction with a basanitic melt to produce the FeO, Na2O, and LREE enrichment in clinopyroxenes. These peridotites then appear to have been affected by a H2O-rich fluid that depleted Al2O3 and Na2O from the rims of clinopyroxenes and produced incipient melt veins in the xenoliths.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017E%26PSL.474..419M','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017E%26PSL.474..419M"><span>Magnesium isotope systematics in Martian meteorites</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Magna, Tomáš; Hu, Yan; Teng, Fang-Zhen; Mezger, Klaus</p> <p>2017-09-01</p> <p>Magnesium isotope compositions are reported for a suite of Martian meteorites that span the range of petrological and geochemical types recognized to date for Mars, including crustal breccia Northwest Africa (NWA) 7034. The δ26Mg values (per mil units relative to DSM-3 reference material) range from -0.32 to -0.11‰; basaltic <span class="hlt">shergottites</span> and nakhlites lie to the heavier end of the Mg isotope range whereas olivine-phyric, olivine-orthopyroxene-phyric and <span class="hlt">lherzolitic</span> <span class="hlt">shergottites</span>, and chassignites have slightly lighter Mg isotope compositions, attesting to modest correlation of Mg isotopes and petrology of the samples. Slightly heavier Mg isotope compositions found for surface-related materials (NWA 7034, black glass fraction of the Tissint <span class="hlt">shergottite</span> fall; δ26Mg > -0.17‰) indicate measurable Mg isotope difference between the Martian mantle and crust but the true extent of Mg isotope fractionation for Martian surface materials remains unconstrained. The range of δ26Mg values from -0.19 to -0.11‰ in nakhlites is most likely due to accumulation of clinopyroxene during petrogenesis rather than garnet fractionation in the source or assimilation of surface material modified at low temperatures. The rather restricted range in Mg isotope compositions between spatially and temporally distinct mantle-derived samples supports the idea of inefficient/absent major tectonic cycles on Mars, which would include plate tectonics and large-scale recycling of isotopically fractionated surface materials back into the Martian mantle. The cumulative δ26Mg value of Martian samples, which are not influenced by late-stage alteration processes and/or crust-mantle interactions, is - 0.271 ± 0.040 ‰ (2SD) and is considered to reflect δ26Mg value of the Bulk Silicate Mars. This value is robust taking into account the range of lithologies involved in this estimate. It also attests to the lack of the Mg isotope variability reported for the inner Solar System bodies at current</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/20080009609','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/20080009609"><span>Duration of a Magma Ocean and Subsequent Mantle Overturn in Mars: Evidence from Nakhlites</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Debaille, V.; Brandon, A. D.; Yin, Q.-Z.; Jacobsen, B.</p> <p>2008-01-01</p> <p>It is now generally accepted that the heat produced by accretion, short-lived radioactive elements such as Al-26, and gravitational energy from core formation was sufficient to at least partially melt the silicate portions of terrestrial planets resulting in a global-scale magma ocean. More particularly, in Mars, the geochemical signatures displayed by <span class="hlt">shergottites</span>, are likely inherited from the crystallization of this magma ocean. Using the short-lived chronometer Sm-146 - Nd-142 (t(sup 1/2) = 103 Myr), the duration of the Martian magma ocean (MMO) has been evaluated to being less than 40 Myr, while recent and more precise ND-142/ND-144 data were used to evaluate the longevity of the MMO to approximately 100 Myr after the solar system formation. In addition, it has been proposed that the end of the crystallization of the MMO may have triggered a mantle overturn, as a result of a density gradient in the cumulate layers crystallized at different levels. Dating the mantle overturn could hence provide additional constraint on the duration of the MMO. Among SNC meteorites, nakhlites are characterized by high epsilon W-182 of approximately +3 and an epsilon Nd-142 similar to depleted <span class="hlt">shergottites</span> of +0.6-0.9. It has hence been proposed that the source of nakhlites was established very early in Mars history (approximately 8-10 Myr). However, the times recorded in HF-182-W-182 isotope system, i.e. when 182Hf became effectively extinct (approximately 50 Myr after solar system formation) are less than closure times recorded in the Sm-146-Nd-142 isotope system (with a full coverage of approximately 500 Myr after solar system formation). This could result in decoupling between the present-day measured epsilon W-182 and epsilon Nd-142 as the SM-146 may have recorded later differentiation events in epsilon ND-142 not observed in epsilon W-182 values. With these potential complexities in short-lived chronological data for SNC's in mind, new Hf-176/Hf-177, Nd-143/Nd-144 and Nd</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=20050167788&hterms=Earth+science+inner+planets&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D80%26Ntt%3DEarth%2Bscience%2Binner%2Bplanets','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=20050167788&hterms=Earth+science+inner+planets&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D80%26Ntt%3DEarth%2Bscience%2Binner%2Bplanets"><span>Lunar and Planetary Science XXXVI, Part 4</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p></p> <p>2005-01-01</p> <p>Contents include the following: High-Resolution Electron Energy-Loss Spectroscopy (HREELS) Using a Monochromated TEM/STEM. Dynamical Evolution of Planets in Open Clusters. Experimental Petrology of the Basaltic <span class="hlt">Shergottite</span> <span class="hlt">Yamato</span> 980459: Implications for the Thermal Structure of the Martian Mantle. Cryogenic Reflectance Spectroscopy of Highly Hydrated Sulfur-bearing Salts. Implications for Core Formation of the Earth from High Pressure-Temperature Au Partitioning Experiments. Uranium-Thorium Cosmochronology. Protracted Core Differentiation in Asteroids from 182Hf-182W Systematics in the Eagle Station Pallasite. Maximizing Mission Science Return Through Use of Spacecraft Autonomy: Active Volcanism and the Autonomous Sciencecraft Experiment. Classification of Volcanic Eruptions on Io and Earth Using Low-Resolution Remote Sensing Data. Isotopic Mass Fractionation Laws and the Initial Solar System (sup26)Al/(sup27)Al Ratio. Catastrophic Disruption of Porous and Solid Ice Bodies (sup187)Re-(sup187)Os Isotope Disturbance in LaPaz Mare Basalt Meteorites. Comparative Petrology and Geochemistry of the LaPaz Mare Basalt Meteorites. A Comparison of the Structure and Bonding of Carbon in Apex Chert Kerogenous Material and Fischer-Tropsch-Type Carbons. Broad Spectrum Characterization of Returned Samples: Orientation Constraints of Small Samples on X-Ray and Other Spectroscopies. Apollo 14 High-Ti Picritic Glass: Oxidation/Reduction by Condensation of Alkali Metals. New Lunar Meteorites from Oman: Dhofar 925, 960 and 961. The First Six Months of Iapetus Observations by the Cassini ISS Camera. First Imaging Results from the Iapetus B/C Flyby of the Cassini Spacecraft. Radiative Transfer Calculations for the Atmosphere of Mars in the 200-900 nm Range. Geomorphologic Map of the Atlantis Basin, Terra Sirenum, Mars. The Meaning of Iron 60: A Nearby Supernova Injected Short-lived Radionuclides into Our Protoplanetary Disk.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=20050167788&hterms=carbon+sulfur+iron+systematics&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D20%26Ntt%3Dcarbon%2Bsulfur%2Biron%2Bsystematics','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=20050167788&hterms=carbon+sulfur+iron+systematics&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D20%26Ntt%3Dcarbon%2Bsulfur%2Biron%2Bsystematics"><span>Lunar and Planetary Science XXXVI, Part 4</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p></p> <p>2005-01-01</p> <p>Contents include the following: High-Resolution Electron Energy-Loss Spectroscopy (HREELS) Using a Monochromated TEM/STEM. Dynamical Evolution of Planets in Open Clusters. Experimental Petrology of the Basaltic <span class="hlt">Shergottite</span> <span class="hlt">Yamato</span> 980459: Implications for the Thermal Structure of the Martian Mantle. Cryogenic Reflectance Spectroscopy of Highly Hydrated Sulfur-bearing Salts. Implications for Core Formation of the Earth from High Pressure-Temperature Au Partitioning Experiments. Uranium-Thorium Cosmochronology. Protracted Core Differentiation in Asteroids from 182Hf-182W Systematics in the Eagle Station Pallasite. Maximizing Mission Science Return Through Use of Spacecraft Autonomy: Active Volcanism and the Autonomous Sciencecraft Experiment. Classification of Volcanic Eruptions on Io and Earth Using Low-Resolution Remote Sensing Data. Isotopic Mass Fractionation Laws and the Initial Solar System (sup26)Al/(sup27)Al Ratio. Catastrophic Disruption of Porous and Solid Ice Bodies (sup187)Re-(sup187)Os Isotope Disturbance in LaPaz Mare Basalt Meteorites. Comparative Petrology and Geochemistry of the LaPaz Mare Basalt Meteorites. A Comparison of the Structure and Bonding of Carbon in Apex Chert Kerogenous Material and Fischer-Tropsch-Type Carbons. Broad Spectrum Characterization of Returned Samples: Orientation Constraints of Small Samples on X-Ray and Other Spectroscopies. Apollo 14 High-Ti Picritic Glass: Oxidation/Reduction by Condensation of Alkali Metals. New Lunar Meteorites from Oman: Dhofar 925, 960 and 961. The First Six Months of Iapetus Observations by the Cassini ISS Camera. First Imaging Results from the Iapetus B/C Flyby of the Cassini Spacecraft. Radiative Transfer Calculations for the Atmosphere of Mars in the 200-900 nm Range. Geomorphologic Map of the Atlantis Basin, Terra Sirenum, Mars. The Meaning of Iron 60: A Nearby Supernova Injected Short-lived Radionuclides into Our Protoplanetary Disk.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/20120012511','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/20120012511"><span>Nature of Reduced Carbon in Martian Meteorites</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Gibson, Everett K., Jr.; McKay, D. S.; Thomas-Keprta, K. L.; Clemett, S. J.; White, L. M.</p> <p>2012-01-01</p> <p>Martian meteorites provide important information on the nature of reduced carbon components present on Mars throughout its history. The first in situ analyses for carbon on the surface of Mars by the Viking landers yielded disappointing results. With the recognition of Martian meteorites on Earth, investigations have shown carbon-bearing phases exist on Mars. Studies have yielded presence of reduced carbon, carbonates and inferred graphitic carbon phases. Samples ranging in age from the first approximately 4 Ga of Mars history [e.g. ALH84001] to nakhlites with a crystallization age of 1.3 Ga [e.g. Nakhla] with aqueous alteration processes occurring 0.5-0.7 Ga after crystallizaton. <span class="hlt">Shergottites</span> demonstrate formation ages around 165-500 Ma with younger aqueous alterations events. Only a limited number of the Martian meteorites do not show evidence of significance terrestrial alterations. Selected areas within ALH84001, Nakhla, <span class="hlt">Yamato</span> 000593 and possibly Tissint are suitable for study of their indigenous reduced carbon bearing phases. Nakhla possesses discrete, well-defined carbonaceous phases present within iddingsite alteration zones. Based upon both isotopic measurements and analysis of Nakhla's organic phases the presence of pre-terrestrial organics is now recognized. The reduced carbon-bearing phases appear to have been deposited during preterrestrial aqueous alteration events that produced clays. In addition, the microcrystalline layers of Nakhla's iddingsite have discrete units of salt crystals suggestive of evaporation processes. While we can only speculate on the origin of these unique carbonaceous structures, we note that the significance of such observations is that it may allow us to understand the role of Martian carbon as seen in the Martian meteorites with obvious implications for astrobiology and the pre-biotic evolution of Mars. In any case, our observations strongly suggest that reduced organic carbon exists as micrometer- size, discrete structures</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2013AGUFMMR23B2362D','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2013AGUFMMR23B2362D"><span>New Bulk Sulfur Measurements of Martian Meteorites - Implications for Sulfur Cycle on Mars</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Ding, S.; Dasgupta, R.; Lee, C.; Wadhwa, M.</p> <p>2013-12-01</p> <p>Magmatic degassing was likely critical in giving rise to a thick atmosphere of ancient Mars and SO2 and H2S could have been key greenhouse gases. How much S was released depends on (1) the S content of the mantle-derived magma and (2) the magmatic sulfur budget of the basaltic crust. While the former is estimated by S content of basaltic melts at sulfide saturation (SCSS) [1,2], assuming mantle-derived magma is sulfide saturated, it is unclear how much S gets trapped during crystallization of basalts in the crust versus how much is released to the atmosphere. S content of the martian crust can be estimated from martian meteorites, yet bulk S concentration data of martian meteorites is limited [3]. Further, most martian meteorites contain cumulus minerals and some have experienced secondary alteration (weathering/ impact effects), which could either deplete or enrich S in these samples. To better constrain the degassing of S from the martian interior, we measured bulk S contents of 7 martian meteorites via high mass-resolution solution ICP-MS [4]. Basaltic <span class="hlt">shergottites</span> Los Angeles, Zagami and NWA 856 have S contents of 2865×224, 1954×91 and 1584×10 ppm, respectively while clinopyroxenites Nakhla and NWA 998 give values of 690×60 and 253×42 ppm S. Olivine-phyric <span class="hlt">shergottites</span> NWA 1068 and Tissint have intermediate S contents of 1280×48 and 2120×68 ppm. The meteorites have lower S contents than the predicted SCSS of ~3500-4500 ppm [2] along liquid line of descent for a liquid similar to <span class="hlt">Yamato</span> 980459 at 1 GPa, estimated using alphaMELTS. Taking into account the possible proportion of inter-cumulus liquid (f= 6-70 wt.%) in the analyzed meteorites estimated by previous studies, the degassed S could be as low as ~300-1900 ppm (estimated by the difference between the SCSS×f and the S in the meteorites). However, nakhlite Nakhla and basaltic <span class="hlt">shergottites</span> NWA 856 and Zagami show higher S than the calculated SCSS×f. In these two meteorites, sulfides occur as</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/20170001342','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/20170001342"><span>Partitioning of F and Cl Between Apatite and a Synthetic <span class="hlt">Shergottite</span> Liquid (QUE 94201) at 4 Gpa from 1300 TO 1500 C</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>McCubbin, F. M.; Barnes, J. J.; Vander Kaaden, K. E.; Boyce, J. W.</p> <p>2017-01-01</p> <p>Apatite [Ca5(PO4)3(F,Cl,OH)] is present in a wide range of planetary materials. Due to the presence of volatiles within its crystal structure (Xsite), many recent studies have attempted to use apatite to constrain the volatile contents of planetary magmas and mantle sources. In order to use the volatile contents of apatite to accurately determine the abundances of volatiles in coexisting silicate melt or fluids, thermodynamic models for the apatite solid solution and for the apatite components in multicomponent silicate melts and fluids are required. Although some thermodynamic models for apatite have been developed, they are incomplete. Furthermore, no mixing model is available for all of the apatite components in silicate melts or fluids, especially for F and Cl components. Several experimental studies have investigated the apatite-melt and apatite-fluid partitioning behavior of F, Cl, and OH in terrestrial and planetary systems, which have determined that apatite-melt partitioning of volatiles are best described as exchange equilibria similar to Fe-Mg partitioning between olivine and silicate melt. However, McCubbin et al., recently reported that the exchange coefficients vary in portions of apatite compositional space where F, Cl, and OH do not mix ideally in apatite. In particular, solution calorimetry data of apatite compositions along the F-Cl join exhibit substantial excess enthalpies of mixing, and McCubbin et al. reported substantial deviations in the Cl-F exchange Kd along the F-Cl apatite join that could be explained by the preferential incorporation of F into apatite. In the present study, we assess the effect of apatite crystal chemistry on F-Cl exchange equilibria between apatite and melt at 4 GPa over the temperature range of 1300-1500 C. The goal of these experiments is to assess the variation in the Ap-melt Cl-F exchange Kd over a broad range of F:Cl ratios in apatite. The results of these experiments could be used to understand at what composition apatite shifts from a hexagonal unit cell with space group P63/m to a unit cell with monoclinic symmetry within space group P21/b. We anticipate that this transition occurs at >70% chlorapatite based on solution calorimetry data.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=19990063444&hterms=Metamorphic+process&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D50%26Ntt%3DMetamorphic%2Bprocess','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=19990063444&hterms=Metamorphic+process&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D50%26Ntt%3DMetamorphic%2Bprocess"><span>Petrology and Geochemistry of a Mg- and Al-Rich Orthopyroxenite Xenolith in the EETA79001 <span class="hlt">Shergottite</span>: Implications for Mars Crustal Evolution</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Berkley, John L.</p> <p>1999-01-01</p> <p>EETA79001 is a Mars meteorite (SNC) consisting of multiple rock types, including two basalt types, olivine and pyroxene xenocrysts, and ultramafic xenoliths. This study is focused on the petrology and geochemistry of one orthopyroxenite xenolith in PTS 68, designated X-1. It consists of chemically homogeneous orthopyroxene cores with exceptionally high Mg/Fe (mg#=85) and Al. Cores are permeated by minute high-Si+Al glassy inclusions, some with augite microlites. Magnesian core areas are mantled by more Fe-rich orthopyroxene rims grading to pigeonite away from cores. The xenolith is transected by cross-cutting shear planes, some of pre-incorporation origin. Major and minor element composition and variation suggest that core areas are primarily igneous, crystallized from a high temperature mafic melt. However, nearly constant mg# across cores suggest metamorphic equilibration. Si+Al inclusions may result from, among other processes, exsolution of feldspathic material during subsolidus cooling, or may be solid materials (alkali feldspar) poikilitically enclosed by growing igneous orthopyroxene crystals. Late reaction with more fractionated melts produced Fe-rich mantles, the whole assemblage later cut by tectonic micro-shear planes. Raw electron microprobe data produced during this study are available on request from the author.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=19990063444&hterms=Igneous+petrology&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D10%26Ntt%3DIgneous%2Bpetrology','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=19990063444&hterms=Igneous+petrology&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D10%26Ntt%3DIgneous%2Bpetrology"><span>Petrology and Geochemistry of a Mg- and Al-Rich Orthopyroxenite Xenolith in the EETA79001 <span class="hlt">Shergottite</span>: Implications for Mars Crustal Evolution</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Berkley, John L.</p> <p>1999-01-01</p> <p>EETA79001 is a Mars meteorite (SNC) consisting of multiple rock types, including two basalt types, olivine and pyroxene xenocrysts, and ultramafic xenoliths. This study is focused on the petrology and geochemistry of one orthopyroxenite xenolith in PTS 68, designated X-1. It consists of chemically homogeneous orthopyroxene cores with exceptionally high Mg/Fe (mg#=85) and Al. Cores are permeated by minute high-Si+Al glassy inclusions, some with augite microlites. Magnesian core areas are mantled by more Fe-rich orthopyroxene rims grading to pigeonite away from cores. The xenolith is transected by cross-cutting shear planes, some of pre-incorporation origin. Major and minor element composition and variation suggest that core areas are primarily igneous, crystallized from a high temperature mafic melt. However, nearly constant mg# across cores suggest metamorphic equilibration. Si+Al inclusions may result from, among other processes, exsolution of feldspathic material during subsolidus cooling, or may be solid materials (alkali feldspar) poikilitically enclosed by growing igneous orthopyroxene crystals. Late reaction with more fractionated melts produced Fe-rich mantles, the whole assemblage later cut by tectonic micro-shear planes. Raw electron microprobe data produced during this study are available on request from the author.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=19880045193&hterms=noble+gases&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D50%26Ntt%3Dnoble%2Bgases','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=19880045193&hterms=noble+gases&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D50%26Ntt%3Dnoble%2Bgases"><span>Laboratory shock emplacement of noble gases, nitrogen, and carbon dioxide into basalt, and implications for trapped gases in <span class="hlt">shergottite</span> EETA 79001</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Wiens, R. C.; Pepin, R. O.</p> <p>1988-01-01</p> <p>Basalts from the Servilleta flows, Taos, NM, described by Lofgren (1983) were analyzed by mass spectrometry for shock-implanted noble gases, N2, and CO2 (which were isotopically labeled) after an exposure to 20-60 GPa shock in the presence of 0.0045-3.0 atm of ambient gas. The results were compared with data available on the constituents of the EETA 79001 meteorite. As expected, the samples shocked in this study attained emplacement efficiencies significantly lower than those apparent for lithology C of EETA 79001. Possible explanations for this difference include atmospheric overpressure at the time of EETA 79001 exposure to shock, the trapping of gas already in vugs by the intruding melt material, or the collapse of gas-filled vugs to form gas-laden glass inclusions.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=20040059920&hterms=Stone+Age&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D30%26Ntt%3DStone%2BAge','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=20040059920&hterms=Stone+Age&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D30%26Ntt%3DStone%2BAge"><span>Rb-Sr and Sm-Nd Isotope Systematics of <span class="hlt">Shergottite</span> NWA 856: Crystallization Age and Implications for Alteration of Hot Desert SNC Meteorites</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Brandon, A. D.; Nyquist, L. E.; Shih, C.-Y.; Wiesmann, H.</p> <p>2004-01-01</p> <p>Nakhlite NWA 998 was discovered in Algeria in 2001, and is unique among the six known members of this group of Martian meteorites in containing significant modal orthopyroxene. Initial petrologic and isotopic data were reported by Irving et al. This 456 gram stone consists mainly of sub-calcic augite with subordinate olivine and minor orthopyroxene, titanomagnetite, pyrrhotite, chlorapatite, and intercumulus An(sub 35) plagioclase. We report here preliminary results of radiogenic isotopic analyses conducted on fragmental material from the main mass.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/20080030951','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/20080030951"><span>Oxygen Fugacity of the Upper Mantle of Mars. Evidence from the Partitioning Behavior of Vanadium in Y980459 (Y98) and other Olivine-Phyric <span class="hlt">Shergottites</span></span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Shearer, C. K.; McKay, G. A.; Papike, J. J.; Karner, J.</p> <p>2006-01-01</p> <p>Using partitioning behavior of V between olivine and basaltic liquid precisely calibrated for martian basalts, we determined the redox state of primitive (olivine-rich, high Mg#) martian basalts near their liquidus. The combination of oxidation state and incompatible element characteristics determined from early olivine indicates that correlations between fO2 and other geochemical characteristics observed in many martian basalts is also a fundamental characteristic of these primitive magmas. However, our data does not exhibit the range of fO2 observed in these previous studies.. We conclude that the fO2 for the martian upper mantle is approximately IW+1 and is incompatible-element depleted. It seems most likely (although clearly open to interpretation) that these mantle-derived magmas assimilated a more oxidizing (>IW+3), incompatible-element enriched, lower crustal component as they ponded at the base of the martian crust.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2002M%26PS...37..835G','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2002M%26PS...37..835G"><span>Sayh al Uhaymir 094: A new martian meteorite from the Oman desert</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Gnos, E.; Hofmann, B.; Franchi, I. A.; Al-Kathiri, A.; Hauser, M.; Moser, L.</p> <p>2002-06-01</p> <p>Sayh al Uhaymir (SaU) 094 is a 223.3 g, partially crusted, strongly to very strongly shocked melanocratic olivine-porphyric rock of the <span class="hlt">shergottite</span> group showing a microgabbroic texture. The rock consists of pyroxene (52.0-58.2 vol%)-dominantly prismatic pigeonite (En60-68Fs20-27Wo7-9) associated with minor augite (En46-49Fs15-16Wo28-31)-brown (shock-oxidized) olivine (Fo65-69; 22.1-31%), completely isotropic interstitial plagioclase glass (maskelynite; An50-64Or0.3-0.9; 8.6-13.0%), chromite and titanian magnesian chromite (0.9-1.0%), traces of ilmenite (Ilm80-86), pyrrhotite (Fe92-100; 0.1-0.2%), merrillite (<<0.1%), and pockets (4.8-6.7%) consisting of green basaltic to basaltic andesitic shock glass that is partially devitrified into a brown to black product along boundaries with the primary minerals. The average maximum dimensions of minerals are: olivine (1.5 mm), pyroxene (0.3 mm) and maskelynite (0.3 mm). Primary melt inclusions in olivine and chromite are common and account for 0.1-0.6% of the rock. X-ray tomography revealed that the specimen contains ~0.4 vol% of shock-melt associated vesicles, up to 3 mm in size, which show a preferred orientation. Fluidization of the maskelynite, melting and recrystallization of pyroxene, olivine and pyrrhotite indicate shock stage S6. Minor terrestrial weathering resulted in calcite-veining and minor oxidation of sulfides. The meteorite is interpreted as paired with SaU 005/008/051. The modal composition is similar to Dar al Gani 476/489/670/735/876, with the exception that neither mesostasis nor titanomagnetite nor apatite are present and that all phases show little zonation. The restricted mineral composition, predominance of chromite among the oxides, and abundance of olivine indicate affinities to the <span class="hlt">lherzolitic</span> <span class="hlt">shergottites</span>.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/1993GeCoA..57..907K','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/1993GeCoA..57..907K"><span>Examination of organic compounds from insoluble organic matter isolated from some Antarctic carbonaceous chondrites by heating experiments</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Komiya, M.; Shimoyama, A.; Harada, K.</p> <p>1993-02-01</p> <p>Insoluble organic matter isolated from five Antarctic CM2 chondrites was heated in a thermal analyzer from room temperature to 800 C under helium atmosphere. Organic compounds from the thermal decomposition of the <span class="hlt">Yamato</span>-791198 sample were studied by a gas chromatograph-mass spectrometer (GC-MS). The number of compounds identified was over 120, belonging mainly to the two following groups: (1) benzene and naphthalene, and their alkyl derivatives; and (2) sulfur-containing heterocycles and their alkyl derivatives. Small amounts of aliphatic hydrocarbons and nitriles were also detected. Relative amounts of compounds released from the five chondrite samples were monitored by the MS with increasing temperature. <span class="hlt">Yamato</span>-74662 and <span class="hlt">Yamato</span>-791198 showed organic compounds mainly over the temperature range of 300-600 C, while the other three (<span class="hlt">Yamato</span>-793321, <span class="hlt">Yamato</span>-86720, and Belgica-7904) did not show any, except small amounts of benzene. These results indicate that the insoluble organics in <span class="hlt">Yamato</span>-74662 and <span class="hlt">Yamato</span>-791198 possess a thermally labile organic fraction, whereas those in <span class="hlt">Yamato</span>-793321, <span class="hlt">Yamato</span>-86720, and Belgica-7904 do not and are graphitic. The difference between the insoluble organic fractions may be related to aqueous alteration and thermal metamorphism on the parent bodies.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016AGUFM.P52A..04U','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016AGUFM.P52A..04U"><span>The Evolution of Water in Martian Atmosphere, Hydrosphere, and Cryosphere: Insights from Hydrogen Isotopes</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Usui, T.; Kurokawa, H.; Alexander, C.; Simon, J. I.; Wang, J.; Jones, J. H.</p> <p>2016-12-01</p> <p>Mars exploration missions provide compelling evidence for the presence of liquid water during the earliest geologic era (Noachian: > 3.9 Ga) of Mars. The amount and stability of liquid water on the surface is strongly influenced by the composition and pressure of the atmosphere. However, the evolution of Noachian atmosphere has been poorly constrained due to uncertainties of atmospheric loss regimes and internal/external factors such as impact flux and volcanic degassing. We can trace the evolution of the early Martian atmosphere and its interaction with the hydrosphere and cryosphere with hydrogen isotope ratios (D/H) because they fractionate during atmospheric escape and during hydrological cycling between the atmosphere, surface waters, and the polar ice caps. This study reports D/H ratios of primordial and 4 Ga-old atmosphere by ion microprobe analyses of Martian meteorites. Analyses of olivine-hosted glass inclusions in the most primitive <span class="hlt">shergottite</span> (<span class="hlt">Yamato</span> 980459) provide a near-chondritic D/H ratio (1.3×SMOW) for the 4.5 Ga primordial water preserved in the mantle. On the other hand, carbonates in Allan Hills 84001 provide a D/H range (1.5-2.0×SMOW) for the Noachian surface water that was isotopically equilibrated with the 4 Ga atmosphere. The latter observation requires that even after the Noachian period the hydrogen isotopes were fractionated significantly to reach the present-day value of 6×SMOW. Using the one-reservoir model of Kurokawa et al. (2014) we can provide minimum estimates on the amounts of hydrogen loss before and after 4 Ga based on the D/H data from the meteorites (1.3×SMOW at 4.5 Ga and 1.5-2.0×SMOW at 4 Ga) assuming the volume of polar surface-ice (20-30 m global equivalent layers, GEL). The model indicates that the hydrogen loss during the first 0.5 billion years (16-54 m GEL) was comparable to those (42-93 mGEL) in the remaining Martian history. These values are distinctly lower than the geological estimates on the volumes of</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2012AGUFMMR11C2507D','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2012AGUFMMR11C2507D"><span>Sulfur Concentration of Martian Magmas at Sulfide Saturation at High Pressures and Temperatures - Implications for Martian Magma Ocean and Magmatic Differentiation</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Ding, S.; Dasgupta, R.</p> <p>2012-12-01</p> <p>Sulfur is critical for a wide range of processes of terrestrial planets including thermal evolution of core and atmosphere and geochemistry of mantle and crust. For Mars, sulfur is particularly important because it may be abundant in the core [1] while SO 2 and H2 S might have exerted a strong greenhouse climate in the past [2]. A critical parameter that affects sulfur distribution during differentiation is the sulfur carrying capacity of mantle melts. However, most experiments constraining sulfur content at sulfide saturation (SCSS) are conducted on FeO poor (~5-12 wt.%) basalts [3] and recent experiments on high-FeO (~16-22 wt.%, [4]) Martian basalts are restricted to ≤0.8 GPa [5]. To constrain SCSS of Martian magmas at mantle conditions, we simulated basalt-sulfide melt equilibria (S added as 15-30 wt.% FeS) in Gr capsules using a piston cylinder at 1-3 GPa and 1500-1700 °C. Two starting compositions, equivalent to olivine-phyric <span class="hlt">shergottites</span> <span class="hlt">Yamato</span>980459 (Y98; ~17.53 wt.% FeO) and NWA 2990 (NWA; ~16.42 wt.% FeO) and thought to be primary magma [6] were used. A composition Y98+1.4 wt.% H2O was also explored to constrain the effect of water on SCSS. All experiments produced quenched sulfide and silicate melts ± opx . FeS species in the NWA glasses was confirmed from peaks at 300-400 cm-1 in Raman spectra [7]. At 1600 °C, SCSS, measured using EPMA, decreases with pressure, 4800 to 3500 ppm from 1 to 2.5 GPa for Y98, ~5440 to 4380 ppm from 1 to 2 GPa for Y98+1.4 wt.% H2O, and 5000 to 3000 ppm from 1 to 3 GPa for NWA. At 2 GPa, SCSS of NWA increases with temperature, 3300 to 4600 ppm from 1500 to 1700 °C. Combining new and previous experiments on Martian basalts [5] (a total of 28 SCSS data with FeO* of 9.3-32.78 wt.%), a preliminary equation of the form LnS (ppm) = a + b.P + c/T +d.XSiO2 + e.XAl2O3 + f.LnXFeO was fitted, where P is in GPa, T in K, and X represents mole fraction of a given oxide. Our study suggests that at conditions of final melt</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/20070023946','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/20070023946"><span>The Shergotites Are Young</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Jones, John H.</p> <p>2007-01-01</p> <p>Recently, Bouvier et al. (2006), interpreting their Pb isotopic data, have inferred that the <span class="hlt">shergottite</span> suite of the SNC (martian) meteorites have ancient ages of approximately 4-4.5 b.y. But conventional wisdom has it that the <span class="hlt">shergottites</span> are much younger (approximately 500-150 m.y.) Are the <span class="hlt">shergottites</span> young or are they ancient rocks whose ages have been reset by metamorphism or alteration?</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_14");'>14</a></li> <li><a href="#" onclick='return showDiv("page_15");'>15</a></li> <li class="active"><span>16</span></li> <li><a href="#" onclick='return showDiv("page_17");'>17</a></li> <li><a href="#" onclick='return showDiv("page_18");'>18</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_16 --> <div id="page_17" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_15");'>15</a></li> <li><a href="#" onclick='return showDiv("page_16");'>16</a></li> <li class="active"><span>17</span></li> <li><a href="#" onclick='return showDiv("page_18");'>18</a></li> <li><a href="#" onclick='return showDiv("page_19");'>19</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="321"> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2012LPI....43.1247V','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2012LPI....43.1247V"><span>Partitioning of F, Cl, and H_2O Between Apatite and a Synthetic <span class="hlt">Shergottite</span> Liquid (QUE 94201) at 1.0 GPa and 990°-1000°C</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Vander Kaaden, K. E.; McCubbin, F. M.; Whitson, E. S.; Hauri, E. H.; Wang, J.</p> <p>2012-03-01</p> <p>Apatite/melt partitioning experiments on a QUE 94201 composition were conducted at 1 GPa and 990°-1000°C in a piston-cylinder press. The partition coefficients for F, Cl, and H_2O are highly variable and seem to correlate strongly with melt F content.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2006epsc.conf..501J','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2006epsc.conf..501J"><span>P Isotope Data of SNC Meteorites and Implications on the Age of the Martian Surface</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Jagoutz, E.; Jotter, R.; Kubny, A.; Zartman, R.</p> <p></p> <p> explain the higher 206 Pb/204 Pb value. It is interesting to notice that the initial Pb from the olivine <span class="hlt">Shergottites</span>, Sayh al Uhaymir 008 and <span class="hlt">Yamato</span> 980459, plot close to that of the Nakhlites, although the petrographically similar Dar al Gani 476 is so altered and contaminated by terrestrial Pb that a meaningful initial Pb isotopic composition cannot be determined. Allowing for the different age for these olivine-bearing <span class="hlt">Shergottites</span>, they might actually come from the same isotopic reservoir. Furthermore, the 142 Nd and 82 W anomalies appear to be restricted to meteorites coming from this Nakhla source. Sr, Nd, and Pb isotopes also 1 indicate that this reservoir was strongly depleted in large ion lithophile elements (LIL), such as U, Rb, Nd, and W, over most of its lifetime. Because the initial Pb isotopic composition has evolved to the right of the geochron, an increase of the U/Pb ratio, possibly accompanying magmatic activity, must have occurred at some intermediate time before the "young event" produced the Nakhlites at 1.25 Ga. Accepting Mars as the source of SNC meteorites, we may speculate on what was the surface expression of the isotopically-manifested petrogenetic processes. Shergotty, Zagami, and Los Angeles might be typical Martian crustal rocks, and the "young event" could be impact related and have no further surface expression. Hence, that crust could be ancient and possibly even 4.55 Ga old. Nakhlites, with their unique exposure age and isotopic uniformity, may well all have come from a single, homogeneous mantle source. Olivine <span class="hlt">Shergottites</span>, showing a similar isotopic composition to Nakhlites, although with different exposure ages, appear to have sampled basalts from the same widespread mantle source at a number of different places. These basalts are likely to be low viscosity surface lava flows of picritic composition, and in some cases those lavas might have assimilated crustal rocks (EETA 79001 [A], Dar al Gani 476). The age of such flows could be</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014LPICo1819.1004S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014LPICo1819.1004S"><span>The Chlorine Isotope Composition of Martian Meteorites</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Sharp, Z. D.; Shearer, C. K.; Agee, C.; Burger, P. V.; McKeegan, K. D.</p> <p>2014-11-01</p> <p>The Cl isotope composition of martian meteorites range from -3.8 to +8.6 per mil. Ol-phyric <span class="hlt">shergottites</span> are lightest; crustally contaminated samples are heaviest, basaltic <span class="hlt">shergottites</span> are in-between. The system is explained as two component mixing.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/20130011110','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/20130011110"><span>The Effects of Oxygen Fugacity on the Crystallization Sequence and Cr Partitioning of an Analog Y-98 Liquid</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Bell, A. S.; Burger, P. V.; Le, Loan; Papike, J. J.; Jones, J.; Shearer, C. K.</p> <p>2013-01-01</p> <p>Interpreting the relationship between "enriched" olivine-phyric <span class="hlt">shergottites</span> (e.g. NWA 1068/1110) and the "enriched" pyroxene-plagioclase <span class="hlt">shergottites</span> (e.g. Shergotty, Los Angeles) is problematic. Symes et al. [1] and Shearer et al. [2]) proposed that the basaltic magma that crystallized to produce olivine-phyric <span class="hlt">shergottite</span> NWA 1068/1110 could produce pyroxene-plagioclase <span class="hlt">shergottites</span> with additional fractional crystallization. However, additional observations indicate that the relationship among the enriched <span class="hlt">shergottites</span> may be more complex [1-3]. For example, Herd [3] concluded that some portion of the olivine megacrysts in this meteorite was xenocrystic in origin, seemingly derived from more reduced basaltic liquids. This conclusion may imply that a variety of complex processes such as magma mixing, entrainment, and assimilation may play important roles in the petrologic history of these meteorites. It is therefore possible that these processes have obscured the petrogenetic linkages between the enriched olivine-phyric <span class="hlt">shergottites</span> and the pyroxene-plagioclase <span class="hlt">shergottites</span>. As a first order step in attempting to unravel these petrologic complexities, this study focuses upon exploring the effect of fO2 on the crystallization history for an analog primitive <span class="hlt">shergottite</span> liquid composition (Y98). Results from this work will provide a basis for reconstructing the record of fO2 in <span class="hlt">shergottites</span>, its effect on both mineral chemistries and valence state partitioning, and a means for examining the role of crystallization on the petrologic linkages between olivine-phyric and pyroxene-plagioclase <span class="hlt">shergottites</span>. A companion abstract [4] explores the behavior of V over this range of fO2.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/1989GeCoA..53.1657G','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/1989GeCoA..53.1657G"><span>Sphalerites in EH chondrites: I. Textural relations, compositions, diffusion profiles, and pressure-temperature histories</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Goresy, Ahmed El; Karin, Ehlers</p> <p>1989-07-01</p> <p>Sphalerite-bearing assemblages in the unequilibrated EH chondrites Qingzhen, <span class="hlt">Yamato</span> 691, and Indarch were studied to understand their pressure and temperature histories. Sphalerite in Qingzhen and in <span class="hlt">Yamato</span> 691 are zoned with descending FeS concentration to troilite. Compositions of sphalerite cores in Qingzhen and <span class="hlt">Yamato</span> 691 are similar (47.03-49.6 mol% FeS in Qingzhen versus 47.4-49.7 mol% FeS in <span class="hlt">Yamato</span> 691). The FeS contents of the sphalerite rims to troilite are comparable (45.98 mol% in Qingzhen, 42.3 mol% in <span class="hlt">Yamato</span> 691). Exsolution lamellae of troilite were found in several sphalerite grains in Qingzhen. The FeS content in these grains also decreases to a value as low as 45.4 mol% FeS near the contact to the lamellae. Secondary homogeneous sphalerite, formed during a late metamorphic episode in <span class="hlt">Yamato</span> 691 (800 M.Y. ago), is characterized by low FeS content (43.2-42.3 mol% FeS). The descending concentration profiles in sphalerites in Qingzhen and <span class="hlt">Yamato</span> 691 were produced by re-equilibration of the sphalerite with the neighbouring troilite at high pressures during late metamorphic episodes. However, the compositions of sphalerite cores may reflect primordial compositions after sphalerite condensation but before its burial in the parent asteroid. We obtain closure temperatures between 639 K and 728 K, and 650 K and 732 K for sphalerites in Qingzhen and <span class="hlt">Yamato</span> 691, respectively. From compositions of sphalerite rims we estimate that the re-equilibration took place at 0.18 kbar in Qingzhen and at 0.77-0.95 kbar in <span class="hlt">Yamato</span> 691. Qingzhen and <span class="hlt">Yamato</span> 691 were metamorphosed at different times and much later after accretion (1.4 B.Y. and 800 M.Y., respectively). Sphalerite in Indarch displays complex textures indicative of multiple metamorphic events. Its FeS-content varies between 53.0 and 56.0 mol%. The grains contain open pores and are subdivided by platelets arranged parallel to (111) planes of the original sphalerite. This is strongly suggestive of sphalerite</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=19790054372&hterms=Allan&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D60%26Ntt%3DAllan','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=19790054372&hterms=Allan&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D60%26Ntt%3DAllan"><span>Allan Hills 77005 - A new meteorite type found in Antarctica</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Mcsween, H. Y., Jr.; Taylor, L. A.; Stolper, E. M.</p> <p>1979-01-01</p> <p>A unique 482.5 g meteorite found in Antarctica appears to be related by igneous differentiation to <span class="hlt">shergottite</span> achondrites, which have close similarities with terrestrial basaltic rocks. Zoned maskelynite with similar compositional ranges and plagioclase of such intermediate compositions as are unknown in other achondrites occur in both <span class="hlt">shergottites</span> and the Allan Hills meteorite. The degree of silica saturation, however, strongly distinguishes the two meteorite types. It is suggested that the Allan Hills meteorite may represent a cumulate rock formed earlier than the <span class="hlt">shergottites</span> from the same or a similar parent magma.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/19920003707','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/19920003707"><span>Nd-142/Nd-144 in SNCs and early differentiation of a heterogeneous Martian mantle</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Nyquist, L. E.; Harper, C. L.; Wiesmann, H.; Bansal, B.; Shih, C.-Y.</p> <p>1991-01-01</p> <p>Sm/Nd correlated variations in Nd-142/Nd-144 have been observed for mineral phases of achondrites from decay of live Sm-146 in the early solar system. Crystallization ages of <span class="hlt">shergottites</span>-nakhlites-Chassigny (SNC) meteorites are less than or = 1.3 Ga, so variations of Nd-142/Nd-144 among mineral phases of the SNC's are not expected. However, if SNC's were derived from source reservoirs of differing Sm/Nd ratios, established while Sm-146 was still alive, and which remained isolated except for magma extraction, then variations in Nd-142/Nd-144 would exist among individual SNC meteorites. Rb-Sr and U-Pb isotopic data for the <span class="hlt">shergottites</span> imply differentiation of their parent planet approximately 4.6 Ga ago. The confirmation of the conclusion that the nakhlites and <span class="hlt">shergottites</span> were derived from different source regions, and that, consequently, the <span class="hlt">shergottite</span> parent body (SPB) mantle was heterogeneous is presented.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016LPICo1921.6198F','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016LPICo1921.6198F"><span>Petrology and Geochemistry of New Paired Martian Meteorites Larkman Nunatak 12240 and Larkman Nunatak 12095</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Funk, R. C.; Peslier, A. H.; Brandon, A. D.; Humayun, M.</p> <p>2016-08-01</p> <p>Two of the latest Martian meteorites found in Antarctica, paired olivine-phyric <span class="hlt">shergottites</span> LAR 12240 and LAR 12095, are described in order to decipher their petrological context, and place constraints on the geological history of Mars.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=19720038932&hterms=chemical+elements&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D20%26Ntt%3Dchemical%2Belements','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=19720038932&hterms=chemical+elements&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D20%26Ntt%3Dchemical%2Belements"><span>Chemical fractionations in meteorites. V - Volatile and siderophile elements in achondrites and ocean ridge basalts.</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Laul, J. C.; Keays, R. R.; Ganapathy, R.; Anders, E.; Morgan, J. W.</p> <p>1972-01-01</p> <p>Eighteen achondrites and 4 terrestrial basalts (3 ocean ridge, 1 continental) were analyzed by radiochemical neutron activation analysis for Ag, Au, Bi, Br, Cd, Co, Cs, Cu, Ga, In, Ir, Rb, Se, Tl and Zn. Samples included 7 eucrites, 5 howardites, 2 nakhlites, 2 <span class="hlt">shergottites</span>, an angrite, and an aubrite. Light and dark portions of the gas-rich meteorites Kapoeta and Pesyanoe were analyzed separately. Nakhlites and <span class="hlt">shergottites</span> have volatile element abundances similar to those in ocean ridge basalts; eucrites, howardites, and angrites show greater depletions by an order of magnitude and less similar abundance patterns. In terms of a two-component model of planetary accretion, the parent planets contained the following percentages of low-temperature material: eucrites 0.8, nakhlites 38, <span class="hlt">shergottites</span> 28. <span class="hlt">Shergottites</span> may be genetically related to L-chondrites. The siderophile element pattern of achondrites resembles that of the moon, but with less extreme depletions.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=19800036000&hterms=Ice+Age&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D90%26Ntt%3DIce%2BAge','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=19800036000&hterms=Ice+Age&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D90%26Ntt%3DIce%2BAge"><span>Measurements of Cl-36 in Antarctic meteorites and Antarctic ice using a Van de Graaff accelerator</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Nishiizumi, K.; Arnold, J. R.; Finkel, R. C.; Elmore, D.; Ferraro, R. D.; Gove, H. E.; Beukens, R. P.; Chang, K. H.; Kilius, L. R.</p> <p>1979-01-01</p> <p>The paper presents measurements of cosmic-ray produced (Cl-36) in Antarctic meteorites and ice using a Van de Graaff accelerator as an ultrasensitive mass spectrometer. Results from this ion counting technique are used to support a two-stage irradiation model for the <span class="hlt">Yamato</span>-7301 and Allan Hills-76008 meteorites and to show a long terrestrial age for Allan Hills-77002. <span class="hlt">Yamato</span>-7304 has a terrestrial age of less than 0.1 m.y., and the (Cl-36) content of the Antarctic ice sample from the <span class="hlt">Yamato</span> mountain is consistent with levels expected in currently depositing snow implying that the age of the ice cap at this site is less than on (Cl-36) half-life.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2013Litho.168....1L','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2013Litho.168....1L"><span>Petrology, geochemistry and Resbnd Os isotopes of peridotite xenoliths from Maguan, Yunnan Province: Implications for the Cenozoic mantle replacement in southwestern China</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Liu, Chuan-Zhou; Wu, Fu-Yuan; Sun, Jing; Chu, Zhu-Yin; Yu, Xue-Hui</p> <p>2013-05-01</p> <p>Petrology, geochemistry and Resbnd Os isotopes of peridotite xenoliths from Maguan (Yunnan Province) are reported in this paper with the aims of constraining the age and evolution of the lithospheric mantle beneath the western margin of the Cathyasia block. The Maguan mantle xenoliths contain predominantly fertile <span class="hlt">lherzolites</span> with whole-rock Al2O3 contents of 2.42-4.99 wt.%, and subordinate clinopyroxene-poor <span class="hlt">lherzolites</span> with Al2O3 contents of 1.19-1.98 wt.%. Their whole-rock CaO, Al2O3 and Na2O decrease along with the increase of MgO, following melt depletion trends. This suggests that the Maguan <span class="hlt">lherzolites</span> represent mantle residues after variable degrees of partial melting. Clinopyroxenes in the fertile <span class="hlt">lherzolites</span> display flat to depleted REE patterns, whereas those in the clinopyroxene-poor <span class="hlt">lherzolites</span> are variably enriched in LREE. Modeling results of Y and Yb contents in clinopyroxenes suggest that the fertile <span class="hlt">lherzolites</span> have experienced ~ 1-5% degrees of partial melting, in contrast with ~ 10-15% for the clinopyroxene-poor <span class="hlt">lherzolites</span>. Both fertile and clinopyroxene-poor <span class="hlt">lherzolites</span> have similarly high equilibrium temperatures, i.e., 911-1120 °C versus 919-941 °C, respectively. The whole-rock 187Os/188Os ratios of clinopyroxene-poor <span class="hlt">lherzolites</span> vary from 0.11764 to 0.12506, which are slightly lower than most fertile <span class="hlt">lherzolites</span> (0.12272-0.12854). Their 187Os/188Os ratios show no correlation with 187Re/188Os ratios or bulk-rock Al2O3 contents. The rhenium depletion ages (TRD) of the <span class="hlt">lherzolites</span> range from 0.15 to 1.08 Ga, whereas the clinopyroxene-poor <span class="hlt">lherzolites</span> have TRD ages of 0.64-1.67 Ga. This suggests the co-existence of Phanerozoic and Proterozoic mantle beneath the western Cathyasia block. Alternatively, the whole lithospheric mantle beneath Maguan was likely formed during the Phanerozoic, given the resemblance of their Os isotopic ratios with those of abyssal peridotites. The latter explanation is consistent with the fact that all the studied</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2008M%26PS...43.1241S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2008M%26PS...43.1241S"><span>Petrogenetic linkages among Martian basalts: Implications based on trace element chemistry of olivine</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Shearer, C. K.; Burger, P. V.; Papike, J. J.; Borg, L. E.; Irving, A. J.; Herd, C.</p> <p>2008-10-01</p> <p>The <span class="hlt">shergottites</span> exhibit a range of major and trace element compositions, crystallization ages, and initial Sr, Nd, Hf, and Pb isotopic compositions. To constrain the physical mechanisms by which <span class="hlt">shergottites</span> obtain their compositional characteristics, we examined the major and trace element record preserved in olivine in the more primitive <span class="hlt">shergottites</span>. Based on such characteristics as the Mg#, V zoning, calculated DNi,Co, the olivine in Y-980459 are most likely phenocrysts. Many of these same characteristics indicate that the olivines in other <span class="hlt">shergottites</span> are not in equilibrium with the adjacent melt. However, in most cases they are not xenocrystic, but additions of olivine from the same basaltic system. Elephant Moraine (EET) A79001 may be an exception with the olivine data suggesting that it is xenocrystic. In this case, the olivine crystallized from a reduced and LREEdepleted melt and was incorporated into an oxidized and enriched basalt. Vanadium and CaO in olivine appear to record the appearance of spinel and pyroxene on the liquidus of most of the <span class="hlt">shergottites</span>. Most of the olivine <span class="hlt">shergottites</span> represent basalts produced by melting of reduced (IW to IW + 1), depleted mantle sources. Olivine data indicate that many of the primary melts derived from this source had similar Ni, Co, and Mn. <span class="hlt">Shergottites</span> such as Northwest Africa (NWA) 1110/1068 and perhaps Roberts Massif (RBT) 04261 that appear to be derived from more enriched sources have distinctly different olivine. In the case of NWA 1110/1068, the olivine data suggests that the enriched component was added to system prior to olivine crystallization.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/20090032652','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/20090032652"><span>Controls on Highly Siderophile Element Concentrations in Martian Basalt: Sulfide Saturation and Under-Saturation</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Righter, Kevin</p> <p>2009-01-01</p> <p>Highly siderophile elements (HSE; Re, Au and the platinum group elements) in <span class="hlt">shergottites</span> exhibit a wide range from very high, similar to the terrestrial mantle, to very low, similar to sulfide saturated mid ocean ridge basalt (e.g., [1]). This large range has been difficult to explain without good constraints on sulfide saturation or under-saturation [2]. A new model for prediction of sulfide saturation places new constraints on this problem [3]. <span class="hlt">Shergottite</span> data: For primitive <span class="hlt">shergottites</span>, pressure and temperature estimates are between 1.2-1.5 GPa, and 1350-1470 C [4]. The range of oxygen fugacities is from FMQ-2 to IW, where the amount of Fe2O3 is low and thus does not have a significant effect on the S saturation values. Finally, the bulk compositions of <span class="hlt">shergottites</span> have been reported in many recent studies (e.g., [5]). All of this information will be used to test whether <span class="hlt">shergottites</span> are sulfide saturated [3]. Modeling values and results: The database for HSE partition coefficients has been growing with many new data for silicates and oxides [6-8] to complement a large sulfide database [9- 11]. Combining these data with simple batch melting models allows HSE contents of mantle melts to be estimated for sulfide-bearing vs. sulfide-free mantle. Combining such models with fractional crystallization modeling (e.g., [12]) allows HSE contents of more evolved liquids to be modeled. Most primitive <span class="hlt">shergottites</span> have high HSE contents (and low S contents) that can be explained by sulfide under-saturated melting of the mantle. An exception is Dhofar 019 which has high S contents and very low HSE contents suggesting sulfide saturation. Most evolved basaltic <span class="hlt">shergottites</span> have lower S contents than saturation, and intermediate HSE contents that can be explained by olivine, pyroxene, and chromite fractionation. An exception is EET A79001 lithology B, which has very low HSE contents and S contents higher than sulfide saturation values . evidence for sulfide saturation</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/20070003723','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/20070003723"><span>Rb-Sr and Sm-Nd Isotopic Studies of Martian Depleted Shergottes SaU 094/005</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Shih, C.-Y.; Nyquist, L. E.; Reese, Y.</p> <p>2007-01-01</p> <p>Sayh al Uhaymir (SaU) 094 and SaU 005 are olivine-phyric <span class="hlt">shergottites</span> from the Oman desert and are considered as pairs. [e.g., 1]. They are very similar to the Libyan desert <span class="hlt">shergottite</span> Dar al Gani (DaG) 476 in petrology, chemistry and ejection age [2-6]. This group of <span class="hlt">shergottites</span>, also recognized as depleted <span class="hlt">shergottites</span> [e.g. 7] has been strongly shocked and contains very low abundances of light rare earth elements (REE). In addition, terrestrial contaminants are commonly present in meteorites found in desert environments. Age-dating these samples is very challenging, but lower calcite contents in the SaU meteorites suggest that they have been subjected to less severe desert weathering than their DaG counterparts [3-4]. In this report, we present Rb-Sr and Sm-Nd isotopic results for SaU 094 and SaU 005, discuss the correlation of their ages with those of other similar <span class="hlt">shergottites</span>, and discuss their petrogenesis.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/19840009021','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/19840009021"><span>Radioactivities in returned lunar materials and in meteorites</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Fireman, E. L.</p> <p>1984-01-01</p> <p>Carbon 14 terrestial ages were determined with low level minicomputers and accelerator mass spectrometry on 1 <span class="hlt">Yamato</span> and 18 Allan Hills and nearby sited meteorites. Techniques for an accelerator mass spectrometer which make C(14) measurements on small samples were developed. Also Be(10) concentrations were measured in Byrd core and Allan Hills ice samples.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/19860019361','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/19860019361"><span>Over 5,600 Japanese collection of Antarctic meteorites: Recoveries, curation and distribution</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Yanai, K.; Kojima, H.</p> <p>1986-01-01</p> <p>The history of recovery of meteorite fragments in the <span class="hlt">Yamato</span> Mountains, Allan Hills, and Victoria Land, Antarctica is reviewed. The Japanese collection of Antarctic meteorites were numbered, weighed, photographed, identified, and classified. Sample distribution of the Japanese Antarctic meteorites is described.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/19980019921','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/19980019921"><span>Lunar Meteorite Queen Alexandra Range 93069 and the Iron Concentration of the Lunar Highlands Surface</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Korotev, Randy L.; Jolliff, Bradley L.; Rockow, Kaylynn M.</p> <p>1996-01-01</p> <p>Lunar meteorite Queen Alexandra Range 93069 is a clast-rich, glassy-matrix regolith breccia of ferroan, highly aluminous bulk composition. It is similar in composition to other feldspathic lunar meteorites but differs in having higher concentrations of siderophile elements and incompatible trace elements. Based on electron microprobe analyses of the fusion crust, glassy matrix, and clasts, and instrumental neutron activation analysis of breccia fragments, QUE 93069 is dominated by nonmare components of ferroan, noritic- anorthosite bulk composition. Thin section QUE 93069,31 also contains a large, impact-melted, partially devitrified clast of magnesian, anorthositic-norite composition. The enrichment in Fe, Sc, and Cr and lower Mg/Fe ratio of lunar meteorites <span class="hlt">Yamato</span> 791197 and <span class="hlt">Yamato</span> 82192/3 compared to other feldspathic lunar meteorites can be attributed to a small proportion (5-10%) of low-Ti mare basalt. It is likely that the non- mare components of <span class="hlt">Yamato</span> 82192/3 are similar to and occur in similar abundance to those of <span class="hlt">Yamato</span> 86032, with which it is paired. There is a significant difference between the average FeO concentration of the lunar highlands surface as inferred from the feldspathic lunar meteorites (mean: approx. 5.0%; range: 4.3-6.1 %) and a recent estimate based on data from the Clementine mission (3.6%).</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://files.eric.ed.gov/fulltext/ED401419.pdf','ERIC'); return false;" href="http://files.eric.ed.gov/fulltext/ED401419.pdf"><span>Adult Education for a Multiethnic Community: Japan's Challenge.</span></a></p> <p><a target="_blank" href="http://www.eric.ed.gov/ERICWebPortal/search/extended.jsp?_pageLabel=advanced">ERIC Educational Resources Information Center</a></p> <p>Sasagawa, Koichi</p> <p></p> <p>Modern education in Japan from 1868 to 1945 stressed "national education" in order to promote a sense of belonging to the Japanese state. The Japanese culture was thought to be superior to that of its "less advanced" East Asian neighbors, and Japanese people were encouraged to adopt a "<span class="hlt">Yamato</span>" identity (the seat of an…</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=19940016419&hterms=Breccia&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D60%26Ntt%3DBreccia','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=19940016419&hterms=Breccia&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D60%26Ntt%3DBreccia"><span>Regolith breccia consisting of H and LL chondrite mixture</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Yanai, Keizo; Kojima, Hideyasu</p> <p>1993-01-01</p> <p>Antarctic meteorite <span class="hlt">Yamato</span>-8424 (Y-8424) is a regolith breccia that is homogenized mixture of H and LL chondrite components. The breccia consists mainly of a fine-grained material with mineral fragments of olivine, pyroxene, and Fe-Ni metal with traces of plagioclase.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=5287701','PMC'); return false;" href="https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=5287701"><span>Two billion years of magmatism recorded from a single Mars meteorite ejection site</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Lapen, Thomas J.; Righter, Minako; Andreasen, Rasmus; Irving, Anthony J.; Satkoski, Aaron M.; Beard, Brian L.; Nishiizumi, Kunihiko; Jull, A. J. Timothy; Caffee, Marc W.</p> <p>2017-01-01</p> <p>The timing and nature of igneous activity recorded at a single Mars ejection site can be determined from the isotope analyses of Martian meteorites. Northwest Africa (NWA) 7635 has an Sm-Nd crystallization age of 2.403 ± 0.140 billion years, and isotope data indicate that it is derived from an incompatible trace element–depleted mantle source similar to that which produced a geochemically distinct group of 327- to 574-million-year-old “depleted” <span class="hlt">shergottites</span>. Cosmogenic nuclide data demonstrate that NWA 7635 was ejected from Mars 1.1 million years ago (Ma), as were at least 10 other depleted <span class="hlt">shergottites</span>. The shared ejection age is consistent with a common ejection site for these meteorites. The spatial association of 327- to 2403-Ma depleted <span class="hlt">shergottites</span> indicates >2 billion years of magmatism from a long-lived and geochemically distinct volcanic center near the ejection site. PMID:28164153</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_15");'>15</a></li> <li><a href="#" onclick='return showDiv("page_16");'>16</a></li> <li class="active"><span>17</span></li> <li><a href="#" onclick='return showDiv("page_18");'>18</a></li> <li><a href="#" onclick='return showDiv("page_19");'>19</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_17 --> <div id="page_18" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_16");'>16</a></li> <li><a href="#" onclick='return showDiv("page_17");'>17</a></li> <li class="active"><span>18</span></li> <li><a href="#" onclick='return showDiv("page_19");'>19</a></li> <li><a href="#" onclick='return showDiv("page_20");'>20</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="341"> <li> <p><a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=19790049197&hterms=Peridotite&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D80%26Ntt%3DPeridotite','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=19790049197&hterms=Peridotite&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D80%26Ntt%3DPeridotite"><span>A petrogenetic model of the relationships among achondritic meteorites</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Stolper, E.; Hays, J. F.; Mcsween, H. Y., Jr.</p> <p>1979-01-01</p> <p>Petrological evidence is used to support the hypothesis that although the magma source regions and parent bodies of basaltic achondrite, <span class="hlt">shergottite</span>, nakhlite, and chassignite meteorites are clearly distinct, they may be simply related. It is proposed that the peridotites which on partial melting generated the parent magmas of the <span class="hlt">shergottite</span> meteorites differed from those which gave rise to eucritic magmas by being enriched in a component rich in alkalis and other volatiles. Similarly, the source regions of the parent magmas of the nakhlite and chassignite meteorites differed from those on the <span class="hlt">shergottite</span> parent body by being still richer in this volatile-rich component. These regions could have been related by processes such as mixture of variable amounts of volatile-rich and volatile-poor components in planetary or nebular settings, or alternatively by variable varying degrees of volatile loss from volatile-rich materials.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=19800035999&hterms=Peridotite&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D70%26Ntt%3DPeridotite','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=19800035999&hterms=Peridotite&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D70%26Ntt%3DPeridotite"><span>Petrogenetic relationship between Allan Hills 77005 and other achondrites</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Mcsween, H. Y., Jr.; Taylor, L. A.; Stolper, E. M.; Muntean, R. A.; Okelley, G. D.; Eldridge, J. S.; Biswas, S.; Ngo, H. T.; Lipschutz, M. E.</p> <p>1979-01-01</p> <p>The paper presents chemical and petrologic data relating the Allan Hills (ALHA) 77005 achondrite from Antarctica and explores their petrogenetic relationship with the <span class="hlt">shergottites</span>. Petrologic similarities with the latter in terms of mineralogy, oxidation state, inferred source region composition, and shock ages suggest a genetic relationship, also indicated by volatile to involatile element ratios and abundances of other trace elements. ALHA 77005 may be a cumulate crystallized from a liquid parental to materials from which the <span class="hlt">shergottites</span> crystallized or a sample of peridotite from which <span class="hlt">shergottite</span> parent liquids were derived. Chemical similarities with terrestrial ultramafic rocks suggest that it provides an additional sample of the only other solar system body with basalt source origins chemically similar to the upper earth mantle.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/28164153','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/28164153"><span>Two billion years of magmatism recorded from a single Mars meteorite ejection site.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Lapen, Thomas J; Righter, Minako; Andreasen, Rasmus; Irving, Anthony J; Satkoski, Aaron M; Beard, Brian L; Nishiizumi, Kunihiko; Jull, A J Timothy; Caffee, Marc W</p> <p>2017-02-01</p> <p>The timing and nature of igneous activity recorded at a single Mars ejection site can be determined from the isotope analyses of Martian meteorites. Northwest Africa (NWA) 7635 has an Sm-Nd crystallization age of 2.403 ± 0.140 billion years, and isotope data indicate that it is derived from an incompatible trace element-depleted mantle source similar to that which produced a geochemically distinct group of 327- to 574-million-year-old "depleted" <span class="hlt">shergottites</span>. Cosmogenic nuclide data demonstrate that NWA 7635 was ejected from Mars 1.1 million years ago (Ma), as were at least 10 other depleted <span class="hlt">shergottites</span>. The shared ejection age is consistent with a common ejection site for these meteorites. The spatial association of 327- to 2403-Ma depleted <span class="hlt">shergottites</span> indicates >2 billion years of magmatism from a long-lived and geochemically distinct volcanic center near the ejection site.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=20040056053&hterms=juveniles&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D10%26Ntt%3Djuveniles','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=20040056053&hterms=juveniles&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D10%26Ntt%3Djuveniles"><span>The Edge of Wetness: The Case for Dry Magmatism on Mars</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Jones, J. H.</p> <p>2004-01-01</p> <p>The issue of whether martian magmas are wet or dry is an important one. The answer to this basic question has profound consequences for how we think about Mars as a planet. Recently, several lines of evidence have been presented that collectively suggest that <span class="hlt">shergottite</span> parent magmas were once wet. These include: (i) phase equilibria studies that indicate that the Shergotty parent magma required 2 wt.% water in order to be co-saturated with both pigeonite and augite, (ii) reverse zoning of light lithophile elements (Li and B) in <span class="hlt">shergottite</span> pyroxenes, suggesting the exsolution and removal of an aqueous fluid, and (iii) measurement of D/H ratios in SNC minerals that are much lower than atmospheric, suggesting that there may be juvenile (primordial) mantle water. Below I will review the evidence for the diametrically opposite case, that <span class="hlt">shergottite</span> magmas were effectively dry (<< 1 wt.% H2O).</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/20060021587','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/20060021587"><span>Ar-Ar Dating of Martian Meteorite, Dhofar 378: An Early Shock Event?</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Park, J.; Bogard, D. D.</p> <p>2006-01-01</p> <p>Martian meteorite, Dhofar 378 (Dho378) is a basaltic <span class="hlt">shergottite</span> from Oman, weighing 15 g, and possessing a black fusion crust. Chemical similarities between Dho378 and the Los Angeles 001 <span class="hlt">shergottite</span> suggests that they might have derived from the same Mars locale. The plagioclase in other <span class="hlt">shergottites</span> has been converted to maskelenite by shock, but Dho378 apparently experienced even more intense shock heating, estimated at 55-75 GPa. Dho378 feldspar (approximately 43 modal %) melted, partially flowed and vesiculated, and then partially recrystallized. Areas of feldspathic glass are appreciably enriched in K, whereas individual plagioclases show a range in the Or/An ratio of approximately 0.18-0.017. Radiometric dating of martian <span class="hlt">shergottites</span> indicate variable formation times of 160-475 Myr, whereas cosmic ray exposure (CRE) ages of <span class="hlt">shergottites</span> indicate most were ejected from Mars within the past few Myr. Most determined Ar-39-Ar-40 ages of <span class="hlt">shergottites</span> appear older than other radiometric ages because of the presence of large amounts of martian atmosphere or interior Ar-40. Among all types of meteorites and returned lunar rocks, the impact event that initiated the CRE age very rarely reset the Ar-Ar age. This is because a minimum time and temperature is required to facilitate Ar diffusion loss. It is generally assumed that the shock-texture characteristics in martian meteorites were produced by the impact events that ejected the rocks from Mars, although the time of these shock events (as opposed to CRE ages) are not directly dated. Here we report Ar-39-Ar-40 dating of Dho378 plagioclase. We suggest that the determined age dates the intense shock heating event this meteorite experienced, but that it was not the impact that initiated the CRE age.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/20150003794','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/20150003794"><span>New Martian Meteorite Is One of the Most Oxidized Found to Date</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Hui, Hejiu; Peslier, Anne; Lapen, Thomas J.; Shafer, John T.; Brandon, Alan D.; Irving, Anthony J.</p> <p>2014-01-01</p> <p>As of 2013, about 60 meteorites from the planet Mars have been found and are being studied. Each time a new Martian meteorite is found, a wealth of new information comes forward about the red planet. The most abundant type of Martian meteorite is a <span class="hlt">shergottite</span>; its lithologies are broadly similar to those of Earth basalts and gabbros; i.e., crustal igneous rocks. The entire suite of <span class="hlt">shergottites</span> is characterized by a range of trace element, isotopic ratio, and oxygen fugacity values that mainly reflect compositional variations of the Martian mantle from which these magmas came. A newly found <span class="hlt">shergottite</span>, NWA 5298, was the focus of a study performed by scientists within the Astromaterials Research and Exploration Science (ARES) Directorate at the Johnson Space Center (JSC) in 2012. This sample was found in Morocco in 2008. Major element analyses were performed in the electron microprobe (EMP) laboratory of ARES at JSC, while the trace elements were measured at the University of Houston by laser inductively coupled plasma mass spectrometry (ICPMS). A detailed analysis of this stone revealed that this meteorite is a crystallized magma that comes from the enriched end of the <span class="hlt">shergottite</span> spectrum; i.e., trace element enriched and oxidized. Its oxidation comes in part from its mantle source and from oxidation during the magma ascent. It represents a pristine magma that did not mix with any other magma or see crystal accumulation or crustal contamination on its way up to the Martian surface. NWA 5298 is therefore a direct, albeit evolved, melt from the Martian mantle and, for its lithology (basaltic <span class="hlt">shergottite</span>), it represents the oxidized end of the <span class="hlt">shergottite</span> suite. It is thus a unique sample that has provided an end-member composition for Martian magmas.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=20070023926&hterms=nD&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D40%26Ntt%3D%253FnD','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=20070023926&hterms=nD&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D40%26Ntt%3D%253FnD"><span>The Early Differentiation History of Mars from W-182-Nd-142 Isotope Systematics in the SNC Meteorites</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Foley, C. Nicole; Wadhwa, M.; Borg, L. E.; Janney, P. E.; Hines, R.; Grove, T. L.</p> <p>2005-01-01</p> <p>We report here the results of an investigation of W and Nd isotopes in the SNC (<span class="hlt">Shergottite</span>-Nakhlite-Chassignite (martian)) meteorites. We have determined that epsilon W-182 values in the nakhlites are uniform within analytical uncertainties and have an average value of approx. 3. Also, while epsilon W-182 values in the <span class="hlt">shergottites</span> have a limited range (from 0.3-0.7), their epsilon Nd-142 values vary considerably (from -0.2-0.9). There appears to be no correlation between epsilon W-182 and epsilon Nd-142 in the nakhlites and <span class="hlt">shergottites</span>. These results shed new light on early differentiation processes on Mars, particularly on the timing and nature of fractionation in silicate reservoirs. Assuming a two-stage model, the metallic core is estimated to have formed at approx. 12 Myr after the beginning of the solar system. Major silicate differentiation established the nakhlite source reservoir before approx. 4542 Ma and the <span class="hlt">shergottite</span> source reservoirs at 4525 [sup +19 sub -21] Ma. These ages imply that, within the uncertainties afforded by the Hf-182-W-182 and Sm-146-Nd-142 chronometers, the silicate differentiation events that established the source reservoirs of the nakhlites and <span class="hlt">shergottites</span> may have occurred contemporaneously, possibly during crystallization of a global magma ocean. The distinct W-182-Nd-142 isotope systematics in the nakhlites and the <span class="hlt">shergottites</span> imply the presence of at least three isotopically distinct silicate reservoirs on Mars, two of which are depleted in incompatible lithophile elements relative to chondrites, and the third is enriched. The two depleted silicate reservoirs most likely reside in the Martian mantle, while the enriched reservoir could be either in the crust or the mantle. Therefore, the W-182-Nd-142 isotope systematics indicate that the nakhlites and the <span class="hlt">shergottites</span> originated from distinct source reservoirs and cannot be petrogenetically related. A further implication is that the source reservoirs of the nakhlites and</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/20150001626','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/20150001626"><span>Peology and Geochemistry of New Paired Martian Meteorites 12095 and LAR 12240</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Funk, R. C.; Brandon, A. D.; Peslier, A.</p> <p>2015-01-01</p> <p>The meteorites LAR 12095 and LAR 12240 are believed to be paired Martian meteorites and were discovered during the Antarctic Search for Meteorites (ANSMET) 2012-2013 Season at Larkman Nunatak. The purpose of this study is to characterize these olivine-phyric <span class="hlt">shergottites</span> by analyzing all mineral phases for major, minor and trace elements and examining their textural relationships. The goal is to constrain their crystallization history and place these <span class="hlt">shergottites</span> among other Martian meteorites in order to better understand Martian geological history.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=20040056036&hterms=Samarium&qs=N%3D0%26Ntk%3DAll%26Ntx%3Dmode%2Bmatchall%26Ntt%3DSamarium','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=20040056036&hterms=Samarium&qs=N%3D0%26Ntk%3DAll%26Ntx%3Dmode%2Bmatchall%26Ntt%3DSamarium"><span>Oxygen Fugacity of the Martian Mantle from Pigeonite/Melt Partitioning of Samarium, Europium and Gadolinium</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Musselwhite, D. S.; Jnes, J. H.; Shearer, C.</p> <p>2004-01-01</p> <p>This study is part of an ongoing effort to calibrate the pyroxene/melt REE oxybarometer for conditions relevant to the martian meteorites. These efforts have been motivated by reports of redox variations among the <span class="hlt">shergottites</span> . We have conducted experiments on martian composition pigeonite/melt rare earth element partitioning as a function of fO2.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=20040056036&hterms=Gadolinium&qs=N%3D0%26Ntk%3DAll%26Ntx%3Dmode%2Bmatchall%26Ntt%3DGadolinium','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=20040056036&hterms=Gadolinium&qs=N%3D0%26Ntk%3DAll%26Ntx%3Dmode%2Bmatchall%26Ntt%3DGadolinium"><span>Oxygen Fugacity of the Martian Mantle from Pigeonite/Melt Partitioning of Samarium, Europium and Gadolinium</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Musselwhite, D. S.; Jnes, J. H.; Shearer, C.</p> <p>2004-01-01</p> <p>This study is part of an ongoing effort to calibrate the pyroxene/melt REE oxybarometer for conditions relevant to the martian meteorites. These efforts have been motivated by reports of redox variations among the <span class="hlt">shergottites</span> . We have conducted experiments on martian composition pigeonite/melt rare earth element partitioning as a function of fO2.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2013E%26PSL.374..156Z','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2013E%26PSL.374..156Z"><span>Geochronology of the Martian meteorite Zagami revealed by U-Pb ion probe dating of accessory minerals</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Zhou, Qin; Herd, Christopher D. K.; Yin, Qing-Zhu; Li, Xian-Hua; Wu, Fu-Yuan; Li, Qiu-Li; Liu, Yu; Tang, Guo-Qiang; McCoy, Timothy J.</p> <p>2013-07-01</p> <p>The precise chronology of geological events on Mars is hampered by the lack of absolute ages for the Martian timescale, and the significant uncertainties that result from the extrapolation of the lunar timescale to Mars (Hartmann and Neukum, 2001). Martian meteorites represent the only samples of Mars currently available. Attempts to identify source craters for the meteorites have thus far proven inconclusive (Hamilton et al., 2003; Lang et al., 2009; Mouginis-Mark and Boyce, 2012>), precluding their use in constraining the absolute Martian timescale. The majority of the known Martian meteorites are basalts ("<span class="hlt">shergottites</span>"); all dated <span class="hlt">shergottites</span> have mineral separate (Rb-Sr or Sm-Nd) ages of <600 Ma (Borg et al., 2005). Here we report a 238U/206Pb age of 182.7±6.9 Ma by ion microprobe analysis of baddeleyite (ZrO2) grains in the Zagami <span class="hlt">shergottite</span>. There is no correlation between discordancy and baddeleyite grain location relative to shock metamorphism. Mineral petrography demonstrates that baddeleyite is the result of late-stage igneous crystallization, and Raman spectroscopy shows that baddeleyite has not been transformed by shock into preservable high-pressure polymorphs. Supported by an age of 153±81 Ma for phosphate grains, obtained using the same method, we conclude that Zagami crystallized at ~180 Ma, in agreement with previous results from mineral separate geochronology. Therefore, the <span class="hlt">shergottites</span> represent igneous rocks preferentially ejected from young terrains on Mars in a small number of ejection events.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016LPICo1921.6120C','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016LPICo1921.6120C"><span>Sidi Ali Ou Azza (L4): A New Moroccan Fall</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Chennaoui Aoudjehane, H.; Agee, C. B.; Aaranson, A.; Bouragaa, A.</p> <p>2016-08-01</p> <p>Sidi Ali Ou Azza is the latest meteorite fall in Morocco, it occurred on 28 July 2015 very close (about 40 km) to Tissint martian <span class="hlt">shergottite</span> fall that occurred on 18 July 2011. It's one of the small group of 23 L4 ordinary chondrite falls.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2013AGUFM.P51H..06B','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2013AGUFM.P51H..06B"><span>Evolution of the martian mantle as recorded by igneous rocks</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Balta, J. B.; McSween, H. Y.</p> <p>2013-12-01</p> <p>Martian igneous rocks provide our best window into the current state of the martian mantle and its evolution after accretion and differentiation. Currently, those rocks have been examined in situ by rovers, characterized in general from orbiting spacecraft, and analyzed in terrestrial laboratories when found as meteorites. However, these data have the potential to bias our understanding of martian magmatism, as most of the available meteorites and rover-analyzed rocks come from the Amazonian (<2 Ga) and Hesperian (~3.65 Ga) periods respectively, while igneous rocks from the Noachian (>3.8 Ga) have only been examined by orbiters and as the unique meteorite ALH 84001. After initial differentiation, the main planetary-scale changes in the structure of Mars which impact igneous compositions are cooling of the planet and thickening of the crust with time. As the <span class="hlt">shergottite</span> meteorites give ages <500 Ma1, they might be expected to represent thick-crust, recent volcanism. Using spacecraft measurements of volcanic compositions and whole rock compositions of meteorites, we demonstrate that the <span class="hlt">shergottite</span> meteorites do not match the composition of the igneous rocks composing the young volcanoes on Mars, particularly in their silica content, and no crystallization or crustal contamination trend reproduces the volcanoes from a <span class="hlt">shergottite</span>-like parent magma. However, we show that the <span class="hlt">shergottite</span> magmas do resemble older martian rocks in composition and mineralogy. The Noachian-aged meteorite ALH 84001 has similar radiogenic-element signatures to the <span class="hlt">shergottites</span> and may derive from a similar mantle source despite the age difference2. Thus, <span class="hlt">shergottite</span>-like magmas may represent melting of mantle sources that were much more abundant early in martian history. We propose that the <span class="hlt">shergottites</span> represent the melting products of an originally-hydrous martian mantle, containing at least several hundred ppm H2O. Dissolved water can increase the silica content of magmas and thus</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=19920032188&hterms=united+kingdom+history&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D60%26Ntt%3Dunited%2Bkingdom%2Bhistory','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=19920032188&hterms=united+kingdom+history&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D60%26Ntt%3Dunited%2Bkingdom%2Bhistory"><span>Exposure histories of lunar meteorites - ALHA81005, MAC88104, MAC88105, and Y791197</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Nishiizumi, K.; Arnold, J. R.; Klein, J.; Fink, D.; Middleton, R.; Kubik, P. W.; Sharma, P.; Elmore, D.; Reedy, R. C.</p> <p>1991-01-01</p> <p>The cosmogenic radionuclides Ca-41, Cl-36, Al-26, and Be-10 in the Allan Hills 81005, MacAlpine Hills 88104, MacAlpine Hills 88105, and <span class="hlt">Yamato</span> 791197 meteorites were measured by accelerator mass spectrometry. Mn-53 in Allan Hills 81005 and <span class="hlt">Yamato</span> 791197 was measured by neutron activation. These four lunar meteorites experienced similar histories. They were ejected from near the surface of the moon ranging in depth down to 400 g/sq cm and had very short transition times (less than 0.1 Ma) from the moon to the earth. A comparison of the cosmogenic nuclide concentrations in MacAlpine Hills 88104 and MacAlpine Hills 88105 clearly indicates that they are a pair from the same fall.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/24869813','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/24869813"><span>Identification and character analysis of the Acerentomidae (Protura) of the northeastern Palearctic (Protura: Acerentomidae).</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Shrubovych, Julia</p> <p>2014-01-21</p> <p>This paper is a summary of proturan fauna from Siberia and the Russian Far East, collectively termed the northeastern Palearctic. Special attention is given to the analysis of Acerentomidae, which is extraordinarily diverse in these regions (31 species). A key to species and a brief exposition of distribution of each genus are provided. A redescription of Imadateiella sharovi is presented, additional morphological characters are added for Nipponentomon khabarovskense, N. bidentatum, Yamatentomon <span class="hlt">yamato</span> and Callientomon chinensis, and additional collection data are given for Y. <span class="hlt">yamato</span>, C. chinensis, Nipponentomon jaceki and N. nippon. A cladistic analysis is presented of hypothetical relationships among the discussed acerentomid taxa. A scheme for ventral porotaxy is proposed, and the taxonomic importance of porotaxic characters within Acerentomata is discussed. Some biogeographical and phylogenetic considerations are given.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=20040062060&hterms=samarium+iron&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D10%26Ntt%3Dsamarium%2Biron','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=20040062060&hterms=samarium+iron&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D10%26Ntt%3Dsamarium%2Biron"><span>Lunar and Planetary Science XXXV: Achondrites: An Awesome Assortment</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p></p> <p>2004-01-01</p> <p>The session "chondrites: An Awesome Assortment" included the following reports:Nucleation of the Widmanstatten Pattern in Iron Meteorites; Compositions of the Group IVB Iron Meteorites; Sm-Nd Age and Initial 87Sr/86Sr for <span class="hlt">Yamato</span> 980318: An Old Cumulate Eucrite; Petrology of New Stannern-trend Eucrites and Eucrite Genesis; The Dichotomous HED Meteorite Suite; Early Thermal Evolution of HED Parent Body; Thermal History of the Lodranite <span class="hlt">Yamato</span> 74357: Constraints from Compositional Zoning and Fe-Mg Ordering; Late Thermal Evolution of Acapulcoites-Lodranites Parent Body: Evidence from Sm-Nd Isotopes and Trace Elements of the LEW 86220 Acapulcoite; Partial Melting Under Reducing Conditions: How are Primitive Achondrites Formed?; Evolution of the Ureilite Parent Body; Complex, Contrasting Behavior of Chromium During Late-Stage Processes in Ureilites; Sahara 99555 and D Orbigny: Possible Pristine Parent Magma of Quenched Angrites; and Devolatilized-Allende Partial Melts as an Analog for Primitive Angrite Magmas.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/1982PolRe..25..260S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/1982PolRe..25..260S"><span>Magnetic properties of low-petrologic grade non-carbonaceous chondrites</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Sugiura, N.; Strangway, D. W.</p> <p>1982-12-01</p> <p>Magnetic properties and paleointensities are reported for several low-petrologic-grade noncarbonaceous chondrites. Enstatite chondrites are far more magnetic than others and record ancient fields of 7-16 Oe. Abee has nearly random NRM in clasts and matrix samples, suggesting preaccretional remanence. Indarch and <span class="hlt">Yamato</span>-691 record high fields, but have a single direction of magnetization, so that it cannot be determined whether the magnetic record is of pre- or postaccretional origin. Bjurbole, Chainpur, Mezo Madaras, and <span class="hlt">Yamato</span>-74191 have random (and stable) NRM components carried by plessite, indicating possible preaccretional remanence. However, Bjurbole and Mezo Madaras are thought to have been reheated to above 500 C after their accretion, and in that case the random NRM in these chondrites could not be preaccretional.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.osti.gov/scitech/biblio/5256989','SCIGOV-STC'); return false;" href="https://www.osti.gov/scitech/biblio/5256989"><span>Degree of equilibration of eucritic pyroxenes and thermal metamorphism of the earliest planetary crust</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Takeda, Hiroshi; Graham, A.L. Natural History Museum, London )</p> <p>1991-06-01</p> <p>The pyroxenes in two new monomict eucrites from Antarctica, <span class="hlt">Yamato</span> 791186 and <span class="hlt">Yamato</span> 792510, have been studied and compared with those of other Antarctic and non-Antarctic eucrites. The purpose of this study is to identify compositional and textural relationship shown by these pyroxenes which may be used as indicators of the thermal history of the meteorite. An attempt is made, using petrographic and compositional criteria, to distinguish between the initial cooling history and subsequent thermal events. It is suggested that it is possible to identify stages of thermal 'metamorphism' which may be used to indicate the conditions on the surface and crust of the parent body. A picture of the geological setting of the HED (Howardites, Eucrites, Diogenites) parent body is proposed, for which thermal metamorphism by impact heating is an important process. 22 refs.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=19920032188&hterms=Accelerator+mass+spectrometry&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D40%26Ntt%3DAccelerator%2Bmass%2Bspectrometry','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=19920032188&hterms=Accelerator+mass+spectrometry&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D40%26Ntt%3DAccelerator%2Bmass%2Bspectrometry"><span>Exposure histories of lunar meteorites - ALHA81005, MAC88104, MAC88105, and Y791197</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Nishiizumi, K.; Arnold, J. R.; Klein, J.; Fink, D.; Middleton, R.; Kubik, P. W.; Sharma, P.; Elmore, D.; Reedy, R. C.</p> <p>1991-01-01</p> <p>The cosmogenic radionuclides Ca-41, Cl-36, Al-26, and Be-10 in the Allan Hills 81005, MacAlpine Hills 88104, MacAlpine Hills 88105, and <span class="hlt">Yamato</span> 791197 meteorites were measured by accelerator mass spectrometry. Mn-53 in Allan Hills 81005 and <span class="hlt">Yamato</span> 791197 was measured by neutron activation. These four lunar meteorites experienced similar histories. They were ejected from near the surface of the moon ranging in depth down to 400 g/sq cm and had very short transition times (less than 0.1 Ma) from the moon to the earth. A comparison of the cosmogenic nuclide concentrations in MacAlpine Hills 88104 and MacAlpine Hills 88105 clearly indicates that they are a pair from the same fall.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=19820037373&hterms=protein+chromatography+contamination&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D10%26Ntt%3Dprotein%2Bchromatography%2Bcontamination','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=19820037373&hterms=protein+chromatography+contamination&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D10%26Ntt%3Dprotein%2Bchromatography%2Bcontamination"><span>Organic analysis of the Antarctic carbonaceous chondrites</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Kotra, R. K.; Shimoyama, A.; Ponnamperuma, C.; Hare, P. E.; Yanai, K.</p> <p>1981-01-01</p> <p>Thus far, organic analysis of carbonaceous chondrites has proven the only fruitful means of examining complex organic matter of extraterrestrial origin. The present paper presents the results of organic analysis of two Antarctic meteorites, Allan Hills (77306) and <span class="hlt">Yamato</span> (74662), which may be considered free from terrestrial contamination. Ion-exchange chromatography, gas chromatography and mass spectrometery of meteorite samples reveal the presence in <span class="hlt">Yamato</span> of 15 and in Allan Hills of 20 protein and nonprotein amino acids, the most abundant of which are glycine and alanine. Abundances of the D and L enantiomers of each amino acid are also found to be nearly equal. Data thus indicate an abiotic extraterrestrial origin for the matter, and confirm a lack of terrestrial contamination.</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_16");'>16</a></li> <li><a href="#" onclick='return showDiv("page_17");'>17</a></li> <li class="active"><span>18</span></li> <li><a href="#" onclick='return showDiv("page_19");'>19</a></li> <li><a href="#" onclick='return showDiv("page_20");'>20</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_18 --> <div id="page_19" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_17");'>17</a></li> <li><a href="#" onclick='return showDiv("page_18");'>18</a></li> <li class="active"><span>19</span></li> <li><a href="#" onclick='return showDiv("page_20");'>20</a></li> <li><a href="#" onclick='return showDiv("page_21");'>21</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="361"> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017M%26PS...52..125C','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017M%26PS...52..125C"><span>Experimental petrology of the Tissint meteorite: Redox estimates, crystallization curves, and evaluation of petrogenetic models</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Castle, Nicholas; Herd, Christopher D. K.</p> <p>2017-01-01</p> <p>Tissint is an olivine-phyric <span class="hlt">shergottite</span> from an incompatible element depleted Martian mantle source. Oxythermobarometry applied to Tissint mineral phases demonstrates that the Tissint magma underwent an increase in oxygen fugacity, from 3.5 log units below the quarz-fayalite-magnetite (QFM) buffer during the early stages of crystallization, to QFM-1.4 during the latter stages. This is the first time that such an oxidation event has been observed in a depleted <span class="hlt">shergottite</span>. The reason for the oxidation event is unclear; however, calculations using the MELTS thermodynamic model suggest that auto-oxidation is insufficient to cause more than 1 log unit of oxidation, and therefore an external oxidation mechanism—such as oxidation by degassing—is required. If volatiles are responsible for the oxidation, then it indicates that volatiles are not exclusively tied to the enriched Martian mantle reservoir. A series of experiments using the Tissint parental magma were carried out under fixed (isothermal) or variable (cooling rate) temperature control, and at either reducing (QFM-3.2) or oxidizing (QFM-1) redox conditions. The observed liquid line of descent supports a potential genetic relationship between basaltic <span class="hlt">shergottites</span> and olivine-phyric <span class="hlt">shergottites</span>. A peritectic relation where olivine is resorbed to form pyroxene is favored by increased oxygen fugacity; if oxidation during crystallization is more common than presently believed, it may explain why olivine is typically anhedral in olivine-phyric <span class="hlt">shergottites</span>. Results from a cooling-rate experiment in which the oxygen fugacity was changed during the latter stages of crystallization resulted in olivine with a Cr compositional profile consistent with oxidized isothermal experiments, despite forming primarily under reducing conditions. A similar profile is observed in Tissint olivines, consistent with its redox history. Our results provide insights into the potential influence of oxidation events on the compositional</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.dtic.mil/docs/citations/ADA501212','DTIC-ST'); return false;" href="http://www.dtic.mil/docs/citations/ADA501212"><span>Beaked and Baleen Whale Hearing: Modeling Responses to Underwater Noise</span></a></p> <p><a target="_blank" href="http://www.dtic.mil/">DTIC Science & Technology</a></p> <p></p> <p>2009-06-01</p> <p>Cramer, M. <span class="hlt">Yamato</span>, M. Zosuls, D. Mountain, R. S. Chadwick, E. K . Dimitriadis, J . Shoshani, and C. O’Connell-Rodwell. 2007. How low can they go...translation). Botsford, J . H. 1969. Theory of temporary threshold shift. J . Acoust. Soc. Am. 49: 440-446. Chadwick, R. S, D. Manoussaki, E. K ...impacts. Polarforschung. 72. Jahrgung, Nr. 2/3: 79-92. Ketten, D. R., T. Rowles , S. Cramer, J . O’Malley, J . Arruda, and P. Evans. 2003. Cranial</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/20080013410','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/20080013410"><span>Sm-Nd for Norite 78236 and Eucrite Y980318/433: Implications for Planetary and Solar System Processes</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Nyquist, L. E.; Shih, C-Y.; Reese, Y. D.</p> <p>2008-01-01</p> <p>Here, we compare Sm-147-Nd-143 and Sm-146-Nd-142 data for lunar norite 78236 to those for approximately 4.54-4.56 Ga old cumulate eucrite <span class="hlt">Yamato</span> 980318/433 and show that the norite data are compatible with its derivation from an isotopic reservoir similar to that from whence the eucrite pair came. Thus, lunar-like Sm-Nd isotopic systematics are not unique to the Earth-Moon system.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=20040062378&hterms=Breccia&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D30%26Ntt%3DBreccia','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=20040062378&hterms=Breccia&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D30%26Ntt%3DBreccia"><span>Petrography of Lunar Meteorite PCA02007, a New Feldspathic Regolith Breccia</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Zeigler, R. A.; Korotev, R. L.; Jolliff, B. L.</p> <p>2004-01-01</p> <p>PCA 02007 is a 22.4 g lunar meteorite collected in 2003 near the Pecora Escarpment in Antarctica [1]. PCA is a feldspathic regolith breccia composed of mature regolith. It is compositionally and texturally similar to other feldspathic lunar meteorites (FLMs) [2] and may be launch paired with <span class="hlt">Yamato</span> 791197 [3]. Here we present a petrographic description and compositions of mineral clasts, glass clasts, lithic clasts, and the bulk meteorite.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.dtic.mil/docs/citations/ADA440830','DTIC-ST'); return false;" href="http://www.dtic.mil/docs/citations/ADA440830"><span>Development of Advanced Active Haptic System for Musculokelelton-Exoskeleton Interactions</span></a></p> <p><a target="_blank" href="http://www.dtic.mil/">DTIC Science & Technology</a></p> <p></p> <p>2005-08-31</p> <p>study sponsor, Dr. David M . Stepp, at (919)549-4329 in the US Army Research Office. Confidentiality Dr. Shoureshi and the above mentioned sponsors...Zurich, Switzerland. [15] <span class="hlt">Yamato</span>, J., J. Ohya , and K. Ishii. Recognizing human action in time-sequential images using hidden Markov model. in...in Computer Vision and Pattern Recognition. 1998. Santa Barbara, CA. [17] Brand, M ., N. Oliver, and A. Pentland. Coupled hidden Markov models for</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.dtic.mil/docs/citations/AD1019204','DTIC-ST'); return false;" href="http://www.dtic.mil/docs/citations/AD1019204"><span>Seeds of Destruction, Seeds of Success: The Survival or Failure of Violent Extremist Organizations</span></a></p> <p><a target="_blank" href="http://www.dtic.mil/">DTIC Science & Technology</a></p> <p></p> <p>2010-06-01</p> <p>or something would instigate the Harumagedon he preached. 4 The precedent for Japanese belief in millennialism goes as far back as the <span class="hlt">Yamato</span>... millennial faith into the traditional Japanese societal cognitive map.” 5 Millenarianism remains relevant to most theologies and faiths today...religious, social, or political group or movement in a coming major transformation of society. Millennialism is one type of millenarianism based on a one</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/20120011125','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/20120011125"><span>What Lunar Meteorites Tell Us About the Lunar Highlands Crust</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Korotev, R. L.; Jolliff, B. L.; Zeigler, R. A.</p> <p>2012-01-01</p> <p>The first meteorite to be found1 that was eventually (1984) recognized to have originated from the Moon is <span class="hlt">Yamato</span> 791197. The find date, November 20, 1979, was four days after the end of the first Conference on the Lunar Highland Crust. Since then, >75 other lunar meteorites have been found, and these meteorites provide information about the lunar highlands that was not known from studies of the Apollo and Luna samples</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2013JSAES..41..122R','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2013JSAES..41..122R"><span>Petrology of ultramafic xenoliths in Cenozoic alkaline rocks of northern Madagascar (Nosy Be Archipelago)</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Rocco, Ivana; Lustrino, Michele; Zanetti, Alberto; Morra, Vincenzo; Melluso, Leone</p> <p>2013-01-01</p> <p>Late Miocene basanites of Nosy Be and Nosy Sakatia islands (Nosy Be Archipelago, northern Madagascar) carry spinel-facies anhydrous ultramafic xenoliths (<span class="hlt">lherzolites</span>, harzburgites and wehrlites). Geothermobarometric estimates indicate that these xenoliths derive from shallow mantle depths of 35-40 km, with those from Nosy Be island showing equilibration T (averages in the range of 945-985 °C) lower than the Nosy Sakatia analogues (averages ranging from 1010 to 1110 °C). One Nosy Sakatia mantle xenolith exhibits relatively fertile <span class="hlt">lherzolite</span> composition, with trace and major element mineral chemistry consistent with a residual character after low degrees (1-2%) of mafic melt extraction. We interpret this composition as that resembling a depleted mantle (DM)-like lithospheric composition before metasomatic overprints. The other <span class="hlt">lherzolites</span> and harzburgites display petrochemical characters consistent with variable extent of partial melting (up to 18%), associated with pronounced metasomatic overprints caused by migrating melts, as highlighted by enrichments in highly incompatible trace elements (e.g. light rare earth elements, LREE and Sr), together with the abundant occurrence of wehrlitic lithologies. The variability of petrochemical features points to different styles of metasomatism and metasomatic agents. The estimated composition of the parental melts of wehrlites matches that of host basanites. The combination of this evidence with the petrographic features, characterized by coarse-granular to porphyroclastic textures and by the presence of olivine without kink-banding, suggests that wehrlites are veins or pockets of high pressure cumulates within the mantle peridotite. The same melts also metasomatized via porous-flow percolation some <span class="hlt">lherzolites</span> and harzburgites. Distinctly, a group of <span class="hlt">lherzolites</span> and harzburgites was metasomatized by a different alkaline melt having markedly lower incompatible trace element contents. Late infiltration of metasomatic fluids</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017GGG....18.1189X','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017GGG....18.1189X"><span>Two-layered oceanic lithospheric mantle in a Tibetan ophiolite produced by episodic subduction of Tethyan slabs</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Xiong, Qing; Griffin, William L.; Zheng, Jian-Ping; Pearson, Norman J.; O'Reilly, Suzanne Y.</p> <p>2017-03-01</p> <p>The origin and evolution of the Yarlung Zangbo ophiolites (South Tibet, China) is the key to the tectonics of the Neo-Tethyan Ocean between Greater India and Asia and the underlying upper mantle dynamics. This study presents a detailed investigation of the Zedang ultramafic body (comprising a harzburgitic and a <span class="hlt">lherzolitic</span> domain) in the eastern Yarlung Zangbo Suture. Major-element compositions and Ti, Y, and HREE concentrations in peridotites and their minerals indicate that the harzburgites experienced higher degrees of melting than the <span class="hlt">lherzolites</span> (˜13-19% versus ˜7-12%). The overall enrichment of LREE, Zr, and Sr in harzburgites and their clinopyroxenes suggest that the harzburgites were pervasively metasomatized (cryptically) by silicate melts. The harzburgites also record local strong metasomatism close to melt channels. Nd isotopes indicate that both metasomatic agents were derived from forearc basaltic magmas that intruded the harzburgites at ˜130-120 Ma. The <span class="hlt">lherzolites</span> did not experience such metasomatism. Thermometry shows that the harzburgites experienced a thorough, lower-temperature reequilibration process in lithosphere, while the <span class="hlt">lherzolites</span> rapidly accreted from the asthenosphere and preserved high equilibration temperatures (up to ˜1320°C). Comparable enrichment in fluid-mobile elements and radiogenic Sr-isotope compositions in both harzburgitic and <span class="hlt">lherzolitic</span> pyroxenes reflect slab-fluid infiltration into both mantle domains. All the evidence and the presence of subduction-related chromitites in the harzburgites suggest that the Zedang harzburgites formed in a possibly Jurassic mature subduction system, while the <span class="hlt">lherzolites</span> accreted later in an early Cretaceous forearc during subduction initiation. The two-layered lithospheric mantle reflects the episodic subduction of the Tethyan slabs.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/20050182099','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/20050182099"><span>Metamorphosed CM and CI Carbonaceous Chondrites Could Be from the Breakup of the Same Earth-crossing Asteroid</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Zolensky, Michael; Abell, Paul; Tonui, Eric</p> <p>2005-01-01</p> <p>Far from being the relatively unprocessed materials they were once believed to be, we now know that a significant number of carbonaceous chondrites were thermally metamorphosed on their parent asteroid(s). Numerous studies indicate that 7 "CM" and 2 "CI" chondrites have been naturally heated, variously, at from 400 to over 700 C on their parent asteroid(s). Petrographic textures reveal that this thermal metamorphism occurred after the dominant aqueous alteration phase, although some meteorites show evidence of a heating event between two aqueous alteration episodes, i.e. pro- and retrograde aqueous alteration. Aside from the issues of the identification of the transient heat source, timing of metamorphism, and the relation of these materials (if any) to conventional CM and CI chondrites, there is also a mystery related to their recovery. All of these meteorites have been recovered from the Antarctic; none are falls or finds from anyplace else. Indeed, the majority have been collected by the Japanese NIPR field parties in the <span class="hlt">Yamato</span> Mountains. In fact, one estimate is that these meteorites account for approx. 64 wt% of the CM carbonaceous chondrites at the NIPR. The reasons for this are unclear and might be due in part to simple sampling bias. However we suggest that this recovery difference is related to the particular age of the <span class="hlt">Yamato</span> Mountains meteorite recovery surfaces, and differences in meteoroid fluxes between the <span class="hlt">Yamato</span> meteorites and recent falls and substantially older Antarctic meteorites. Additional information is included in the original extended abstract.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/20140002778','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/20140002778"><span>Water Contents of the Mantle Beneath the Rio Grande Rift: FTIR Analysis of Kilbourne Hole Peridotite Xenoliths</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Schaffer, Lillian A.; Peslier, Anne; Brandon, Alan</p> <p>2013-01-01</p> <p>Although nominally anhydrous mantle minerals contain only trace amounts of water, they are the main reservoir of water in the mantle. Added up at the scale of the Earth's mantle, these trace amounts of water represent oceans worth in mass]. Mantle xenoliths from Kilbourne Hole in southern New Mexico are ideal to study mantle water distribution in a rift tectonic setting as they come from a recently-erupted maar in the middle of the Rio Grande Rift. Eleven <span class="hlt">lherzolites</span>, one harzburgite, and one dunite are being analyzed for water contents by FTIR. The xenoliths will also be analyzed for major and trace element composition, Fe3+/Summation (Fe) ratios, and characterized petrologically. Olivines exhibit variable water contents with less water at the rims compared to the cores. This is probably due to H loss during decompression and xenolith transport by the host magma. Mantle water contents appear to have been primarily preserved in the core of the olivines, based on diffusion modeling of the typically plateau-shaped water content profiles across these grains. Water concentrations are in equilibrium between clino- and orthopyroxene, but olivine concentrations are typically not in equilibrium with those of either pyroxene. <span class="hlt">Lherzolites</span> analyzed so far have water contents of 2-12 ppm H2O in olivines, 125-165 ppm H2O in orthopyroxenes, and 328-447 ppm H2O in clinopyroxenes. These water contents are similar to, but with a narrower range, than those for the respective minerals in other continental peridotite xenoliths. The <span class="hlt">lherzolites</span> have bulk-rock (BR) Al2O3 contents that range between 3.17 and 3.78 wt%, indicating similar degrees of partial melting, which could explain the narrow range of their pyroxene water contents. Primitive mantle normalized rare earth element (REE) profiles of the bulk <span class="hlt">lherzolites</span> vary from light REE depleted to flat, with no significant differences between, nor relation to, their mineral water contents. Consequently, the metasomatic agents that</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016AGUFM.V31B3091L','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016AGUFM.V31B3091L"><span>The Mg-Sr-Nd-Hf Isotopic Compositions of Beiyan Mantle Xenoliths: Implications on the Melt/Fluid-Rock Interaction</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Li, P.; Lu, Y.; Li, S.</p> <p>2016-12-01</p> <p>It has been widely confirmed that mantle metasomatism plays an important role in the refertilization of lithospheric mantle. However, the mechanism of metasomatism including the nature and source of metasomatic flux is still difficult to be thoroughly revealed. We present an integrated study of whole-rock major and trace elements and Mg-Sr-Nd-Hf isotopes for mantle xenoliths and host basalts at Beiyan, Shandong Province in eastern China. The primary objective is to clarify the periods of metasomatism and provide constrains on the interaction between xenolith and melt/fluid. Based on the mineral component, Beiyan xenoliths were subdivided into four types: <span class="hlt">lherzolite</span>, cpx-rich <span class="hlt">lherzolite</span>, wehrlite and olivine clinopyroxenite. These samples show variable Mg# values, decreasing from 89.4 90.2 in <span class="hlt">lherzolites</span>, 85.9 89.6 in cpx-rich <span class="hlt">lherzolites</span>, 81.2 87.3 in wehrlites, till 77.7 79.4 in olivine clinopyroxenites. Low Mg# values, LREE-enriched patterns and the occurrence of hydrous minerals such as phlogopite, amphibole, feldspar and carbonates such as calcite, ankerite and reacted texture suggest subsequent melt/fluid addition. Relative to the Mg isotopic composition of <span class="hlt">lherzolites</span> (δ26Mg = -0.21±0.06‰ (2SD, n=3)), which are similar to the average δ26Mg of normal mantle (-0.25±0.07‰ [1]), δ26Mg of cpx-rich <span class="hlt">lherzolites</span> (-0.18±0.07‰ (2SD, n=4)) are heavier, and δ26Mg of wehrlites (-0.31±0.07‰ (2SD, n=9)) are lighter. Combining with the Sr-Nd-Hf isotopic results, at least two-stage melt/fluid-rock interactions occurred in Beiyan xenoliths, which formed the isotopic heterogeneous. The distinct heavy Mg isotopic compositions and fertile Sr-Nd-Hf isotopic compositions in cpx-rich <span class="hlt">lherzolites</span> indicate that they are the products of interaction between <span class="hlt">lherzolite</span> and fluid derived from subducted Pacific slab which may inherit heavy Mg isotopic compositions of abyssal peridotite. The basaltic melt metasomatism with light Mg isotopic (δ26Mg = -0.54‰ to -0.40</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://pubs.er.usgs.gov/publication/70017502','USGSPUBS'); return false;" href="http://pubs.er.usgs.gov/publication/70017502"><span>Rare earth element contents and multiple mantle sources of the transform-related Mount Edgecumbe basalts, southeastern Alaska</span></a></p> <p><a target="_blank" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Riehle, J.R.; Budahn, J.R.; Lanphere, M.A.; Brew, D.A.</p> <p>1994-01-01</p> <p>Pleistocene basalt of the Mount Edgecumbe volcanic field (MEF) is subdivided into a plagioclase type and an olivine type. Th/La ratios of plagioclase basalt are similar to those of mid-ocean-ridge basalt (MORB), whereas those of olivine basalt are of continental affinity. Rare earth element (REE) contents of the olivine basalt, which resemble those of transitional MORB, are modelled by 10-15% partial melting of fertile spinel-plagioclase <span class="hlt">lherzolite</span> followed by removal of 8-13% olivine. It is concluded that olivine basalt originated in subcontinental spinel <span class="hlt">lherzolite</span> and that plagioclase basalt may have originated in suboceanic lithosphere of the Pacific plate. -from Authors</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/servlets/purl/945809','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/servlets/purl/945809"><span>Olivine compositions from the Hawaii Scientific Drilling Project, Phase 2: Evidence for a peridotite mantle source region</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Putirka, K D; Ryerson, F J</p> <p>2008-10-27</p> <p>To the extent that mantle plumes reflect whole mantle convection, Hawaii may provide the clearest window into Earth's lower mantle. Samples from the Hawaii Scientific Drilling Project (HSDP) thus provide valuable tests for models of mantle mineralogy and composition. In this vein, it has been argued recently that Hawaiian olivines, especially those from the shield-building phase as sampled by HSDP, are so high in Ni (Sobolev et al., 2005, 2007), and that Hawaiian whole rocks are so low in CaO (Herzberg, 2006) and high in SiO{sub 2} (Hauri, 1996) that a peridotite mantle source cannot generate such compositions. The Hawaiian plume, so the argument goes, is thus supposedly rich in pyroxenite, and possibly olivine-free. However, comparisons of HSDP olivines to <span class="hlt">lherzolites</span>, and HSDP whole rocks to <span class="hlt">lherzolites</span> and partial melting experiments belie these premises. Testable predictions of the pyroxenite model also fail. New comparisons instead show that Hawaiian lavas can be produced from a peridotite source. First, it is unclear that the Hawaiian source is enriched in NiO. The NiO contents of olivines hosted by <span class="hlt">lherzolites</span> (GEOROC) have the same range as olivines from the HSDP; indeed, the maximum NiO for olivines from <span class="hlt">lherzolites</span> (0.6 wt.%) is as high as that reported for olivines from any oceanic volcano locality. There is a compositional separation between <span class="hlt">lherzolite</span>- and HSDP-hosted olivines. But HSDP olivines are not NiO enriched so much as <span class="hlt">lherzolite</span> olivines are higher in Fo at a given NiO. Lower Fo contents at Hawaii (at a given NiO) ensue because olivine compositions there follow a liquid line of descent, where both Ni and Mg decrease with differentiation. In contrast, subsolidus equilibria involving orthopyroxene enforce a higher and less variable Fo content for <span class="hlt">lherzolite</span>-derived olivines. Moreover, the pyroxenite mantle model predicts that whole rocks with low CaO and high SiO{sub 2} should host olivines with high NiO. But in HSDP samples, neither correlation</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/1992CoMP..111..126H','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/1992CoMP..111..126H"><span>Thermal history of the upper mantle beneath a young back-arc extensional zone: ultramafic xenoliths from San Luis Potosí, Central Mexico</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Heinrich, Wilhelm; Besch, Thomas</p> <p>1992-06-01</p> <p>At the San Luis Potosí (SLP) volcanic field (Central Mexico), Quaternary basanites and tuff breccias have sampled a suite of ultramafic xenoliths, predominately spinel <span class="hlt">lherzolites</span>, spinel-olivine websterites, spinel pyroxenites, and hornblende-rich pyroxenites. Spinel <span class="hlt">lherzolites</span> from the La Ventura maars have protogranular to equigranular textures, those from the Santo Domingo maars are strongly sheared. Both spinel-<span class="hlt">lherzolite</span> types show similar whole-rock major and trace-element abundances. They are fertile to slightly depleted with mineralogical and geochemical heterogeneities induced by partial melting processes. Pyroxenites with either magmatic or metamorphic textures are high-pressure cumulates. Hornblende-rich pyroxenites are genetically linked to the host basanites. Most of the protogranular spinel <span class="hlt">lherzolites</span> contain veinlets of glass along grain boundaries. These glasses are chemically homogeneous and have trachybasaltic to trachyandesitic compositions. Mg- and Fe2+-partitioning between olivine and glass suggests chemical equilibrium between the melts represented by the glasses and the spinel-<span class="hlt">lherzolite</span> mineral assemblage at about 1,000°C and 10 to 15 kbar. The melts are interpreted to be of upper mantle origin. They may have been formed by in-situ partial melting in the presence of volatiles or represent percolating melts chemically buffered by the spinel-<span class="hlt">lherzolite</span> mineral assemblage at uppermost mantle conditions. Mineral chemistry in all rock types of the whole xenolith suite reveals distinct disequilibrium features reflecting partial re-equilibration stages towards lower temperatures estimated to be from 1,050°C to 850°C at 9 to 15 kbar. The presence of similar zoning and exsolution features mainly documented in pyroxenes along with similar maximum and minimum temperatures requires all sampled xenoliths to have undergone the same temperature regime within the upper mantle. The sheared spinel <span class="hlt">lherzolites</span> from the Sto. Domingo field are interpreted</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014Litho.210...14L','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014Litho.210...14L"><span>The Cenozoic lithospheric mantle beneath the interior of South China Block: Constraints from mantle xenoliths in Guangxi Province</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Li, Xi-Yao; Zheng, Jian-Ping; Sun, Min; Pan, Shao-Kui; Wang, Wei; Xia, Qun-Ke</p> <p>2014-12-01</p> <p>In contrast to the coastal regions of the South China Block (SCB), little is known about the subcontinental lithospheric mantle beneath the interior of the SCB. Mantle xenoliths entrained in Cenozoic basalts in the eastern and central Guangxi Province, the interior of the SCB, includes spinel harzburgites, clinopyroxene-poor <span class="hlt">lherzolites</span>, <span class="hlt">lherzolites</span> and olivine websterites. The mineral chemistry of the harzburgites and clinopyroxene-poor <span class="hlt">lherzolites</span> is moderately refractory [Mg# value of olivine (Mg#Ol) = 90.2-91.3], whereas other <span class="hlt">lherzolite</span> is more fertile (Mg#Ol = 89.3). Zoned olivines (Mg#Ol = 83.7-88.8) in the harzburgites and zoned olivine xenocrysts (Mg#Ol = 75.2-82) in the basalts reflect disequilibrium between olivines and the basaltic host melts during magma ascent. An olivine websterite (Mg#Ol = 87.5) is similar to the <span class="hlt">lherzolite</span> in mineral chemistry. The REE patterns of clinopyroxenes in these xenoliths vary from LREE-depleted, to flat, to LREE-enriched patterns, and commonly exhibit positive Sr anomalies and negative Nb, Zr and Ti anomalies. The peridotitic xenoliths mostly experienced moderate to high degree of melt extraction (F = 10-20%) and were modified by silicate metasomatism. We thus suggest that the harzburgites and clinopyroxene-poor <span class="hlt">lherzolites</span> with high Mg#Ol values represent ancient (Proterozoic) lithospheric mantle, preserved beneath the Guangxi Province. In contrast, the minor, fertile (low-Mg#Ol) <span class="hlt">lherzolites</span> represent lithospheric mantle accreted during the Phanerozoic, and a small amount of pyroxenite was produced via interaction between peridotite and silicate-rich melts. The mantle-accretion process that occurred beneath the SCB during the Mesozoic to Cenozoic time extended into Guangxi Province. The lithospheric mantle beneath the interior of the SCB is heterogeneous, featuring various types of peridotite and co-existing pyroxenite. This heterogeneity also indicates that the lithospheric mantle beneath the regions affected by</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015EGUGA..1711482F','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015EGUGA..1711482F"><span>Crystal preferred orientations of minerals from mantle xenoliths in alkali basaltic rocks form the Catalan Volcanic Zone (NE Spain)</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Fernández-Roig, Mercè; Galán, Gumer; Mariani, Elisabetta</p> <p>2015-04-01</p> <p>Mantle xenoliths in alkali basaltic rocks from the Catalan Volcanic Zone, associated with the Neogene-Quaternary rift system in NE Spain, are formed of anhydrous spinel <span class="hlt">lherzolites</span> and harzburgites with minor olivine websterites. Both peridotites are considered residues of variable degrees of partial melting, later affected by metasomatism, especially the harzburgites. These and the websterites display protogranular microstructures, whereas <span class="hlt">lherzolites</span> show continuous variation between protogranular, porphyroclastic and equigranular forms. Thermometric data of new xenoliths indicate that protogranular harzburgites, <span class="hlt">lherzolites</span> and websterites were equilibrated at higher temperatures than porphyroclastic and equigranular <span class="hlt">lherzolites</span>. Mineral chemistry also indicates lower equilibrium pressure for porphyroclastic and equigranular <span class="hlt">lherzolites</span> than for the protogranular ones. Crystal preferred orientations (CPOs) of olivine and pyroxenes from these new xenoliths were determined with the EBSD-SEM technique to identify the deformation stages affecting the lithospheric mantle in this zone and to assess the relationships between the deformation fabrics, processes and microstructures. Olivine CPOs in protogranular harzburgites, <span class="hlt">lherzolites</span> and a pyroxenite display [010]-fiber patterns characterized by a strong point concentration of the [010] axis normal to the foliation and girdle distribution of [100] and [001] axes within the foliation plane. Olivine CPO symmetry in porphyroclastic and equigranular <span class="hlt">lherzolites</span> varies continuously from [010]-fiber to orthorhombic and [100]-fiber types. The orthorhombic patterns are characterized by scattered maxima of the three axes, which are normal between them. The rare [100]-fiber patterns display strong point concentration of [100] axis, with normal girdle distribution of the other two axes, which are aligned with each other. The patterns of pyroxene CPOs are more dispersed than those of olivine, especially for clinopyroxene, but</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2012EGUGA..1412630G','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2012EGUGA..1412630G"><span>Geochemical and Sr-Nd isotopic characteristics of mantle xenoliths from NE Spain</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Galán, G.; Oliveras, V.</p> <p>2012-04-01</p> <p>Mantle xenoliths in alkaline mafic lavas and pyroclasts from the Neogene-Quaternary volcanism in NE Spain are studied using major, trace element geochemistry and Sr-Nd isotopes, to compare the lithospheric mantle of this area with that of other European zones, and to assess the different processes that conditioned its evolution. The xenoliths mostly come from two volcanoes and are mainly formed of anhydrous spinel <span class="hlt">lherzolites</span> and harzburgites, in approximately equal proportion. Accessory amphibole and phlogopite are occasional, as it happens with plagioclase, which appears in corona textures around <span class="hlt">lherzolite</span> spinel. Much subordinated cumulate pyroxenite xenoliths (olivine wbsterite, clinopyroxenite types) are also found. Textures are mostly protogranular, but there are also porphyroclastic, transitional between protogranular and porphyroclastic, and equigranular forms among <span class="hlt">lherzolites</span>. Pyrometamorphic textures are observed in a few xenoliths. Co-variation diagrams for basaltic components and MgO concentrations in whole rock analyses show gradation from <span class="hlt">lherzolites</span> to harzburgites. This is also the case for compatible and mildly incompatible trace elements, but not for the most incompatible ones. This gradual variation is also confirmed by mineral compositions, most of which correspond to off-craton xenoliths. REE patterns for <span class="hlt">lherzolites</span> and for their clinopyroxene are LREE and MREE depleted, whereas for harzburgites are LREE and MREE enriched. U-shaped REE patterns are rarely observed in <span class="hlt">lherzolite</span> clinopyroxene that also shows more significant negative anomalies at Zr and Ti. Clinopyroxene from harzburgites is also remarked by more significant negative anomalies at Nb, Ti and Zr, and by higher Th and U abundances, than <span class="hlt">lherzolite</span> clinopyroxene . Sr and Nd isotopic compositions for clinopyroxene define a continuous and inverse trend from DMM <span class="hlt">lherzolites</span> to enriched harzburgites (87Sr/86Sr: 0.702486-0.709772; 143Nd/144Nd: 0.513359-0.512411). Harzburgite</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=19870046777&hterms=endogenic+processes&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D30%26Ntt%3Dendogenic%2Bprocesses','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=19870046777&hterms=endogenic+processes&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D30%26Ntt%3Dendogenic%2Bprocesses"><span>Lunar and Planetary Science Conference, 17th, Houston, TX, Mar. 17-21, 1986, Proceedings. Part 2</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Ryder, Graham (Editor); Schubert, Gerald (Editor)</p> <p>1987-01-01</p> <p>The topics discussed in this volume include lunar endogenic rocks and processes; lunar regoliths and breccias; the terrestrial planets; <span class="hlt">shergottites</span>; primitive materials, exposure, and atmospheres; and impacts and crater tectonics. Papers are presented on the petrology and geochemistry of alkali gabbronorites from lunar breccia 67975; the formation of Apollo 17 orange and black glass beads; mixing levels, the Apennine Front soil component, and compositional trends in the Apollo 15 soils; the meteorite component of Apollo 16 noritic impact melt breccias; and constraints on the lithospheric structure of Venus from mechanical models and tectonic surface features. Consideration is also given to a fractal interpretation of topography and geoid spectra on the earth, moon, Venus, and Mars; rare earth patterns in <span class="hlt">shergottite</span> phosphates and residues; nuclide production by primary cosmic-ray protons; gas chromatographic instrumentation for the analysis of aerosols and gases in Titan's atmosphere; and finite-element models of non-Newtonian crater relaxation.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=20000094532&hterms=Bern&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D60%26Ntt%3DBern','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=20000094532&hterms=Bern&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D60%26Ntt%3DBern"><span>Radiometric Ages of Martian Meteorites compared to Martian Surfaces Ages</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Nyquist, L. E.; Shih, C.-Y.</p> <p>1999-01-01</p> <p>The surprisingly young Rb-Sr age of the Shergotty meteorite contributed to early suggestions that it might be of martian origin. their redox state and oxygen isotopic compositions linked the <span class="hlt">shergottites</span> to the clino-pyroxenite nakhlites and the dunite Chassigny, causing them to be grouped as SNC meteorites. These characteristics, but especially the similarity of the elemental and isotopic compositions of gases trapped in <span class="hlt">shergottites</span> to those of the martian atmosphere, have caused the martian origin of the SNC and related meteorites to be widely accepted. Although the young ages were one of the early hints of a martian origin for the SNC meteorites, their interpretation has remained somewhat ambiguous. We will review the radiometric ages of the martian meteorites and attempt to place them into the context of martian surface ages.</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_17");'>17</a></li> <li><a href="#" onclick='return showDiv("page_18");'>18</a></li> <li class="active"><span>19</span></li> <li><a href="#" onclick='return showDiv("page_20");'>20</a></li> <li><a href="#" onclick='return showDiv("page_21");'>21</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_19 --> <div id="page_20" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_18");'>18</a></li> <li><a href="#" onclick='return showDiv("page_19");'>19</a></li> <li class="active"><span>20</span></li> <li><a href="#" onclick='return showDiv("page_21");'>21</a></li> <li><a href="#" onclick='return showDiv("page_22");'>22</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="381"> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/20110011532','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/20110011532"><span>Effect of Cooling Rate and Oxygen Fugacity on the Crystallization of the Queen Alexandra Range 94201 Martian Melt Composition</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Koizumi, E.; Mikouchi, T.; McKay, G.; Schwandt, C.; Monkawa, A.; Miyamoto, M.</p> <p>2002-01-01</p> <p>Although many basaltic <span class="hlt">shergottites</span> have been recently found in north African deserts, QUE94201 basaltic <span class="hlt">shergottite</span> (QUE) is still important because of its particular mineralogical and petrological features. This meteorite is thought to represent its parent melt composition [1 -3] and to crystallize under most reduced condition in this group [1,4]. We performed experimental study by using the synthetic glass that has the same composition as the bulk of QUE. After homogenization for 48 hours at 1300 C, isothermal and cooling experiments were done under various conditions (e.g. temperature, cooling rates, and redox states). Our goals are (1) to verify that QUE really represents its parent melt composition, (2) to estimate a cooling rate of this meteorite, (3) to clarify the crystallization sequences of present minerals, and (4) to verity that this meteorite really crystallized under reduced condition.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/1985JGRS...90...38J','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/1985JGRS...90...38J"><span>Identification of the youngest meteorites and a discussion of the possibility that they came from Mars</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Jones, J. H.</p> <p>1985-11-01</p> <p>The <span class="hlt">shergottites</span> are a group of basaltic meteorites which are very similar in appearance to terrestrial basalts. On the Earth basalts are formed by volcanic activity. Because the <span class="hlt">shergottites</span> so resemble terrestrial basalts and because they are apparently very young ( 1.3 billion years), it has been inferred that they come from a large planet. Small planets and asteroids lose heat from their interiors quickly and stop producing hot basaltic liquids early in their history. It appears that gases trapped in one shergotite found in Antarctica (BETA 79001) are chemically similar to the martian atmosphere (as measured by the Viking mission). The controversial speculation that the shergotites are samples of mars is examined in detail.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2012AGUFM.P11B1822S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2012AGUFM.P11B1822S"><span>Mantle evolution on Mars: Constraints from Lu-Hf and Sm-Nd isotope systematics of SNC meteorites</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Scherer, E. E.; Kurahashi, E.; Mezger, K.</p> <p>2012-12-01</p> <p>The long-lived 176Lu-176Hf and 147Sm-143Nd isotope systems are commonly employed to track the evolution of complementary mantle and crust reservoirs. The four elements involved are refractory and lithophile, and thus their relative abundances are not expected to have been changed by accretion or core formation. Subsequent silicate differentiation processes, however, e.g., the formation of crust by extraction of melts from the mantle, will fractionate Lu/Hf and Sm/Nd. This typically leaves a depleted mantle with higher Lu/Hf and Sm/Nd values than those of the undifferentiated, presumably chondritic parental reservoir. On the other hand, these same values in crustal rocks tend to be lower than those of their source. (Apparent exceptions are the Martian <span class="hlt">shergottites</span>, which tend to have lower Lu/Hf as expected, but Sm/Nd higher than their presumed sources. Such decoupling of the two isotope systems may be explained by two-stage melting [e.g., 1, 5].) The ensuing chemical variability among secondary and later generation silicate reservoirs causes their isotopic compositions (e.g., 176Hf/177Hf and 143Nd/144Nd) to diverge from that of the bulk silicate planet over hundreds of millions of years. The resulting isotopic diversity preserved (SNC) meteorites is being used to constrain the differentiation history, melting mineralogy, and dynamics of the Martian mantle [e.g., 1-8]. However, interpretations based on the initial isotope compositions of Hf and Nd strongly depend on the accuracy of crystallization ages. The ages of <span class="hlt">shergottites</span> in particular are debated (e.g., [3,4,7]). To resolve this issue and gain a better understanding of Martian mantle evolution, we are investigating the Lu-Hf and Sm-Nd systematics of bulk SNC meteorites and constructing internal (mineral) isochrons. Eleven bulk Martian meteorites (5 <span class="hlt">shergottites</span>, 4 nakhlites, and 2 chassignites) were digested without prior leaching in high-pressure autoclaves for 5 days. Initial ɛ176Hf and ɛ143Nd values</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/23065902','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/23065902"><span>Tissint martian meteorite: a fresh look at the interior, surface, and atmosphere of Mars.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Aoudjehane, H Chennaoui; Avice, G; Barrat, J-A; Boudouma, O; Chen, G; Duke, M J M; Franchi, I A; Gattacceca, J; Grady, M M; Greenwood, R C; Herd, C D K; Hewins, R; Jambon, A; Marty, B; Rochette, P; Smith, C L; Sautter, V; Verchovsky, A; Weber, P; Zanda, B</p> <p>2012-11-09</p> <p>Tissint (Morocco) is the fifth martian meteorite collected after it was witnessed falling to Earth. Our integrated mineralogical, petrological, and geochemical study shows that it is a depleted picritic <span class="hlt">shergottite</span> similar to EETA79001A. Highly magnesian olivine and abundant glass containing martian atmosphere are present in Tissint. Refractory trace element, sulfur, and fluorine data for the matrix and glass veins in the meteorite indicate the presence of a martian surface component. Thus, the influence of in situ martian weathering can be unambiguously distinguished from terrestrial contamination in this meteorite. Martian weathering features in Tissint are compatible with the results of spacecraft observations of Mars. Tissint has a cosmic-ray exposure age of 0.7 ± 0.3 million years, consistent with those of many other <span class="hlt">shergottites</span>, notably EETA79001, suggesting that they were ejected from Mars during the same event.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017E%26PSL.463...56W','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017E%26PSL.463...56W"><span>Chalcophile elements in Martian meteorites indicate low sulfur content in the Martian interior and a volatile element-depleted late veneer</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Wang, Zaicong; Becker, Harry</p> <p>2017-04-01</p> <p>It is generally believed that the Martian mantle and core are rich in sulfur and that <span class="hlt">shergottites</span> originated from sulfide-saturated magma. However, recent work suggests that the high FeO contents would require very high S concentrations in <span class="hlt">shergottite</span> parent magmas at sulfide saturation. Here we combine new and published data on chalcophile elements in <span class="hlt">shergottites</span>, nakhlites and ALH84001 to constrain the sulfide saturation state of the parent magmas and the chalcophile element concentrations in their mantle sources. Regardless of the MgO content and the long-term depletion history of incompatible lithophile elements as indicated by initial ε143Nd, different groups of <span class="hlt">shergottites</span> display limited variations in ratios of Pt, Pd, Re, Cu, S, Se and Te. The emplacement of most <span class="hlt">shergottites</span> within the crust and limited variations of ratios of chalcophile elements with substantial differences in volatility during eruption (e.g., Cu/S, Cu/Se and Pt/Re) indicate little degassing losses of S, Se, Te and Re from <span class="hlt">shergottites</span>. Limited variations in ratios of elements with very different sulfide-silicate melt partition coefficients and negative correlations of chalcophile elements with MgO require a sulfide-undersaturated evolution of the parent magmas from mantle source to emplacement in the crust, consistent with the FeO-based argument. Sulfide petrography and the komatiite-like fractionation of platinum group elements (PGE) in <span class="hlt">shergottites</span> also support this conclusion. The absence of accumulated sulfides in the ancient Martian cumulate ALH84001 results in very low contents of PGE, Re, Cu, Se and Te in this meteorite, hinting that sulfide-undersaturated magmas may have occurred throughout the Martian geological history. The negative correlation of Cu and MgO contents in <span class="hlt">shergottites</span> suggests approximately 2 ± 0.4 (1s) μg/g Cu in the Martian mantle. The ratios of Cu, S, Se and Te indicate 360 ± 120 μg/g (1s) S, 100 ± 27 ng/g (1s) Se and 0.50 ± 0.25 ng/g (1s) Te in the</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2013GeCoA.120...17S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2013GeCoA.120...17S"><span>Petrogenetic linkages among fO2, isotopic enrichments-depletions and crystallization history in Martian basalts. Evidence from the distribution of phosphorus in olivine megacrysts</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Shearer, C. K.; Aaron, P. M.; Burger, P. V.; Guan, Y.; Bell, A. S.; Papike, J. J.</p> <p>2013-11-01</p> <p>An important geochemical characteristic of the <span class="hlt">shergottites</span> is the large range in initial Sr isotopic ratios and initial ɛNd values. The depleted olivine-phyric <span class="hlt">shergottites</span> are commonly reduced (˜IW+1) and exhibit limited variation in fO2 during crystallization, whereas the enriched olivine-phyric <span class="hlt">shergottites</span> are more oxidized and exhibit a substantial variation in fO2 during crystallization (˜IW+1 (1 log unit above the iron-wüstite buffer) to FMQ+0.7 (0.7 log units above the fayalite-magnetite-quartz buffer). Using a reduced, depleted <span class="hlt">shergottite</span> Y980459 (Y98) and an oxidized, enriched <span class="hlt">shergottite</span> (NWA1183), we reconstructed the crystallization history of the olivine megacrysts using phosphorus zoning and placed trace element variation and indices of oxygen fugacity into the context of that crystallization history. The olivine megacrysts in Y98 and NWA1183 exhibited various episodes of growth defined by the P zoning. Common to both samples were continuous and discontinuous oscillatory chemical zoning in the outer portions of the olivine megacrysts. However, the morphologies of the cores suggest a xenocrystic origin for the core of Y98 and a phenocrystic origin for the core of NWA1183. Phosphorus in the olivine ranges from less than 0.02 to up to 0.70 wt.% P2O5. The P in the olivine megacrysts manifests subtle, but real differences, in the P content of different <span class="hlt">shergottite</span> melts, incompatible element behavior of P during olivine crystallization, and solute trapping during periods of rapid olivine growth. Although P should behave incompatibly in basaltic systems, there is little relationship between the isotopic characteristics and P content in the enriched-depleted array of <span class="hlt">shergottites</span>. In the olivine, Al is generally correlated with P enrichment and reflects a coupled substitution of P-Al. On the other hand, V is not correlated with P in Y98, but correlated with P in the oscillatory zoned regions of the olivine in NWA1183. The changes in correlation to P</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2013CoMP..166.1469W','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2013CoMP..166.1469W"><span>Effect of melt composition on basalt and peridotite interaction: laboratory dissolution experiments with applications to mineral compositional variations in mantle xenoliths from the North China Craton</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Wang, Chunguang; Liang, Yan; Xu, Wenliang; Dygert, Nick</p> <p>2013-11-01</p> <p>Interaction between basaltic melts and peridotites has played an important role in modifying the lithospheric and asthenospheric mantle during magma genesis in a number of tectonic settings. Compositions of basaltic melts vary considerably and may play an important role in controlling the kinetics of melt-peridotite interaction. To better understand the effect of melt composition on melt-peridotite interaction, we conducted spinel <span class="hlt">lherzolite</span> dissolution experiments at 2 GPa and 1,425 °C using the dissolution couple method. The reacting melts include a basaltic andesite, a ferro-basalt, and an alkali basalt. Dissolution of <span class="hlt">lherzolite</span> in the basaltic andesite and the ferro-basalt produced harzburgite-<span class="hlt">lherzolite</span> sequences with a thin orthopyroxenite layer at the melt-harzburgite interface, whereas dissolution of <span class="hlt">lherzolite</span> in the alkali basalt produced a dunite-harzburgite-<span class="hlt">lherzolite</span> sequence. Systematic variations in mineral compositions across the lithological units are observed. These mineral compositional variations are attributed to grain-scale processes that involve dissolution, precipitation, and reprecipitation and depend strongly on reacting melt composition. Comparison of mineral compositional variations across the dissolution couples with those observed in mantle xenoliths from the North China Craton (NCC) helps to assess the spatial and temporal variations in the extent of siliceous melt and peridotite interaction in modifying the lithospheric mantle beneath the NCC. We found that such melt-rock interaction mainly took place in Early Cretaceous, and is responsible for the enrichment of pyroxene in the lithospheric mantle. Spatially, siliceous melt-peridotite interaction took place in the ancient orogens with thickened lower crust.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016CoMP..171...77W','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016CoMP..171...77W"><span>Formation of orthopyroxenite by reaction between peridotite and hydrous basaltic melt: an experimental study</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Wang, Chunguang; Liang, Yan; Dygert, Nick; Xu, Wenliang</p> <p>2016-09-01</p> <p>The consequences of hydrous basaltic melts and peridotite interaction were examined experimentally in Au-Pd, Pt, and graphite capsules using the reaction couple method. Reactions between a hydrous basaltic andesite (4 wt% H2O) and dunite or <span class="hlt">lherzolite</span> in an Au-Pd capsule at 1 GPa and 1200 °C produce a melt-bearing orthopyroxenite-dunite sequence. Reactions between a hydrous ferro-basalt and <span class="hlt">lherzolite</span> in Pt or Au-Pd capsules at 0.8-2 GPa and 1250-1385 °C produce a melt-bearing orthopyroxenite-harzburgite sequence. Reactions between the ferro-basalt and <span class="hlt">lherzolite</span> in graphite capsules (not designed to retain water) result in a melt-bearing dunite-harzburgite sequence at 1 GPa and a melt-bearing harzburgite-<span class="hlt">lherzolite</span> sequence at 2 GPa. The orthopyroxenite from the hydrous reaction experiments has a high porosity, and it is separated by a sharp lithological interface from the dunite or harzburgite. Orthopyroxenes in the orthopyroxenite are large in size with resorbed olivine inclusions. Formation of the high-porosity orthopyroxenite in the hydrous melt-rock reaction experiments is determined by the liquidus phase relation of the interface reacting melt and reaction kinetics. Reaction between orthopyroxene-saturated hydrous melt and olivine at melt-rock interface produces orthopyroxenite. Water infiltration induces hydrous melting of the <span class="hlt">lherzolite</span>, producing a dunite or an orthopyroxene-depleted harzburgite. Efficient diffusive exchange between the partial melt and the hydrous reacting melt promotes orthopyroxene-oversaturation around the melt-rock interfacial region. The simplified experiments reveal end-member processes for understanding the formation of orthopyroxenite in the upper mantle. The presence of orthopyroxenites in mantle samples is a strong indication of hydrous melt and peridotite interaction.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017Tectp.698...16F','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017Tectp.698...16F"><span>Deformation and seismic anisotropy of the subcontinental lithospheric mantle in NE Spain: EBSD data on xenoliths from the Catalan Volcanic Zone</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Fernández-Roig, Mercè; Galán, Gumer; Mariani, Elisabetta</p> <p>2017-02-01</p> <p>Mantle xenoliths in Neogene-Quaternary basaltic rocks related to the European Cenozoic Rift System serve to assess the evolution of the subcontinental lithospheric mantle beneath the Catalan Volcanic Zone in NE Spain. Crystallographic preferred orientations, major element composition of minerals, and temperature and pressure estimates have been used to this end. The mantle consists of spinel <span class="hlt">lherzolites</span>, harzburgites and subordinate websterites. Protogranular microstructures are found in all peridotites and websterites, but <span class="hlt">lherzolites</span> also display finer-grained porphyroclastic and equigranular microstructures. The dominant olivine deformation fabric is [010] fiber, but subordinate orthorhombic and [100]-fiber types are also present, especially in porphyroclastic and equigranular <span class="hlt">lherzolites</span>. The fabric strength (J index = 10.12-1.91), equilibrium temperature and pressure are higher in xenoliths with [010]-fiber fabric and decrease in those with orthorhombic and [100]-fiber type. Incoherence between olivine and pyroxene deformation fabric is mostly found in porphyroclastic and equigranular <span class="hlt">lherzolites</span>. Seismic anisotropy, estimated from the crystal preferred orientations, also decreases (AVp = 10.2-2.60%; AVs max = 7.95-2.19%) in porphyroclastic and equigranular <span class="hlt">lherzolites</span>. The olivine [010]-fiber fabric points to deformation by simple shear or transpression which is likely to have occured during the development of late-Hercynian strike-slip shear zones, and to subsequent annealing during late Hercynian decompression, Permian and Cretaceous rifting. Also, it cannot be excluded that the percolation of mafic magmas during these extensional events provoked the refertilization of the lithospheric mantle. However, no clear relationship has been observed between fabric strength and mineral mode and composition. Later transtensional deformation during late Alpine orogenesis, at higher stress and decreasing temperature and pressure, transformed the earlier fabric into</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=20040059917&hterms=Weathering&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D90%26Ntt%3DWeathering','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=20040059917&hterms=Weathering&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D90%26Ntt%3DWeathering"><span>Lunar and Planetary Science XXXV: Martian Meteorites: Chemical Weathering</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p></p> <p>2004-01-01</p> <p>The session "Martian Meteorites: Chemical Weathering" included the following reports:Chemical Weathering Records of Martian Soils Preserved in the Martian Meteorite EET79001; Synchrotron X-Ray Diffraction Analysis of Meteorites in Thin Section: Preliminary Results; A Survey of Olivine Alteration Products Using Raman Spectroscopy; and Rb-Sr and Sm-Nd Isotope Systematics of <span class="hlt">Shergottite</span> NWA 856: Crystallization Age and Implications for Alteration of Hot Desert SNC Meteorites.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://pubs.er.usgs.gov/publication/70010791','USGSPUBS'); return false;" href="http://pubs.er.usgs.gov/publication/70010791"><span>Maskelynite: Formation by explosive shock</span></a></p> <p><a target="_blank" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Milton, D.J.; De Carli, P. S.</p> <p>1963-01-01</p> <p>When high pressure (250 to 300 kilobars) was applied suddenly (shock-loading) to gabbro, the plagioclase was transformed to a noncrystalline phase (maskelynite) by a solid-state reaction at a low temperature, while the proxene remained crystalline. The shock-loaded gabbro resembles meteorites of the <span class="hlt">shergottite</span> class; this suggests that the latter formed as a result of shock. The shock-loading of gabbro at 600 to 800 kilobars raised the temperature above the melting range of the plagioclase.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/11540310','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/11540310"><span>The origin of inner planet atmospheres.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Owen, T</p> <p>1994-01-01</p> <p>A comet-impact model for Mars uses the current atmosphere with argon as the index volatile and assumes a surface pressure of about 40 mb. The model also allows for changes in surface pressure. The model is based on analysis of gases trapped in <span class="hlt">Shergottite</span> and Nakhlite meteorites. Tests of the model include the identification of noble gases in comets and the presence of nitrogen compounds in Jupiter identified by the Galileo probe.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016M%26PS...51.2111S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016M%26PS...51.2111S"><span>The chlorine isotope composition of Martian meteorites 2. Implications for the early solar system and the formation of Mars</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Sharp, Zachary; Williams, Jeffrey; Shearer, Charles; Agee, Carl; McKeegan, Kevin</p> <p>2016-11-01</p> <p>We determined the chlorine isotope composition of 16 Martian meteorites using gas source mass spectrometry on bulk samples and in situ secondary ion microprobe analysis on apatite grains. Measured δ37Cl values range from -3.8 to +8.6‰. The olivine-phyric <span class="hlt">shergottites</span> are the isotopically lightest samples, with δ37Cl mostly ranging from -4 to -2‰. Samples with evidence for a crustal component have positive δ37Cl values, with an extreme value of 8.6‰. Most of the basaltic <span class="hlt">shergottites</span> have intermediate δ37Cl values of -1 to 0‰, except for Shergotty, which is similar to the olivine-phyric <span class="hlt">shergottites</span>. We interpret these data as due to mixing of a two-component system. The first component is the mantle value of -4 to -3‰. This most likely represents the original bulk Martian Cl isotope value. The other endmember is a 37Cl-enriched crustal component. We speculate that preferential loss of 35Cl to space has resulted in a high δ37Cl value for the Martian surface, similar to what is seen in other volatile systems. The basaltic <span class="hlt">shergottites</span> are a mixture of the other two endmembers. The low δ37Cl value of primitive Mars is different from Earth and most chondrites, both of which are close to 0‰. We are not aware of any parent-body process that could lower the δ37Cl value of the Martian mantle to -4 to -3‰. Instead, we propose that this low δ37Cl value represents the primordial bulk composition of Mars inherited during accretion. The higher δ37Cl values seen in many chondrites are explained by later incorporation of 37Cl-enriched HCl-hydrate.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/20160007506','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/20160007506"><span>Petrology and Geochemistry of New Paired Martian Meteorites Larkman Nunatak 12240 and Larkman Nunatak 12095</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Funk, R. C.; Peslier, A. H.; Brandon, A. D.; Humayun, M.</p> <p>2016-01-01</p> <p>Two of the latest Martian meteorites found in Antarctica, paired olivine-phyric <span class="hlt">shergottites</span> LAR 12240 and LAR 12095, are described in order to decipher their petrological context, and place constraints on the geological history of Mars. This project identifies all phases found in LAR 12240 and 12095 and analyzes them for major and trace elements. The textural relationships among these phases are examined in order to develop a crystallization history of the magma(s) that formed these basalts.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/17737107','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/17737107"><span>Maskelynite: Formation by Explosive Shock.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Milton, D J; de Carli, P S</p> <p>1963-05-10</p> <p>When high pressure (250 to 300 kilobars) was applied suddenly (shock-loading) to gabbro, the plagioclase was transformed to a noncrystalline phase (maskelynite) by a solid-state reaction at a low temperature, while the proxene remained crystalline. The shock-loaded gabbro resembles meteorites of the <span class="hlt">shergottite</span> class; this suggests that the latter formed as a result of shock. The shock-loading of gabbro at 600 to 800 kilobars raised the temperature above the melting range of the plagioclase.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/20080026098','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/20080026098"><span>Characterization and Petrologic Interpretation of Olivine-Rich Basalts at Gusev Crater, Mars</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>McSween, H. Y.; Wyatt, M. B.; Gellert, R.; Bell, J. F., III; Morris, R. V.; Herkenhoff, K. E.; Crumpler, L. S.; Milam, K. A.; Stockstill, K. R.; Tornabene, L. L.; <a style="text-decoration: none; " href="javascript:void(0); " onClick="displayelement('author_20080026098'); toggleEditAbsImage('author_20080026098_show'); toggleEditAbsImage('author_20080026098_hide'); "> <img style="display:inline; width:12px; height:12px; " src="images/arrow-up.gif" width="12" height="12" border="0" alt="hide" id="author_20080026098_show"> <img style="width:12px; height:12px; display:none; " src="images/arrow-down.gif" width="12" height="12" border="0" alt="hide" id="author_20080026098_hide"></p> <p>2006-01-01</p> <p>Rocks on the floor of Gusev crater are basalts of uniform composition and mineralogy. Olivine, the only mineral to have been identified or inferred from data by all instruments on the Spirit rover, is especially abundant in these rocks. These picritic basalts are similar in many respects to certain Martian meteorites (olivine-phyric <span class="hlt">shergottites</span>). The olivine megacrysts in both have intermediate compositions, with modal abundances ranging up to 20-30%. Associated minerals in both include low-calcium and high-calcium pyroxenes, plagioclase of intermediate composition, iron-titanium-chromium oxides, and phosphate. These rocks also share minor element trends, reflected in their nickel-magnesium and chromium-magnesium ratios. Gusev basalts and <span class="hlt">shergottites</span> appear to have formed from primitive magmas produced by melting an undepleted mantle at depth and erupted without significant fractionation. However, apparent differences between Gusev rocks and <span class="hlt">shergottites</span> in their ages, plagioclase abundances, and volatile contents preclude direct correlation. Orbital determinations of global olivine distribution and compositions by thermal emission spectroscopy suggest that olivine-rich rocks may be widespread. Because weathering under acidic conditions preferentially attacks olivine and disguises such rocks beneath alteration rinds, picritic basalts formed from primitive magmas may even be a common component of the Martian crust formed during ancient and recent times.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/19940011917','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/19940011917"><span>The dregs of crystallization in Zagami</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Mccoy, T. J.; Keil, K.; Taylor, G. J.</p> <p>1993-01-01</p> <p>The Zagami <span class="hlt">shergottite</span> is a basaltic meteorite which formed when a phenocryst-bearing lava flow was emplaced at or near the surface of Mars. Recently, a cm-sized olivine-rich lithology has been identified in Zagami by Mossbauer spectroscopy. Olivine is extremely rare in <span class="hlt">shergottites</span>, particularly in Zagami and Shergotty, where it occurs only as minute grains. We report petrologic and microprobe studies of this olivine-rich lithology. This material represents the last few percent of melt and is highly enriched in phosphates, opaques and mesostases, all of which are late-stage crystallization products. Phosphates replaced augite as a phenocryst phase when the magma became saturated in P. This late stage melt also includes a fayalite-bearing, multi-phase intergrowth which crystallized after the melt became too rich in iron to crystallize pigeonite. We can now reconstruct the entire crystallization history of the Zagami <span class="hlt">shergottite</span> from a deep-seated magma chamber to crystallization of the final few percent of melt in a near-surface dike or thick flow. Small pockets (tens of microns) of late-stage melt pockets are ubiquitous but volumetrically minor in Zagami. We do not know the physical relationship between these areas and the cm-sized olivine-rich material described here. It is possible that these small pockets were mobile, forming larger areas. Perhaps inspection of the entire hand specimen of Zagami would clarify this relationship.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/20090043037','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/20090043037"><span>Chlorine Abundances in Martian Meteorites</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Bogard, D.D.; Garrison, D.H.; Park, J.</p> <p>2009-01-01</p> <p>Chlorine measurements made in martian surface rocks by robotic spacecraft typically give Chlorine (Cl) abundances of approximately 0.1-0.8%. In contrast, Cl abundances in martian meteorites appear lower, although data is limited, and martian nakhlites were also subjected to Cl contamination by Mars surface brines. Chlorine abundances reported by one lab for whole rock (WR) samples of Shergotty, ALH77005, and EET79001 range 108-14 ppm, whereas Cl in nakhlites range 73-1900 ppm. Measurements of Cl in various martian weathering phases of nakhlites varied 0.04-4.7% and reveal significant concentration of Cl by martian brines Martian meteorites contain much lower Chlorine than those measured in martian surface rocks and give further confirmation that Cl in these surface rocks was introduced by brines and weathering. It has been argued that Cl is twice as effective as water in lowering the melting point and promoting melting at shallower martian depths, and that significant Cl in the <span class="hlt">shergottite</span> source region would negate any need for significant water. However, this conclusion was based on experiments that utilized Cl concentrations more analogous to martian surface rocks than to <span class="hlt">shergottite</span> meteorites, and may not be applicable to <span class="hlt">shergottites</span>.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://pubs.er.usgs.gov/publication/70031054','USGSPUBS'); return false;" href="http://pubs.er.usgs.gov/publication/70031054"><span>Characterization and petrologic interpretation of olivine-rich basalts at Gusev Crater, Mars</span></a></p> <p><a target="_blank" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>McSween, H.Y.; Wyatt, M.B.; Gellert, Ralf; Bell, J.F.; Morris, R.V.; Herkenhoff, K. E.; Crumpler, L.S.; Milam, K.A.; Stockstill, K.R.; Tornabene, L.L.; Arvidson, R. E.; Bartlett, P.; Blaney, D.; Cabrol, N.A.; Christensen, P.R.; Clark, B. C.; Crisp, J.A.; Des Marais, D.J.; Economou, T.; Farmer, J.D.; Farrand, W.; Ghosh, A.; Golombek, M.; Gorevan, S.; Greeley, R.; Hamilton, V.E.; Johnson, J. R.; Joliff, B.L.; Klingelhofer, G.; Knudson, A.T.; McLennan, S.; Ming, D.; Moersch, J.E.; Rieder, R.; Ruff, S.W.; Schrorder, C.; de Souza, P.A.; Squyres, S. W.; Wanke, H.; Wang, A.; Yen, A.; Zipfel, J.</p> <p>2006-01-01</p> <p>Rocks on the floor of Gusev crater are basalts of uniform composition and mineralogy. Olivine, the only mineral to have been identified or inferred from data by all instruments on the Spirit rover, is especially abundant in these rocks. These picritic basalts are similar in many respects to certain Martian meteorites (olivine-phyric <span class="hlt">shergottites</span>). The olivine megacrysts in both have intermediate compositions, with modal abundances ranging up to 20-30%. Associated minerals in both include low-calcium and high-calcium pyroxenes, plagioclase of intermediate composition, iron-titanium-chromium oxides, and phosphate. These rocks also share minor element trends, reflected in their nickel-magnesium and chromium-magnesium ratios. Gusev basalts and <span class="hlt">shergottites</span> appear to have formed from primitive magmas produced by melting an undepleted mantle at depth and erupted without significant fractionation. However, apparent differences between Gusev rocks and <span class="hlt">shergottites</span> in their ages, plagioclase abundances, and volatile contents preclude direct correlation. Orbital determinations of global olivine distribution and compositions by thermal emission spectroscopy suggest that olivine-rich rocks may be widespread. Because weathering under acidic conditions preferentially attacks olivine and disguises such rocks beneath alteration rinds, picritic basalts formed from primitive magmas may even be a common component of the Martian crust formed during ancient and recent times. Copyright 2006 by the American Geophysical Union.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=19940016412&hterms=Peridotite&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D50%26Ntt%3DPeridotite','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=19940016412&hterms=Peridotite&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D50%26Ntt%3DPeridotite"><span>The carbon components in SNC meteorites of feldspathic harzburgite composition</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Wright, I. P.; Douglas, C.; Pillinger, C. T.</p> <p>1993-01-01</p> <p>Two meteorites collected in Antarctica, ALH A77005 and LEW 88516, have characteristics which link them to the <span class="hlt">shergottite</span> group of SNC meteorites. Essentially, ALH A77005 and LEW 88516 are feldspathic harzburgites, being comprised of roughly equal quantities of olivine and pyroxene, with an additional few percent of feldspar which has subsequently been converted to maskelynite by shock. The meteorites represent samples of a cumulate rock which is itself composed of two different lithologies: in one, large pyroxenes poikilitically enclose olivine crystals, while the other consists of interstitial areas made up of pyroxene, olivine, maskelynite, whitlockite, troilite, ilmenite and chlorapatite. It has been proposed that meteorites such as ALH A77005 (and LEW 88516) are relict samples of the source peridotite from which the other <span class="hlt">shergottites</span> formed. As such it should be informative to study in detail the carbon components present within these samples, in order to make comparisons with data from other <span class="hlt">shergottites</span>. Although not plutonic in origin, and therefore not sampling a truly deep source, analyses of ALH A77005 and LEW 88516 should assist with attempts to define the bulk carbon isotopic composition of Mars. This has been assessed previously through analyses of carbon of presumed magmatic origin in other SNC meteorites, but the carbon isotopic compositions obtained seem to be at variance with what might be expected. It is important to constrain the carbon isotopic composition of Mars as well as possible so that models of atmospheric evolution, based on carbon isotopic data, can yield the most reliable results.</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_18");'>18</a></li> <li><a href="#" onclick='return showDiv("page_19");'>19</a></li> <li class="active"><span>20</span></li> <li><a href="#" onclick='return showDiv("page_21");'>21</a></li> <li><a href="#" onclick='return showDiv("page_22");'>22</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_20 --> <div id="page_21" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_19");'>19</a></li> <li><a href="#" onclick='return showDiv("page_20");'>20</a></li> <li class="active"><span>21</span></li> <li><a href="#" onclick='return showDiv("page_22");'>22</a></li> <li><a href="#" onclick='return showDiv("page_23");'>23</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="401"> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2008JGRE..113.6002R','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2008JGRE..113.6002R"><span>The nature of Martian fluids based on mobile element studies in salt-assemblages from Martian meteorites</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Rao, M. N.; Nyquist, L. E.; Wentworth, S. J.; Sutton, S. R.; Garrison, D. H.</p> <p>2008-06-01</p> <p>The S, Cl, and Br abundances determined in salt assemblages in Nakhla and Lafayette olivine fracturefillings and in gas-rich impact-melt (GRIM) glasses from Shergotty and EET79001 Lithologies A & B using EMPA/EDS/APS X-ray Microprobe techniques are compared with the S and Cl abundances determined by Gooding and coworkers in similar samples using quadrupole mass-spectrometric techniques. All the analytical methods yield relatively high Cl and low SO3 abundances in Nakhla indicating a SO3/Cl ratio of ~0.2. The same ratio in Lafayette secondary salts seems to be ~2. In the case of GRIM glasses from Shergotty and EET79001 Lith A & Lith B, the SO3 abundance is found to be high whereas the Cl abundance is low yielding a SO3/Cl ratio of ~5-300 (large errors are associated with these ratios because of low Cl signals). The salts found in Nakhla fracturefillings are inferred to have formed from Cl-rich fluids (high pH) near nakhlite source region on Mars, whereas the secondary minerals found in <span class="hlt">shergottite</span> GRIM glasses seem to be associated with SO3-rich fluids (low pH) near <span class="hlt">shergottite</span> source region on Mars. The Cl-rich fluids seem to have infiltrated into the nakhlite source region ~600 Ma ago, whereas the SO3-rich fluids likely percolated into the <span class="hlt">shergottite</span> source region at ~180 Ma (or less) suggesting the possible existence of two types of fluid sources on Mars.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/20090012324','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/20090012324"><span>LU-HF Age of Martian Meteorite Larkman Nunatek 06319</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Shafer, J. T.; Brandon, A. D.; Lapen, T. J.; Righter, M.; Beard, B.; Peslier, A. H.</p> <p>2009-01-01</p> <p>Lu-Hf isotopic data were collected on mineral separates and bulk rock powders of LAR 06319, yielding an age of 197+/- 29 Ma. Sm-Nd isotopic data and in-situ LA-ICP-MS data from a thin section of LAR 06319 are currently being collected and will be presented at the 2009 LPSC. These new data for LAR 06319 extend the existing data set for the enriched <span class="hlt">shergottite</span> group. Martian meteorites represent the only opportunity for ground truth investigation of the geochemistry of Mars [1]. At present, approximately 80 meteorites have been classified as Martian based on young ages and distinctive isotopic signatures [2]. LAR 06319 is a newly discovered (as part of the 2006 ANSMET field season) martian meteorite that represents an important opportunity to further our understanding of the geochemical and petrological constraints on the origin of Martian magmas. Martian meteorites are traditionally categorized into the <span class="hlt">shergottite</span>, nakhlite, and chassignite groups. The <span class="hlt">shergottites</span> are further classified into three distinct isotopic groups designated depleted, intermediate, and enriched [3,4] based on the isotope systematics and compositions of their source(s).</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016M%26PS...51.2092W','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016M%26PS...51.2092W"><span>The chlorine isotopic composition of Martian meteorites 1: Chlorine isotope composition of Martian mantle and crustal reservoirs and their interactions</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Williams, J. T.; Shearer, C. K.; Sharp, Z. D.; Burger, P. V.; McCubbin, F. M.; Santos, A. R.; Agee, C. B.; McKeegan, K. D.</p> <p>2016-11-01</p> <p>The Martian meteorites record a wide diversity of environments, processes, and ages. Much work has been done to decipher potential mantle sources for Martian magmas and their interactions with crustal and surface environments. Chlorine isotopes provide a unique opportunity to assess interactions between Martian mantle-derived magmas and the crust. We have measured the Cl-isotopic composition of 17 samples that span the range of known ages, Martian environments, and mantle reservoirs. The 37Cl of the Martian mantle, as represented by the olivine-phyric <span class="hlt">shergottites</span>, NWA 2737 (chassignite), and Shergotty (basaltic <span class="hlt">shergottite</span>), has a low value of approximately -3.8‰. This value is lower than that of all other planetary bodies measured thus far. The Martian crust, as represented by regolith breccia NWA 7034, is variably enriched in the heavy isotope of Cl. This enrichment is reflective of preferential loss of 35Cl to space. Most basaltic <span class="hlt">shergottites</span> (less Shergotty), nakhlites, Chassigny, and Allan Hills 84001 lie on a continuum between the Martian mantle and crust. This intermediate range is explained by mechanical mixing through impact, fluid interaction, and assimilation-fractional crystallization.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/20869751','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/20869751"><span>Temporal variation of 240Pu/239Pu atom ratio and 239+240Pu inventory in water columns of the Japan Sea.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Yamada, Masatoshi; Zheng, Jian</p> <p>2010-11-01</p> <p>The (239+240)Pu concentrations and (240)Pu/(239)Pu atom ratios were determined by alpha spectrometry and double-focusing SF-ICP-MS for seawater samples obtained in 1984 and 1993 from the <span class="hlt">Yamato</span> and Tsushima Basins of the Japan Sea in the western North Pacific margin. The total (239+240)Pu inventories in the whole water columns were approximately doubled during the period from 1984 to 1993 in the two basins. The increasing rates were estimated to be 5.1 Bq m(-2)yr(-1) in the <span class="hlt">Yamato</span> Basin and 4.2 Bq m(-2)yr(-1) in the Tsushima Basin and they corresponded to ~0.02% of the annual (239+240)Pu inflow rate into the Japan Sea through the Tsushima Strait. The mean (240)Pu/(239)Pu atom ratios were ~0.240 and significantly higher than the mean global fallout ratio of 0.18. Furthermore, there were no temporal or spatial variations of (240)Pu/(239)Pu atom ratios during this period in the Japan Sea. The total (239+240)Pu inventories originating from the close-in fallout increased from 17.6 Bq m(-2) to 34.6 Bq m(-2) in the <span class="hlt">Yamato</span> Basin and from 20.1 Bq m(-2) to 34.6 Bq m(-2) in the Tsushima Basin; however, the relative percentage of ~40% from the close-in fallout was unchanged during this period. A likely mechanism for the increasing Pu inventory would be the continuous inflow of the Tsushima Current from the western North Pacific, and the removal of Pu from surface waters by scavenging onto the settling particles, followed by regeneration of Pu from the settling particles during the downward transport. Copyright © 2010 Elsevier B.V. All rights reserved.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.dtic.mil/docs/citations/ADA253101','DTIC-ST'); return false;" href="http://www.dtic.mil/docs/citations/ADA253101"><span>The Fairness Debate in U.S.-Japan Economic Relations</span></a></p> <p><a target="_blank" href="http://www.dtic.mil/">DTIC Science & Technology</a></p> <p></p> <p>1991-01-01</p> <p>United States. 1. Benjamin. Roger W. II. Kokusai Daigaku (<span class="hlt">Yamato</span>-machi. Niigata-ken. Japan). Nichi-Bei Kankei Kenkyfijo. HF1456.5.J3F34 1991 337.73052...reflect the opinions or policies of the sponsors of RAND research. Published 1991 by RAND 1700 Main Street, P.O. Box 2138, Santa Monica, CA 90407-2138 R...Negotiations (1989), Prestowitz (1988), Bergsten and Cline (1985), Cohen (1990), Komiya (1988), and Shinohara ( 1991 ). 8There is a potential</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.dtic.mil/docs/citations/ADA525925','DTIC-ST'); return false;" href="http://www.dtic.mil/docs/citations/ADA525925"><span>Measurement of Contractile Stress Generated by Cultured Rat Muscle on Silicon Cantilevers for Toxin Detection and Muscle Performance Enhancement</span></a></p> <p><a target="_blank" href="http://www.dtic.mil/">DTIC Science & Technology</a></p> <p></p> <p>2010-06-01</p> <p>scientific community and society in general. By creating lab -on- chip systems that allow high-throughput, real-time experimentation, research costs would...developments of bio-molecular motors as on- chip devices using single molecule techniques. Lab on a Chip 7: 1633–1643. 10. Tanaka Y, Sato K, Shimizu T, <span class="hlt">Yamato</span> M...Okano T, et al. (2007) A micro- spherical heart pump powered by cultured cardiomyocytes. Lab on a Chip 7: 207–212. 11. Boillee S, Vande Velde C</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/20050182075','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/20050182075"><span>Petrography of Lunar Meteorite MET 01210, A New Basaltic Regolith Breccia</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Zeigler, R. A.; Korotev, R. L.; Jolliff, B. L.; Haskin, L. A.</p> <p>2005-01-01</p> <p>Lunar meteorite MET 01210 (hereafter referred to as MET) is a 22.8 g breccia collected during the 2001 field season in the Meteorite Hills, Antarctica. Although initially classified as an anorthositic breccia, MET is a regolith breccia composed predominantly of very-low-Ti (VLT) basaltic material. Four other brecciated lunar meteorites (NWA 773, QUE 94281, EET 87/96, <span class="hlt">Yamato</span> 79/98) with a significant VLT basaltic component have been identified. We present here the petrography and bulk major element composition of MET and compare it to previously studied basaltic lunar meteorite breccias.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/1992Metic..27..490C','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/1992Metic..27..490C"><span>The meteorite collection sites of Antarctica</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Cassidy, William; Harvey, Ralph; Schutt, John; Delisle, Georg; Yanai, Keizo</p> <p>1992-12-01</p> <p>The characteristics of the six major regions associated with meteorite stranding surfaces in Antarctica are described, which include the MacKay Glacier/David Glacier region (containing Allan Hills); (2) North Victoria Land; (3) the Lewis Cliff area; (4) the Thiel Mountains, Pecora Escarpment, and Patuxent Range; (5) the <span class="hlt">Yamato</span> Mountains meteorite stranding surface; and (6) the Sor Rondane Mountains. Five models for the production of meteorite stranding surfaces are reviewed. These are: (1) simple deflation of the ice sheet, (2) passive receiver of falling meteorites, (3) stagnant ice against an absolute barrier, (4) slow-moving ice impeded by a subice barrier, and (5) ice masses in collision.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/19860019355','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/19860019355"><span>Terrestrial ages of Antarctic meteorites: Implications for concentration mechanisms</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Schultz, L.</p> <p>1986-01-01</p> <p>Antarctic meteorites differ from meteorites fallen in other places in their mean terrestrial ages. Boeckl estimated the terrestrial half-life for the disintegration of stone meteorites by weathering under the climatic conditions of the Western United States to be about 3600 years. Antarctic meteorites, however, have terrestrial ages up to 70000 years, indicating larger weathering half-lives. The terrestrial ages of meteorites are determined by their concentration of cosmic-ray-produced radionuclides with suitable half-lives (C-14, Al-26, and Cl-36). These radionuclides have yielded reliable ages for the Antarctic meteorites. The distribution of terrestrial ages of Allan Hills and <span class="hlt">Yamato</span> meteorites are examined.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2012Icar..221.1183F','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2012Icar..221.1183F"><span>Impact ejection of lunar meteorites and the age of Giordano Bruno</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Fritz, Jörg</p> <p>2012-11-01</p> <p>Based on literature data from lunar meteorites and orbital observations it is argued that the lunar crater Giordano Bruno (22 km ∅) formed more than 1 Ma ago and probably ejected the lunar meteorites <span class="hlt">Yamato</span> 82192/82193/86032 at 8.5 ± 1.5 Ma ago from the Th-poor highlands of the Moon. The efficiency and time scale to deliver 3He-rich lunar material into Earth’s sediments is discussed to assess the temporal relationship between the Giordano Bruno cratering event and a 1 Ma enduring 3He-spike which is observed in 8.2 Ma old sediments on Earth.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://pubs.usgs.gov/of/1983/0172/report.pdf','USGSPUBS'); return false;" href="https://pubs.usgs.gov/of/1983/0172/report.pdf"><span>Garnet peridotites from Williams kimberlites, north-central Montana, U.S.A</span></a></p> <p><a target="_blank" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Hearn, B.C.; McGee, E.S.</p> <p>1983-01-01</p> <p>Two Williams kimberlites, 250x350m and 37x390m, in the eastern part of a swarm of 30 middle Eocene alnoitic diatremes in north-central Montana, USA, contain xenoliths of garnet-bearing <span class="hlt">lherzolites</span>, harzburgites and dunites, in addition to spinel peridotites and upper and lower crustal amphibolites and granulites. Colluvial purple, red, and pink garnets are dominantly Mg- and Cr-rich, indicating their derivation From peridotites or megacrysts, and have CaO and Cr2O3 contents that fall in the <span class="hlt">lherzolite</span> trend. Temperatures were calculated by the Lindsley-Dixon 20 kb method for <span class="hlt">lherzolites</span> and by the O'Neill-Wood method for harzburgites and dunites, and pressures were calculated by the MacGregor method, or were assumed to be 50 kb for dunites. Most peridotites equilibrated at 1220-1350?C and 50-60 kb, well above a 44mW/m2 shield geotherm and on or at higher P than the graphite-diamond boundary. Four <span class="hlt">lherzolites</span> are low T-P (830-990?C, 23-42 kb) and are close to the shield geotherm. All four low T-P <span class="hlt">lherzolites</span> have coarse textures whereas the high T-P cluster has both coarse and porphyroclastic textures, indicating a range of conditions of deformation and recrystallization in a restricted high T-P range. The tiny size (0.01-0.2 mm) of granulated and euhedral olivines in several xenoliths shows that deformation was occurring just prior to incorporation in kimberlite and that ascent was rapid enough (40-70 km/hr) to retard Further coarsening of fine-grained olivine. For other high T-P peridotites, cessation of deformation and beginning of recrystallization before or during inclusion in kimberlite is suggested by larger (up to 3mm) euhedral olivines in a matrix of fine granulated olivine or by optical continuity of large and nearby small olivines. Two low T-P <span class="hlt">lherzolites</span> contain distinctive, phlogopite-rimmed, 5-8mm clots of moderate-Cr garnet + Cr-spinel + Cr-diopside + enstatite that are inferred to have formed by reaction of an initial high-Cr garnet brought into the</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016E%26PSL.438...57X','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016E%26PSL.438...57X"><span>Southward trench migration at ∼130-120 Ma caused accretion of the Neo-Tethyan forearc lithosphere in Tibetan ophiolites</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Xiong, Qing; Griffin, William L.; Zheng, Jian-Ping; O'Reilly, Suzanne Y.; Pearson, Norman J.; Xu, Bo; Belousova, Elena A.</p> <p>2016-03-01</p> <p>The preservation of ultrahigh-pressure and super-reduced phases (diamond, moissanite, etc.) in the harzburgites and chromitites of the Yarlung Zangbo ophiolites (South Tibet, China) has major implications for mantle recycling and lithosphere evolution in the tectonic system related to the closing of the Neo-Tethyan Ocean. However, important aspects of the genesis of these enigmatic ophiolites and the related geodynamic evolution are still unclear. In the Zedang ophiolite of the eastern Yarlung Zangbo Suture, detailed mineral chemical data reveal that the harzburgite domain in the east [spinel Cr# (mole Cr3+/(Cr3+ + Al3+) = 0.62-0.33] is more depleted than the <span class="hlt">lherzolite</span> domain in the west (spinel Cr# = 0.30-0.17) and shows much lower equilibration temperatures (by ∼250-150 °C) than the <span class="hlt">lherzolites</span>. Clinopyroxene trace-element compositions indicate that the harzburgites underwent pervasive metasomatism after melt extraction, while the <span class="hlt">lherzolites</span> did not. New zircon U-Pb ages show that the harzburgites were intruded by dolerite dykes with chilled margins at ∼130-128 Ma, consistent with the widespread mafic magmatism at ∼130-120 Ma in the Yarlung Zangbo ophiolites. Nd-Hf isotopic data indicate that the Zedang <span class="hlt">lherzolites</span> subcreted the pre-emplaced harzburgites concurrently with the intrusion of the dolerite dykes into the harzburgites, and that the <span class="hlt">lherzolites</span> and dolerites both were derived from upwelling asthenosphere with minor slab input. Available zircon geochronology and Hf-isotope data show that juvenile magmatism in the adjacent Gangdese Arc was almost completely interrupted from ∼130-120 Ma. We suggest that the extension of the overlying harzburgitic lithosphere, subcretion of <span class="hlt">lherzolites</span>, intrusion of mafic dykes, and the waning of Gangdese-Arc magmatism all reflect a southward trench migration in the Neo-Tethyan subduction system from the Gangdese Arc to the oceanic forearc lithosphere. This magmatic relocation and tectonic linkage are inferred to</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2008AGUFM.V43F2200H','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2008AGUFM.V43F2200H"><span>Mantle Xenoliths from the Calatrava Volcanic Province, Spain - Evidence for Carbonatite- Silicate Interaction in the Upper Mantle.</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Humphreys, E. R.; Bailey, K.; Hawkesworth, C. J.; Wall, F.</p> <p>2008-12-01</p> <p>Mantle xenoliths entrained in pyroclastic tuffs from the Calatrava Volcanic Province (CVP), Spain represent a snapshot of the lithospheric mantle from the last 10 Ma. They display significant heterogeneity in modal mineralogy and mineral chemistry. The presence of carbonate as inclusions in mantle minerals and the chemical composition of the clinopyroxenes suggest interaction of the lithospheric mantle with a compositionally different melt or fluid phase. Our study details the chemical complexity of xenoliths from this province, and seeks to distinguish the effects of partial melting and carbonatite-mantle interaction. The CVP is an alkaline volcanic province (8 to 1.6 Ma) located in a failed rift in central Spain. Volcanoes are dominantly maars or cinder cones, some of which are associated with minor lava extrusions. Carbonate forms a major component in many pyroclastic deposits (Bailey et al., 2005) and xenolithic material is prolific in most pyroclastic tuff rings. Mantle xenoliths are abundant and they show an affinity to pyroclastic tuffs including a melilitite or leucitite silicate component. Nodules encompassing <span class="hlt">lherzolite</span>, wehrlite, harzburgite, pyroxenites and a range of composite lithologies have been studied from three localities. The dominant nodule composition from the CVP is spinel <span class="hlt">lherzolite</span>, but wehrlite is also common. Mg numbers of olivines from <span class="hlt">lherzolites</span> and wehrlites show a strong bimodality with wehrlitic olivines being enriched in iron Fo(84.7-85.5) whereas <span class="hlt">lherzolites</span> show mantle values of Fo(89.6-90.6). The analysed wehrlites contain phlogopite in major quantities; a rare mineral component for Cenozoic European mantle xenoliths. Texturally, wehrlites differ from <span class="hlt">lherzolites</span> primarily as a result of reaction textures and disequilibrium features. Spongy clinopyroxene reaction halos are commonly associated with interstitial melt and spinels also show reaction textures with granular boundaries, enriched in chromium and iron. <span class="hlt">Lherzolites</span></p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2009Litho.108...37B','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2009Litho.108...37B"><span>Mantle peridotites from the Dinaridic ophiolite belt and the Vardar zone western belt, central Balkan: A petrological comparison</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Bazylev, B. A.; Popević, A.; Karamata, S.; Kononkova, N. N.; Simakin, S. G.; Olujić, J.; Vujnović, L.; Memović, E.</p> <p>2009-03-01</p> <p>The nearly parallel Dinaridic ophiolite belt and the Vardar zone western belt are assumed to be the remnants of two distinct oceanic basins, constituting different parts of the Tethys Ocean that separated the Gondwana and Eurasia continents during Mesozoic time. These belts comprise numerous large peridotite massifs and small bodies whose petrology was poorly known. This paper presents a large set of internally consistent analytical data for peridotites, including primary mineralogy, major-element chemistry and clinopyroxene geochemistry for massifs of both the ophiolitic belts. We propose, discuss and apply a set of mineralogical, geochemical and petrologic criteria that allow a recognition of the probable geodynamic setting of formation of the ultramafic massifs. Ultramafic massifs of the Vardar zone western belt gradually change in composition northwards from depleted spinel <span class="hlt">lherzolites</span> (Banjska massif) to depleted harzburgites (Maljen massif); these bodies originated in the same geodynamic setting, probably a back-arc spreading center. By contrast, the Dinaridic belt ultramafic massifs include several different types that formed in different geodynamic environments. Orogenic <span class="hlt">lherzolites</span>, interpreted as subcontinental peridotites (Kozara, Čavka, Borja, Sjenički Ozren and Bistrica massifs) are dominated by fertile spinel and plagioclase <span class="hlt">lherzolites</span> with subordinate amounts of depleted spinel <span class="hlt">lherzolite</span>, spinel harzburgite, rare dunite and very rare vein garnet clinopyroxenite. The inferred subcontinental peridotites of these massifs are not co-magmatic with neighboring basalts and cannot be considered as members of a single ophiolitic assemblage. Massifs of two other types are less common in the Dinaridic ophiolite belt. These are composed of spinel <span class="hlt">lherzolite</span>-harzburgite (Zlatibor and possibly Bosanski Ozren massifs) and depleted harzburgite (Tuzinje and Brezovica massifs); both probably originated in a suprasubduction environment. The available data suggest</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2013GeCoA.115..241X','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2013GeCoA.115..241X"><span>Large magnesium isotope fractionation in peridotite xenoliths from eastern North China craton: Product of melt-rock interaction</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Xiao, Yan; Teng, Fang-Zhen; Zhang, Hong-Fu; Yang, Wei</p> <p>2013-08-01</p> <p>To investigate the effects of melt-rock interaction on Mg isotope fractionation and mantle Mg isotopic heterogeneity, we report high-precision Mg isotopic data of olivine (Ol), orthopyroxene (Opx), clinopyroxene (Cpx) and spinel (Spl) for 25 peridotite xenoliths from the eastern North China craton. These xenoliths range from <span class="hlt">lherzolites</span>, Cpx-rich <span class="hlt">lherzolites</span> to wehrlites, and are variably metasomatised. The <span class="hlt">lherzolites</span> have Ol with Fo contents from 89 to 90 and have a homogeneous Mg isotopic composition (δ26Mg = -0.26 to -0.20), similar to the typical mantle value. By contrast, Cpx-rich <span class="hlt">lherzolites</span> and wehrlites have lower Ol with Fo contents (78-88) and exhibit larger Mg isotopic variations, with δ26Mg ranging from -0.39 to +0.09. The δ26Mg values of minerals in these xenoliths are also variable and range from -0.45 to -0.03 in Ol, from -0.26 to -0.01 in Opx, from -0.34 to +0.22 in Cpx and from -0.16 to +0.25 in Spl. Inter-mineral fractionations between coexisting pyroxene and Ol in <span class="hlt">lherzolites</span> and most isotopically light wehrlites (Δ26MgOpx-Ol = -0.04 to +0.09‰; Δ26MgCpx-Ol = + 0.02 to +0.25‰) vary as a function of temperature and are consistent with equilibrium inter-mineral isotope fractionations. By contrast, large disequilibrium Mg isotope fractionation occurs between coexisting pyroxene and Ol in the majority of Cpx-rich <span class="hlt">lherzolites</span> (Δ26MgOpx-Ol = +0.16 to +0.32‰; Δ26MgCpx-Ol = +0.04 to +0.34‰). Both types of isotope fractionations also occur between Spl and Ol, with Spl being consistently heavier than Ol (Δ26MgSpl-Ol = +0.15 to +0.55‰). Overall, the isotopically equilibrated but light wehrlites may result from mantle metasomatism by isotopically light melt, whereas large disequilibrium isotope fractionations in Cpx-rich peridotites likely reflect kinetic isotope fractionation during melt-peridotite interaction. Both processes result in the heterogeneous Mg isotopic composition of the lithospheric mantle beneath the eastern North China</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2013EGUGA..15..371K','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2013EGUGA..15..371K"><span>Nature and Evolution of the lithospheric mantle beneath the Hoggar swell (Algeria): a record from mantle xenoliths.</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Kourim, Fatna; Bodinier, Jean-Louis; Alard, Olivier; Bendaoud, Abderrahmane; Vauchez, Alain; Dautria, Jean-Marie</p> <p>2013-04-01</p> <p>The mantle xenoliths sampled by the Quaternary alkaline volcanics from the Tahalgha district (Central Hoggar) represent the subcontinental lithospheric mantle beneath the boundary between two major structural domains of the Tuareg Shield: the "Polycyclic Central Hoggar" to the East and the "Western Hoggar", or "Pharusian Belt", to the West. Samples were collected from volcanic centres located on both sides of the 4°10, a major lithospheric shear zone separating these two domains. Although showing substantial variations in their deformation microstructures, equilibrium temperatures, and modal and chemical compositions, the studied samples do not display systematic variations of these features across the 4°10. The observed variations rather record small-scale heterogeneities distributed throughout the whole studied area and mostly related to the asthenosphere-lithosphere interaction events associated with the evolution of the Hoggar swell, in the Cenozoic. These features include partial annealing of pre-existing deformation microstructures, post-deformation metasomatic reactions, and trace-element enrichment, coupled with heating from 750-900°C (low-temperature <span class="hlt">lherzolites</span>) to 900-1150°C (intermediate-T <span class="hlt">lherzolites</span> and high-T harzburgites and wehrlites). Trace element modelling confirms that the whole range of REE fractionation observed in the Tahalgha xenoliths may be accounted for by reactive porous flow involving a single stage of basaltic melt infiltration into a LREE-depleted protolith. The striking correlations between equilibrium temperatures and trace-element enrichments favor a scenario whereby the high-temperature peridotites record advective heat transport along melt conduits while the intermediate- and low-temperature <span class="hlt">lherzolites</span> would represent more conductive heating of the host Mechanical Boundary Layer. This indicates that the lithosphere did not reach thermal equilibrium, suggesting that the inferred heating event was transient and rapidly erased</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/16710568','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/16710568"><span>Garnets from the Camafuca-Camazambo kimberlite (Angola).</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Correia, Eugénio A; Laiginhas, Fernando A T P</p> <p>2006-06-01</p> <p>This work presents a geochemical study of a set of garnets, selected by their colors, from the Camafuca-Camazambo kimberlite, located on northeast Angola. Mantle-derived garnets were classified according to the scheme proposed by Grütter et al. (2004) and belong to the G1, G4, G9 and G10 groups. Both sub-calcic (G10) and Ca-saturated (G9) garnets, typical, respectively, of harzburgites and <span class="hlt">lherzolites</span>, were identified. The solubility limit of knorringite molecule in G10D garnets suggests they have crystallized at a minimum pressure of about 40 to 45 kbar (4-4.5 GPa). The occurrence of diamond stability field garnets (G10D) is a clear indicator of the potential of this kimberlite for diamond. The chemistry of the garnets suggests that the source for the kimberlite was a <span class="hlt">lherzolite</span> that has suffered a partial melting that formed basaltic magma, leaving a harzburgite as a residue.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2013EGUGA..15.5541B','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2013EGUGA..15.5541B"><span>A Dynamic study of Mantle processes applying In-situ Methods to Compound Xenoliths: implications for small to intermediate scale heterogeneity</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Baziotis, Ioannis; Asimow, Paul; Koroneos, Antonios; Ntaflos, Theodoros; Poli, Giampero</p> <p>2013-04-01</p> <p>The mantle is the major geochemical reservoir of most rock-forming elements in the Earth. Convection and plate-tectonic driven processes act to generate local and regional heterogeneity within the mantle, which in turn through thermal and chemical interactions modulates ongoing geophysical processes; this feedback shapes the dynamics of the deep interior. Consequently, these processes contribute to the evolution of the earth throughout its geological history. Up to now, the heterogeneity of the mantle has been extensively studied in terms of conventional methods using basalt chemistry, bulk rock and mineral major and trace element analysis of isolated xenolith specimens of varying lithology, and massif exposures. The milestone of the present study, part of an ongoing research project, is the application of in-situ analytical methods such as microprobe, LA-ICP-MS and high resolution SEM in order to provide high quality major and trace element analyses as well as elemental distribution of the coexisting phases in the preserved intra-mantle lithologies, Particularly, in the context of the current study we used selected compound xenoliths from San Carlos (Arizona, USA), Kilbourne Hole (New Mexico, USA), Cima Dome and Dish Hill suites (California, USA), San Quintin (Baja California, Mexico) and Chino Valley (Arizona, USA), from the Howard Wilshire collection archived at the Smithsonian Institution. The selection of these compound xenoliths was based upon freshness and integrity of specimens, maximum distance on both sides of lithologic contacts, and rock types thought most likely to represent subsolidus juxtaposition of different lithologies that later partially melted in contact. The San Carlos samples comprise composite xenoliths with websterite, <span class="hlt">lherzolite</span> and clinopyroxenite layers or clinopyroxenite veins surrounded by <span class="hlt">lherzolite</span> or orthopyroxenite-rich rims. The Kilbourne Hole suite comprises spinel-(olivine) clinopyroxenite and orthopyroxenite dikes cutting</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2013AGUFM.V33A2724S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2013AGUFM.V33A2724S"><span>Water contents of the mantle beneath the Rio Grande Rift: FTIR analysis of Kilbourne Hole peridotite xenoliths</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Schaffer, L. A.; Peslier, A. H.; Brandon, A. D.</p> <p>2013-12-01</p> <p>Although nominally anhydrous mantle minerals contain only trace amounts of water, they are the main reservoir of water in the mantle. Added up at the scale of the Earth's mantle, these trace amounts of water represent oceans worth in mass [1,2]. Mantle xenoliths from Kilbourne Hole in southern New Mexico are ideal to study mantle water distribution in a rift tectonic setting as they come from a recently-erupted maar in the middle of the Rio Grande Rift. Eleven <span class="hlt">lherzolites</span>, one harzburgite, and one dunite are being analyzed for water contents by FTIR. The xenoliths will also be analyzed for major and trace element composition, Fe3+/ΣFe ratios, and characterized petrologically. Olivines exhibit variable water contents with less water at the rims compared to the cores. This is probably due to H loss during decompression and xenolith transport by the host magma. Mantle watercontents appear to have been primarily preserved in the core of the olivines, based on diffusion modeling of the typically plateau-shaped water content profiles across these grains.Water concentrations are in equilibrium between clino- and orthopyroxene, but olivine concentrations are typically not in equilibrium with those of either pyroxene. <span class="hlt">Lherzolites</span> analyzed so far have water contents of 2-12 ppm H2O in olivines, 125-165 ppm H2O in orthopyroxenes, and 328-447 ppm H2O in clinopyroxenes. These water contents are similar to, but with a narrower range, than those for the respective minerals in other continental peridotite xenoliths [3]. The <span class="hlt">lherzolites</span> have bulk-rock (BR) Al2O3 contents that range between 3.17 and 3.78 wt.%, indicating similar degrees of partial melting, which could explain the narrow range of their pyroxene water contents. Primitive mantle normalized rare earth element (REE) profiles of the bulk <span class="hlt">lherzolites</span> vary from light REE depleted to flat, with no significant differences between, nor relation to, their mineral water contents. Consequently, the metasomatic agents that</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/18487189','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/18487189"><span>Metasomatized lithosphere and the origin of alkaline lavas.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Pilet, Sébastien; Baker, Michael B; Stolper, Edward M</p> <p>2008-05-16</p> <p>Recycled oceanic crust, with or without sediment, is often invoked as a source component of continental and oceanic alkaline magmas to account for their trace-element and isotopic characteristics. Alternatively, these features have been attributed to sources containing veined, metasomatized lithosphere. In melting experiments on natural amphibole-rich veins at 1.5 gigapascals, we found that partial melts of metasomatic veins can reproduce key major- and trace-element features of oceanic and continental alkaline magmas. Moreover, experiments with hornblendite plus <span class="hlt">lherzolite</span> showed that reaction of melts of amphibole-rich veins with surrounding <span class="hlt">lherzolite</span> can explain observed compositional trends from nephelinites to alkali olivine basalts. We conclude that melting of metasomatized lithosphere is a viable alternative to models of alkaline basalt formation by melting of recycled oceanic crust with or without sediment.</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_19");'>19</a></li> <li><a href="#" onclick='return showDiv("page_20");'>20</a></li> <li class="active"><span>21</span></li> <li><a href="#" onclick='return showDiv("page_22");'>22</a></li> <li><a href="#" onclick='return showDiv("page_23");'>23</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_21 --> <div id="page_22" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_20");'>20</a></li> <li><a href="#" onclick='return showDiv("page_21");'>21</a></li> <li class="active"><span>22</span></li> <li><a href="#" onclick='return showDiv("page_23");'>23</a></li> <li><a href="#" onclick='return showDiv("page_24");'>24</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="421"> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2010EGUGA..12.2853S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2010EGUGA..12.2853S"><span>Garnet peridotites and chlorite harzburgites from Cima di Gagnone (Central Alps, Switzerland). Examples of subduction-zone serpentinite dehydration</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Scambelluri, Marco; Rampone, Elisabetta; Pettke, Thomas; Reusser, Eric</p> <p>2010-05-01</p> <p>Dehydration of oceanic serpentinites is rarely documented in nature because few rocks are exhumed from beyond the antigorite breakdown. Chlorite (chl) harzburgites from Almirez (Betic Cordillera, Spain) presently are the only known case (1-3). The garnet (grt) <span class="hlt">lherzolites</span> from Cima di Gagnone have long been long considered to be serpentinized oceanic mantle subducted to 2.5 GPa and 800°C (4). Hence, they are unique in the Alps and relevant. Here we present the trace element survey of Gagnone grt <span class="hlt">lherzolites</span> and associated chl harzburgites to test an origin from serpentinites and to characterize the fluids they released at breakdown of major hydrous phases. The grt peridotites are foliated and contain olivine (ol), ortho- and clinopyroxene (opx, cpx), Ca-amphibole (amph). Poikiloblastic grt overgrows former foliation(s) and is partially equilibrated with the above minerals. Olivine + ilmenite replace former Ti-clinohumite. Grt hosts solid polyphase inclusions deriving from co-genetic fluids: inclusions are both primary and along trails which never cut the grain boundaries. Chl harzburgites are texturally similar to the Betic ones (1) and can display foliated and massive textures. Massive rocks have randomly oriented ol and opx, minor chl, Ti-clinohumite and locally carbonate. Foliated harzburgites have dominant ol; opx and chl parallel the foliation and display equilibrium textures. Ol and opx of chl harzburgites also contain solid polyphase inclusions (from coexisting fluid) very similar to those of the Betic harzburgites (2). Chl harzburgites may also derive from retrogressed grt peridotites; in this case post-kinematic chl overgrows grt. In the field, chl harzburgites are associated with eclogites and HP metarodingites, which form stretched dikes of previous MORB materials discirdant to compositonal layering in peridotites. This indicates a common eclogite-facies equilibration of mafic and ultramafic material, most likely of former oceanic origin. Cpx from grt</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/17831161','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/17831161"><span>Diamonds in an upper mantle peridotite nodule from kimberlite in southern wyoming.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>McCallum, M E; Eggler, D H</p> <p>1976-04-16</p> <p>Diamonds in a serpentinized garnet peridotite nodule from a diatreme in southern Wyoming are the first known occurrence in an upper mantle peridotite xenolith from a kimberlite intrusion in North America as well as the second authenticated occurrence of diamonds from kimberlite pipes in North America. The nodule is believed to have come from a section of depleted (partially melted) <span class="hlt">lherzolite</span> at a depth of 130 to 180 kilometers.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.dtic.mil/docs/citations/ADA211806','DTIC-ST'); return false;" href="http://www.dtic.mil/docs/citations/ADA211806"><span>Investigations of Eurasian Seismic Sources and Upper Mantle Structure</span></a></p> <p><a target="_blank" href="http://www.dtic.mil/">DTIC Science & Technology</a></p> <p></p> <p>1989-05-25</p> <p>occurring as the odd xenolith in kimberlites and other igneous intrusions, or exposed in mountain peridotites and ophiolite sequences-and carry with them...are observed frequently in kimberlites , so it seems safe to assume that the proposed reaction occurs in the Earth’s uppermost mantle. Recent...velocities of garnet <span class="hlt">lherzolites</span> and their geophysical importance, in The Mantle Sample: Inclusions in Kimberlites and Other Volcanics, edited by .. R. Boyd</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/10102809','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/10102809"><span>Clinoenstatite in alpe arami peridotite: additional evidence of very high pressure</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Bozhilov; Green; Dobrzhinetskaya</p> <p>1999-04-02</p> <p>Observations by transmission electron microscopy show that lamellae of clinoenstatite are present in diopside grains of the Alpe Arami garnet <span class="hlt">lherzolite</span> of the Swiss Alps. The simplest interpretation of the orientation, crystallography, and microstructures of the lamellae and the phase relationships in this system is that the lamellae originally exsolved as the high-pressure C-centered form of clinoenstatite. These results imply that the rocks were exhumed from a minimum depth of 250 kilometers before or during continental collision.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017JAfES.127..235C','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017JAfES.127..235C"><span>Petrological characteristics of mantle xenoliths from the Azrou-Timahdite quaternary basalts, middle atlas, Morocco: A mineral chemistry perspective</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Chanouan, Lhoussaine; Ikenne, Moha; Gahlan, Hisham A.; Arai, Shoji; Youbi, Nasrrddine</p> <p>2017-03-01</p> <p>Quaternary alkali basalts of the Azrou-Timahdite area contain a wide variety of ultramafic mantle xenoliths (e.g. <span class="hlt">lherzolites</span>, wehrlites, pyroxenites and amphibolites). A comprehensive mineral chemistry studies using electron probe micro-analysis (EPMA) and laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS) allows us to propose a petrogenetic history of these ultramafic rocks. The studied mantle xenoliths contain spinel, which attests for their derivation from depths from 30 to 70 km, i.e. the intermediate zone of continental lithospheric upper mantle. The olivine forsterite (Fo) content is higher in <span class="hlt">lherzolites</span> than in wehrlite, Fo88-91 and Fo80-83, respectively. The orthopyroxene is enstatite with relatively high Mg number (Mg#) (0.88-0.91). The clinopyroxene displays Mg# (0.88-0.92) similar to or slightly higher than that of olivine and orthopyroxene, indicating equilibrium between these phases. Progressive depletion of this ratio in <span class="hlt">lherzolite</span> clinopyroxene suggests the generation of peridotitic rocks through a series of partial melting processes at different degrees. LREE enrichment in clinopyroxene combined with decoupling of Ti and Na (Fusible major elements) indicates mantle metasomatic processes, which possibly resulted in recrystallization of clinopyroxene. The wehrlitic lithologies are possibly the end product of the metasomatism. The LaN/YbN and Ti/Eu ratios of spine-bearing <span class="hlt">lherzolites</span> and non-spongy clinopyroxenes combined with the low Ti contents and the Zr and Nb negative anomalies argue for an alkali-silicate metasomatism. Given the above scenario, we conclude that the mineralogical variations in the upper mantle beneath this part of the Middle Atlas Mountains can be attributed to a combination of mantle processes including partial melting that occurs in response of a mantle upwelling, and an alkali-silicate metasomatism.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2010Litho.115..223U','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2010Litho.115..223U"><span>Multiple melting stages and refertilization as indicators for ridge to subduction formation: The New Caledonia ophiolite</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Ulrich, Marc; Picard, Christian; Guillot, Stéphane; Chauvel, Catherine; Cluzel, Dominique; Meffre, Sébastien</p> <p>2010-03-01</p> <p>The origin of the New Caledonia ophiolite (South West Pacific), one of the largest in the world, is controversial. This nappe of ultramafic rocks (300 km long, 50 km wide and 2 km thick) is thrust upon a smaller nappe (Poya terrane) composed of basalts from mid-ocean ridges (MORB), back arc basins (BABB) and ocean islands (OIB). This nappe was tectonically accreted from the subducting plate prior and during the obduction of the ultramafic nappe. The bulk of the ophiolite is composed of highly depleted harzburgites (± dunites) with characteristic U-shaped bulk-rock rare-earth element (REE) patterns that are attributed to their formation in a forearc environment. In contrast, the origin of spoon-shaped REE patterns of <span class="hlt">lherzolites</span> in the northernmost klippes was unclear. Our new major element and REE data on whole rocks, spinel and clinopyroxene establish the abyssal affinity of these <span class="hlt">lherzolites</span>. Significant LREE enrichment in the <span class="hlt">lherzolites</span> is best explained by partial melting in a spreading ridge, followed by near in-situ refertilization from deeper mantle melts. Using equilibrium melting equations, we show that melts extracted from these <span class="hlt">lherzolites</span> are compositionally similar to the MORB of the Poya terrane. This is used to infer that the ultramafic nappe and the mafic Poya terrane represent oceanic lithosphere of a single marginal basin that formed during the late Cretaceous. In contrast, our spinel data highlights the strong forearc affinities of the most depleted harzburgites whose compositions are best modeled by hydrous melting of a source that had previously experienced depletion in a spreading ridge. The New Caledonian boninites probably formed during this second stage of partial melting. The two melting events in the New Caledonia ophiolite record the rapid transition from oceanic accretion to convergence in the South Loyalty Basin during the Late Paleocene, with initiation of a new subduction zone at or near the ridge axis.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=19800039413&hterms=Igneous+petrology&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D10%26Ntt%3DIgneous%2Bpetrology','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=19800039413&hterms=Igneous+petrology&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D10%26Ntt%3DIgneous%2Bpetrology"><span>A summary of the petrology and geochemistry of pristine highlands rocks</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Norman, M. D.; Ryder, G.</p> <p>1979-01-01</p> <p>The petrology and geochemistry of pristine lunar highlands rock samples consisting of ferroan anorthosites, norites, troctolites, spinel troctolites/dunite/<span class="hlt">lherzolite</span>, and KREEP, are described. In addition, petrographic and chemical evidence is presented which shows that low-siderophile rocks are the result of endogenous igneous activity and not impact melt differentiation. For example, these rocks contain Fe-metal as a late-crystallizing phase, and have W/La ratios higher than polymict breccias.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/1997CRASE.325..671V','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/1997CRASE.325..671V"><span>Le volcanisme fissural néoprotérozoïque des séries du Dja inférieur, de Yokadouma (Cameroun) et de Nola (RCA) — Signification géotectonique</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Vicat, Jean-Paul; Pouclet, André; Nkoumbou, Charles; Mouangué, Aubin Semé</p> <p>1997-11-01</p> <p>The basic intrusions in the lower Dja, Yokadouma and Nola Neoproterozoic Séries, around 1 Ga, display a continental tholeiitic composition. The magmas are generated from a spinel <span class="hlt">lherzolite</span> source sharing lithospheric and asthenospheric components, suggesting a lithospheric thinning. This magmatism has to be related to an extensional phase which favored the pre-Pan-African trough formation in the northern part of the Congo Craton.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016Litho.252....1M','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016Litho.252....1M"><span>Geochemical record of subduction initiation in the sub-arc mantle: Insights from the Loma Caribe peridotite (Dominican Republic)</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Marchesi, Claudio; Garrido, Carlos J.; Proenza, Joaquín A.; Hidas, Károly; Varas-Reus, María Isabel; Butjosa, Lidia; Lewis, John F.</p> <p>2016-05-01</p> <p>The Loma Caribe peridotite body is mainly composed of serpentinized spinel harzburgites and <span class="hlt">lherzolites</span> and minor orthopyroxene-bearing dunites and dunites. Modal proportions, mineral and whole-rock major and trace element compositions generally coincide with those of abyssal mantle rocks from mid-ocean ridges for the <span class="hlt">lherzolites</span>, and refractory supra-subduction peridotites for the harzburgites and dunites. The clinopyroxene-bearing harzburgites have intermediate compositions that overlap with those of residual mantle from both these settings. Major elements in the peridotites were mostly undisturbed by serpentinization and/or seafloor weathering whereas light rare earth elements (LREE) and large ion lithophile elements (LILE) were enriched by syn- and/or post-melting interaction with fluids/melts. Major element variations indicate that protoliths of the Loma Caribe peridotites mostly melted at 1-2 GPa and 1250 °C-1500 °C, as normal mid-ocean ridge and supra-subduction zone mantle. The MREE/HREE fractionations in both whole rocks and clinopyroxene can be explained by initial low (5%-6%) fractional melting of a garnet <span class="hlt">lherzolite</span> source followed by variable (5%-20%) melting in the spinel stability field. The <span class="hlt">lherzolites</span> and clinopyroxene-bearing harzburgites are residues of increasing melting triggered by increasing addition of slab fluids to a spinel peridotite source, while melting of the harzburgite protoliths was likely the result of focused flux of slab hydrous melts. The dunites and orthopyroxene-bearing dunites are products of pyroxene dissolution in residual peridotites caused by reaction with two different subduction-related melts, probably the parental magmas of Early Cretaceous low-Ti island arc tholeiites (IAT) and boninites from Central Hispaniola, respectively. We conclude that the geochemical heterogeneity of the Loma Caribe peridotites records shifting conditions of melting during the development of subduction beneath the incipient Greater Antilles</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2012CoMP..164..441T','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2012CoMP..164..441T"><span>Carbonate-rich melt infiltration in peridotite xenoliths from the Eurasian-North American modern plate boundary (Chersky Range, Yakutia)</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Tschegg, Cornelius; Ntaflos, Theodoros; Akinin, Vyacheslav V.; Hauzenberger, Christoph</p> <p>2012-09-01</p> <p>A suite of mainly spinel peridotite and subordinate pyroxenite xenoliths and megacrysts were studied in detail, enabling us to characterize upper mantle conditions and processes beneath the modern North American-Eurasian continental plate boundary. The samples were collected from 37-Ma-old basanites cropping out in the Main Collision Belt of the Chersky Range, Yakutia Republic (Russian Far East). The spinel <span class="hlt">lherzolites</span> reflect a mantle sequence, equilibrated at temperatures of 890-1,025 °C at pressures of 1.1-2 GPa, with melt extraction estimated to be around 2-6 %. The spinel harzburgites are characterized by lower P-T equilibration conditions and estimated melt extraction up to 12 %. Minor cryptic metasomatic processes are recorded in the clinopyroxene trace elements, revealing that percolating hydrous fluid-rich melts and basaltic melts affected the peridotites. One of the <span class="hlt">lherzolites</span> preserves a unique melt droplet with primary dolomite in perfect phase contact with Na-rich aluminosilicate glass and sodalite. On the basis of the well-constrained P-T frame of the xenolith suite, as well as the rigorously documented melt extraction and metasomatic history of this upper mantle section, we discuss how a carbonated silicate melt infiltrated the <span class="hlt">lherzolite</span> at depth and differentiated into an immiscible carbonate and silicate liquid shortly before the xenolith was transported to the surface by the host basalt. Decreasing temperatures triggered crystallization of primary dolomite from the carbonate melt fraction and sodalite as well as quenched glass from the Na-rich aluminosilicate melt fraction. Rapid entrainment and transport to the Earth's surface prevented decarbonatization processes as well as reaction phenomena with the host <span class="hlt">lherzolite</span>, preserving this exceptional snapshot of upper mantle carbonatization and liquid immiscibility.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016EGUGA..1811144M','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016EGUGA..1811144M"><span>Geochemical record of subduction initiation in the sub-arc mantle: insights from Loma Caribe peridotite (Dominican Republic)</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Marchesi, Claudio; Garrido, Carlos J.; Proenza, Joaquín A.; Hidas, Károly; Varas-Reus, María Isabel; Butjosa, Lidia; Lewis, John F.</p> <p>2016-04-01</p> <p>The Loma Caribe peridotite body is mainly composed of serpentinized spinel harzburgite and <span class="hlt">lherzolite</span> and minor (Opx-bearing) dunite. Modal proportions, mineral and whole-rock major and trace element compositions generally coincide with those of abyssal mantle rocks from mid-ocean ridges for <span class="hlt">lherzolite</span> and refractory supra-subduction peridotites for harzburgite and (Opx-) dunite. Cpx-bearing harzburgite has intermediate compositions that overlap those of residual mantle from both these settings. Major elements in peridotite were mostly undisturbed by serpentinization and/or seafloor weathering whereas LREE and LILE were enriched by syn- and/or post-melting interaction with fluids/melts. Major element variations support that protoliths of Loma Caribe peridotite mostly melted at 1-2 GPa and 1300-1500 °C, as normal mid-ocean ridge and supra-subduction zone mantle. MREE/HREE fractionations in whole-rocks and clinopyroxene can be explained by initial low (5-6%) fractional melting of a garnet <span class="hlt">lherzolite</span> source followed by variable (5-20%) melting in the spinel stability field. <span class="hlt">Lherzolite</span> and Cpx-harzburgite are residues of increasing melting triggered by increasing addition of fluids to a spinel peridotite source, while melting of the harzburgite protolith was likely promoted by focused flux of hydrous melts. Dunite and Opx-bearing dunite are products of pyroxene dissolution in residual peridotite caused by reaction with two different subduction-related melts, likely the parental magmas of Early Cretaceous low-Ti IAT and boninite from Central Hispaniola, respectively. We propose that the geochemical heterogeneity of Loma Caribe peridotite records shifting conditions of melting during the development of subduction beneath the incipient Greater Antilles paleo-island arc in the Early Cretaceous. The common presence in the Caribbean realm of oceanic mantle rocks related to subduction indicates that most peri-Caribbean ophiolitic bodies are not fragments of an oceanic</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/20150019464','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/20150019464"><span>Water in the Lithospheric Mantle Beneath a Phanerozoic Continental Belt: FTIR Analyses of Alligator Lake Xenoliths (Yukon, Canada)</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Gelber, McKensie; Peslier, Ann H.; Brandon, Alan D.</p> <p>2015-01-01</p> <p>Water in the mantle influences melting, metasomatism, viscosity and electrical conductivity. The Alligator Lake mantle xenolith suite is one of three bimodal peridotite suites from the northern Canadian Cordillera brought to the surface by alkali basalts, i.e., it consists of chemically distinct <span class="hlt">lherzolites</span> and harzburgites. The <span class="hlt">lherzolites</span> have equilibration temperatures about 50 C lower than the harzburgites and are thought to represent the fertile upper mantle of the region. The harzburgites might have come from slightly deeper in the mantle and/or be the result of a melting event above an asthenospheric upwelling detected as a seismic anomaly at 400-500 km depth. Major and trace element data are best interpreted as the <span class="hlt">lherzolite</span> mantle having simultaneously experienced 20-25% partial melting and a metasomatic event to create the harzburgites. Well-characterized xenoliths are being analyzed for water by FTIR. Harzburgites contain 29-52 ppm H2O in orthopyroxene (opx) and (is) approximately140 ppm H2O in clinopyroxene (cpx). The <span class="hlt">lherzolites</span> have H2O contents of 27-150 ppm in opx and 46-361 ppm in cpx. Despite correlating with enrichments in LREE, the water contents of the harzburgite pyroxenes are low relative to those of typical peridotite xenoliths, suggesting that the metasomatic agents were water-poor, contrarily to what has been suggested before. The water content of cpx is about double that of opx indicating equilibrium. Olivine water contents are low ((is) less than 5 ppm H2O) and out of equilibrium with those of opx and cpx, which may be due to H loss during xenolith ascent. This is consistent with olivines containing more water in their cores than their rims. Olivines exclusively exhibit water bands in the 3400-3000 cm-1 range, which may be indicative of a reduced environment.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/20110007913','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/20110007913"><span>Comparisons of Mineralogy Between Cumulate Eucrites and Lunar Meteorites Possibly from the Farside Anorsothitic Crust</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Takeda, H.; Yamaguchi, A.; Hiroi, T.; Nyquist, L. E.; Shih, C.-Y.; Ohtake, M.; Karouji, Y.; Kobayashi, S.</p> <p>2011-01-01</p> <p>Anorthosites composed of nearly pure anorthite (PAN) at many locations in the farside highlands have been observed by the Kaguya multiband imager and spectral profiler [1]. Mineralogical studies of lunar meteorites of the Dhofar 489 group [2,3] and <span class="hlt">Yamato</span> (Y-) 86032 [4], all possibly from the farside highlands, showed some aspects of the farside crust. Nyquist et al. [5] performed Sm-Nd and Ar-Ar studies of pristine ferroan anorthosites (FANs) of the returned Apollo samples and of Dhofar 908 and 489, and discussed implications for lunar crustal history. Nyquist et al. [6] reported initial results of a combined mineralogical/chronological study of the <span class="hlt">Yamato</span> (Y-) 980318 cumulate eucrite with a conventional Sm-Nd age of 4567 24 Ma and suggested that all eucrites, including cumulate eucrites, crystallized from parental magmas within a short interval following differentiation of their parent body, and most eucrites participated in an event or events in the time interval 4400- 4560 Ma in which many isotopic systems were partially reset. During the foregoing studies, we recognized that variations in mineralogy and chronology of lunar anorthosites are more complex than those of the crustal materials of the HED parent body. In this study, we compared the mineralogies and reflectance spectra of the cumulate eucrites, Y-980433 and 980318, to those of the Dhofar 307 lunar meteorite of the Dhofar 489 group [2]. Here we consider information from these samples to gain a better understanding of the feldspathic farside highlands and the Vesta-like body.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://pubs.er.usgs.gov/publication/70015625','USGSPUBS'); return false;" href="http://pubs.er.usgs.gov/publication/70015625"><span>DUPAL anomaly in the Sea of Japan: Pb, Nd, and Sr isotopic variations at the eastern Eurasian continental margin</span></a></p> <p><a target="_blank" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Tatsumoto, M.; Nakamura, Y.</p> <p>1991-01-01</p> <p>Volcanic rocks from the eastern Eurasian plate margin (southwestern Japan, the Sea of Japan, and northeastern China) show enriched (EMI) component signatures. Volcanic rocks from the Ulreung and Dog Islands in the Sea of Japan show typical DUPAL anomaly characteristics with extremely high ??208/204 Pb (up to 143) and enriched Nd and Sr isotopic compositions (??{lunate}Nd = -3 to -5, 87Sr 86Sr = ~0.705). The ??208/204 Pb values are similar to those associated with the DUPAL anomaly (up to 140) in the southern hemisphere. Because the EMI characteristics of basalts from the Sea of Japan are more extreme than those of southwestern Japan and inland China basalts, we propose that old mantle lithosphere was metasomatized early (prior to the Proterozoic) with subduction-related fluids (not present subduction system) so that it has been slightly enriched in incompatible elements and has had a high Th/U for a long time. The results of this study support the idea that the old subcontinental mantle lithosphere is the source for EMI of oceanic basalts, and that EMI does not need to be stored at the core/ mantle boundary layer for a long time. Dredged samples from seamounts and knolls from the <span class="hlt">Yamato</span> Basin Ridge in the Sea of Japan show similar isotopic characteristics to basalts from the Mariana arc, supporting the idea that the <span class="hlt">Yamato</span> Basin Ridge is a spreading center causing separation of the northeast Japan Arc from Eurasia. ?? 1991.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/1987GeCoA..51..741D','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/1987GeCoA..51..741D"><span>Chemical studies of H chondrites. II - Weathering effects in the Victoria Land, Antarctic population and comparison of two Antarctic populations with non-Antarctic falls</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Dennison, J. E.; Lipschutz, M. E.</p> <p>1987-03-01</p> <p>The authors report RNAA data for 14 siderophile, lithophile and chalcophile volatile/mobile trace elements in interior portions of 45 different H4-6 chondrites (49 samples) from Victoria Land, Antarctica and 5 H5 chondrites from the <span class="hlt">Yamato</span> Mts., Antarctica. Relative to H5 chondrites of weathering types A and B, all elements are depleted (10 at statistically significant levels) in extensively weathered (types B/C and C) samples. Chondrites of weathering types A and B seem compositionally uncompromised and as useful as contemporary falls for trace-element studies. When data distributions for these 14 trace elements in non-Antarctic H chondrite falls and unpaired samples from Victoria Land and from the <span class="hlt">Yamato</span> Mts. (Queen Maud Land) are compared statistically, numerous significant differences are apparent. These and other differences give ample cause to doubt that the various sample populations derive from the same parent population. The observed differences do no reflect weathering, chance or other trivial causes: a preterrestrial source must be responsible.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014PolSc...8..255B','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014PolSc...8..255B"><span>The effects of parent-body hydrothermal heating on amino acid abundances in CI-like chondrites</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Burton, Aaron S.; Grunsfeld, Sarah; Elsila, Jamie E.; Glavin, Daniel P.; Dworkin, Jason P.</p> <p>2014-09-01</p> <p>We determined the amino acid abundances and enantiomeric compositions of the Antarctic CI1 carbonaceous chondrites <span class="hlt">Yamato</span> (Y)-86029 and Y-980115, as well as the Ivuna and Orgueil CI1 carbonaceous chondrites by liquid chromatography with fluorescence detection and time-of-flight mass spectrometry. Y-86029 and Y-980115 both show evidence of parent-body heating (500-600 °C) in addition to aqueous alteration, while Ivuna and Orgueil only show evidence for aqueous alteration. In contrast to Ivuna and Orgueil, which each contain ˜70 nmol/g of amino acids in acid-hydrolyzed, water extracts, both heated <span class="hlt">Yamato</span> CI meteorites contain only low levels of amino acids that were primarily L-enantiomers of proteinogenic amino acids, indicating that they are likely to be terrestrial in origin. Because indigenous amino acids have been found in meteorites that have experienced metamorphic temperatures of >1000 °C with only minimal aqueous alteration, heating alone is not sufficient to explain the lack of amino acids in Y-86029 and Y-980115. Rather, our data suggest that the combination of heating and aqueous alteration has a profound destructive effect on amino acids in meteorites. This finding has implications for the origins of amino acids and other molecules in the early evolution of our solar system.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/19980004741','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/19980004741"><span>Workshop on Parent-Body and Nebular Modification of Chondritic Materials</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Zolensky, M. E. (Editor); Krot, A. N. (Editor); Scott, E. R. D. (Editor)</p> <p>1997-01-01</p> <p>Topics considered include: thermal Metamorphosed Antarctic CM and CI Carbonaceous Chondrites in Japanese Collections, and Transformation Processes of Phyllosilicates; use of Oxygen Isotopes to Constrain the Nebular and Asteroidal Modification of Chondritic Materials; effect of Revised Nebular Water Distribution on Enstatite Chondrite Formation; interstellar Hydroxyls in Meteoritic Chondrules: Implications for the Origin of Water in the Inner Solar System; theoretical Models and Experimental Studies of Gas-Grain Chemistry in the Solar Nebula; chemical Alteration of Chondrules on Parent Bodies; thermal Quenching of Silicate Grains in Protostellar Sources; an Experimental Study of Magnetite Formation in the Solar Nebula; the Kaidun Meteorite: Evidence for Pre- and Postaccretionary Aqueous Alteration; a Transmission Electron Microscope Study of the Matrix Mineralogy of the Leoville CV3 (Reduced-Group) Carbonaceous Chondrite: Nebular and Parent-Body Features; rubidium-Strontium Isotopic Systematic of Chondrules from the Antarctic CV Chondrites <span class="hlt">Yamato</span> 86751 and <span class="hlt">Yamato</span> 86009: Additional Evidence for Late Parent-Body Modification; oxygen-Fugacity Indicators in Carbonaceous Chondrites: Parent-Body Alteration or High-Temperature Nebular Oxidation; thermodynamic Modeling of Aqueous Alteration in CV Chondrites; asteroidal Modification of C and O Chondrites: Myths and Models; oxygen Fugacity in the Solar Nebular; and the History of Metal and Sulfides in Chondrites.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.osti.gov/scitech/biblio/5870369','SCIGOV-STC'); return false;" href="https://www.osti.gov/scitech/biblio/5870369"><span>Mantle metasomatism</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Menzies, M.; Hawkesworth, C.</p> <p>1986-01-01</p> <p>The concept of metasomatism and its role in the geochemical enrichment and depletion processes in upper mantle rocks remains contentious. This volume makes a comprehensive contribution to the study of metasomatic and enrichment processes: origin and importance in determining trace element and isotopic heterogeneity in the lithospheric mantle. It begins with a theoretical thermodynamic and experimental justification for metasomatism and proceeds to present evidence for this process from the study of mantle xenoliths. Finally the importance of metasomatism in relation to basaltic volcanism is assessed. The contents are as follows: Dynamics of Translithospheric Migration of Metasomatic Fluid and Alkaline Magma. Solubility of Major and Trace Elements in Mantle Metasomatic Fluids: Experimental Constraints. Mineralogic and Geochemical Evidence for Differing Styles of Metasomatism in Spinel <span class="hlt">Lherzolite</span> Xenoliths: Enriched Mantle Source Regions of Basalts. Characterization of Mantle Metasomatic Fluids in Spinel <span class="hlt">Lherzolites</span> and Alkali Clinophyroyxenites from the West Eifel and South-West Uganda. Metasomatised Harzburgites in Kimberlite and Alkaline Magmas: Enriched Resites and ''Flushed'' <span class="hlt">Lherzolites</span>. Metasomatic and Enrichment Phenomena in Garnet-Peridotite Facies Mantle Xenoliths from the Matsoku Kimberlite Pipe Lesotho. Evidence for Mantle Metasomatism in Periodite Nodules from the Kimberley Pipes South Africa. Metasomatic and Enrichment Processes in Lithospheric Peridotites, an Effective of Asthenosphere-Lithosphere Interaction. Isotope Variations in Recent Volcanics: A Trace Element Perspective. Source Regions of Mid-Ocean Ridge Basalts: Evidence for Enrichment Processes. The Mantle Source for the Hawaiian Islands: Constraints from the Lavas and Ultramafic Inclusions.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2004Litho..77..395M','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2004Litho..77..395M"><span>Peridotitic mantle xenoliths from kimberlites on the Ekati Diamond Mine property, N.W.T., Canada: major element compositions and implications for the lithosphere beneath the central Slave craton</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Menzies, Andrew; Westerlund, Kalle; Grütter, Herman; Gurney, John; Carlson, Jon; Fung, Agnes; Nowicki, Tom</p> <p>2004-09-01</p> <p>The composition, structure and thermal state of the lithosphere beneath the Slave craton have been studied by analysing over 300 peridotitic mantle xenoliths or multiphase xenocrysts entrained within kimberlites in the Lac de Gras area. These xenoliths are derived from seven kimberlites located on the Ekati Diamond Mine™ property and define a detailed stratigraphic profile through the central Slave lithosphere from less than 120 km down to ˜200 km. Two dominant peridotite types are present, namely garnet-bearing harzburgite and <span class="hlt">lherzolite</span> with rare occurrences of chromite-facies peridotite, websterite and wehrlite. The pressures and temperatures ( P- T's) defined by the entire data-set range from 28 to 62 kbar and 650 to 1250 °C, respectively, and approximately intersect the diamond stability field at 900 °C and 42 kbar. There is no apparent change in the geotherm with depth that is discernable beyond the resolution of the various thermobarometers. The peridotites can be divided into two compositional zones—a shallow layer dominated by garnet harzburgite that straddles the diamond-graphite boundary and a deeper layer that is strongly dominated by garnet <span class="hlt">lherzolite</span>. Compositionally, the harzburgites (and to a lesser extent, the shallow <span class="hlt">lherzolites</span>) are ultra-depleted relative to the more fertile deeper layer, irrespective of whether they reside within the graphite or diamond stability field. This ultra-depleted layer beneath Ekati continues to ˜150 km.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015JAfES.111...26N','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015JAfES.111...26N"><span>Sub-continental lithospheric mantle structure beneath the Adamawa plateau inferred from the petrology of ultramafic xenoliths from Ngaoundéré (Adamawa plateau, Cameroon, Central Africa)</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Nkouandou, Oumarou F.; Bardintzeff, Jacques-Marie; Fagny, Aminatou M.</p> <p>2015-11-01</p> <p>Ultramafic xenoliths (<span class="hlt">lherzolite</span>, harzburgite and olivine websterite) have been discovered in basanites close to Ngaoundéré in Adamawa plateau. Xenoliths exhibit protogranular texture (<span class="hlt">lherzolite</span> and olivine websterite) or porphyroclastic texture (harzburgite). They are composed of olivine Fo89-90, orthopyroxene, clinopyroxene and spinel. According to geothermometers, <span class="hlt">lherzolites</span> have been equilibrated at 880-1060 °C; equilibrium temperatures of harzburgite are rather higher (880-1160 °C), while those of olivine websterite are bracketed between 820 and 1010 °C. The corresponding pressures are 1.8-1.9 GPa, 0.8-1.0 GPa and 1.9-2.5 GPa, respectively, which suggests that xenoliths have been sampled respectively at depths of 59-63 km, 26-33 km and 63-83 km. Texture and chemical compositional variations of xenoliths with temperature, pressure and depth on regional scale may be ascribed to the complex history undergone by the sub-continental mantle beneath the Adamawa plateau during its evolution. This may involve a limited asthenosphere uprise, concomitantly with plastic deformation and partial melting due to adiabatic decompression processes. Chemical compositional heterogeneities are also proposed in the sub-continental lithospheric mantle under the Adamawa plateau, as previously suggested for the whole Cameroon Volcanic Line.</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_20");'>20</a></li> <li><a href="#" onclick='return showDiv("page_21");'>21</a></li> <li class="active"><span>22</span></li> <li><a href="#" onclick='return showDiv("page_23");'>23</a></li> <li><a href="#" onclick='return showDiv("page_24");'>24</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_22 --> <div id="page_23" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_21");'>21</a></li> <li><a href="#" onclick='return showDiv("page_22");'>22</a></li> <li class="active"><span>23</span></li> <li><a href="#" onclick='return showDiv("page_24");'>24</a></li> <li><a href="#" onclick='return showDiv("page_25");'>25</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="441"> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.osti.gov/scitech/biblio/5065217','SCIGOV-STC'); return false;" href="https://www.osti.gov/scitech/biblio/5065217"><span>Isotopic and trace element composition of the upper mantle beneath a young continental rift: results from Kilbourne Hole, New Mexico</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Roden, M.F.; Irving, A.J.; Murthy, V.R.</p> <p>1988-02-01</p> <p>Clinopyroxenes (cpx) separated from discrete spinel <span class="hlt">lherzolite</span> xenoliths from Kilbourne Hole, New Mexico, are compositionally and isotopically heterogeneous. On a Nd-Sr isotope correlations diagram, the cpx plot largely within the mantle array, from near Bulk Earth to depleted MORB values. None of the bulk xenoliths are equivalent to primitive mantle; all have undergone one or more depletion events and some have been enriched in incompatible elements. Cpx from spinel pyroxenite dikes and <span class="hlt">lherzolite</span> wallrocks of composite xenoliths are relatively homogeneous (isotopically) and similar to OIB and some MORB. The wallrocks are isotopically equilibrated with the pyroxenites or nearly so, and have negative Nd model ages; we infer that the pyroxenite-forming event caused enrichment in incompatible elements in the contiguous wallrock. The pyroxenite parent magma was probably a primitive basanite characterized by low Hf/Sm and Ti/Sm ratios relative to primitive mantle as a consequence of residual garnet. Old but disparate Sr and Nd model ages require that MORB-related spinel <span class="hlt">lherzolites</span> have had a complicated history and differentiated from primitive mantle more than 1 b.y. ago. Two plausible models, one involving more than one depletion event and the second involving mixing of mantle components depleted at distinct times, can explain the common observation that Sr model ages are older than Nd model ages.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/20170001659','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/20170001659"><span>Lead in Martian Meteorites-- Observations and Inconsistencies: I. Chassigny</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Jones, J. H.; Simon, J. I.; Usui, T.</p> <p>2017-01-01</p> <p>The history of Pb isotope analyses of the martian meteorites (SNC) and their interpretations is laden with difficulties. Two different analytical groups have interpreted their ancient (= 4 Ga) <span class="hlt">shergottite</span> Pb ages as primary [1-5]. A Nakhla age of approximately 4.3 Ga has been interpreted to be primary as well [2]. This is in stark contrast to the young (= 1.4 Ga) crystallization ages defined by the Rb-Sr, Sm-Nd, Lu-Hf, and KAr systems [6]. Possibly, a better interpretation for the ancient Pb ages is that they reflect the formation times of the various SNC source regions [7]. A difficulty in dealing with Pb is that terrestrial contamination is ubiquitous, unlike the other chronometer systems noted above. This issue is complicated by the fact that radioactive decay causes localized mineral damage. So washing and leaching to remove Pb contamination tends to remove in situ radiogenic Pb. This issue is further compounded because U and Th are often concentrated in phosphates and other minor phases, so the leaching process tends to remove these, especially phosphates. Another difficulty is that it is not clear whether the observed Pb isotopic variation in leachates, residues, and ion-microprobe analyses is due to terrestrial or to indigenous martian Pb contamination [e.g., 8]. A third difficulty is that the <span class="hlt">shergottites</span> on the one hand, and the nakhlites and chassignites on the other, appear to have come from separate source regions with different chemical compositions [e.g., 7]. Thus, it is expected that their Pb isotopic characteristics would be different. And even if all these meteorite types came from the same source region, their igneous ages differ considerably. The nakhlites and chassignites are 1.4 Ga and the <span class="hlt">shergottites</span> are = 600 Ma [e.g., 6]. This age difference alone should assure that the two distinct SNC groups have differing Pb isotopic signatures.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017M%26PS...52..251B','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017M%26PS...52..251B"><span>Chemical layering in the upper mantle of Mars: Evidence from olivine-hosted melt inclusions in Tissint</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Basu Sarbadhikari, A.; Babu, E. V. S. S. K.; Vijaya Kumar, T.</p> <p>2017-02-01</p> <p>Melting of Martian mantle, formation, and evolution of primary magma from the depleted mantle were previously modeled from experimental petrology and geochemical studies of Martian meteorites. Based on in situ major and trace element study of a range of olivine-hosted melt inclusions in various stages of crystallization of Tissint, a depleted olivine-phyric <span class="hlt">shergottite</span>, we further constrain different stages of depletion and enrichment in the depleted mantle source of the <span class="hlt">shergottite</span> suite. Two types of melt inclusions were petrographically recognized. Type I melt inclusions occur in the megacrystic olivine core (Fo76-70), while type II melt inclusions are hosted by the outer mantle of the olivine (Fo66-55). REE-plot indicates type I melt inclusions, which are unique because they represent the most depleted trace element data from the parent magmas of all the depleted <span class="hlt">shergottites</span>, are an order of magnitude depleted compared to the type II melt inclusions. The absolute REE content of type II displays parallel trend but somewhat lower value than the Tissint whole-rock. Model calculations indicate two-stage mantle melting events followed by enrichment through mixing with a hypothetical residual melt from solidifying magma ocean. This resulted in 10 times enrichment of incompatible trace elements from parent magma stage to the remaining melt after 45% crystallization, simulating the whole-rock of Tissint. We rule out any assimilation due to crustal recycling into the upper mantle, as proposed by a recent study. Rather, we propose the presence of Al, Ca, Na, P, and REE-rich layer at the shallower upper mantle above the depleted mantle source region during the geologic evolution of Mars.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.osti.gov/scitech/biblio/1006637','SCIGOV-STC'); return false;" href="https://www.osti.gov/scitech/biblio/1006637"><span>The nature of Martian fluids based on mobile element studies in salt-assemblages from Martian meteorites</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Rao, M.N.; Nyquist, L.E.; Wentworth, S.J.; Sutton, S.R.; Garrison, D.H.</p> <p>2008-08-04</p> <p>The S, Cl, and Br abundances determined in salt assemblages in Nakhla and Lafayette olivine fracture fillings and in gas-rich impact-melt (GRIM) glasses from Shergotty and EET79001 Lithologies A & B using EMPA/EDS/APS X-ray Microprobe techniques are compared with the S and Cl abundances determined by Gooding and coworkers in similar samples using quadrupole mass-spectrometric techniques. All the analytical methods yield relatively high Cl and low SO{sub 3} abundances in Nakhla indicating a SO{sub 3}/Cl ratio of {approx}0.2. The same ratio in Lafayette secondary salts seems to be {approx}2. In the case of GRIM glasses from Shergotty and EET79001 Lith A & Lith B, the SO{sub 3} abundance is found to be high whereas the Cl abundance is low yielding a SO{sub 3}/Cl ratio of {approx}5--300 (large errors are associated with these ratios because of low Cl signals). The salts found in Nakhla fracturefillings are inferred to have formed from Cl-rich fluids (high pH) near nakhlite source region on Mars, whereas the secondary minerals found in <span class="hlt">shergottite</span> GRIM glasses seem to be associated with SO{sub 3}-rich fluids (low pH) near <span class="hlt">shergottite</span> source region on Mars. The Cl-rich fluids seem to have infiltrated into the nakhlite source region {approx}600 Ma ago, whereas the SO{sub 3}-rich fluids likely percolated into the <span class="hlt">shergottite</span> source region at {approx}180 Ma (or less) suggesting the possible existence of two types of fluid sources on Mars.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=19940007579&hterms=noble+gases&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D30%26Ntt%3Dnoble%2Bgases','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=19940007579&hterms=noble+gases&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D30%26Ntt%3Dnoble%2Bgases"><span>Nitrogen and noble gases in a glass sample from LEW88516</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Becker, R. H.; Pepin, R. O.</p> <p>1993-01-01</p> <p>The Antarctic meteorite LEW88516 has been classified as a member of the SNC group of meteorites, specifically a <span class="hlt">shergottite</span>. It is reported to be remarkably similar in mineralogy, petrogenesis and chemistry to the previously known ALH77005 <span class="hlt">shergottite</span>, with both being compositionally distinct from other <span class="hlt">shergottites</span>. LEW88516 shows pervasive shock features and has been found to contain glass veins attributable to a shock origin. In an effort to determine whether the glass in LEW88516 contains any of the isotopically-heavy trapped nitrogen component observed in EETA 79001 glass, as well as the related high-Ar-40/Ar-36 and high-Xe-129/Xe-132 components, we undertook an analysis of an 11.9 mg glass sample (LEW88516,4) provided to us by H. Y. McSween, Jr. as part of a consortium study of this meteorite. Nitrogen and noble gases were extracted from LEW88516,4 in a series of combustion steps at increasing temperatures followed by a final pyrolysis. Initial steps at 550 C were intended to remove any surface-sited nitrogen-containing contaminants, while the 700 C step was expected to show the onset of release of a trapped argon component, based on our previous data for EETA 79001. It was hoped that the bulk of any trapped gas release would be concentrated in one of two steps at 1100 C and approximately 1400 C, maximizing our analytical sensitivity. Results of the analysis are shown. Except for He and Ne, data obtained for the 550 C steps will be omitted from further consideration on the assumption that they represent terrestrial contamination.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=20030111517&hterms=EU&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D90%26Ntt%3DEU','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=20030111517&hterms=EU&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D90%26Ntt%3DEU"><span>Oxygen Fugacity of the Martian Mantle From Pyroxene/Melt Partitioning of REE</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Musselwhite, D. S.; Jones, J. H.</p> <p>2003-01-01</p> <p>This study is part of an ongoing effort to calibrate the pyroxene/melt REE oxybarometer for conditions relevant to the martian meteorites. Redox variations have been reported among the <span class="hlt">shergottites</span>. Wadhwa used the Eu and Gd augite/melt partitioning experiments of McKay, designed for the LEW86010 angrite, to infer a range of fo2 for the <span class="hlt">shergottites</span>. Others inferred fo2 using equilibria between Fe-Ti oxides. There is fairly good agreement between the Fe-Ti oxide determinations and the estimates from Eu anomalies in terms of which meteorites are more or less oxidized. The Eu anomaly technique and the Fe-Ti oxide technique both essentially show the same trend, with Shergotty and Zagami being the most oxidized and QUE94201 and DaG 476 being the most reduced. Thus, the variation in fo2 appears to be both real and substantive. However, although the redox trends indicated by the two techniques are similar, there is as much as two log unit offset between the results of three researchers. One explanation for this offset is that the Eu calibration used for the <span class="hlt">shergottites</span> was actually designed for the LEW86010 angrite, a silica-undersaturated basalt whose pyroxene (diopside) compositions are rather extreme. To correct this, experiments have been conducted on the redox relationship of Eu partitioning relative to Sm and Gd for pyroxene/melt compositions more relevant to Martian meteorites. We report here preliminary results for experiments on pigeonite/melt partitioning as a function of fO2.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/1994Metic..29R.511N','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/1994Metic..29R.511N"><span>Exposure histories of ALH 84001 and ALHA 77005</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Nishiizumi, K.; Caffee, M. W.; Finkel, R. C.</p> <p>1994-07-01</p> <p>From cosmogenic nuclide studies of SNC meteorites exposure histories, ejection conditions from the hypothesized martian parent body, and genetic relationships between SNC meteorites were determined. Previous studies show ablation to have been very low in at least three <span class="hlt">shergottites</span>, ALHA 77005, Shergotty, and EETA 79001. This suggests that the atmospheric entry velocity and/or entry angle of <span class="hlt">shergottites</span> must have been much lower than of ordinary chondrites. We report the results of cosmogenic radionuclides in the newly classified SNC meteorite ALH 84001 and additional studies of ALHA 77005. Be-10 (half-life = 1.5 m.y.) and Cl-36 (0.30 m.y.) results are presented for these two meteorites along with previous measurements of the <span class="hlt">shergottite</span> LEW 88516. Aluminum-26 (0.71 m.y.) measurements are in progress. We received two chips on opposite sides of ALH 84001. Two subsamples, at depths of 0.5-3.5 mm and 7-9 mm, from fusion crust were separated from ALH 84001,97. The C-14 terrestrial age is 6.5 +/- 1.3 k.y. The noble gas exposure age is reported to be 14 +/- 2 m.y. The Be-10 and Cl-36 concentrations in three subsamples are nearly constant. A reasonable interpretation is that there are no SCR (solar cosmic ray) effects at these sample depths. The Be-10 production rate is estimated to be 21-24 atom/min-kg based on recovered size and over 3 cm of ablation depth. The Be-10 concentration indicates that ALH 84001 was exposed to cosmic rays 4-7 m.y. in a 4 pi geometry. The Be-10 exposure age is significantly shorter than noble gas exposure age. Three of the subsamples of ALHA 77005 measured for cosmogenic radionuclides are aliquots from the noble gas study. Chemical analysis and Al-26 measurements for these three subsamples are in progress.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016M%26PS...51.2036M','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016M%26PS...51.2036M"><span>Heterogeneous distribution of H2O in the Martian interior: Implications for the abundance of H2O in depleted and enriched mantle sources</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>McCubbin, Francis M.; Boyce, Jeremy W.; Srinivasan, Poorna; Santos, Alison R.; Elardo, Stephen M.; Filiberto, Justin; Steele, Andrew; Shearer, Charles K.</p> <p>2016-11-01</p> <p>We conducted a petrologic study of apatite within 12 Martian meteorites, including 11 <span class="hlt">shergottites</span> and one basaltic regolith breccia. These data were combined with previously published data to gain a better understanding of the abundance and distribution of volatiles in the Martian interior. Apatites in individual Martian meteorites span a wide range of compositions, indicating they did not form by equilibrium crystallization. In fact, the intrasample variation in apatite is best described by either fractional crystallization or crustal contamination with a Cl-rich crustal component. We determined that most Martian meteorites investigated here have been affected by crustal contamination and hence cannot be used to estimate volatile abundances of the Martian mantle. Using the subset of samples that did not exhibit crustal contamination, we determined that the enriched <span class="hlt">shergottite</span> source has 36-73 ppm H2O and the depleted source has 14-23 ppm H2O. This result is consistent with other observed geochemical differences between enriched and depleted <span class="hlt">shergottites</span> and supports the idea that there are at least two geochemically distinct reservoirs in the Martian mantle. We also estimated the H2O, Cl, and F content of the Martian crust using known crust-mantle distributions for incompatible lithophile elements. We determined that the bulk Martian crust has 1410 ppm H2O, 450 ppm Cl, and 106 ppm F, and Cl and H2O are preferentially distributed toward the Martian surface. The estimate of crustal H2O results in a global equivalent surface layer (GEL) of 229 m, which can account for at least some of the surface features on Mars attributed to flowing water and may be sufficient to support the past presence of a shallow sea on Mars' surface.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017Litho.282..326G','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017Litho.282..326G"><span>Age and evolution of the lithospheric mantle beneath the Khanka Massif: Geochemical and Re-Os isotopic evidence from Sviyagino mantle xenoliths</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Guo, Peng; Xu, Wen-Liang; Wang, Chun-Guang; Wang, Feng; Ge, Wen-Chun; Sorokin, A. A.; Wang, Zhi-Wei</p> <p>2017-06-01</p> <p>New geochemical and Re-Os isotopic data of mantle xenoliths entrained in Cenozoic Sviyagino alkali basalts from the Russian Far East provide insights into the age and evolution of the sub-continental lithospheric mantle (SCLM) beneath the Khanka Massif, within the Central Asian Orogenic Belt (CAOB). These mantle xenoliths are predominantly spinel <span class="hlt">lherzolites</span> with minor spinel harzburgite. The <span class="hlt">lherzolites</span> contain high whole-rock concentrations of Al2O3 and CaO, with low forsterite content in olivine (Fo = 89.5-90.3%) and low Cr# in spinel (0.09-0.11). By contrast, the harzburgite is more refractory, containing lower whole rock Al2O3 and CaO contents, with higher Fo (91.3%) and spinel Cr# (0.28). Their whole rock and mineral compositions suggest that the <span class="hlt">lherzolites</span> experienced low-degree (1-4%) batch melting and negligible metasomatism, whereas the harzburgite underwent a higher degree (10%) of fractional melting, and experienced minor post-melting silicate metasomatism. Two-pyroxene rare earth element (REE)-based thermometry (TREE) yields predominant equilibrium temperatures of 884-1043 °C, similar to values obtained from two-pyroxene major element-based thermometry (TBKN = 942-1054 °C). Two <span class="hlt">lherzolite</span> samples yield high TREE relative to TBKN (TREE - TBKN ≥ 71 °C), suggesting that they cooled rapidly as a result of the upwelling of hot asthenospheric mantle material that underplated a cold ancient lithosphere. The harzburgite with a low Re/Os value has an 187Os/188Os ratio of 0.11458, yielding an Os model age (TMA) relative to the primitive upper mantle (PUM) of 2.09 Ga, and a Re depletion ages (TRD) of 1.91 Ga; both of which record ancient melt depletion during the Paleoproterozoic ( 2.0 Ga). The 187Os/188Os values of <span class="hlt">lherzolites</span> (0.12411-0.12924) correlate well with bulk Al2O3 concentrations and record the physical mixing of ancient mantle domains and PUM-like ambient mantle material within the asthenosphere. This indicates that the SCLM beneath the Khanka</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016Litho.248..339K','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016Litho.248..339K"><span>Asthenosphere-lithosphere interactions in Western Saudi Arabia: Inferences from 3He/4He in xenoliths and lava flows from Harrat Hutaymah</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Konrad, Kevin; Graham, David W.; Thornber, Carl R.; Duncan, Robert A.; Kent, Adam J. R.; Al-Amri, Abdullah M.</p> <p>2016-04-01</p> <p>Extensive volcanic fields on the western Arabian Plate have erupted intermittently over the last 30 Ma following emplacement of the Afar flood basalts in Ethiopia. In an effort to better understand the origin of this volcanism in western Saudi Arabia, we analyzed 3He/4He, and He, CO2 and trace element concentrations in minerals separated from xenoliths and lava flows from Harrat Hutaymah, supplemented with reconnaissance He isotope data from several other volcanic fields (Harrat Al Birk, Harrat Al Kishb and Harrat Ithnayn). Harrat Hutaymah is young (< 850 ka) and the northeasternmost of the volcanic fields. There is a remarkable homogeneity of 3He/4He trapped within most xenoliths, with a weighted mean of 7.54 ± 0.03 RA (2σ, n = 20). This homogeneity occurs over at least eight different xenolith types (including spinel <span class="hlt">lherzolite</span>, amphibole clinopyroxenite, olivine websterite, clinopyroxenite and garnet websterite), and encompasses ten different volcanic centers within an area of ~ 2500 km2. The homogeneity is caused by volatile equilibration between the xenoliths and fluids derived from their host magma, as fluid inclusions are annealed during the infiltration of vapor-saturated magmas along crystalline grain boundaries. The notable exceptions are the anhydrous spinel <span class="hlt">lherzolites</span>, which have a lower weighted mean 3He/4He of 6.8 ± 0.3 RA (2σ, n = 2), contain lower concentrations of trapped He, and have a distinctly depleted light rare earth element signature. 3He/4He values of ~ 6.8 RA are also commonly found in spinel <span class="hlt">lherzolites</span> from harrats Ithnayn, Al Birk, and from Zabargad Island in the Red Sea. Olivine from non-xenolith-bearing lava flows at Hutaymah spans the He isotope range of the xenoliths. The lower 3He/4He in the anhydrous spinel <span class="hlt">lherzolites</span> appears to be tied to remnant Proterozoic lithosphere prior to metasomatic fluid overprinting. Elevated 3He/4He in the western harrats has been observed only at Rahat (up to 11.8 RA; Murcia et al., 2013), a</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2017MinDe..52..845D','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2017MinDe..52..845D"><span>Lithological and geochemical constraints on the magma conduit systems of the Huangshan Ni-Cu sulfide deposit, NW China</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Deng, Yu-Feng; Song, Xie-Yan; Hollings, Pete; Chen, Lie-Meng; Zhou, Taofa; Yuan, Feng; Xie, Wei; Zhang, Dayu; Zhao, Bingbing</p> <p>2017-08-01</p> <p>Magmatic Ni-Cu sulfide deposits in northern Xinjiang, China, are associated with small mafic-ultramafic complexes, with the sulfide ores generally occurring in ultramafic rocks. The Huangshan deposit (up to 65 Mt of ore at 0.49% Ni and 0.31% Cu), one of the largest magmatic Ni-Cu deposits in northern Xinjiang, is composed of a layered sequence of lower websterite, lower <span class="hlt">lherzolite</span>, websterite, norite-gabbro, gabbro, diorite, and gabbronorite, with sulfide mineralization mainly found in the lower <span class="hlt">lherzolite</span>, lower websterite, and websterite. Systematic variations of the major oxides and trace elements suggest that the rocks of the Huangshan deposit are fractionated from the same parental magma, with the sharp contact and discontinuous trends of major oxide contents between different lithologies implying intrusion of four distinct stages of magma from a single deep-seated staging chamber. The reversals in olivine Fo contents and major oxides in the lower <span class="hlt">lherzolite</span> were the result of inhomogeneity in olivine within the lower chamber. The Se/S ratios (63.1˜150 × 10-6) and the negative correlation between Se/S and δ34S (0.63˜2.42‰) of the sulfide ores suggest that a large contribution of crustal S caused the sulfide segregation. The sulfides in the lower <span class="hlt">lherzolite</span> have lower Cu contents (1386-2200 ppm) and Cu/Pd ratios (2.31 × 105-1.36 × 106) relative to those in the mineralized lower websterite (Cu = 2300 to 18,700 ppm, and Cu/Pd = 6.65 × 105 to 2.73 × 106). A positive correlation between Pd/Ir and Ni/Ir for the vein-textured sulfides in the lower websterite likely reflects fractionated sulfides picked up by a new pulse of magma. In contrast, the restricted range of Pd/Ir ratios indicates that the PGE contents of the disseminated sulfides in the lower <span class="hlt">lherzolite</span> resulted from reaction between the sulfides and new pulses of S-undersaturated magma.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016MinDe.tmp...70D','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016MinDe.tmp...70D"><span>Lithological and geochemical constraints on the magma conduit systems of the Huangshan Ni-Cu sulfide deposit, NW China</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Deng, Yu-Feng; Song, Xie-Yan; Hollings, Pete; Chen, Lie-Meng; Zhou, Taofa; Yuan, Feng; Xie, Wei; Zhang, Dayu; Zhao, Bingbing</p> <p>2016-12-01</p> <p>Magmatic Ni-Cu sulfide deposits in northern Xinjiang, China, are associated with small mafic-ultramafic complexes, with the sulfide ores generally occurring in ultramafic rocks. The Huangshan deposit (up to 65 Mt of ore at 0.49% Ni and 0.31% Cu), one of the largest magmatic Ni-Cu deposits in northern Xinjiang, is composed of a layered sequence of lower websterite, lower <span class="hlt">lherzolite</span>, websterite, norite-gabbro, gabbro, diorite, and gabbronorite, with sulfide mineralization mainly found in the lower <span class="hlt">lherzolite</span>, lower websterite, and websterite. Systematic variations of the major oxides and trace elements suggest that the rocks of the Huangshan deposit are fractionated from the same parental magma, with the sharp contact and discontinuous trends of major oxide contents between different lithologies implying intrusion of four distinct stages of magma from a single deep-seated staging chamber. The reversals in olivine Fo contents and major oxides in the lower <span class="hlt">lherzolite</span> were the result of inhomogeneity in olivine within the lower chamber. The Se/S ratios (63.1˜150 × 10-6) and the negative correlation between Se/S and δ34S (0.63˜2.42‰) of the sulfide ores suggest that a large contribution of crustal S caused the sulfide segregation. The sulfides in the lower <span class="hlt">lherzolite</span> have lower Cu contents (1386-2200 ppm) and Cu/Pd ratios (2.31 × 105-1.36 × 106) relative to those in the mineralized lower websterite (Cu = 2300 to 18,700 ppm, and Cu/Pd = 6.65 × 105 to 2.73 × 106). A positive correlation between Pd/Ir and Ni/Ir for the vein-textured sulfides in the lower websterite likely reflects fractionated sulfides picked up by a new pulse of magma. In contrast, the restricted range of Pd/Ir ratios indicates that the PGE contents of the disseminated sulfides in the lower <span class="hlt">lherzolite</span> resulted from reaction between the sulfides and new pulses of S-undersaturated magma.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2013E%26PSL.362...66M','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2013E%26PSL.362...66M"><span>Mantle refertilization by melts of crustal-derived garnet pyroxenite: Evidence from the Ronda peridotite massif, southern Spain</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Marchesi, Claudio; Garrido, Carlos J.; Bosch, Delphine; Bodinier, Jean-Louis; Gervilla, Fernando; Hidas, Károly</p> <p>2013-01-01</p> <p>Geochemical studies of primitive basalts have documented the presence of crustal-derived garnet pyroxenite in their mantle sources. The processes whereby melts with the signature of garnet pyroxenite are produced in the mantle are, however, poorly understood and somewhat controversial. Here we investigate a natural example of the interaction between melts of garnet pyroxenite derived from recycled plagioclase-rich crust and surrounding mantle in the Ronda peridotite massif. Melting of garnet pyroxenite at ˜1.5 GPa generated spinel websterite residues with MREE/HREE fractionation and preserved the positive Eu anomaly of their garnet pyroxenite precursor in whole-rock and clinopyroxene. Reaction of melts from garnet pyroxenite with depleted surrounding peridotite generated secondary fertile spinel <span class="hlt">lherzolite</span>. These secondary <span class="hlt">lherzolites</span> differ from common spinel <span class="hlt">lherzolite</span> from Ronda and elsewhere by their lower-Mg# in clinopyroxene, orthopyroxene and olivine, lower-Cr# in spinel and higher whole-rock Al2O3, CaO, Sm/Yb and FeO* at a given SiO2. Remarkably, secondary spinel <span class="hlt">lherzolite</span> shows the geochemical signature of ghost plagioclase in the form of positive Eu and Sr anomalies in whole-rock and clinopyroxene, reflecting the transfer of a low-pressure crustal imprint from recycled pyroxenite to hybridized peridotite. Garnet pyroxenite melting and melt-peridotite interaction, as shown in the Ronda massif, may explain how the signature of subducted or delaminated crust is transferred to the mantle and how a garnet pyroxenite component is introduced into the source region of basalts. The efficiency of these processes in conveying the geochemical imprint of crustal-derived garnet pyroxenite to extruded lavas depends on the reactivity of pyroxenite melt with peridotite and the mantle permeability, which may be controlled by prior refertilization reactions similar to those documented in the Ronda massif. Highly fertile heterogeneities produced by pyroxenite</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/19790015696','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/19790015696"><span>Trace element contents of selected antarctic meteorites, 1. Ph.D. Thesis</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Biswas, S.; Ngo, H. T.; Lipschutz, M. E.</p> <p>1979-01-01</p> <p>Data are reported for volatile/mobile Ag, As, Au, Bi, Cd, Co, Cs, Cu, Ga, In, Rb, Sb, Se, Te, T1 and Zn in exterior and/or interior samples of four Antarctic meteorites: 77005 (unique achondrite); 77257 (unreilite); 77278 (L3); 77299 (H3). Exterior samples reflect contamination and/or leaching by weathering but trace element (ppm-ppt) contents in interior samples seem reasonable for representatives of these rare meteoritic types. The 77005 achondrite seems related to <span class="hlt">shergottites</span>; other samples extend compositional ranges previously known for their types. With suitable precautions, Antarctic meteorite finds yield trace element data as reliable as those obtained from previously known falls.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/20100010148','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/20100010148"><span>Sm-Nd Isotopic Studies of Two Nakhlites, NWA 5790 and Nakhla</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>C.-Y. Shih; Nyquist, L. E.; Reese, Y.; Jambon, A.</p> <p>2010-01-01</p> <p>NWA 5790 is a Martian meteorite recently found in the Mauritania part of the Saharan desert and is classified as a nakhlite, containing a small amount of interstitial plagioclase. Unlike other Martian meteorites ( e.g., <span class="hlt">shergottites</span>), nakhlites have been only moderately shocked and their original igneous textures are still well-preserved. In this report, we present Sm-Nd isotopic data for NWA 5790 and Nakhla, a rare "fall" nakhlite, correlate their ages with those of other nakhlites and discuss their petrogenesis.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/20080026344','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/20080026344"><span>Ar-Ar Dating of Martian Chassignites, NWA2737 and Chassigny, and Nakhlite MIL03346</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Bogard, D. D.; Garrison, D. H.</p> <p>2006-01-01</p> <p>Until recently only three nakhlites and one chassignite had been identified among martian meteorites. These four exhibit very similar radiometric ages and cosmic ray exposure (CRE) ages, indicating that they may have derived from a common location on Mars and were ejected into space by a single impact. This situation is quite different from that of martian <span class="hlt">shergottites</span>, which exhibit a range of radiometric ages and CRE ages (1). Recently, several new nakhlites and a new martian dunite (NWA2737) have been recognized. Here we report our results of Ar-39-Ar-40 dating for the MIL03346 nakhlite and the NWA2737 "chassignite", along with new results on Chassigny.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014AGUFM.P51E3986O','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014AGUFM.P51E3986O"><span>What Can Spectral Properties of Martian Surface and Snc Can Tell Us about the Martian Crust Composition and Evolution</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Ody, A.; Poulet, F.; Baratoux, D.; Quantin, C.; Bibring, J. P.</p> <p>2014-12-01</p> <p>While the study of Martian meteorites can provide detailed information about the crust and mantle composition and evolution, remote-sensing observations, through the merging of compositional and geological data, allow highlighting planetary-scale trends of the Martian crustal evolution [1,2]. Recently, the analysis of the global distribution of mafic minerals [3] has put new constraints on the Martian crust formation and evolution. One of the major results is a past global event of olivine-bearing fissural volcanism that has filled craters and low depressions in the southern highlands and a large part of the Northern plains during the late Noachian/early Hesperian. Petrologic models show that this sudden increase of the olivine content at the Noachian-Hesperian boundary could be the result of a rapid thickening of the lithosphere at the end of the Noachian era [4]. A recent study based on the OMEGA/MEx data has shown that the spectral properties of the <span class="hlt">shergottites</span> are similar to those of some Noachian and Hesperian terrains [5]. To contrary, the Nakhla spectral properties are very different from those of the observable surface and could be representative of Amazonian terrains buried under dust. These results are best explained with an old age of the <span class="hlt">shergottites</span> [6] and with the present understanding of the evolution of magma composition at a planetary scale [7]. On the other hand, if <span class="hlt">shergottites</span> are young [8], the similarities between the <span class="hlt">shergottites</span> and ancient terrains implies that exceptional conditions of melting with respect to the ambient mantle (e.g., hot spots or water-rich mantle source) were responsible for the formation of these samples [9]. References: [1] McSween et al., 2009, Science, 324. [2] Ehlmann & Edwards 2014, AREPS, vol. 42. [3] Ody et al., 2013, JGR,117,E00J14. [4] Ody et al., 2014, 8th Inter. Conf. on Mars,#1190. [5] Ody et al., 2013, 44th LPSC, #1719. [6] Bouvier et al., 2009, EPSL, 280. [7] Baratoux et al., 2013, JGR, 118. [8] Nyquist</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=19940007544&hterms=Bohr+Niels&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D40%26Ntt%3DBohr%252C%2BNiels','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=19940007544&hterms=Bohr+Niels&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D40%26Ntt%3DBohr%252C%2BNiels"><span>Moessbauer spectroscopy of the SNC meteorite Zagami</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Agerkvist, D. P.; Vistisen, L.</p> <p>1993-01-01</p> <p>We have performed Mossbauer spectroscopy on two different pieces of the meteorite Zagami belonging to the group of SNC meteorites. In one of the samples we found a substantial amount of olivine inter grown with one kind of pyroxene, and also another kind of pyroxene very similar to the pyroxene in the other sample we examined. Both samples showed less than 1 percent of Fe(3+) in the silicate phase. The group of SNC meteorites called <span class="hlt">shergottites</span>, to which Zagami belongs, are achondrites whose texture, mineralogy and composition resembles those of terrestrial diabases. The results from the investigation are presented.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=19860063594&hterms=formation+planets&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D80%26Ntt%3Dformation%2Bplanets','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=19860063594&hterms=formation+planets&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D80%26Ntt%3Dformation%2Bplanets"><span>Formation ages and evolution of Shergotty and its parent planet from U-Th-Pb systematics</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Chen, J. H.; Wasserburg, G. J.</p> <p>1986-01-01</p> <p>The isotopic composition of Pb from Shergotty, Zagami, and EETA 79001 meteorites was determined for different phases. Using phases with low U-238/Pb-204 ratio, the initial leads of these meteorites were defined. Samples from all three meteorites were shown to have distinct initial leads, and, thus to have evolved from different reservoirs over most of solar system history in a low U-238/Pb-204 environment. It follows that the parent planet of the <span class="hlt">shergottites</span> has a high Pb-204 concentration relative to U and must also be high in other volatiles. The possibility of the Martian origin of the SNC-type meteorites is discussed.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/20040191778','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/20040191778"><span>The First Billion Years of Martian History as Seen from the SNC Meteorites: A Review</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Jones, J. H.</p> <p>2004-01-01</p> <p>There are currently 28 known, distinct samples of Mars that have been liberated from that planet by impacts and subsequently delivered to the Earth. The formation ages of these samples range from 4.5 b.y. to 180 m.y. Collectively, these samples are called SNC meteorites after the major petrologic subdivisions: <span class="hlt">Shergottite</span>, Nakhlite, Chassigny. Texturally, most of these meteorites are cumulates or partial cumulates. However, a few may represent real melt compositions: EET79001B, Y9800459, QUE94201, and the groundmass of EET79001A.</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_21");'>21</a></li> <li><a href="#" onclick='return showDiv("page_22");'>22</a></li> <li class="active"><span>23</span></li> <li><a href="#" onclick='return showDiv("page_24");'>24</a></li> <li><a href="#" onclick='return showDiv("page_25");'>25</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_23 --> <div id="page_24" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_21");'>21</a></li> <li><a href="#" onclick='return showDiv("page_22");'>22</a></li> <li><a href="#" onclick='return showDiv("page_23");'>23</a></li> <li class="active"><span>24</span></li> <li><a href="#" onclick='return showDiv("page_25");'>25</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="461"> <li> <p><a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=19920001032&hterms=Peridotite&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D60%26Ntt%3DPeridotite','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=19920001032&hterms=Peridotite&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D60%26Ntt%3DPeridotite"><span>Clays on Mars: Review of chemical and mineralogical evidence</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Banin, Amos; Gooding, James L.</p> <p>1991-01-01</p> <p>Mafic igneous bedrock is inferred for Mars, based on spectrophotometric evidence for pyroxene (principally in optically dark areas of the globe) and the pyroxenite-peridotite petrology of <span class="hlt">shergottite</span> nakhlite chassignite (SNC) meteorites. Visible and infrared spectra of reddish-brown surface fines (which dominate Martian bright areas) indicate ferric iron and compare favorably (though not uniquely) with spectra of palagonitic soils. Laboratory studies of SNC's and Viking Lander results support a model for Martian soil based on chemical weathering of mafic rocks to produce layer structured silicates (clay minerals), salts, and iron oxides.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/20080026137','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/20080026137"><span>Calibration of the EU Oxybarometer for Nakhlites</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Makishima, J.; McKay, G.; Le, L.; Miyamoto; Mikouchi, T.</p> <p>2006-01-01</p> <p>Martian meteorites have various characteristics, which are direct clues to understanding the petrogenesis of Mars rocks. The variation in oxidation state among the Martian meteorites must have important implications for redox conditions of the Martian crust/mantle and overall differentiation on Mars. Wadhwa [1] and Herd et al. [2] reported that Martian basalts were formed under a range of oxidation states, suggesting complex petrogenesis processes. The nakhlites, which have rather different characteristics from basaltic <span class="hlt">shergottites</span>, may give us additional clues to Martian petrogenesis. The oxidation states of meteorites are usually described by the oxygen fugacity (fO2) under which the meteorites crystallized. One of the methods to estimate the oxygen fugacity is the depth of Eu anomaly. Eu(2+)/Eu(3+) is determined by the oxygen fugacity and partitioning is different for Eu(2+) and Eu(3+). Therefore, the depth of Eu anomaly in a mineral is a function of the oxygen fugacity and the Eu2+/Eu3+ in the melt from which the mineral crystallized. This method has some advantages over another major method, the two-oxide oxybarometer [3], which can more easily be affected by subsolidus processes. The Eu oxybarometer can analyze the cores of the earliest formed crystals in Martian meteorites, which means it can give us a better indication of the oxygen fugacity of the parent melt. The calibration of the Eu oxybarometer has been done with the basaltic <span class="hlt">shergottites</span> before [4]. However, it has never been applied to nakhlites (Oe et al. [5] measured the depth of Eu anomaly in the synthetic pyroxene only at QFM). Partition coefficients are strongly affected by phase compositions, especially pyroxene Ca content and melt Al content [e.g., 5,6]. The composition of nakhlite pyroxene is rather different from basaltic <span class="hlt">shergottite</span> pyroxene. Thus, there may be problems in applying the Eu oxybarometer calibration for the basaltic <span class="hlt">shergottites</span> [7] to nakhlites. Thus, we report in this</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/1986GeCoA..50..955C','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/1986GeCoA..50..955C"><span>Formation ages and evolution of Shergotty and its parent planet from U-Th-Pb systematics</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Chen, J. H.; Wasserburg, G. J.</p> <p>1986-06-01</p> <p>The isotopic composition of Pb from Shergotty, Zagami, and EETA 79001 meteorites was determined for different phases. Using phases with low U-238/Pb-204 ratio, the initial leads of these meteorites were defined. Samples from all three meteorites were shown to have distinct initial leads, and, thus to have evolved from different reservoirs over most of solar system history in a low U-238/Pb-204 environment. It follows that the parent planet of the <span class="hlt">shergottites</span> has a high Pb-204 concentration relative to U and must also be high in other volatiles. The possibility of the Martian origin of the SNC-type meteorites is discussed.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=19860063594&hterms=LEAD+Pb&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D40%26Ntt%3DLEAD%2BPb','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=19860063594&hterms=LEAD+Pb&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D40%26Ntt%3DLEAD%2BPb"><span>Formation ages and evolution of Shergotty and its parent planet from U-Th-Pb systematics</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Chen, J. H.; Wasserburg, G. J.</p> <p>1986-01-01</p> <p>The isotopic composition of Pb from Shergotty, Zagami, and EETA 79001 meteorites was determined for different phases. Using phases with low U-238/Pb-204 ratio, the initial leads of these meteorites were defined. Samples from all three meteorites were shown to have distinct initial leads, and, thus to have evolved from different reservoirs over most of solar system history in a low U-238/Pb-204 environment. It follows that the parent planet of the <span class="hlt">shergottites</span> has a high Pb-204 concentration relative to U and must also be high in other volatiles. The possibility of the Martian origin of the SNC-type meteorites is discussed.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=19930030880&hterms=clay&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D40%26Ntt%3Dclay','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=19930030880&hterms=clay&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D40%26Ntt%3Dclay"><span>Soil mineralogy and chemistry on Mars - Possible clues from salts and clays in SNC meteorites</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Gooding, James L.</p> <p>1992-01-01</p> <p>If the <span class="hlt">shergottite</span>, nakhlite, and chassignite (SNC) meteorites' parent planet is Mars, then the aqueous precipitates found in them imply that oxidizing, water-based solutions may have been chemically active on that planet over the past 200-1300 million yrs. It is suggested that the mixture of aqueous precipitates found in the SNCs furnish a self-consistent model for the bulk elemental composition of surface sediments at the Viking Lander sites. Further mineralogical and stable-isotope studies of the secondary minerals may establish the limits for biological activity over the last 1300 million years of Mars' water-based chemistry.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=19920001032&hterms=clay&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D50%26Ntt%3Dclay','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=19920001032&hterms=clay&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D50%26Ntt%3Dclay"><span>Clays on Mars: Review of chemical and mineralogical evidence</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Banin, Amos; Gooding, James L.</p> <p>1991-01-01</p> <p>Mafic igneous bedrock is inferred for Mars, based on spectrophotometric evidence for pyroxene (principally in optically dark areas of the globe) and the pyroxenite-peridotite petrology of <span class="hlt">shergottite</span> nakhlite chassignite (SNC) meteorites. Visible and infrared spectra of reddish-brown surface fines (which dominate Martian bright areas) indicate ferric iron and compare favorably (though not uniquely) with spectra of palagonitic soils. Laboratory studies of SNC's and Viking Lander results support a model for Martian soil based on chemical weathering of mafic rocks to produce layer structured silicates (clay minerals), salts, and iron oxides.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/19930014003','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/19930014003"><span>Workshop on chemical weathering on Mars, part 2</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Burns, Roger (Editor); Banin, Amos (Editor)</p> <p>1992-01-01</p> <p>The third Mars Surface and Atmosphere Through Time (MSATT) Workshop, which was held 10-12 Sep. 1992, at Cocoa Beach/Cape Kennedy, focused on chemical weathering of the surface of Mars. The 30 papers presented at the workshop described studies of Martian weathering processes based on results from the Viking mission experiments, remote sensing spectroscopic measurements, studies of the <span class="hlt">shergottite</span>, nakhlite, and chassignite (SNC) meteorites, laboratory measurements of surface analog materials, and modeling of reaction pathways. A summary of the technical sessions is presented and a list of workshop participants is included.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2003AGUFM.P12B1066S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2003AGUFM.P12B1066S"><span>Geochemical modeling of the Martian mantle reservoir: Upwelling plume origin for SNC meteorites</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Shimoda, G.; Ikeda, Y.; Kita, N. T.; Morishita, Y.; Imae, N.</p> <p>2003-12-01</p> <p>SNC meteorites (<span class="hlt">shergottites</span>, nakhlites and chassignite) are widely accepted as their origin from Mars. Although individual SNC meteorites have been studied intensively to understand their petrogenesis, a question of how the parental magma was generated in Martian mantle has never been answered. Considering the absence of plate tectonics in Martian mantle, upwelling plume could be the only way to generate magma in Martian mantle. In addition, SNC meteorites have initial 143Nd/144Nd and 87Sr/86Sr ratios of which range is wider than all terrestrial basalts. Their strongly depleted and enriched isotopic compositions suggest the existence of terrestrial-mantle like depleted reservoir and crust-like enriched reservoir in Mars. In this study, we propose a new geochemical model involving upwelling plume from the deep Martian mantle, based on the results of high-pressure experiments and the geochemical analyses from the literatures. Our model successfully explains the early evolution of Martian mantle reservoirs in relation to the isotopic and trace element characteristics of later generated SNC source magmas. Our model assumes basically three steps, (1) the early mantle differentiation by magma ocean (~4.5Ga) to produce the deep mantle reservoir, (2) the first stage melting of a plume to produce nakhlites magma (~1.3Ga), and (3) the second stage melting of the same plume to produce <span class="hlt">shergottites</span> magma (<600Ma). We examine plausible physical and chemical conditions (pressure, temperature, mineral assemblages and melting degree) at each step to estimate rare earth element (REE) compositions of magmas. These estimated REE compositions are well agreement with the parental magma compositions of nakhlites and <span class="hlt">shergottites</span> which are estimated from the pyroxene core compositions. For the further examination of this model, initial 143Nd/144Nd and 87Sr/86Sr ratios of the nakhlite and <span class="hlt">shergottite</span> are calculated with our model assuming the bulk-silicate Mars initial 143Nd/144Nd and 87</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/20070003720','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/20070003720"><span>Ar-39-Ar-40 Ages of Two Nakhlites, MIL03346 and Y000593: A Detailed Analysis</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Park, Jisun; Garrison, Daniel; Bogard, Donald</p> <p>2007-01-01</p> <p>Radiometric dating of martian nakhlites by several techniques have given similar ages of approx.1.2-1.4 Ga [e.g. 1, 2]. Unlike the case with <span class="hlt">shergottites</span>, where the presence of martian atmosphere and inherited radiogenic Ar-40 produce apparent Ar-39-Ar-40 ages older than other radiometric ages, Ar-Ar ages of nakhlites are similar to ages derived by other techniques. However, even in some nakhlites the presence of trapped martian Ar produces some uncertainty in the Ar-Ar age. We present here an analysis of such Ar-Ar ages from the MIL03346 and Y000593 nakhlites.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/19980002913','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/19980002913"><span>Phase Equilibrium Investigations of Planetary Materials</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Grove, T. L.</p> <p>1997-01-01</p> <p>This grant provided funds to carry out experimental studies designed to illuminate the conditions of melting and chemical differentiation that has occurred in planetary interiors. Studies focused on the conditions of mare basalt generation in the moon's interior and on processes that led to core formation in the <span class="hlt">Shergottite</span> Parent Body (Mars). Studies also examined physical processes that could lead to the segregation of metal-rich sulfide melts in an olivine-rich solid matrix. The major results of each paper are discussed below and copies of the papers are attached as Appendix I.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2012EGUGA..1412161M','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2012EGUGA..1412161M"><span>Mineral and whole rock compositions of peridotites from Loma Caribe (Dominican Republic): insights into the evolution of the oceanic mantle in the Caribbean region</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Marchesi, C.; Garrido, C. J.; Proenza, J. A.; Konc, Z.; Hidas, K.; Lewis, J.; Lidiak, E.</p> <p>2012-04-01</p> <p>Several mantle peridotite massifs crop out as isolated dismembered bodies in tectonic belts along the northern margin of the Caribbean plate, especially in Cuba, Guatemala, Jamaica, Hispaniola and Puerto Rico. Among these bodies, the Loma Caribe peridotite forms the core of the Median Belt in central Dominican Republic and is considered to have been emplaced in Aptian time as result of the collision between an oceanic plateau (the Duarte plateau terrane) and the primitive Caribbean island arc. This peridotite massif is mainly composed of clinopyroxene-rich harzburgite, harzburgite, <span class="hlt">lherzolite</span> and dunite which mainly have porphyroclastic texture with strongly deformed orthopyroxene porphyroclasts, as commonly observed in ophiolitic mantle tectonites. Mg# [100*Mg/(Mg+Fe2+)] of olivine increases from lower values in <span class="hlt">lherzolite</span> (89-90), to higher values in harzburgite (89-91) and dunite (91-92). Orthopyroxene in harzburgite has higher Mg# (91-92) and lower Al2O3 (0.89 to 1.12 wt.%) than in <span class="hlt">lherzolite</span> (Mg# = 89-91; Al2O3 = 2.4-3.5wt.%), similarly to clinopyroxene (Mg# = 94-95 and Al2O3 = 0.89-1.10 wt% in harzburgite, versus Mg# = 86-94 and Al2O3 = 2.3-4.0 wt% in <span class="hlt">lherzolite</span>). Cr# [Cr/(Cr+Al)] of spinel spans from 0.30 in <span class="hlt">lherzolite</span> to 0.88 in dunite. These variations in terms of Mg# in olivine and Cr# in spinel overlap the mineral compositions in both abyssal and supra-subduction zone peridotites. The sample/chondrite REE concentrations of peridotites are variable (0.002 < LREE chondrite-normalized < 0.11 and 0.002 < HREE chondrite-normalized < 1.02) and their HREE contents generally reflect the clinopyroxene proportions in the samples, i.e. harzburgite has lower HREE abundances than <span class="hlt">lherzolite</span>. These trace element abundances are transitional between those of highly depleted supra-subduction peridotites from ophiolites in eastern Cuba and those of fertile mantle rocks in ultramafic massifs from Puerto Rico. Chondrite-normalized patterns are U-shaped (i.e., relatively</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2012EGUGA..1413129K','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2012EGUGA..1413129K"><span>Petrogenetic implications from ultramafic rocks and pyroxenites in ophiolitic occurrences of East Othris, Greece</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Koutsovitis, P.; Magganas, A.</p> <p>2012-04-01</p> <p>Ultramafic rocks and pyroxenites in east Othris are included within ophiolitic units near the villages of Vrinena, Karavomilos, Pelasgia, Eretria, Agios Georgios, Aerino and Velestino. The first five ophiolitic occurrences are estimated to have been emplaced between the Oxfordian and Tithonian-Berriasian[1,2,3], while the latter two have been emplaced during the Eocene[4]. Ultramafic rocks include variably serpentinized harzburgites and <span class="hlt">lherzolites</span>. Pyroxenites are usually found in the form of crosscutting veins within the harzburgites. Ultramafic rocks include depleted <span class="hlt">lherzolites</span>, with Al2O3 ranging from 1.12 to 1.80 wt% and Cr from 3250 to 3290 ppm, as well as moderate to highly depleted serpentinized harzburgites, with Al2O3 ranging from 0.69 to 1.98 wt% and Cr from 2663 to 5582 ppm. Pyroxenites have generally higher Al2O3 ranging from 1.91 to 3.08 wt% and variable Cr ranging from 1798 to 3611 ppm. <span class="hlt">Lherzolites</span> mostly include olivines (Fo=87.07-89.23) and clinopyroxenes (Mg#=85.71-90.12). Spinels from Eretria <span class="hlt">lherzolite</span> (TiO2=0.02-0.08 wt%, Al2O3=36.06-42.45 wt%, Cr#=31.67-36.33) are compositionally similar with those of MORB peridotites[5], while those from Vrinena <span class="hlt">lherzolite</span> (TiO2=0.16-0.43 wt%, Al2O3=6.90-22.12 wt%, Cr#=57.69-76.88) are similar to SSZ peridotites[5]. Serpentinized harzburgites include few olivines (Fo=90.51-91.15), enstatite porphyroclasts (Mg#=87.42-88.91), as well as fine grained enstatites of similar composition. Harzburgites from Pelasgia, Eretria and Agios Georgios include spinels (TiO2=0.03-0.08 wt%, Al2O3=23.21-31.58 wt%, Cr#=45.21-56.85) which do not clearly show if they are related with MORB or SSZ peridotites[5]. Spinels from Karavomilos harzburgite (TiO2=0.02-0.05 wt%, Al2O3=45.71-50.85 wt%, Cr#=16.84-22.32) are compositionally similar with MORB peridotites[5], whereas spinels from Vrinena harzburgite (TiO2=0.15-0.19 wt%, Al2O3=1.42-1.86 wt% Cr#=91.64-93.47) with SSZ peridotites[5]. Pyroxenites include clinopyroxenes (Mg#=84</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2006AGUFM.V23D0651L','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2006AGUFM.V23D0651L"><span>Kinetics of Peridotite and Pyroxenite-derived Melts Interaction: Implications for the Style and Extent of Melt-rock Reaction in the Mantle</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Lo Cascio, M.; Liang, Y.</p> <p>2006-12-01</p> <p>Distinct geochemical and petrologic features of ocean floor basalts and mantle peridotites suggest that the upper mantle is lithologically heterogeneous, consisting predominantly of peridotite and a small amount of eclogite [1]. An important issue of this marble cake mantle, is the nature of the peridotite and pyroxenite interface during mantle melting. It has been suggested that during mantle melting eclogite and peridotite develop a reactive boundary layer composed of a second generation eclogite and a layer of orthopyroxenite [2]. The existence of such a boundary layer has also been used to explain the observation that oceanic basalts are extracted with only limited interaction with the surrounding peridotite [3]. In spite of recent progresses, the kinetics of peridotite and pyroxenite-derived melts reaction is still not well understood. It is likely that there are two regimes of peridotite-pyroxenite melt interaction: a high T/low P regime where both the peridotite and pyroxenite are partially molten; and a low T/high P regime where only pyroxenite is partially molten. In this study we explored the kinetics of such interactions in both regimes by conducting <span class="hlt">lherzolite</span> dissolution experiments using a pyroxenite-derived melt at 1300°C and 1-2 GPa. Dissolution couples were formed by juxtaposing pre-synthesized rods of a basaltic andesite (54.6% SiO2, Mg# 0.42), whose composition is similar to pyroxenite derived liquid at 1300°C and 2 GPa [1,4], and a <span class="hlt">lherzolite</span> (ol+opx+cpx) in a Pt and graphite lined Mo capsule. The <span class="hlt">lherzolite</span> solidus is below 1300°C at 1 GPa [5], but above 1300°C at 2 GPa. <span class="hlt">Lherzolite</span> hardly dissolves (~35 μm in 6 hours) into the melt at 2 GPa and a thin opx layer (<10 μm thick) decorated with a few garnet crystals is observed at the <span class="hlt">lherzolite</span>-melt interface. From the concentration profiles of Al2O3 and MgO in the melt, we estimated the effective binary diffusion coefficient at 10^{-12}m2/s. Assuming an average mantle upwelling rate of ~50</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015EGUGA..1712342P','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015EGUGA..1712342P"><span>Petrological features of mantle xenoliths from Handler Ridge, Northern Victoria Land (NVL) , Antarctica</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Pelorosso, Beatrice; Bonadiman, Costanza; Coltorti, Massimo; Giacomoni, Pier Paolo; Ntaflos, Theodoros; Grégoire, Michel</p> <p>2015-04-01</p> <p>A petrological study of ultramafic xenoliths from Handler Ridge has been carried out, in order to characterize the lithospheric mantle domain of the Western Antarctic Rift System, from Mt Melbourne (74°21'S 164°42'E) to Handler Ridge (72°31'167°18'E). Samples are mainly anhydrous spinel (sp)-bearing <span class="hlt">lherzolites</span>, but few wehrlites also occur. Two textures were recognized: i) medium to coarse grained and ii) fine grained types. Evidences of melt/rock interaction (secondary clinopyroxene cpx2, cpx spongy and cloudy rims, glassy patches) can be also observed. Olivine (ol) is forsteritic in composition with Fo varying from 87.5 to 91.0. Within <span class="hlt">lherzolites</span> a more fertile group can be recognized with Fo ranging between 87.5 and 88.6. In wehrlites ol varies from Fo 84.5 to 86.1. NiO ranges from 0. 28 to 0.44 wt% for <span class="hlt">lherzolites</span>, while it has a lower content for wehrlites (0.20-0.40 wt%) As for ol, orthopyroxene (opx) in the most fertile <span class="hlt">lherzolites</span> presents mg# from 88.1 to 88.3, while it varies from 88.3 to 91 in the residual <span class="hlt">lherzolitic</span> group. None differences in Al2O3 and TiO2 contents between the two groups were recognized. In chondrite-normalized incompatible element patterns opx is depleted in light REE (LREE), with remarkable Ti and Zr positive anomalies. In <span class="hlt">lherzolites</span> mg# of primary clinopyroxene (cpx1) varies between 87.6 and 92.1. As for ol and opx, two groups can be recognized, although some overlap exists for two samples. Al2O3 and TiO2 vary from 3.68-6.51 wt% and from 0.19 to 0.71 wt% respectively. Secondary cpx (cpx2) is generally richer in FeO, TiO2 and N2O with respect to cpx1. In wehrlites cpx is characterized by very low mg# (84.3-88.6) and higher TiO2 contents (0.69-1.39 wt%) than <span class="hlt">lherzolites</span>. Irrespective to the lithology, chondrite-normalized incompatible trace element cpx1 patterns are variable enriched in Th, U, Nb, and Ta with negative Sr, Zr and Hf anomalies. Two trends can be recognized. The first one with (La/Yb)N varying from 1.28 to 9</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016AGUFM.T23F..08L','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016AGUFM.T23F..08L"><span>Differing Styles of Magmatic Emplacement and the Formation of Different Crustal Types during the Opening of Back-Arc Basins, a Case in Point from the East Sea/Sea of Japan</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Lee, S. M.</p> <p>2016-12-01</p> <p>The key issue in understanding the geology of back-arc basins is their similarity and difference with global mid-ocean ridges. Studies of back-arc basins are difficult relative to ridges because they often lie beneath thick sediment and are split by political boundaries. The Sea of Japan also known as the East Sea of Korea comprises of three major back-arc basins with unique characteristics, and thus may be a good place to investigate the processes that determine the framework of back-arc basins. The Japan Basin which opened up first around 32 Ma represents a classic example of an oceanic crust developed at a ridge-like setting. With 6-7 km thick crust, it has smooth seafloor where magnetic anomaly patterns can be well-recognized, suggesting that emplacement of crust occurred at a narrow strip (neovolcanic zone). Such characteristics contrast with those basins in the southwest that developed later. In both the <span class="hlt">Yamato</span> and Ulleung basins, the seafloor is underlain by a thick crust (10-15 km), twice that of typical oceanic crust. No magnetic anomaly patterns could be recognized, and yet this crust is often referred to as `thicker oceanic crust' or `anomalous-thick oceanic crust' because the seismic velocity structure resembles that of normal oceanic crust at the top. However, recent detailed study by Sato and others finds that the velocity of the thick crust under <span class="hlt">Yamato</span> basin is lower than that of mid-ocean ridges of similar age. The crust is uniformly thick in both the <span class="hlt">Yamato</span> and Ulleung basins, an observation which was not obvious in the latter case due thick sediment but confirmed by the analysis of gravity anomaly. I argue that the mode of emplacement during the early stages of opening was quite different in the case of these two basins close to the continent. A large buoyancy involving a rapid upwelling of large melt is likely to have been the dominant force as opposed to uniform forces exerted by steady plate separation. Also unlike mid-ocean ridges, the sudden</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/24740066','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/24740066"><span>Isotopic links between atmospheric chemistry and the deep sulphur cycle on Mars.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Franz, Heather B; Kim, Sang-Tae; Farquhar, James; Day, James M D; Economos, Rita C; McKeegan, Kevin D; Schmitt, Axel K; Irving, Anthony J; Hoek, Joost; Dottin, James</p> <p>2014-04-17</p> <p>The geochemistry of Martian meteorites provides a wealth of information about the solid planet and the surface and atmospheric processes that occurred on Mars. The degree to which Martian magmas may have assimilated crustal material, thus altering the geochemical signatures acquired from their mantle sources, is unclear. This issue features prominently in efforts to understand whether the source of light rare-earth elements in enriched <span class="hlt">shergottites</span> lies in crustal material incorporated into melts or in mixing between enriched and depleted mantle reservoirs. Sulphur isotope systematics offer insight into some aspects of crustal assimilation. The presence of igneous sulphides in Martian meteorites with sulphur isotope signatures indicative of mass-independent fractionation suggests the assimilation of sulphur both during passage of magmas through the crust of Mars and at sites of emplacement. Here we report isotopic analyses of 40 Martian meteorites that represent more than half of the distinct known Martian meteorites, including 30 <span class="hlt">shergottites</span> (28 plus 2 pairs, where pairs are separate fragments of a single meteorite), 8 nakhlites (5 plus 3 pairs), Allan Hills 84001 and Chassigny. Our data provide strong evidence that assimilation of sulphur into Martian magmas was a common occurrence throughout much of the planet's history. The signature of mass-independent fractionation observed also indicates that the atmospheric imprint of photochemical processing preserved in Martian meteoritic sulphide and sulphate is distinct from that observed in terrestrial analogues, suggesting fundamental differences between the dominant sulphur chemistry in the atmosphere of Mars and that in the atmosphere of Earth.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/20080026133','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/20080026133"><span>Rb-Sr and Sm-Nd Isotopic Studies of Antarctic Nakhlite MIL 03346</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Shih, C.-Y.; Nyquist, L. E.; Reese, Y.</p> <p>2006-01-01</p> <p>Nakhlites are olivine-bearing clinopyroxenites with cumulate textures, and probably came from Mars [e.g., 1]. A total of seven nakhlites have been identified so far. Unlike other martian meteorites (e.g., <span class="hlt">shergottites</span>), nakhlites have been only moderately shocked and their original igneous textures are still well-preserved. Also, these meteorites have similarly older crystallization ages of approx.1.3 Ga compared to <span class="hlt">shergottites</span> with ages of approx.0.18-0.57 Ga [e.g., 2]. MIL 03346 is characterized by abundant (approx.20 vol %) glassy mesostasis, indicating that it cooled rapidly and probably formed near the top [3] or at the bottom [4] of the chilled margin of a thick intrusive body. The mesostasis quenched from the trapped intercumulus liquid may provide information on the parent magma compositions of the nakhlites. In this report, we present Rb-Sr and Sm-Nd isotopic data for MIL 03346, discuss correlation of its age with those of other nakhlites and the nature of