Science.gov

Sample records for lovozero alkaline massif

  1. Crystal structure of hydrogen-bearing vuonnemite from the Lovozero alkaline massif

    SciTech Connect

    Rastsvetaeva, R. K. Aksenov, S. M.; Verin, I. A.; Lykova, I. S.

    2011-05-15

    Hydrogen-bearing vuonnemite from the Shkatulka hyperagpaitic pegmatite (the Lovozero alkaline massif, Kola Peninsula) was studied by single-crystal X-ray diffraction. The triclinic unit-cell parameters are as follows: a = 5.4712(1) Angstrom-Sign , b = 7.1626(1) Angstrom-Sign , c = 14.3702(3) Angstrom-Sign , {alpha} = 92.623(2) Degree-Sign , {beta} = 95.135(1) Degree-Sign , {gamma} = 90.440(1) Degree-Sign , sp. gr. P1, R = 3.4%. The Na{sup +} cations and H{sub 2}O molecules are ordered in sites between the packets. The water molecules are hydrogen bonded to the PO{sub 4} tetrahedra.

  2. Kalsilite of the Khibiny and Lovozero alkaline plutons, Kola Peninsula

    NASA Astrophysics Data System (ADS)

    Pakhomovsky, Ya. A.; Yakovenchuk, V. N.; Ivanyuk, G. Yu.

    2009-12-01

    Kalsilite—a typical mineral of ore-bearing zones of the Khibiny and Lovozero plutons—was formed after low-Si and high-K nepheline in one of three ways: (1) by relatively high-temperature replacement of Na with K; (2) due to orthoclase-kalsilite poikiloblastesis in foidolites and overlapping foyaites; or (3) by replacement of nepheline with zeolite.

  3. A Pb isotope investigation of the Lovozero Agpaitic Nepheline Syenite, Kola Peninsula, Russia

    NASA Astrophysics Data System (ADS)

    Zartman, R. E.; Kogarko, L. N.

    2014-01-01

    For the first time Pb isotope composition was established in Lovozero rocks and raremetal ores, which is important for identifying their sources. The world's largest layered intrusion of agpaitic nepheline syenite-the Lovozero alkaline massif—is located near the center of the Kola Peninsula in Russia. This superlarge complex plutonic body hosts the economically important loparite and eudiallyte deposits [1]. These deposits contain immense resources of REE, Nb, Ta, Zr, and constitute a world class mineral district. The Lovozero massif belongs to the Kola ultramafic alkaline and carbonatitic province (KACP) of Devonian age. Previous bulk rock studies have shown that the initial Sr and Nd isotope ratios of Lovozero rocks plot in the depleted mantle quadrant of Sr-Nd diagrams [2]. More recently, Hf isotope data obtained by Kogarko et al. (3) confirm that the Lovozero and Khibina massifs with ɛHf between 6 and 8 are derived predominantly from a depleted mantle source. It was shown that Sr, Nd, and Hf abundances are significantly elevated in the Kola alkaline rocks, and thus their isotopic compositions are relatively insensitive to minor contamination by the overlying crustal rocks. By contrast, Pb in the KACP rocks is a much more sensitive indicator of a crustal component. In this paper we investigate the lead isotopic signature of all resentative types of Lovozero rocks (Table 1) in order to further characterize their mantle sources. The Lovozero massif consists of four intrusive phases. Rocks of phase I (mostly nepheline syenites) comprise about 5% of the total volume, phase II (urtites, foyaite, lujavrites) forms the main portion of the massif comprising 77% in volume, and phase III (eudialyte lujavrites) contributes about 18%. Country rocks are represented by Devonian effusive rocks and Archean gneisses.

  4. The rare-metal ore potential of the Proterozoic alkaline ultramafic massifs from eastern part of the Baltic Shield in the Kola alkaline province.

    NASA Astrophysics Data System (ADS)

    Sorokhtina, Natalia; Kogarko, Lia

    2014-05-01

    The Kola Alkaline Province consists of intrusions of two main stages of the intraplate alkaline magmatism. The early stage of igneous activity occurred in Proterozoic 1.9 billion years ago, the next in Paleozoic at 380 million years. The Proterozoic alkaline magmatism produced Gremyakha-Vyrmes and Elet'ozero large alkaline-ultrabasic massifs, Tiksheozero carbonatite massif and numerous small syenite complexes. Paleozoic magmatism on Baltic Shield exhibited more widely, than Proterozoic. The world largest Khibiny and Lovozero alkaline intrusions, numerous alkaline-ultrabasic massifs with carbonanites, alkaline dike swarms and diatremes were formed. It is well known that carbonatites of Paleozoic alkaline-ultrabasic massifs contain large-scale deposits of rare-metal ores (Afanasiev et al., 1998). The metasomatic rocks on foidolites and carbonatites of Gremyakha-Vyrmes are final products of differentiation of Proterozoic alkaline-ultrabasic magma enriched in incompatible elements, including Nb and Zr similar to Paleozoic carbonatites. The massif Gremyakha-Vyrmes is one of the largest titanomagnetite-ilmenite deposits in Russia associated with ultrabasites. Our investigation showed that albite-microcline and aegirine-albite metasomatites formed rich rare-metal ores consisting of 3.2 wt. % Nb2O5 and 0.7 ZrO2. Zircon and pyrochlore-group minerals represent the main minerals of rare-metal ores. The following evolutionary sequences of pyrochlore group minerals has been observed: betafite or U pyrochlore - Na-Ca pyrochlore - Ba-Sr pyrochlore - "silicified" pyrochlore - Fe-Nb, Al-Nb silicates. Such evolution from primary Nb oxides to secondary silicates under low temperature hydrothermal conditions is similar to the evolution of rare metal phases in Paleozoic alkaline massifs analogous to Lovozero syenites and in carbonatites. The rare metal minerals of Gremyakha-Vyrmes crystallized in high alkaline hydrothermal environment at increased activity of Nb, Ta, Zr, U, Th and at

  5. Kyanoxalite, a new cancrinite-group mineral species with extraframework oxalate anion from the Lovozero alkaline pluton, Kola Peninsula

    NASA Astrophysics Data System (ADS)

    Chukanov, N. V.; Pekov, I. V.; Olysych, L. V.; Massa, W.; Yakubovich, O. V.; Zadov, A. E.; Rastsvetaeva, R. K.; Vigasina, M. F.

    2010-12-01

    Kyanoxalite, a new member of the cancrinite group, has been identified in hydrothermally altered hyperalkaline rocks and pegmatites of the Lovozero alkaline pluton, Kola Peninsula, Russia. It was found at Mount Karnasurt (holotype) in association with nepheline, aegirine, sodalite, nosean, albite, lomonosovite, murmanite, fluorapatite, loparite, and natrolite and at Mt. Alluaiv. Kyanoxalite is transparent, ranging in color from bright light blue, greenish light blue and grayish light blue to colorless. The new mineral is brittle, with a perfect cleavage parallel to (100). Mohs hardness is 5-5.5. The measured and calculated densitiesare 2.30(1) and 2.327 g/cm3, respectively. Kyanoxalite is uniaxial, negative, ω = 1.794(1), ɛ = 1.491(1). It is pleochroic from colorless along E to light blue along O. The IR spectrum indicates the presence of oxalate anions C2O{4/2-} and water molecules in the absence of CO{3/2-} Oxalate ions are confirmed by anion chromatography. The chemical composition (electron microprobe; water was determined by a modified Penfield method and carbon was determined by selective sorption from annealing products) is as follows, wt %: 19.70 Na2O, 1.92 K2O, 0.17 CaO, 27.41 Al2O3, 38.68 SiO2, 0.64 P2O5, 1.05 SO3, 3.23 C2O3, 8.42 H2O; the total is 101.18. The empirical formula (Z = 1) is (Na6.45K0.41Ca0.03)Σ6.89(Si6.53Al5.46O24)[(C2O4)0.455(SO4)0.13(PO4)0.09(OH)0.01]Σ0.68 · 4.74H2O. The idealized formula is Na7(Al5-6Si6-7O24)(C2O4)0.5-1 · 5H2O. Kyanoxalite is hexagonal, the space group is P63, a = 12.744(8), c = 5.213(6) -ray powder diffraction pattern are as follows, [ d, [A] ( I, %)( hkl)]: 6.39(44) (110), 4.73 (92) (101), 3.679 (72) (300), 3.264 (100) (211, 121), 2.760 (29) (400), 2.618 (36) (002), 2.216, (29) (302, 330). According to the X-ray single crystal study ( R = 0.033), two independent C2O4 groups statistically occupy the sites on the axis 63. The new mineral is the first natural silicate with an additional organic anion and is the most

  6. Fractionation of Zr and Hf during the differentiation of peralkaline magmatic system (Lovozero rare metal deposit, Kola Peninsula)

    NASA Astrophysics Data System (ADS)

    Kogarko, Liya

    2016-04-01

    Zirconium and hafnium are valuable strategic metals. We assessed principal features of the distribution of these elements in peralkaline rocks, ores and rock-forming and accessory minerals of Lovozero complex. The accumulation of these elements during the evolution of alkaline magma of Lovozero deposit up to extremely high concentrations in eudialyte ores (5-8% ZrO2 and 1200-1800 ppm Hf) has been established. These ores represent valuable complex raw material not only for Zr and Hf, but for REE as well. We evaluated partition coefficients of these elements in alkaline pyroxenes (aegirines) from porphyry-like agpaitic lujavrites of Lovozero massif which are 0.40 for zirconium and 0.58 for hafnium. We assessed variations of Zr/Hf ratio for all the rocks of Lovozero alkaline massif. The growth of this ratio in the course of the evolution of alkaline magma has been observed from 38 in the earliest magmatic phase, to 44 in the second phase and to 51-53 in the latest manifestation of alkaline magmatsm. On the basis of the obtained data and equations of equilibrium and fractional crystallization the model of the fractionation of zirconium and hafnium during the evolution of Lovozero intrusion has been constructed. We have demonstrated that the source of strongly enriched magmatic systems similar to Lovozero rare metal deposit is short-lived enriched reservoir - metasomatized and carbonatized mantle substrate. We investigated the fractionation of zirconium and hafnium in carbonatized mantle xenoliths from East Antarctica. The elevated Zr/Hf ratios (up to 125) in metasomatized xenoliths by comparison with the chondritic value have been found. The main reactions of carbonate metasomatism lead to the replacement of primary orthopyroxene by clinopyroxene 2Mg2Si2O6 + CaMg(CO3)2 = 2Mg2SiO4 + CaMgSi2O6 + 2CO2 3CaMg(CO3)2 + CaMgSi2O6 = 4CaCO3 + 2Mg2SiO4 + 2CO2 The substantial expansion of the clinopyroxene crystallization field results in increase of Zr/Hf ratio in equilibrium

  7. K-alkaline rocks and lamproites of Tomtor massif

    NASA Astrophysics Data System (ADS)

    Vladykin, Nikolai

    2015-04-01

    Tomtor massif of the largest volcano-plutonic deep alkaline-carbonatite massifs world central type. Area of massif occupy 240 km2 and carbonatites stock is 40 km2. The super large deposit of Nb, TR, Y, Sc, Sr ,REE (Frolov et al. 2001)is found within the massif. The numerical publication are devoted to the ore mineralization there. But the geological struc-ture of the massif and the chemistry of its constituting rocks are not well understood. We obtained new ages based on U-Pb zircon and mica Ar-Ar method (Kotov, Vladykin et al. 2014 Vladykin et al. 2015). The massif was created in 2 stages: 700 and 400 Ma. We (Vla-dykin et al 1998) found rocks of lamproite series and proposed a new scheme of magmatism and the ore.genesis (Vladykin 2007, 2009). Biotite - pyroxenite, peridotite originated in first stage and then intruded iolites, nepheline and alkali syenite. Syenites occupy 70% of -massif and contain 12-13% K2O and 2-4% Na2O showing the K-alkaline-ultramafic nature of Tomtor volcano-plutonic massif (Vladykin 2009). The first stage was accomplished by nelsonitov calcite, dolomite and ankerite carbonatites. Second stage (400Ma) volcanics picrite - lamproite veins and eruptive breccias meli-lite, melanephelinites, tinguaites appered. These rocks are cut by carbonatites of second stage. It was finished by intensive explosive eruption of a silicate (lamproite) tuffs lavobrec-cia kimberlite formed Ebelyakhdiamondiferous placer, melilite rocks in diatremes (feeders), as well as carbonate-phosphate (kamaforite) explosive tuffs with siderite ores. This carbona-tite complex is preserved within the subsidence caldera. Tuff eruption in conjunction with gas and hydrothermal activity determined its rare metal mineralization. These rocks contain to: Nb- 21%, TR-15%, Y-1.5%, Sc-1%, Zr- 0,5% Zn-, Sr-6%, Ti-8%, Ba-4%, V - 8000 ppm, Be- 300 ppm, Ga- 80 ppm, Cr- 1200ppm, Ni- 230 ppm, Mo- 145 ppm, Pb- 4300 ppm, Th- 1500 ppm, U-193 ppm. Picrite - olivine (rare leucite) lamproite and

  8. Yegorovite, Na4[Si4O8(OH)4]·7H2O, a new mineral from the Lovozero alkaline pluton, Kola Peninsula

    NASA Astrophysics Data System (ADS)

    Pekov, I. V.; Zubkova, N. V.; Chukanov, N. V.; Zadov, A. E.; Grishin, V. G.; Pushcharovsky, D. Yu.

    2010-12-01

    A new mineral, yegorovite, has been identified in the late hydrothermal, low-temperature assemblage of the Palitra hyperalkaline pegmatite at Mt. Kedykverpakhk, Lovozero alkaline pluton, Kola Peninsula, Russia. The mineral is intimately associated with revdite and megacyclite, earlier natrosilite, microcline, and villiaumite. Yegorovite occurs as coarse, usually split prismatic (up to 0.05 × 0.15 × 1 mm) or lamellar (up to 0.05 × 0.7 × 0.8 mm) crystals. Polysynthetic twins and parallel intergrowths are typical. Mineral individuals are combined in bunches or chaotic groups (up to 2 mm); radial-lamellar clusters are less frequent. Yegorovite is colorless, transparent with vitreous luster. Cleavage is perfect parallel to (010) and (001). Fracture is splintery; crystals are readily split into acicular fragments. The Mohs hardness is ˜2. Density is 1.90(2) g/cm3 (meas) and 1.92 g/cm3 (calc). Yegorovite is biaxial (-), with α = 1.474(2), β = 1.479(2), and γ = 1.482(2), 2 V meas > 70°, 2 V calc = 75°. The optical orientation is X ∧ a ˜ 15°, Y = c, Z = b. The IR spectrum is given. The chemical composition determined using an electron microprobe (H2O determined from total deficiency) is (wt %): 23.28 Na2O, 45.45 SiO2, 31.27 H2Ocalc; the total is 100.00. The empirical formula is Na3.98Si4.01O8.02(OH)3.98 · 7.205H2O. The idealized formula is Na4[Si4O8(OH)4] · 7H2O. Yegorovite is monoclinic, space group P21/ c. The unit-cell dimensions are a = 9.874, b= 12.398, c = 14.897 Å, β = 104.68°, V = 1764.3 Å3, Z = 4. The strongest reflections in the X-ray powder pattern ( d, Å ( I, %)([ hkl]) are 7.21(70)[002], 6.21(72)[012, 020], 4.696(44)[022], 4.003(49)[211], 3.734(46)[ bar 2 13], 3.116(100)[024, 040], 2.463(38)[ bar 4 02, bar 2 43]. The crystal structure was studied by single-crystal method, R hkl = 0.0745. Yegorovite is a representative of a new structural type. Its structure consists of single chains of Si tetrahedrons [Si4O8(OH)4]∞ and sixfold polyhedrons

  9. Structure, age, and ore potential of the Burpala rare-metal alkaline massif, northern Baikal region

    NASA Astrophysics Data System (ADS)

    Vladykin, N. V.; Sotnikova, I. A.; Kotov, A. B.; Yarmolyuk, V. V.; Sal'nikova, E. B.; Yakovleva, S. Z.

    2014-07-01

    The Burpala alkaline massif is a unique geological object. More than 50 Zr, Nb, Ti, Th, Be, and REE minerals have been identified in rare-metal syenite of this massif. Their contents often reach tens of percent, and concentrations of rare elements in rocks are as high as 3.6% REE, 4% Zr, 0.5% Y, 0.5% Nb, 0.5% Th, and 0.1% U. Geological and geochemical data show that all rocks in the Burpala massif are derivatives of alkaline magma initially enriched in rare elements. These rocks vary in composition from shonkinite, melanocratic syenite, nepheline and alkali syenites to alaskite and alkali granite. The extreme products of magma fractionation are rare-metal pegmatites, apatite-fluorite rocks, and carbonatites. The primary melts were related to the enriched EM-2 mantle source. The U-Pb zircon ages of pulaskite (main intrusive phase) and rare-metal syenite (vein phase) are estimated at 294 ± 1 and 283 ± 8 Ma, respectively. The massif was formed as a result of impact of the mantle plume on the active continental margin of the Siberian paleocontinent.

  10. Vigrishinite, Zn2Ti4 - x Si4O14(OH,H2O,□)8, a new mineral from the Lovozero alkaline complex, Kola Peninsula, Russia

    NASA Astrophysics Data System (ADS)

    Pekov, I. V.; Britvin, S. N.; Zubkova, N. V.; Chukanov, N. V.; Bryzgalov, I. A.; Lykova, I. S.; Belakovskiy, D. I.; Pushcharovsky, D. Yu.

    2013-12-01

    A new mineral vigrishinite, epistolite-group member and first layer titanosilicate with species-defining Zn, was found at Mt. Malyi Punkaruaiv, in the Lovozero alkaline complex, Kola Peninsula, Russia. It occurs in a hydrothermally altered peralkaline pegmatite and is associated with microcline, ussingite, aegirine, analcime, gmelinite-Na, and chabazite-Ca. Vigrishinite forms rectangular or irregularly shaped lamellae up to 0.05 × 2 × 3 cm flattened on [001]. They are typically slightly split and show blocky character. The mineral is translucent to transparent and pale pink, yellowish-pinkish or colorless. The luster is vitreous. The Mohs' hardness is 2.5-3. Vigrishinite is brittle. Cleavage is {001} perfect. D meas = 3.03(2), D calc = 2.97 g/cm3. The mineral is optically biaxial (-), α = 1.755(5), β = 1.82(1), γ = 1.835(8), 2 V meas = 45(10)°, 2 V calc = 50°. IR spectrum is given. The chemical composition (wt %; average of 9 point analyses, H2O is determined by modified Penfield method) is as follows: 0.98 Na2O, 0.30 K2O, 0.56 CaO, 0.05 SrO, 0.44 BaO, 0.36 MgO, 2.09 MnO, 14.39 ZnO, 2.00 Fe2O3, 0.36 Al2O3, 32.29 SiO2, 29.14 TiO2, 2.08 ZrO2, 7.34 Nb2O5, 0.46 F, 9.1 H2O, -0.19 O=F2, total is 101.75. The empirical formula calculated on the basis of Si + Al = 4 is: H7.42(Zn1.30Na0.23Mn0.22Ca0.07Mg0.07K0.05Ba0.02)Σ1.96(Ti2.68Nb0.41Fe{0.18/3+}Zr0.12)Σ3.39(Si3.95Al0.05)Σ4 20.31F0.18. The simplified formula is: Zn2Ti4- x Si4O14(OH,H2O,□)8 ( x < 1). Vigrishinite is triclinic, space group P , a = 8.743(9), b = 8.698(9), c = 11.581(11)Å, α = 91.54(8)°, β = 98.29(8)°, γ = 105.65(8)°, V = 837.2(1.5) Å3, Z = 2. The strongest reflections in the X-ray powder pattern ( d, Å, - I[ hkl]) are: 11.7-67[001], 8.27-50[100], 6.94-43[01, 10], 5.73-54[11, 002], 4.17-65[020, 2, 200], and 2.861-100[30, 22, 004, 11]. The crystal structure model was obtained on a single crystal, R = 0.171. Vigrishinite and murmanite are close in the structure of the TiSiO motif, but

  11. Solid Inclusions in Au-nuggets, genesis and derivation from alkaline rocks of the Guli Massif, Northern Siberia

    NASA Astrophysics Data System (ADS)

    Dvorani, Sami N.

    2016-04-01

    A total of 112 Au-nuggets, collected from alluvial placer deposits of the Ingarinda River from the Guli massif, located in northem Siberia, Russia, were investigated. The Guli massif consists of a huge dunite-clinopyroxenite complex (the largest complex in the world), an alkaline to highly alkaline rock suite (melilite, nephelinite, ijolite) enveloping the dunite and carbonatite intrusions, associated with disseminated schlieren type chromitite and Au-Ag, Pt placer deposits. The nuggets are characterized by various sizes and shapes and show chemical compositions Au, Au-Ag and AuCu, typical for a derivate of carbon-atites and/or ultramafic complexes. A great variety of oxide, silicate, REE-minerals, carbonate and sulphide inclusions have been detected in the nuggets, which are identical in mineralogy and chemical composition to mineral constituents of the alkaline to highly alkaline rock suite surrounding the Guli dunite core complex thus, considered as the source for Au-nuggets.

  12. Origin of mafic and ultramafic cumulates from the Ditrău Alkaline Massif, Romania

    NASA Astrophysics Data System (ADS)

    Pál-Molnár, Elemér; Batki, Anikó; Almási, Enikő; Kiss, Balázs; Upton, Brian G. J.; Markl, Gregor; Odling, Nicholas; Harangi, Szabolcs

    2015-12-01

    Mafic-ultramafic cumulates enclosed in gabbroic-dioritic rocks form part of the Mesozoic Ditrău Alkaline Massif in the Eastern Carpathians, Romania. The poikilitic olivine- and pyroxene-rich and nearly mono mineralic hornblendite rocks display typical cumulate textures with early crystallised olivine (Fo75-73), diopside and augite. In the early stages of their genesis the amphibole was intercumulus whilst in later stages it acquired cumulus status as the fractionating magma evolved. Using major and trace element compositions of minerals and whole-rock samples the origin of these cumulates is determined and the parental magma composition and depth of emplacement are calculated. Cumulus clinopyroxene has more primitive composition than intercumulus amphibole suggesting closed system fractionation for the evolution of poikilitic olivine- and pyroxene-rich cumulates. The evolution of the amphibole-rich mesocumulates is more clearly the result of closed system crystallisation dominated by the precipitation of clinopyroxene and amphibole cumulus crystals. Lamprophyre dykes of the Ditrău Alkaline Massif are proposed to reflect multiple basanitic parental magma batches from which the cumulus olivine and clinopyroxene crystallised. Relative to these dykes the calculated equilibrium melts for intercumulus amphibole in the cumulates was more primitive whilst that for the cumulus amphibole was more evolved. The calculated crystallisation temperature and pressure of ~ 1000-1050 °C and ~ 0.7 GPa, based on the composition of the amphiboles, indicate crystallisation at lower crustal depths. Rare earth element compositions are consistent with an intra-plate tectonic setting.

  13. Petrographic, geochemical and isotopic evidence of crustal assimilation processes in the Ponte Nova alkaline mafic-ultramafic massif, SE Brazil

    NASA Astrophysics Data System (ADS)

    Azzone, Rogério Guitarrari; Montecinos Munoz, Patricio; Enrich, Gaston Eduardo Rojas; Alves, Adriana; Ruberti, Excelso; Gomes, Celsode Barros

    2016-09-01

    Crustal assimilation plus crystal fractionation processes of different basanite magma batches control the evolution of the Ponte Nova cretaceous alkaline mafic-ultramafic massif in SE Brazil. This massif is composed of several intrusions, the main ones with a cumulate character. Disequilibrium features in the early-crystallized phases (e.g., corrosion and sieve textures in cores of clinopyroxene crystals, spongy-cellular-textured plagioclase crystals, gulf corrosion texture in olivine crystals) and classical hybridization textures (e.g., blade biotite and acicular apatite crystals) provide strong evidence of open-system behavior. All samples are olivine- and nepheline-normative rocks with basic-ultrabasic and potassic characters and variable incompatible element enrichments. The wide ranges of whole-rock 87Sr/86Sri and 143Nd/144Ndi ratios (0.70432-0.70641 and 0.512216-0.512555, respectively) are indicative of crustal contribution from the Precambrian basement host rocks. Plagioclase and apatite 87Sr/86Sr ratios (0.70422-0.70927) obtained for the most primitive samples of each intrusion indicate disequilibrium conditions from early- to principal-crystallization stages. Isotope mixing-model curves between the least contaminated alkaline basic magma and heterogeneous local crustal components indicate that each intrusion of the massif is differentiated from the others by varied degrees of crustal contribution. The primary mechanisms of crustal contribution to the Ponte Nova massif involve the assimilation of host rock xenoliths during the development of the chamber environment and the assimilation of partial melts from the surrounding host rocks. Thermodynamic models using the melts algorithm indicate that parental alkaline basic magmas can be strongly affected by contamination processes subsequently to their initial stages of crystallization when there is sufficient energy to assimilate partial melts of crustal host rocks. The assimilation processes are considered to

  14. Zvyaginite, NaZnNb2Ti[Si2O7]2O(OH,F)3(H2O)4 + x ( x < 1), a new mineral of the epistolite group from the Lovozero Alkaline Pluton, Kola Peninsula, Russia

    NASA Astrophysics Data System (ADS)

    Pekov, I. V.; Lykova, I. S.; Chukanov, N. V.; Yapaskurt, V. O.; Belakovskiy, D. I.; Zolotarev, A. A.; Zubkova, N. V.

    2014-12-01

    A new mineral, zvyaginite, a member of the epistolite group, has been found at Mt. Malyi Punkaruaiv, Lovozero Alkaline Complex, Kola Peninsula, Russia. It occurs in a hydrothermally altered peralkaline pegmatite and is associated with ussingite, microcline, aegirine, sphalerite, vigrishinite, and sauconite. Zvyaginite forms rectangular or irregular-shaped lamellae up to 0.1 × 1 × 2 cm in size when flattened [001]. The mineral is translucent to transparent and colorless, pearly-white, yellowish brownish, pale pink, or violet pink. The luster is nacreous on crystal faces and greasy on broken surfaces. Its Mohs' hardness is 2.5-3. Zvyaginite is brittle. The cleavage parallel to {001} is perfect. D meas = 2.88(3), D calc = 2.94 g/cm3. The mineral is optically biaxial (-), α = 1.626(5), β = 1.714(3), γ = 1.740(5), 2 V meas = 45(15)°, 2 V calc = 55°. The IR spectrum is given. Chemical composition is as follows (wt %; average of five point analyses; H2O was determined using the modified Penfield method): 4.74 Na2O, 0.22 K2O, 0.77 CaO, 1.36 MnO, 0.24 FeO, 9.61 ZnO, 0.19 Al2O3, 29.42 SiO2, 12.33 TiO2, 27.22 Nb2O5, 1.94 F, 12.65 H2O, -0.82 -O = F2, for a total of 99.87. The empirical formula calculated on the basis of Si + Al = 4 is: Na1.24K0.04Ca0.11Mn0.16Fe0.03Zn0.96Nb1.66Ti1.25(Si3.97Al0.03)Σ4O15.07(OH)2.10F0.83(H2O)4.64. The simplified formula is: NaZnNb2Ti[Si2O7]2O(OH,F)3(H2O)4 + x ( x < 1), Zvyaginite is triclinic, , a = 8.975(3), b = 8.979(3), c = 12.135(4) Å, α = 74.328(9)°, β = 80.651(8)°, γ = 73.959(8)°, V = 900.8(6) Å3, Z = 2. The strongest reflections in the X-ray powder pattern ( d, Å- I[ hkl]) are: 11.72-100[001], 5.83-40[002], 5.28-53[-1-11, 112], 4.289-86[200, 021], 3.896-36[-1-12, -201, 003, 022, 113], 2.916-57[310, 132, 004], 2.862-72[130, 312]. The model of the crystal structure was obtained on a single crystal, R = 0.159. Zvyaginite and epistolite are similar in the structure of the NbTiSiO motif, but differ from each other in composition

  15. Voronkovite, Na15(Na,Ca,Ce)3(Mn,Ca)3Fe3Zr3Si26O72(OH,O)4Cl · H2O, a new mineral species of the eudialyte group from the Lovozero alkaline pluton, Kola Peninsula, Russia

    NASA Astrophysics Data System (ADS)

    Khomyakov, A. P.; Nechelyustov, G. N.; Rastsvetaeva, R. K.

    2009-12-01

    This paper describes a new member of the eudialyte group named in honor of Alexander Alexandrovich Voronkov (1928-1982), the prominent Russian crystallographer. The new mineral has been found in the Shkatulka hyperalkaline pegmatite body at Mt. Alluaiv, Lovozero alkaline pluton, Kola Peninsula, Russia. The mineral is associated with microcline, sodalite, nepheline, aegirine, terskite, lomonosovite, vuonnemite, shkatulkalite, manganoneptunite, and sphalerite. Voronkovite occurs as rounded, poorly faced crystals up to 2-5 mm across. The new mineral is light brown, with vitreous luster and conchoidal fracture. The streak is white. Voronkovite is transparent and brittle; the Mohs hardness is 5; cleavage or parting is not observed. D(meas) = 2.97(2) g/cm3 (volumetric method); D(calc) = 2.95 g/cm3. The new mineral is uniaxial, positive, pleochroic from lemon yellow along X to brownish pink along Y, and is not luminescent in UV light. Voronkovite easily dissolves and gelates in acid at room temperature. The new mineral is trigonal, space group R3, a = 14.205(7), c = 30.265(15) Å, V = 5289(8) Å3, Z = 3. The strongest reflections in the X-ray diffraction pattern [ d, Å ( I)( hkl)] are 2.970(100)(315), 4.316(85)(205), 2.848(84)(404), 3.221(43)(208), 3.536(41)(027), 3.039(41)(119). The chemical composition (electron microprobe, H2O determined with chemical analysis) is as follows, wt %: 15.84 Na2O, 0.28 K2O, 3.08 CaO, 1.76 SrO, 4.65 MnO, 3.53 FeO, 0.93 La2O3, 1.36 Ce2O3, 0.68 Nd2O3, 0.15 Al2O3, 49.48 SiO2, 0.33 TiO2, 14.11 ZrO2, 0.23 HfO2, 0.91 Nb2O5, 0.44 Cl, 0.21 F, 1.56 H2O, 0.19 -O = (Cl,F)2; total is 99.34. The empirical formula calculated on the basis of Si + Al = 26 ( Z = 3) is as follows: (Na13.96Sr0.54K0.19)Σ14.69(Na1.64Ca0.92Ce0.26 La0.18)Σ3.00(Mn2.06Ca0.81Nd0.13)Σ3.00(F1.54Zr0.60Na0.48Nb0.21Ti0.13Hf0.04)Σ3.00Zr3.00(Si1.91Al0.09)Σ2.00(Si24O72)[(OH)2.98 O1.02]Σ4(Cl0.39F0.35)Σ0.74 · 1.23H2O. The simplified formula is Na15(Na,Ca,Ce)3(Mn,Ca)3Fe3Zr3Si26O72(OH

  16. Model of formation of the Khibiny-Lovozero ore-bearing volcanic-plutonic complex

    NASA Astrophysics Data System (ADS)

    Arzamastsev, A. A.; Arzamastseva, L. V.; Zhirova, A. M.; Glaznev, V. N.

    2013-09-01

    The paper presents the results of a study of the large Paleozoic ore-magmatic system in the northeastern Fennoscandian Shield comprising the Khibiny and Lovozero plutons, the Kurga intrusion, volcanic rocks, and numerous alkaline dike swarms. As follows from the results of deep drilling and 3D geophysical simulation, large bodies of rocks pertaining to the ultramafic alkaline complex occur at the lower level of the ore-magmatic system. Peridotite, pyroxenite, melilitolite, melteigite, and ijolite occupy more than 50 vol % of the volcanic-plutonic complex within the upper 15 km accessible to gravity exploration. The proposed model represents the ore-magmatic system as a conjugate network of mantle magmatic sources localized at different depth levels and periodically supplying the melts belonging to the two autonomous groups: (1) ultramafic alkaline rocks with carbonatites and (2) alkali syenites-peralkaline syenites, which were formed synchronously having a common system of outlet conduits. With allowance for the available isotopic datings and new geochronological evidence, the duration of complex formation beginning from supply of the first batches of melt into calderas and up to postmagmatic events, expressed in formation of late pegmatoids, was no less than 25 Ma.

  17. Carboniferous magmatism in the Evora Massif (southwest Portugal, Ossa-Morena Zone): from typical arc calc-alkaline to adakitic-like magmatism

    NASA Astrophysics Data System (ADS)

    Lima, Selma M.; Neiva, Ana M. R.; Ramos, Joao M. F.

    2014-05-01

    The Evora Massif is one of the subdivisions of western Ossa-Morena Zone. It is a dome-like structure mainly composed of Ediacaran, Cambrian and Ordovician country rocks, affected by medium- and high-grade metamorphism coeval with the emplacement of several mafic to felsic intrusive bodies. The last magmatic event recorded in this area (Carboniferous) consists of calc-alkaline volcanism and voluminous plutonism (mainly composed by tonalites, gabbros, diorites and late-orogenic granodiorites and granites) [1]. Detailed chemical and isotopic studies from Evora Massif plutons were performed in the last few years. Whole-rock chemical and isotopic data suggest that the Hospitais tonalite (HT), Alto de Sao Bento area (ASB) and Reguengos de Monsaraz pluton (RM) resulted from fractional crystallization of mantle-derived magmas followed by mixing with variable proportions of crustal melts [2-4]. U-Pb ID-TIMS data indicate an age of 337-335 for the RM [4]. The Pavia pluton is a multiphase granitic body constructed incrementally by the episodic emplacement of several batches of magma (at 328 Ma, ca. 324 Ma and 319-317 Ma) [5]. The main granitic phases range from tonalite to two-mica granite that contain rare surmicaceous and fine-grained enclaves, and granitic and amphibolitic xenoliths. On the other hand, they are cut by abundant rhyodacite porphyries, microgranites (s.l.) and pegmatite dikes, predominantly oriented NE-SW and NW-SE. Although each phase seems to represent a distinct batch of magma, whole-rock Sr-Nd isotopic data suggest a similar and fairly homogenous source for all the constituent phases. Initial 87Sr/86Sr varies between 0.70428 and 0.7058 and ɛ Ndt ranges from -3.4 to +0.4, pointing towards a mantle or juvenile crust origin. A higher variation is observed in whole-rock δ18O (5.6-9.6 o), consistent with assimilation of crust. The PP was interpreted as the result of assimilation-fractional crystallization of a basaltic magma. Substantial differences between

  18. A New Occurrence of Alkaline Magmatism on the Kola Peninsula: An Agpaitic Dyke in the Kandalaksha Region.

    NASA Astrophysics Data System (ADS)

    Akimenko, Mariya; Kogarko, Lia; Sorokhtina, Natalia; Kononkova, Natalia; Mamontov, Vladimir

    2015-04-01

    high concentrations of Zr, Sr, Ba, and REEs in the agpaitic dyke of the "Mokhnatye Roga" area provide evidence for the restitic character of this rock. It was previously demonstrated that differentiation of nepheline syenite magma of the Lovozero massif resulted in significant accumulation of these elements at the latest stages of evolution of alkaline magma [3]. REFERENCES 1. O. A. Bogatikov, O. V. Petrov, and A. F. Morozov, Petrographic code of Russia. Magmatic, metamorphic, metasomatic, and impact formations (VSEGEI, St. Petersburg, 2009) [in Russian]. 2. A. A. Arzamastsev, B. V. Belyatsky, and L. V. Arzamastseva, Lithos 51, 27 (2000). 3. V. I. Gerasimovskii, V. P. Volkov, L. N. Kogarko, A. I. Polyakov, T. V. Saprykina, and Yu. A. Balashov, Geochemistry of the Lovozero alkaline massif (Moscow, 1966) [in Russian].

  19. Relationships between gas geochemistry and release rates and the geomechanical state of igneous rock massifs

    NASA Astrophysics Data System (ADS)

    Nivin, Valentin A.; Belov, Nikolai I.; Treloar, Peter J.; Timofeyev, Vladimir V.

    2001-07-01

    In contrast to sedimentary sequences, the relationships between the stressed state of igneous rocks and the chemistry and physical properties of gases contained within them are not well known. Here, we attempt to fill this gap by using, as an example, the apatite-nepheline and rare-metal ore deposits hosted within the Khibiny and Lovozero alkaline nepheline-syenite complexes of the Kola Peninsula, NW Russia. These massifs are characterized by unusually high, for igneous rocks, contents of multi-component, essentially hydrogen-hydrocarbon, gases and also by high hardness, elasticity and unevenly distributed, subhorizontal tectonic stresses. Relationships between the chemical and dynamic characteristics of the gases and the geomechanical properties of the host rocks have been examined using field observations and laboratory experiments. Patterns of gas release variations in time and space, gas emissions from rock pillars during artificial loading, variations of gas pressure in sealed shot-holes and changes in liberation rates of gaseous components during experimental rock loading are suggested to result from changes in rock stress and deformation state. Gas compositions in sealed shot-holes in stressed rocks change with time. Partly, this is due to belated release of gases held in fluid inclusions and isolated voids and their subsequent mixing with gases held in interconnected fracture systems as the included gases are preferentially released as fluid inclusion arrays are opened during later stages of stress build-up. Partly, it may also be because released gases may react with new fracture surfaces to generate enhanced levels of reduced H 2 gases.

  20. Ulvöspinel from xenoliths of contact-altered volcanic and volcanosedimentary rocks in nepheline syenites of the Khibiny and Lovozero plutons

    NASA Astrophysics Data System (ADS)

    Ivanyuk, G. Yu.; Korchak, Yu. A.; Pakhomovsky, Ya. A.; Men'shikov, Yu. P.; Yakovenchuk, V. N.

    2012-12-01

    Ulvöspinel is a typical accessory mineral of xenoliths of volcanic and volcanosedimentary rocks in alkaline syenites of the Khibiny and Lovozero plutons. Ulvöspinel forms homogeneous Cr- and V-rich grains in slightly altered olivine basalts, basaltic tuffs, and tuffites and is enriched in Mn and Si in the course of contact-metasomatic alteration of these rocks. The strongly reduced conditions of contact metamorphism controlled by ascending flows of hydrocarbon gases and hydrogen sulfide gave rise to the subsolidus decomposition of primary ulvöspinel and Ti-high magnetite with the formation of ilmenite lamellae and then, with decreasing redox potential, of the second-generation latticed ulvöspinel lamellae.

  1. Kondyor Massif, Russia

    NASA Technical Reports Server (NTRS)

    2008-01-01

    This is neither an impact crater nor a volcano. It is a perfect circular intrusion, about 10 km in diameter with a topographic ridge up to 600 m high. The Kondyor Massif is located in Eastern Siberia, Russia, north of the city of Khabarovsk. It is a rare form of igneous intrusion called alkaline-ultrabasic massif and it is full of rare minerals. The river flowing out of it forms placer mineral deposits. Last year 4 tons of platinum were mined there. A remarkable and very unusual mineralogical feature of the deposit is the presence of coarse crystals of Pt-Fe alloy, coated with gold. This 3-D perspective view was created by draping a simulated natural color ASTER composite over an ASTER-derived digital elevation model.

    The image was acquired on June 10, 2006, and is located at 57.6 degrees north latitude, 134.6 degrees east longitude.

    The U.S. science team is located at NASA's Jet Propulsion Laboratory, Pasadena, Calif. The Terra mission is part of NASA's Science Mission Directorate.

  2. Tracing the Cambro-Ordovician ferrosilicic to calc-alkaline magmatic association in Iberia by in situ U-Pb SHRIMP zircon geochronology (Gredos massif, Spanish Central System batholith)

    NASA Astrophysics Data System (ADS)

    Díaz-Alvarado, Juan; Fernández, Carlos; Chichorro, Martim; Castro, Antonio; Pereira, Manuel Francisco

    2016-06-01

    U-Pb geochronological study of zircons from nodular granites and Qtz-diorites comprising part of Variscan high-grade metamorphic complexes in Gredos massif (Spanish Central System batholith) points out the significant presence of Cambro-Ordovician protoliths among the Variscan migmatitic rocks that host the Late Carboniferous intrusive granitoids. Indeed, the studied zone was affected by two contrasted tectono-magmatic episodes, Carboniferous (Variscan) and Cambro-Ordovician. Three main characteristics denote a close relation between the Cambro-Ordovician protholiths of the Prado de las Pozas high-grade metamorphic complex, strongly reworked during the Variscan Orogeny, and other Cambro-Ordovician igneous domains in the Central Iberian Zone of the Iberian Massif: (1) geochemical features show the ferrosilicic signature of nodular granites. They plot very close to the average analysis of the metavolcanic rocks of the Ollo de Sapo formation (Iberia). Qtz-diorites present typical calc-alkaline signatures and are geochemically similar to intermediate cordilleran granitoids. (2) Both Qtz-diorite and nodular granite samples yield a significant population of Cambro-Ordovician ages, ranging between 483 and 473 Ma and between 487 and 457 Ma, respectively. Besides, (3) the abundance of zircon inheritance observed on nodular granites matches the significant component of inheritance reported on Cambro-Ordovician metagranites and metavolcanic rocks of central and NW Iberia. The spatial and temporal coincidence of both peraluminous and intermediate granitoids, and specifically in nodular granites and Qtz-diorite enclaves of the Prado de las Pozas high-grade complex, is conducive to a common petrogenetic context for the formation of both magmatic types. Tectonic and geochemical characteristics describe the activity of a Cambro-Ordovician arc-back-arc tectonic setting associated with the subduction of the Iapetus-Tornquist Ocean and the birth of the Rheic Ocean. The extensional

  3. Eudialyte-group minerals in rocks of Lovozero layered complex at Mt. Karnasurt and Mt. Kedykvyrpakhk

    NASA Astrophysics Data System (ADS)

    Ivanyuk, G. Yu.; Pakhomovsky, Ya. A.; Yakovenchuk, V. N.

    2015-12-01

    Eudialyte-bearing interbeds within layers I-4 (Mt. Karnasurt) and II-4 (Mt. Kedykvyrpakhk) in the layered complex of the Lovozero Pluton are localized symmetrically relative to the loparite-bearing ijolite-malignite layer; the content of eudialyte decreases from underlying nepheline syenite to overlying foidolite. Eudialyte-group minerals fill the interstices between nepheline, sodalite, and microcline-perthite crystals in all rock types and are partially replaced with georgechaoite and minerals of the lovozerite group as a result of hydrothermal alteration. Variations in the chemical composition of the eudialyte-group minerals are mainly controlled by block substitution NaFeZrCl ↔ LnMn(Nb,Ti)S producing eudialyte proper, manganoeudialyte (sharply predominant), kentbrooksite, alluaivite, and a phase intermediate between manganoeudialyte and alluaivite. As the total Ln2O3 content increases, the relative amounts of Ce and La oxides increases linearly in the proportion Ce2O3: La2O3 = 2.5: 1. In the phases containing lower than 3 wt % La2O3, Nd becomes the next REE after Ce. It is very likely that (mangano)eudialyte was mostly formed after parakeldyshite and other anhydrous zirconium-silicate under effect of residual fluids enriched in Ca and Mn, which took part in fenitization of basalt, tuff, and tuffite of the Lovozero Formation.

  4. Craddock Massif and Vinson Massif remeasured

    USGS Publications Warehouse

    Gildea, Damien; Splettstoesser, John F.

    2007-01-01

    The highest peak in Antarctica, the Vinson Massif (78º35’S, 85º25’W), is at an elevation of 4892 m (16,046 ft), as determined in 2004. Measurements of the elevation have fluctuated over the years, from its earliest surveyed elevation of 5140 m (16,859 ft), to its present height. Vinson Massif and three of its near neighbors in the Sentinel Range of the Ellsworth Mountains are the highest peaks in Antarctica, making them a favorite objective of mountaineers. Well over 1,100 people have climbed Vinson since the first ascent by a team in the 1966-67 austral summer. The range is composed of Crashsite quartzite, making the Sentinel’s very resistant to erosion. Very accurate elevations have been achieved annually by GPS mapping done by a climbing team sponsored by the Omega Foundation, active in Antarctica since 1998. The Craddock Massif now includes Mt. Craddock, the ninth highest peak in Antarctica, at 4368 m (14,327 ft). Both are named for Campbell Craddock*, a U.S. geologist active in Antarctic research beginning in 1959-60.

  5. Minerals of zirconolite group from fenitized xenoliths in nepheline syenites of Khibiny and Lovozero plutons, Kola Peninsula

    NASA Astrophysics Data System (ADS)

    Menshikov, Yu. P.; Mikhailova, Yu. A.; Pakhomovsky, Ya. A.; Yakovenchuk, V. N.; Ivanyuk, G. Yu.

    2015-12-01

    Zirconolite, its Ce-, Nd-, and Y-analogs, and laachite, another member of the zirconolite group, are typomorphic minerals of the fenitized xenoliths in nepheline syenite and foidolite of the Khibiny-Lovozero Complex, Kola Peninsula, Russia. All these minerals are formed at the late stage of fenitization as products of ilmentie alteration under the effect of Zr-bearing fluids. The diversity of these minerals is caused by the chemical substitutions of Na and Ca for REE, Th, and U compensated by substitution of Ti and Zr for Nb, Fe and Ta, as well as by the redistribution of REE between varieties enriched in Ti (HREE) or Nb (LREE). The results obtained can be used in the synthesis of Synroc-type titanate ceramics assigned for the immobilization of actinides.

  6. Geochemistry of alkali syenites from the Budun massif and their petrogenetic properties (Ol'khon Island)

    NASA Astrophysics Data System (ADS)

    Makrygina, V. A.; Suvorova, L. F.; Zarubina, O. V.; Bryanskii, N. V.

    2016-07-01

    The first data on the geochemistry of the alkali syenite massif in Cape Budun of Ol'khon Island, where it makes contact in the south with the Khuzir gabbroid massif, are presented. Syenites occur among granite gneisses of the Sharanur dome and, like its granites, are enriched with Zr and REEs, but depleted in other trace elements. They contain anorthoclase, corundum, rare nepheline, zircon, and hercynite and are accompanied by desilicified pegmatites. Their unusual geochemical properties allow the assumption that alkaline magmas resulted from the interaction between basic and granitoid melts.

  7. The tectonics of anorthosite massifs

    NASA Technical Reports Server (NTRS)

    Seyfert, C. K.

    1981-01-01

    Anorthosite massifs developed approximately 1.4 to 1.5 billion years ago along an arch which developed parallel to a zone of continental separation as a block which included North America, Europe, and probably Asia separated from a block which included parts of South America, Africa, India, and Australia. Anorthosite massifs also developed at the same time along a belt which runs through the continents which comprise Gondwanaland (South America), Africa, India, Australia, and Antarctica. This was a zone of continental separation which subsequently became a zone of continental collision about 1.2 billion years ago. The northern anorthosite belt also parallels an orogenic belt which was active between 1.8 and 1.7 billion years ago. Heat generated during this mountain building period helped in the formation of the anorthosites.

  8. Time of formation and genesis of yttrium-zirconium mineralization in the Sakharjok massif, Kola Peninsula

    NASA Astrophysics Data System (ADS)

    Vetrin, V. R.; Skublov, S. G.; Balashov, Yu. A.; Lyalina, L. M.; Rodionov, N. V.

    2014-12-01

    The Kola geotectonic province in the northeastern Fennoscandian Shield accommodates a significant number of alkaline rock massifs differing in age. They are of mantle and mantle-crustal origin (alkali and nepheline syenites, carbonatites) and related to crustal sources (Neoarchean alkali granites). Among them, the Neoarchean Sakharjok nepheline syenite massif is related to the oldest intrusions of this kind bearing yttrium-zirconium mineralization. The crystallization of alkali syenite pertaining to the first intrusive phase of the intrusive Sakharjok massif is dated to 2645 ± 7 Ma, and this implies that this syenite postdated alkali granites (2.66-2.67 Ga). To date the yttrium-zirconium ore, we applied the local U-Pb method to zircon crystals occurring in the mineralized block hosted in nepheline syenite. The earliest fragments of zircon crystallized 1832 ± 7 Ma ago; the age of metamorphism is estimated at 1784 ± 13 Ma. These dates indicate the Paleoproterozoic age of the yttrium-zirconium mineralization, which was formed as a product of fluid reworking of the Neoarchean nepheline syenite of the Sakharjok massif.

  9. Structural Pattern, P-t Conditions and Timing of Alpine Deformation In The Argentera Massif (western Alps)

    NASA Astrophysics Data System (ADS)

    Corsini, M.; Caby, R.; Ruffet, G.

    The Argentera massif is located in the southern part of the Western Alps and belongs to the paleo-European basement. It forms the southernmost crystalline massif of the external domain. Hercynian high-grade metamorphic rocks and Carboniferous sedi- mentary basins were intruded at the end of the Hercynian orogen by the calc-alkaline Argentera granite. This massif experienced a polyphase deformation history, Hercy- nian and Alpine. The Alpine history is characterized by the development of a network of NNW-SSE trending transcurrent dextral ductile shear zones branching into E-W ductile thrust faults with a top to the south displacement. We interpret the uplift of the massif as the result of movements along these shear zones, relative to a sub-meridian compressional event. Our P-T condition estimates indicate a regional temperature at ca 350 rC for pressure at 0.35-0.4 GPa for Alpine metamorphism implying a mini- mum burial of 14 km for the Argentera massif. 39Ar-40Ar analyses of neo-crystallized phengites collected within a major E-W alpine crosscutting the late Hercynian Argen- tera granite shear zone (Frema Morte) yielded an age at ca 22.5 Ma. This is the first absolute age constraint of a late Alpine metamorphism in the external crystalline mas- sifs of the Western Alps. This metamorphism could result from overload imposed by thrusting of the internal nappes between 28 Ma and 22.5 Ma.

  10. Maldzhangarsky rare metal carbonatite massif in the NE-part of the Anabar shield.

    NASA Astrophysics Data System (ADS)

    Vladykin, Nikolai

    2015-04-01

    In the SW part of the Anabar shield Th-anomaly was he drilled by ALROSA company by 6 bore holes to a depth of 100 m, which revealed a new Maldzhangarsky rare metal carbonatite massif (Vladykin 2008). It is oval-shaped and elongated NW to SE having dimensions 4.2 x 2.5 km.. and total square ~ 10.5 km2 Carbonatites are from mean- to fine-grained light-colored. Mineral and chemical composition, tracery, dolomite are ankerite and carbonaties. Besides the carbonate it is composed by phlogopite, apatite, alkali amphibole, rarely magnetite and accessory minerals like pyrochlore, zircon, barito-celestine, rare earth carbonates and apatite, reaching 20-30%. In addition to the prevailing carbonatite the carbonatized pyroxenite xenoliths were found in the drilling cores. Geochemical study of the Maldzhangarsky massif carbonatites indicated the presence of significant quantities of typical carbonatite elements- Sr, Ba, Nb, Ta, P, Y, TRE, which is similar to the carbonatites of the Tomtor massif. Many parts of the massif are the ores for Nb, TR, Sr and P. The highest concentrations based on TRE 100 analyses of Nb-8000 ppm, Y-800 ppm; TRE-4%, Sr-10%,. The REE patterns of carbonanites are highly inclined with the r sharp prevalence of light REE on heavy with a rather steep slope., There are now Eu anomalies which is typical for the mantle carbonitetes, and which evidence for the early fractionation of alkaline carbonatite fluid orliquid from silicate melt. Pair correlation of rare earth elements in carbonatite shows their origin from a single source. The intrusive nature of the drilled carbonatites of Maldzhangarsky massif suggest them to be the top part of the unexposed massif. The belonging of this massif to any genetic type is unclear and needs more detail exploration. RBRF grant (15-05-01005). Vladykin N.v. New rare metal ore karbonatitov province EAST of the Anabarskiy shield. In: Geochemistry of magmatic rocks, St. Petersburg, 2008, pp. 24-27.

  11. Serpentinization and Life: Motivations for Drilling the Atlantis Massif

    NASA Astrophysics Data System (ADS)

    Frueh-Green, G. L.; Lang, S. Q.; Brazelton, W. J.; Schrenk, M. O.

    2014-12-01

    The Atlantis Massif, located at the intersection of the Atlantis transform fault and the Mid-Atlantic Ridge at 30°N, is one of the best-studied oceanic core complexes (OCCs) and is the target of IODP Expedition 357 late 2015. Drilling will address two exciting discoveries in ridge research: off-axis, serpentinite-hosted hydrothermal activity and carbonate precipitation, exemplified by the Lost City hydrothermal field, and the significance of tectono-magmatic processes in forming heterogeneous and variably serpentinized lithosphere as key components of slow spreading ridges. Serpentinization reactions at moderate- to low-temperatures result in alkaline fluids, characterized by elevated concentrations of abiotic hydrogen, methane and low molecular weight hydrocarbons, and which lead to precipitation of carbonate and brucite upon mixing with seawater. These highly reactive systems have major consequences for lithospheric cooling, global geochemical cycles, carbon sequestration and microbial activity. However, little is known about the nature and distribution of microbial communities in subsurface ultramafic environments and the potential for a hydrogen-based deep biosphere in areas of active serpentinization and fluid circulation. The continuous flux of reduced compounds provides abundant thermodynamic energy to drive chemolithoautotrophy, however, carbon availability may be limited in these high pH environments and represent a challenge for microbial growth. Here we review serpentinization processes as fundamental to understanding the evolution of oceanic lithosphere and discuss open questions related to the impact of serpentinization on the subsurface biosphere. Motivations for drilling the shallow subseafloor of the Atlantis Massif include: (1) exploring the extent and activity of the subsurface biosphere in young ultramafic and mafic seafloor; (2) quantifying the role of serpentinization in driving hydrothermal systems, in sustaining microbiological communities

  12. Geochemistry and petrogenesis of post-collisional ultrapotassic syenites and granites from southernmost Brazil: the Piquiri Syenite Massif.

    PubMed

    Nardi, Lauro V S; Plá-Cid, Jorge; Bitencourt, Maria de Fátima; Stabel, Larissa Z

    2008-06-01

    The Piquiri Syenite Massif, southernmost Brazil, is part of the post-collisional magmatism related to the Neoproterozoic Brasiliano-Pan-African Orogenic Cycle. The massif is about 12 km in diameter and is composed of syenites, granites, monzonitic rocks and lamprophyres. Diopside-phlogopite, diopside-biotite-augite-calcic-amphibole, are the main ferro-magnesian paragenesis in the syenitic rocks. Syenitic and granitic rocks are co-magmatic and related to an ultrapotassic, silica-saturated magmatism. Their trace element patterns indicate a probable mantle source modified by previous, subduction-related metasomatism. The ultrapotassic granites of this massif were produced by fractional crystallization of syenitic magmas, and may be considered as a particular group of hypersolvus and subsolvus A-type granites. Based upon textural, structural and geochemical data most of the syenitic rocks, particularly the fine-grained types, are considered as crystallized liquids, in spite of the abundance of cumulatic layers, schlieren, and compositional banding. Most of the studied samples are metaluminous, with K2O/Na2O ratios higher than 2. The ultrapotassic syenitic and lamprophyric rocks in the Piquiri massif are interpreted to have been produced from enriched mantle sources, OIB-type, like most of the post-collisional shoshonitic, sodic alkaline and high-K tholeiitic magmatism in southernmost Brazil. The source of the ultrapotassic and lamprophyric magmas is probably the same veined mantle, with abundant phlogopite + apatite + amphibole that reflects a previous subduction-related metasomatism. PMID:18506262

  13. The Lassell Massif - a Silicic Lunar Volcano

    NASA Astrophysics Data System (ADS)

    Ashley, J.; Robinson, M. S.; Stopar, J. D.; Glotch, T. D.; Hawke, B. R.; Lawrence, S. J.; Jolliff, B. L.; Greenhagen, B. T.; Paige, D. A.

    2013-12-01

    Lunar volcanic processes were dominated by mare-producing basaltic extrusions. However, limited occurrences of non-mare, geochemically evolved (Si-enriched) volcanic deposits have long been suspected on the basis of spectral anomalies (red spots), landform morphologies, and the occurrence of minor granitic components in Apollo sample suites [e.g., 1-5]. The LRO Diviner Lunar Radiometer Experiment (Diviner) measured thermal emission signatures considered diagnostic of highly silicic rocks in several red spot areas [6,7], within the Marius domes [8], and from the Compton-Belkovich feature on the lunar farside [9]. The present study focuses on the Lassell massif red spot (14.73°S, 350.97°E) located in northeastern Mare Nubium near the center of Alphonsus A crater. Here we use Diviner coverage co-projected with Lunar Reconnaissance Orbiter Camera (LROC) images [10] and digital elevation models to characterize the Lassell massif geomorphology and composition. Localized Diviner signatures indicating relatively high silica contents correlate with spatially distinct morphologic features across the Lassell massif. These features include sub-kilometer scale deposits with clear superposing relationships between units of different silica concentrations. The zone with the strongest signal corresponds to the southern half of the massif and the Lassell G and K depressions (formerly thought to be impact craters [11]). These steep-walled pits lack any obvious raised rims or ejecta blankets that would identify them as impact craters; they are likely explosive volcanic vents or collapse calderas. This silica-rich area is contained within the historic red spot area [4], but does not appear to fully overlap with it, implying compositionally distinct deposits originating from the same source region. Low-reflectance deposits, exposed by impact craters and mass wasting across the massif, suggest either basaltic pyroclastics or minor late-stage extrusion of basaltic lavas through vents

  14. Geochemistry of carbonatites of the Tomtor massif

    USGS Publications Warehouse

    Kravchenko, S.M.; Czamanske, G.; Fedorenko, V.A.

    2003-01-01

    Carbonatites compose sheet bodies in a 300-m sequence of volcanic lamproites, as well as separate large bodies at depths of >250-300 m. An analysis of new high-precision data on concentrations of major, rare, and rare earth elements in carbonatites shows that these rocks were formed during crystallization differentiation of a carbonatite magma, which resulted in enrichment of the later melt fractions in rare elements and was followed by autometasomatic and allometasomatic hydrothermal processes. Some independent data indicate that the main factor of ore accumulation in the weathered rock zone (also known as the "lower ore horizon" comprising metasomatized volcanics with interbedded carbonatites) was hydrothermal addition of Nb and REEs. The giant size of the Tomtor carbonatite-nepheline syenite massif caused advanced magma differentiation, extensive postmagmatic metasomatism and recrystallization of host rocks, and strong enrichment of carbonatites in incompatible rare and rare earth elements (except for Ta, Zr, Ti, K, and Rb) compared to the rocks of many other carbonatite massifs. We suggest that a wide range of iron contents in carbonatites-2 can be related to extensive magnetite fractionation at the magmatic stage in different parts of the huge massif. Copyright ?? 2003 by MAIK "Nauka/Interperiodica" (Russia).

  15. Tertiary carbonate development on the Shenhu Massif, South China Sea

    SciTech Connect

    Turner, N.L. ); Siemann-Gartmann, S. )

    1994-07-01

    The Shenhu Massif lies between the Zhu III Depression to the northwest, the Kaiping/Baiyun depressions to the northeast, and the Xisha Basin to the south. Major faulting began in the Paleocene, and initial basins formed on and around the Shenhu Massif during this time. Continental coarse clastics, derived from the massif area, filled the basins prior to the middle Oligocene though larger, deeper basins may have contained lacustrine environments. During the marine incursion from the middle Oligocene and until the early Miocene, coarse clastics were deposited adjacent to exposed basement areas, fine marine clastics were deposited on the massif, carbonate buildups formed along the massif rim, and carbonate platforms developed from the massif edge back into the shallow-water high-massif interior. In mid-lower Miocene, the carbonate areas were reduced in size and replaced by shales. Carbonate deposition as layers and mounds was reestablished over much of the Shenhu Massif in the early and middle Miocene. Prodelta shales in the east Shenhu Massif area and coarser clastics present in clinoforms in the Baiyun Depression are the distal components of a southerly prograding delta system located to the north. Carbonates continued to develop along the southeast side of the west Shenhu Massif during the latter part of the middle Miocene, but fine clastics dominated the rest of the area except in the Kaiping/Baiyun Depression where coarser clastics from the delta were deposited. Amoco and its partners, Nanhai West Oil Co. and Kerr-McGee Co., have begun evaluation of the Shenhu Massif area with the drilling of a Miocene carbonate buildup, the Amoco 23-1 Baodao prospect.

  16. Experimental and Modeling Studies of Massif Anorthosites

    NASA Technical Reports Server (NTRS)

    Longhi, John

    1999-01-01

    This termination report covers the latter part of a single research effort spanning several grant cycles. During this time there was a single title, "Experimental and Modeling Studies of Massif Anorthosites", but there were several contract numbers as the mode and location of NASA contract administration changed. Initially, the project was funded as an increment to the PI's other grant, "Early Differentiation of the Moon: Experimental and Modeling Studies", but subsequently it became an independent grant. Table 1 contains a brief summary of the dates and contract numbers.

  17. ALP (Alkaline Phosphatase) Test

    MedlinePlus

    ... known as: ALK PHOS; Alkp Formal name: Alkaline Phosphatase Related tests: AST ; ALT ; GGT ; Bilirubin ; Liver Panel ; Bone Markers ; Alkaline Phosphatase Isoenzymes; Bone Specific ALP All content on Lab ...

  18. Granite emplacement during contemporary shortening and normal faulting: structural and magnetic study of the Veiga Massif (NW Spain)

    NASA Astrophysics Data System (ADS)

    Roman-Berdiel, T.; Pueyo-Morer, E. L.; Casas-Sainz, A. M.

    1995-12-01

    The Veiga Massif belongs to the calc-alkaline series of Hercynian granitic rocks of the Ibero-Armorican arc The Veiga granodiorite intruded during the Upper Carboniferous into the core of the WNW-ESE N-verging 'Ollo de Sapo' antiform, formed by Precambrian and Palaeozoic metasediments. Internal fabrics show that magma intrusion was contemporary with shortening. Measurements of feldspars orientations and anisotropy of magnetic susceptibility (AMS) throughout the granite are consistent and indicate a foliation striking WNW-ESE (parallel-to-folding), with a constant dip of 75-85 °N. The zonation of bulk low-field susceptibility is related to mineral content and indicates a more basic composition at the southern and western borders. The difference in elevation between outcrops (more than 600 m) allows us to infer the three-dimensional attitude of granite fabrics throughout the Massif. Syn-magmatic fabric folds are preserved in the inner part of the igneous body. The highest degree of magnetic anisotropy is observed in areas located near the bottom and top of the intrusion. At the scale of the Massif, foliation is convergent toward the bottom of the intrusion, along a line located at its northern border, where the magma source is interpreted to be located. In the western border of the Massif, the presence of C and S structures indicates that magma cooling was coeval with movement of the Chandoiro fault, a N-S striking normal fault with a N290E hanging wall displacement direction. These results indicate that emplacement of the Veiga granite is coeval with NNE-SSW shortening and with an WNW-ESE extension direction, parallel to the trend of the late folds.

  19. Spatial thermal radiometry contribution to the Massif armoricain and the Massif central (France) litho-structural study

    NASA Technical Reports Server (NTRS)

    Scanvic, J. Y. (Principal Investigator)

    1980-01-01

    The author has identified the following significant results. Although the limited number of images received did not permit construction of a thermal inertia map, important geological details were obtained in the areas of lithology and tectonics. Interpretation of day, night, and seasonal imagery resulted in differentiating broad calcareous and dolomitic units in the Causse Plateau. In the Massif amoricain, some granite massifs were delineated which were not observed by LANDSAT. Neotectonic faults were also revealed.

  20. Application of remote sensing to the photogeologic mapping of the region of the Itatiaia alkaline complex. M.S. Thesis; [Minas Gerais, Rio De Janeiro, Sao Paulo, and Itatiaia, Brazil

    NASA Technical Reports Server (NTRS)

    Dejesusparada, N. (Principal Investigator); Rodrigues, J. E.

    1981-01-01

    Remote sensing methods applied to geologically complex areas, through interaction of ground truth and information obtained from multispectral LANDSAT images and radar mosaics were evaluated. The test area covers parts of Minos Gerais, Rio De Janeiro and Sao Paulo states and contains the alkaline complex of Itatiaia and surrounding Precambrian terrains. Geological and structural mapping was satisfactory; however, lithological varieties which form the massif's could not be identified. Photogeological lineaments were mapped, some of which represent the boundaries of stratigraphic units. Automatic processing was used to classify sedimentary areas, which includes the talus deposits of the alkaline massifs.

  1. Re-Os geochemistry and geochronology of the Ransko gabbro-peridotite massif, Bohemian Massif

    NASA Astrophysics Data System (ADS)

    Ackerman, Lukáš; Pašava, Jan; Erban, Vojtěch

    2013-10-01

    The Ransko gabbro-peridotite massif in Eastern Bohemia is a strongly differentiated intrusive complex, which hosts low-grade Ni-Cu ores mainly developed close to the contact of olivine-rich rocks with gabbros, in troctolites, and to a much lesser extent in both pyroxene and olivine gabbros and plagioclase-rich peridotites. Gabbro, troctolite, peridotite and Ni-Cu ores from the Jezírka Ni-Cu (PGE) deposit, considered to be a typical example of the liquid segregation style of mineralization, were analyzed for Re-Os concentrations and isotopic ratios. Seven barren and mineralized samples from the Jezírka deposit yielded a Re-Os regression of 341.5 ± 7.9 Ma (MSWD = 69). Strongly mineralized peridotite with mantle-like initial 187Os/188Os ratio of 0.125 suggests that Os as well as other PGE present in the Ni-Cu mineralization are predominantly of mantle origin. On the other hand, barren and low-mineralized samples have radiogenic initial 187Os/188Os ratios of 0.14-0.16 suggesting some import of Re and/or radiogenic 187Os most likely through contamination by continental crust during magma emplacement. The Re-Os age of the Ransko Massif is significantly younger than the previously suggested Lower Cambrian age, but it is similar to and/or younger than the age of metamorphism of the adjacent Kutná Hora crystalline complex and the Moldanubian unit. Therefore, it is likely that the emplacement of the Ransko massif and its Ni-Cu mineralization was closely connected with the late-stage evolution of the Kutná Hora crystalline complex.

  2. Alkaline "Permanent" Paper.

    ERIC Educational Resources Information Center

    Pacey, Antony

    1991-01-01

    Discussion of paper manufacturing processes and their effects on library materials focuses on the promotion of alkaline "permanent" paper, with less acid, by Canadian library preservation specialists. Standards for paper acidity are explained; advantages of alkaline paper are described, including decreased manufacturing costs; and recyclability is…

  3. Anodes for alkaline electrolysis

    DOEpatents

    Soloveichik, Grigorii Lev

    2011-02-01

    A method of making an anode for alkaline electrolysis cells includes adsorption of precursor material on a carbonaceous material, conversion of the precursor material to hydroxide form and conversion of precursor material from hydroxide form to oxy-hydroxide form within the alkaline electrolysis cell.

  4. Alkaline igneous rocks

    SciTech Connect

    Fitton, J.G.; Upton, B.G.J.

    1987-01-01

    In this volume, an international team of scientists provides an up-to-date overview of the nature, origin, and evolution of alkaline magmas. Particular attention is paid to carbonatites, lamprophyres, and lamproites which are rock suites of current interest not recently reviewed elsewhere. Recent work on the classical alkaline provinces of East Africa, South Greenland, and the Kola Peninsula is included together with reviews of other areas of alkaline magmatism in North and South America, East Greenland, Europe, West Africa, and the ocean basins. Other papers discuss the impact of experimental isotopic and geochemical studies of the petrogenesis of alkaline rocks. This book will be of interest to petrologists and geochemists studying alkaline igneous rocks, and to other earth scientists as a reference on the rapidly expanding field of igneous petrology.

  5. Alkaline battery operational methodology

    DOEpatents

    Sholklapper, Tal; Gallaway, Joshua; Steingart, Daniel; Ingale, Nilesh; Nyce, Michael

    2016-08-16

    Methods of using specific operational charge and discharge parameters to extend the life of alkaline batteries are disclosed. The methods can be used with any commercial primary or secondary alkaline battery, as well as with newer alkaline battery designs, including batteries with flowing electrolyte. The methods include cycling batteries within a narrow operating voltage window, with minimum and maximum cut-off voltages that are set based on battery characteristics and environmental conditions. The narrow voltage window decreases available capacity but allows the batteries to be cycled for hundreds or thousands of times.

  6. Genesis of rare-metal pegmatites and alkaline apatite-fluorite rocks of Burpala massi, Northern Baikal folded zone

    NASA Astrophysics Data System (ADS)

    Sotnikova, Irina; Vladykin, Nikolai

    2015-04-01

    Burpalinsky rare metal alkaline massif in the Northern Baikal folded zone in southern margin of Siberian Platform, is a of intrusion central type, created 287 Ma covering area of about 250 km2. It is composed of nepheline syenites and pulaskites grading to quartz syenites in the contacts. Veines and dykes are represented by shonkinites, sodalite syenite, leucocratic granophyres, alkali granites and numerous rare metal alkaline syenite pegmatites and two dykes of carbonatites. All rocks except for granites are cut by a large apatite-fluorite dyke rocks with mica and magnetite, which in turn is cut by alaskite granites dyke. The massif has been studied by A.M. Portnov, A.A. Ganzeev et al. (1992) Burpalinsky massif is highly enriched with trace elements, which are concentrated in pegmatite dykes. About 70 rare-metal minerals we found in massif. Zr-silicates: zircon, eudialyte, lovenite, Ti-lovenite, velerite, burpalite, seidozerite, Ca- seidozerite, Rosenbuschite, vlasovite, katapleite, Ca-katapleite, elpidite. Ti- minerals:- sphene, astrophyllite, ramsaite, Mn-neptunite bafertisite, chevkinite, Mn-ilmenite, pirofanite, Sr-perrerit, landauite, rutile, anatase, brookite; TR- minerals - loparite, metaloparite, britolite, rinkolite, melanocerite, bastnesite, parisite, ankilite, monazite, fluocerite, TR-apatite; Nb- minerals - pyrochlore, loparite. Other rare minerals leucophanite, hambergite, pyrochlore, betafite, torite, thorianite, tayniolite, brewsterite, cryolite and others. We have proposed a new scheme massif: shonkinites - nepheline syenites - alkaline syenite - quartz syenites - veined rocks: mariupolites, rare-metal pegmatites, apatite, fluorite rock alyaskite and alkaline granites and carbonatites (Sotnikova, 2009). Apatite-fluorite rocks are found in the central part of massif. This is a large vein body of 2 km length and a 20 m width cutting prevailing pulaskites. Previously, these rocks were regarded as hydrothermal low-temperature phase. New geological and

  7. (222)Rn activity concentration differences in groundwaters of three Variscan granitoid massifs in the Sudetes (NE Bohemian Massif, SW Poland).

    PubMed

    Przylibski, Tadeusz A; Gorecka, Joanna

    2014-08-01

    Based on research conducted in three Variscan granitoid massifs located within the crystalline Bohemian Massif, the authors confirmed that the higher the degree of their erosional dissection, the smaller the concentration of (222)Rn in groundwaters circulating in these massifs. This notion implies that radon waters and high-radon waters, from which at least some of the dissolved radon should be removed before feeding them as drinking water to the water-supply system, could be expected in granitoid massifs which have been poorly exposed by erosion. At the same time, such massifs must be taken into account as the areas of possible occurrence of radon medicinal waters, which in some countries can be used for balneotherapy in health resorts. Slightly eroded granitoid massifs should be also regarded as very probable radon prone areas or areas of high radon potential. PMID:24657989

  8. Deeply Eroded Massif Anorthosite and Nepheline Syenite of the Chimakurti-Uppalapadu Plutons, Peninsular India: Cospatial but not Comagmatic

    NASA Astrophysics Data System (ADS)

    Kumar, K.; Frost, C. D.; Frost, B. R.

    2001-12-01

    Massif anorthosites are generally thought to be ultimately of mantle origin. However, the lack of samples representing primitive liquid compositions and paucity of early cumulates limits the understanding of the processes that produced them. Some of the most deeply eroded massif anorthosite complexes are exposed within the southern Eastern Ghat Belt of Peninsular India, and provide an excellent opportunity to study the processes that operated in the deep magma chambers beneath the massifs. In this area Si-undersaturated nepheline syenites are associated with anorthosite complexes, a case that is not reported elsewhere in the world. The objectives of the present study are two fold: 1) to identify the processes that acted at the lowest level of the anorthosite complexes and 2) to determine the relationship between cospatial anorthosites and nepheline syenites. Cospatial alkaline-tholeiitic magmatism is strikingly displayed in the Chimakurti-Uppalapadu plutons within Prakasam Province. The Chimakurti pluton is concentrically zoned, and from core to margin consists of 1) olivine clinopyroxenite, 2) anorthosite, 3) olivine gabbronorite and 4) gabbronorite. It emplaced at mid-crustal depths (~6 kb; 16-18 km) and is undeformed and unmetamorphosed. Comparably deep-seated massifs are strongly metamorphosed (Adirondacks) and unmetamorphosed ones typically have shallow emplacement histories (Laramie). Unlike many massif anorthosite complexes, the Chimakurti pluton is associated with a gravity high of the order of 20 to 30 mGal; consistent with the presence of ultramafic cumulates. The Uppalapadu pluton is composed of nepheline syenite (NS). An arcuate band of hornblende syenite with pockets of quartz syenite and ferro-syenite (HQF series) is present between the two plutons. Field, petrographic, mineralogical and geochemical evidence suggests that the Clinopyroxenite-Anorthosite-Gabbro (CAG) suite of Chimakurti is formed by crystal-liquid fractionation (compounded by

  9. A Comparative Analysis on Models of Higher Education Massification

    ERIC Educational Resources Information Center

    Pan, Maoyuan; Luo, Dan

    2008-01-01

    Four financial models of massification of higher education are discussed in this essay. They are American model, Western European model, Southeast Asian and Latin American model and the transition countries model. The comparison of the four models comes to the conclusion that taking advantage of nongovernmental funding is fundamental to dealing…

  10. Massification and the Large Lecture Theatre: From Panic to Excitement

    ERIC Educational Resources Information Center

    Arvanitakis, James

    2014-01-01

    In this article I examine the role of the contemporary university in light of the mass increase in class sizes that has occurred on an international scale. While we may look nostalgically back to a time when lectures numbered a few hundred students and tutorials had as few as ten, massification at undergraduate level is an inescapable fact of…

  11. Entrepreneurship and Image Management in Higher Education: Pillars of Massification

    ERIC Educational Resources Information Center

    Mount, Joan; Belanger, Charles H.

    2004-01-01

    Mass higher education has taken hold in the developed nations, and a widely held belief exists that higher education is a "right." With massification have emerged two notable trends: an entrepreneurial emphasis fuelled by the revenue-cost squeeze ensuing from reduced and realigned government funding; and a quest for differentiation through "Image…

  12. Massification in Higher Education: Large Classes and Student Learning

    ERIC Educational Resources Information Center

    Hornsby, David J.; Osman, Ruksana

    2014-01-01

    In introducing the special issue on "Large Class Pedagogy: Opportunities and Challenges of Massification" the present editorial takes stock of the emerging literature on this subject. We seek to contribute to the massificaiton debate by considering one result of it: large class teaching in higher education. Here we look to large classes…

  13. The last stages of the Avalonian-Cadomian arc in NW Iberian Massif: isotopic and igneous record for a long-lived peri-Gondwanan magmatic arc

    NASA Astrophysics Data System (ADS)

    Andonaegui, Pilar; Arenas, Ricardo; Albert, Richard; Sánchez Martínez, Sonia; Díez Fernández, Rubén; Gerdes, Axel

    2016-06-01

    The upper allochthonous units of NW Iberian Massif contain an extensive Cambrian magmatism (c. 500 Ma), covering felsic to mafic compositions. The magmatic activity generated large massifs of granitoids and gabbros, with calc-alkaline and tholeiitic compositions respectively. Petrological and geochemical features of these massifs are characteristic of volcanic arc. The plutons intruded siliciclastic sedimentary series deposited in the periphery of the West Africa Craton. U-Pb/Hf isotopic compositions of detrital zircon in the siliciclastic host series, indicate continental arc activity between c. 750 Ma and c. 500 Ma. It was characterized by a large variety of isotopic sources, including from very old continental input, even Archean, to the addition of a significant amount of juvenile mafic material. These isotopic sources experienced an extensive mixing that explains the composition and isotopic features (εHft from - 50 until + 15) of the represented Cambrian plutons. The Cambrian igneous rocks of the upper units of NW Iberia are related to the latest activity of the Avalonian-Cadomian arc. From the Middle Cambrian arc activity in the periphery of Gondwana was replaced by pronounced extension associated with the development of continental rifting, which finally led to separation of the microcontinent Avalonia. Subsequent drifting of Avalonia to the North caused progressive opening one of the main Paleozoic ocean, the Rheic Ocean.

  14. Geochemical characteristics of rare earth elements in soil of the Ditru Massif, Eastern Carpathians, Romania

    NASA Astrophysics Data System (ADS)

    Ion, Adriana

    2013-04-01

    The present paper describes the level of rare earth elements in soils developed from Ditrău massif area for evaluating of the background of these elements and accurate assessment of environmental impact. Also this paper contributed to understanding the important role of parent rocks in pedogenic processes. The Ditrău Alkaline Massif represent an intrusion body with a internal zonal structure, which was emplaced into pre-Alpine metamorphic rocks of the Bucovinian nappe complex close the Neogene - Quaternary volcanic arc of the Calimani-Guurghiu- Harghita Mountain chain. The center of massif was formed by nepheline syenite, which is surrounded by syenite and monazonite. North-western and north-eastern marginal sectors are composed of hornblende gabbro/hornblendite, alkali diorite, monzodiorite, monzosyenites and alkali granite. Small discrete ultramafic bodies (kaersutite-bearing peridotite, olivine, pyroxenite and hornblendite) and alkali gabbros occur in the Jolotca area. All this rocks are cut by late-stage dykes with a large variety of composition including tinguaite, phonolite, nepheline syenite, microsyenite, and aplite. The types of soils predominant in this zone are lithosoils. These soils are shallow developed, have low content in organic matter and reflects mineralogical and geochemical composition of the bedrock. The soil samples were collected from 70 location for all type of representative rocks (approximately 10 soil sampling points for each type of rock). The samples were analyzed by inductively coupled plasma mass spectrometry (ICP-MS). The pH values of these samples varied from 3.6 to 7.3, in general, the soils from massif area are acid or weakly acidic. The pH controls the abundance of REE in soil, the concentration of REE increases with decreasing pH values. In soil samples analyzed the contents of REE follow the order: Ce > La > Nd > Pr > Sm > Eu > Gd > Dy > Yb > Er > Tb > Ho >Tm. ∑ REE varied from 52.59 μg g-1 to 579.2 μg g-1 , the average

  15. Alkaline flooding injection strategy

    SciTech Connect

    French, T.R.; Josephson, C.B.

    1992-03-01

    The objective of this project is to improved alkali-surfactant flooding methods, and this includes determining the proper design of injection strategy. Several different injection strategies have been used or suggested for recovering heavy oils with surfactant-enhanced alkaline flooding methods. Oil recovery was compared for four different injection strategies: (1) surfactant followed by polymer, (2) surfactant followed by alkaline polymer, (3) alkaline surfactant followed by polymer, and (4) alkali, surfactant, and polymer mixed in a single formulation. The effect of alkaline preflush was also studied under two different conditions. All of the oil recovery experiments were conducted under optimal conditions with a viscous, non-acidic oil from Hepler (KS) oil field. The coreflood experiments were conducted with Berea sandstone cores since field core was not available in sufficient quantity for coreflood tests. The Tucker sand of Hepler field is a Class I fluvial dominated deltaic reservoir, as classified by the Department of Energy, which has been selected as the site of a DOE-sponsored field pilot test.

  16. The Apollo 17 samples: The Massifs and landslide

    NASA Technical Reports Server (NTRS)

    Ryder, Graham

    1992-01-01

    More than 50 kg of rock and regolith samples, a little less than half the total Apollo 17 sample mass, was collected from the highland stations at Taurus-Littrow. Twice as much material was collected from the North Massif as from the South Massif and its landslide (the apparent disproportionate collecting at the mare sites is mainly a reflection of the large size of a few individual basalt samples). Descriptions of the collection, documentation, and nature of the samples are given. A comprehensive catalog is currently being produced. Many of the samples have been intensely studied over the last 20 years and some of the rocks have become very familiar and depicted in popular works, particularly the dunite clast (72415), the troctolite sample (76535), and the station 6 boulder samples. Most of the boulder samples have been studied in Consortium mode, and many of the rake samples have received a basic petrological/geochemical characterization.

  17. The Lassell massif-A silicic lunar volcano

    NASA Astrophysics Data System (ADS)

    Ashley, J. W.; Robinson, M. S.; Stopar, J. D.; Glotch, T. D.; Hawke, B. Ray; van der Bogert, C. H.; Hiesinger, H.; Lawrence, S. J.; Jolliff, B. L.; Greenhagen, B. T.; Giguere, T. A.; Paige, D. A.

    2016-07-01

    Lunar surface volcanic processes are dominated by mare-producing basaltic extrusions. However, spectral anomalies, landform morphology, and granitic or rhyolitic components found in the Apollo sample suites indicate limited occurrences of non-mare, geochemically evolved (Si-enriched) volcanic deposits. Recent thermal infrared spectroscopy, high-resolution imagery, and topographic data from the Lunar Reconnaissance Orbiter (LRO) show that most of the historic "red spots" and other, less well-known locations on the Moon, are indeed silica rich (relative to basalt). Here we present a geologic investigation of the Lassell massif (14.65°S, 350.96°E) near the center of Alphonsus A basin in Mare Nubium, where high-silica thermal emission signals correspond with morphological indications of viscous (possibly also explosive) extrusion, and small-scale, low-reflectance deposits occur in a variety of stratigraphic relationships. Multiple layers with stair-step lobate forms suggest different eruption events or pulsing within a single eruption. Absolute model ages derived from crater size-frequency distributions (CSFDs) indicate that the northern parts of the massif were emplaced at ∼4 Ga, before the surrounding mare. However, CSFDs also indicate the possibility of more recent resurfacing events. The complex resurfacing history might be explained by either continuous resurfacing due to mass wasting and/or the emplacement of pyroclastics. Relatively low-reflectance deposits are visible at meter-scale resolutions (below detection limits for compositional analysis) at multiple locations across the massif, suggestive of pyroclastic activity, a quenched flow surface, or late-stage mafic materials. Compositional evidence from 7-band UV/VIS spectral data at the kilometer-scale and morphologic evidence for possible caldera collapse and/or explosive venting support the interpretation of a complex volcanic history for the Lassell massif.

  18. Miocene mass-transport sediments, Troodos Massif, Cyprus

    USGS Publications Warehouse

    Lord, A.R.; Harrison, R.W.; BouDagher-Fadel, M.; Stone, B.D.; Varol, O.

    2009-01-01

    Sediment mass-transport layers of submarine origin on the northern and southern flanks of the Troodos ophiolitic massif are dated biostratigraphically as early Miocene and late Miocene, respectively and therefore represent different seismogenic events in the uplift and erosional history of the Troodos terrane. Analysis of such events has potential for documenting Miocene seismic and uplift events regionally in the context of changing stress field directions and plate vectors through time. ?? 2009 The Geologists' Association.

  19. The French Atlantic littoral and the Massif Armoricain, part 3

    NASA Technical Reports Server (NTRS)

    Verger, F. (Principal Investigator); Scanvic, J. Y.; Monget, J. M.

    1977-01-01

    The author has identified the following significant results: (1) An original map of lineaments of the Armorican Massif and the Vendean platform was prepared. (2) Validity of spatial information through comparison with maps of various kinds, such as geological, geophysical, morphological, etc., was verified. (3) It was confirmed that LANDSAT images, in many cases, reflect data on deep phenomena which were only accessible geophysically and by means of borings. Tectonic domains were outlined, and known lineaments were extended.

  20. Complete Alpine reworking of the northern Menderes Massif, western Turkey

    NASA Astrophysics Data System (ADS)

    Cenki-Tok, B.; Expert, M.; Işık, V.; Candan, O.; Monié, P.; Bruguier, O.

    2016-07-01

    This study focuses on the petrology, geochronology and thermochronology of metamorphic rocks within the northern Menderes Massif in western Turkey. Metasediments belonging to the cover series of the Massif record pervasive amphibolite-facies metamorphism culminating at ca. 625-670 °C and 7-9 kbars. U-Th-Pb in situ ages on monazite and allanite from these metapelites record crustal thickening and nappe stacking associated with the internal imbrication of the Anatolide-Taurides platform during the Eocene. In addition, new 39Ar/40Ar single muscovite grain analyses on deformed rocks were performed in three localities within the northern Menderes Massif and ages range from 19.8 to 25.5 Ma. These mylonites may be related to both well-known detachments, Simav to the north and Alaşehir to the south, which accommodate Oligo-Miocene exhumation of the Menderes core complex. U-Th-Pb data on monazite grains (22.2 ± 0.2 Ma) from migmatites emplaced within the Simav detachment confirm these ages.

  1. Alkaline quinone flow battery.

    PubMed

    Lin, Kaixiang; Chen, Qing; Gerhardt, Michael R; Tong, Liuchuan; Kim, Sang Bok; Eisenach, Louise; Valle, Alvaro W; Hardee, David; Gordon, Roy G; Aziz, Michael J; Marshak, Michael P

    2015-09-25

    Storage of photovoltaic and wind electricity in batteries could solve the mismatch problem between the intermittent supply of these renewable resources and variable demand. Flow batteries permit more economical long-duration discharge than solid-electrode batteries by using liquid electrolytes stored outside of the battery. We report an alkaline flow battery based on redox-active organic molecules that are composed entirely of Earth-abundant elements and are nontoxic, nonflammable, and safe for use in residential and commercial environments. The battery operates efficiently with high power density near room temperature. These results demonstrate the stability and performance of redox-active organic molecules in alkaline flow batteries, potentially enabling cost-effective stationary storage of renewable energy. PMID:26404834

  2. Origin and U-Pb dating of zircon-bearing nepheline syenite xenoliths preserved in basaltic tephra (Massif Central, France)

    NASA Astrophysics Data System (ADS)

    Paquette, Jean-Louis; Mergoil-Daniel, Juliette

    2009-08-01

    Zircon-bearing xenoliths in continental basalts are often interpreted as witnesses of the continental basement uplifted during volcanic eruptions. Nevertheless, their origin is still debated. The Devès basaltic plateau belongs to the alkaline volcanic province of the French Massif Central. In few outcrops, zircon-bearing nepheline syenite xenoliths were preserved. U-Pb dating of the zircon crystals define an age of 956 ± 11 kyr constraining the crystallisation time of the zircons and consequently of the host xenoliths. This age, together with mineral chemistry arguments lead us to conclude that these minerals do not derive from a continental protolith. Rather, they likely result from the crystallisation of a liquid characterised by a nepheline-felspar composition and produced by the differentiation of a basaltic magma or, alternatively, by the low degree partial melting of a metasomatised lithospheric mantle. Such alkaline sialic rock and xenoliths may occur in large volumes at depth and generate the large amounts of zircon megacrysts discovered worldwide in secondary deposits within continental basaltic provinces.

  3. Alkaline Phosphatase in Stem Cells

    PubMed Central

    Štefková, Kateřina; Procházková, Jiřina; Pacherník, Jiří

    2015-01-01

    Alkaline phosphatase is an enzyme commonly expressed in almost all living organisms. In humans and other mammals, determinations of the expression and activity of alkaline phosphatase have frequently been used for cell determination in developmental studies and/or within clinical trials. Alkaline phosphatase also seems to be one of the key markers in the identification of pluripotent embryonic stem as well as related cells. However, alkaline phosphatases exist in some isoenzymes and isoforms, which have tissue specific expressions and functions. Here, the role of alkaline phosphatase as a stem cell marker is discussed in detail. First, we briefly summarize contemporary knowledge of mammalian alkaline phosphatases in general. Second, we focus on the known facts of its role in and potential significance for the identification of stem cells. PMID:25767512

  4. Social Class Barriers of the Massification of Higher Education in Taiwan

    ERIC Educational Resources Information Center

    Ru-Jer, Wang

    2012-01-01

    In recent years, the rapid growth of higher education in Taiwan has led to an essential shift from education for the elite to the massification of higher education. Although this massification is making higher education more accessible, one of the main concerns is whether opportunities for higher education are the same among all social classes in…

  5. Massification without Equalisation: The Politics of Higher Education, Graduate Employment and Social Mobility in Hong Kong

    ERIC Educational Resources Information Center

    Lee, Siu-yau

    2016-01-01

    This article explains why the massification of higher education in Hong Kong has, contrary to the predictions of received wisdom, failed to enhance the upward social mobility of the youth in the city. Building upon recent literature in political science, it argues that massification can take different forms, which in turn determine the effects of…

  6. Higher Education, Changing Labour Market and Social Mobility in the Era of Massification in China

    ERIC Educational Resources Information Center

    Mok, Ka Ho; Wu, Alfred M.

    2016-01-01

    This article attempts to investigate the relationship between the massification of higher education, labour market and social mobility in contemporary China. Though only a short period of time has elapsed from elite to mass education, China's higher education has been characterised as a wide, pervasive massification process. Similar to other East…

  7. Alkaline fuel cells applications

    NASA Astrophysics Data System (ADS)

    Kordesch, Karl; Hacker, Viktor; Gsellmann, Josef; Cifrain, Martin; Faleschini, Gottfried; Enzinger, Peter; Fankhauser, Robert; Ortner, Markus; Muhr, Michael; Aronson, Robert R.

    On the world-wide automobile market technical developments are increasingly determined by the dramatic restriction on emissions as well as the regimentation of fuel consumption by legislation. Therefore there is an increasing chance of a completely new technology breakthrough if it offers new opportunities, meeting the requirements of resource preservation and emission restrictions. Fuel cell technology offers the possibility to excel in today's motive power techniques in terms of environmental compatibility, consumer's profit, costs of maintenance and efficiency. The key question is economy. This will be decided by the costs of fuel cell systems if they are to be used as power generators for future electric vehicles. The alkaline hydrogen-air fuel cell system with circulating KOH electrolyte and low-cost catalysed carbon electrodes could be a promising alternative. Based on the experiences of Kordesch [K. Kordesch, Brennstoffbatterien, Springer, Wien, 1984, ISBN 3-387-81819-7; K. Kordesch, City car with H 2-air fuel cell and lead-battery, SAE Paper No. 719015, 6th IECEC, 1971], who operated a city car hybrid vehicle on public roads for 3 years in the early 1970s, improved air electrodes plus new variations of the bipolar stack assembly developed in Graz are investigated. Primary fuel choice will be a major issue until such time as cost-effective, on-board hydrogen storage is developed. Ammonia is an interesting option. The whole system, ammonia dissociator plus alkaline fuel cell (AFC), is characterised by a simple design and high efficiency.

  8. Mohorovicic discontinuity depth analysis beneath North Patagonian Massif

    NASA Astrophysics Data System (ADS)

    Gómez Dacal, M. L.; Tocho, C.; Aragón, E.

    2013-05-01

    The North Patagonian Massif is a 100000 km2, sub-rectangular plateau that stands out 500 to 700 m higher in altitude than the surrounding topography. The creation of this plateau took place during the Oligocene through a sudden uplift without noticeable internal deformation. This quite different mechanical response between the massif and the surrounding back arc, the short time in which this process took place and a regional negative Bouguer anomaly in the massif area, raise the question about the isostatic compensation state of the previously mentioned massif. In the present work, a comparison between different results about the depth of the Mohorovicic discontinuity beneath the North Patagonian Massif and a later analysis is made. It has the objective to analyze the crustal thickness in the area to contribute in the determination of the isostatic balance and the better understanding of the Cenozoic evolution of the mentioned area. The comparison is made between four models; two of these were created with seismic information (Feng et al., 2006 and Bassin et al., 2000), another model with gravity information (Barzaghi et al., 2011) and the last one with a combination of both techniques (Tassara y Etchaurren, 2011). The latter was the result of the adaptation to the work area of a three-dimensional density model made with some additional information, mainly seismic, that constrain the surfaces. The work of restriction and adaptation of this model, the later analysis and comparison with the other three models and the combination of both seismic models to cover the lack of resolution in some areas, is presented here. According the different models, the crustal thickness of the study zone would be between 36 and 45 Km. and thicker than the surrounding areas. These results talk us about a crust thicker than normal and that could behave as a rigid and independent block. Moreover, it can be observed that there are noticeable differences between gravimetric and seismic

  9. Structure and modeling of disorder in miserite from the Murun (Russia) and Dara-i-Pioz (Tajikistan) massifs

    NASA Astrophysics Data System (ADS)

    Kaneva, Ekaterina; Lacalamita, Maria; Mesto, Ernesto; Schingaro, Emanuela; Scordari, Fernando; Vladykin, Nikolay

    2014-01-01

    The structure, structural disorder and chemistry of miserite from the charoite-bearing rocks of the Murun massif (Russia) and from alkaline-syenite pegmatitic rocks of the Dara-i-Pioz massif (Tajikistan) were investigated employing a combination of electron microprobe, single crystal diffraction and micro-Fourier transform infrared spectroscopy analysis. Chemical analysis of the sample investigated by X-ray diffraction evidenced that Dara-i-Pioz miserite has a greater REE concentration than Murun miserite (~0.22 vs. 0.05 apfu, respectively) and also contains Y (0.14 apfu), which is absent in Murun miserite. The occurrence of a band at about 1,600 cm-1 testified to the presence of H2O in miserite at hand. Structural analyses yielded average cell parameters of a = 10.092, b = 16.016, c = 7.356 Å, α = 96.60°, β = 111.27° and γ = 76.34°. Anisotropic structural refinement in space group P converged at similar values for the analyzed samples ( R ~3.4, R w ~3.8 %). An interesting feature shown by both the miserite specimen is the presence, revealed by difference Fourier analysis, of a disordered part of the structure. This turned out to be due to the flipping of the tetrahedra belonging to the isolated [Si2O7]6- diorthogroups, one of the two radicals (the other is [Si12O30]12-) characterizing the miserite structure. The sixfold and seven-vertex Ca polyhedra linked to the inverted diorthogroups show variation in coordination number with respect to those of the ordered structure.

  10. Long-term landscape evolution of the southeast Brazilian highlands: comparison of two alkaline intrusions areas

    NASA Astrophysics Data System (ADS)

    Doranti Tiritan, Carolina; Hackspacher, Peter Christian; Glasmacher, Ulrich Anton

    2016-04-01

    The southeast Brazilian highlands records a long history of tectonic and magmatic events that were consequence of the South Atlantic Ocean opening. After the rifting process has ceased, an epeirogenic uplift of the continental crust has started in response to the drifting of the South American Platform over a thermal anomaly that accompanied an intense alkaline and basaltic magmatism. Related Late Cretaceous alkaline intrusions are distributed from the southeast Brazilian coast to the interior of the South American Platform. The landscape evolution is associated with several distinct exhumation events at the South American passive continental margin (Hackspacher 2004; Doranti et al, 2014). The present study intent providing insights on the behaviour of the coupled magmatic tectonic-erosional system, comparing thermochronological data from two alkaline intrusions, Poços de Caldas Alkaline Massif (PCAM) and São Sebastião Island (SSI). The PCAM is the biggest alkaline structure located in the interior of the continent, 300km from the coastline (Rio de Janeiro). The structure is formed as a caldera, covering over 800km2, intruding Precambrian basement around 83Ma, nepheline syenites, phonolites and tinguaites intruded in a continuous and rapid sequence lasting between 1 to 2 Ma. Meanwhile, the SSI (236km²) is located at the coast, 200 km southeast of the city of São Paulo and is characterized by an intrusion in Precambrian granitic-gnaissic rocks affected by the Panafrican/Brazilian Orogen. This crystalline basement is intruded by Early Cretaceous subalkaline basic and acid dykes, as well as by Late Cretaceous alkaline stocks (syenites) and dykes (basanite to phonolite). The Apatite Fission-Track ages for PCAM range from 333.3±27.6 to 94.0±13.7 Ma at the surrounded metamorphic basement area, and 76.8±10.9 to 48.7±10.7 Ma in the alkaline Massif. The older ages, are concentrated on the lower topography region (700 until 1200m) in the north side alkaline massif

  11. Petrogenetic characteristics of mafic-ultramafic massifs in Nizhne-Derbinsk complex (East Sayan Mountains)

    NASA Astrophysics Data System (ADS)

    Cherkasova, T.; Chernishov, A.; Goltsova, Yu; Timkin, T.; Abramova, R.

    2015-11-01

    The article describes the results of petrographic, petrochemical, petrofabric, mineralogical and geochemical studies of the major rock groups potentially Cu, Ni, Pt ore- bearing mafic-ultramafic massifs in the Nizhne- Derbinsk complex (Eastern Sayan Mountains). Based on the data interpretation the investigated massifs can be classified as peridotite- pyroxenite-gabbronorite formation of geosynclinal regime in Altai-Sayan folding area. Significant massif deformation occurred during the final post-consolidation formation stage. The petrographic features of gabbro and petrofabric patterns of the rock-forming minerals in the Burlakski and Nizhne-Derbinsk massifs indicated the fact that massifs were involved in the accretion-collisional development stage of the Central Asian folding belt during the final formation stages the Nizhne-Derbinsk complex.

  12. Petrological Characterization of the Triassic Paleosurface in the Northern Bohemian Massif

    NASA Astrophysics Data System (ADS)

    Yao, Kouakou; Thiry, Medard; Szuszkiewicz, Adam; Turniak, Krzysztof

    2010-05-01

    ‘Albitization' is a widespread alteration process affecting sedimentary, igneous and metamorphic rocks. Albitized facies usually show a pinkish to red colour, depending on the degree of alteration. The main mineralogical process of this phenomenon is the pseudomorphic replacement of the primary Ca-Na plagioclases by secondary albite (Na). During this replacement biotite is often transformed to chlorite and inclusions of hematite, apatite, titanite, and calcite develop. So far, albitization has been systematically regarded as caused by magmatic derived hydrothermal brines, alkaline metasomatism reactions (Cathelineau, 1986; Petersson and Eliasson, 1997), or as a low grade metamorphic facies (Boles and Coombs, 1977). Recent studies in the Morvan Massif granites (Ricordel et al., 2007; Parcerisa et al., 2009) showed that the albitization there is related to the Triassic paleosurface. The decrease of this alteration with depth and its paleomagnetic age support the link of the albitization to the Triassic paleosurface. Furthermore, the petrographic data suggest the import of sodium by weathering solutions. The enrichement in Na+ of the fluids that triggered this alteration is probably linked to the Triassic salt deposits. Albitised pinkish facies have been recognized in the northern part of the Bohemian Massif (Polish Sudetes). Typical igneous and metamorphic rocks of the Klodzko area (southern Poland) are granites, granodiorites, schists, amphibolite, and gneisses, mostly of Paleozoic age. Three sites in the Klodzko area were sampled in detail from N to S: (1) Laski quarry, (2) Laski village, and (3) Chwalislaw. Here, the occurrence of the albitization is well developed and specific in its mineralogical paragenesis. Throughout the sample sites different albitization stages can be observed. The most albitized and therefore reddish facies can be found at the Laski village granite that consists of primary quartz and K-feldspar, biotite, and development of secondary

  13. Zirconology of ultrabasic rocks of the Karabash massif (Southern Urals)

    NASA Astrophysics Data System (ADS)

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

    2016-07-01

    Dating of zircon (SHRIMP) from dunite and harzburgite of the Karabash massif was carried out for the first time. Relics of ancient crystals (1940 ± 30 Ma in harzburgite, 1860 ± 16 Ma in dunite) provide evidence for the Paleoproterozoic age of the protolith. The morphological peculiarities of zircon crystals allow us to assume differentiation of the magmatic source 1720 m. y. ago. The major variety of zircons indicates stages of metamorphic evolution in the Neoproterozoic (530-560 Ma) and Early-Late Ordovician (440-480 Ma).

  14. Use of Digital Elevation Models to understand map landforms and history of the magmatism Khibiny Massif (Kola Peninsula, Russia)

    NASA Astrophysics Data System (ADS)

    Chesalova, Elena; Asavin, Alex

    2016-04-01

    most intense free gas emission. The technical possibilities that are offered by Remote Sensing (RS) and Geographical Information Systems (GIS) facilitate the geomorphological investigation of inhospitable and inaccessible mountain areas Digital Elevation Models (DEMs) are valuable tools for approximation of the real world's continuous surface. They allow a visual analysis of the earth's surface morphology, quanti?cation of sediment volumes and the calculation of topographic derivatives such as the slope gradient, slope aspect and pro?le curvature that consume ?eld investigations and optimize time The project has been sponsored by programmm Presidium of RAS P44. Reference Ivanyuk G, Kalashnikov A, Mikhailova J, Konoplyova N, Goryainov P, Yakovenchuk V, Pakhomovsky Y. Self-Organization of the Khibiny Alkaline Massif (Kola Peninsula, Russia). In Earth Sciences, Dr. Imran Ahmad Dar(Ed.), ISBN: 978-953-307-861-8, InTech, Available from: http://www.intechopen.com/books/earth-sciences/self-organization-of-the-khibiny-alkaline -massif -kolapeninsula-russia INTECH Open Access Publisher; 2012, Head7, P.131-156.

  15. Apatite fission track thermochronology of Khibina Massif (Kola Peninsula, Russia): Implications for post-Devonian Tectonics of the NE Fennoscandia

    NASA Astrophysics Data System (ADS)

    Veselovskiy, Roman V.; Thomson, Stuart N.; Arzamastsev, Andrey A.; Zakharov, Vladimir S.

    2015-12-01

    The thermal history of the Kola Peninsula area of NE Fennoscandia remains almost fully unknown because of the absence of any thermochronological data such as apatite and/or zircon fission track or (Usbnd Th)/He ages. In order to fill this gap and to constrain the post-Devonian erosion and exhumation history of this region, we present the results of apatite fission track (AFT) dating of eleven samples selected from the cores taken from different depths of the northern part of the Khibina intrusive massif. The Rbsbnd Sr isochron age of this alkaline magmatic complex which is located at the center of Kola Peninsula is 368 + 6 Ma (Kramm and Kogarko, 1994). Samples were analyzed from depths between + 520 and - 950 m and yielded AFT ages between 290 and 268 Ma with an age uncertainty (1σ) of between ± 19 Ma (7%) and ± 42 Ma (15%). Mean track lengths (MTL) lie between 12.5 and 14.4 μm. Inverse time-temperature modeling was conducted on the age and track length data from seven samples of the Khibina massif. Thermal histories that best predict the measured data from three samples with the most reliable data show three stages: (1) 290-250 Ma-rapid cooling from > 110 °C to 70 °C/50 °C for lower/upper sample correspondingly; (2) 250-50 Ma-a stable temperature stage; (3) 50-0 Ma-slightly increased cooling rates down to modern temperatures. We propose that the first cooling stage is related to late-Hercynian orogenesis; the second cooling stage may be associated with tectonics accompanying with opening of Arctic oceanic basin. The obtained data show that geothermal gradient at the center of Kola Peninsula has remained close to the modern value of 20 °C/km for at least the last 250 Myr. AFT data show that the Khibina massif has been exhumed not more then 5-6 km in the last 290 Myr.

  16. Exotic crustal components at the northern margin of the Bohemian Massif-Implications from Usbnd Thsbnd Pb and Hf isotopes of zircon from the Saxonian Granulite Massif

    NASA Astrophysics Data System (ADS)

    Sagawe, Anja; Gärtner, Andreas; Linnemann, Ulf; Hofmann, Mandy; Gerdes, Axel

    2016-06-01

    The Saxonian Granulite Massif is located at the northern margin of the Saxo-Thuringian Zone of the peri-Gondwana Bohemian Massif. Eight felsic and mafic granulites were studied with respect to their geochemistry and Usbnd Pb zircon geochronology. The felsic granulites are interpreted to be derived from continental crust of possible granitoid composition. An origin from depleted mantle sources with IAT to MORB composition can be assumed for the mafic granulites. The peak of metamorphism is thought to be timed at about 340 Ma, while several earlier metamorphic events are supposed to have occurred at about 355-360, 370-375, 405, and 450 Ma. They reveal a complex and polyphased geologic evolution of the Saxonian Granulite Massif. Protolith emplacement likely took place at c. 450 and 494 Ma. Hf isotopic data suggest Mesoproterozoic crustal ages at least for parts of the massif. As these crustal ages are exotic for the Bohemian Massif, their origin has to be searched elsewhere. Potential source areas could be Amazonia and Baltica, of which the latter is the one preferred. Furthermore, a composite architecture with at least two components-the felsic granulites with Mesoproterozoic crustal model ages, and the mafic granulites of potential island arc origin-is hypothesised. Their amalgamation to the recent appearance of the Saxonian Granulite Massif is likely bracketed between 375 and 340 Ma.

  17. Silica in alkaline brines

    USGS Publications Warehouse

    Jones, B.F.; Rettig, S.L.; Eugster, H.P.

    1967-01-01

    Analysis of sodium carbonate-bicarbonate brines from closed basins in volcanic terranes of Oregon and Kenya reveals silica contents of up to 2700 parts per million at pH's higher than 10. These high concentrations of SiO 2 can be attributed to reaction of waters with silicates, and subsequent evaporative concentration accompanied by a rise in pH. Supersaturation with respect to amorphous silica may occur and persist for brines that are out of contact with silicate muds and undersaturated with respect to trona; correlation of SiO2 with concentration of Na and total CO2 support this interpretation. Addition of moredilute waters to alkaline brines may lower the pH and cause inorganic precipitation of substantial amounts of silica.

  18. Bifunctional alkaline oxygen electrodes

    NASA Technical Reports Server (NTRS)

    Swette, L.; Kackley, N.; Mccatty, S. A.

    1991-01-01

    The authors describe the identification and testing of electrocatalysts and supports for the positive electrode of moderate-temperature, single-unit, rechargeable alkaline fuel cells. Recent work on Na(x)Pt3O4, a potential bifunctional catalyst, is described, as well as the application of novel approaches to the development of more efficient bifunctional electrode structures. The three dual-character electrodes considered here showed similar superior performance; the Pt/RhO2 and Rh/RhO2 electrodes showed slightly better performance than the Pt/IrO2 electrode. It is concluded that Na(x)Pt3O4 continues to be a promising bifunctional oxygen electrode catalyst but requires further investigation and development.

  19. Geochemical study of the granitic rocks from the Ryongnam massif, Geochang, South Korea

    NASA Astrophysics Data System (ADS)

    Han, M.; Kim, J.; Yang, K.

    2009-12-01

    The geochemical studies on the granitic rocks of the central part of the Ryongnam massif were carried out in order to constrain the petrogenesis and the paleotectonic environment. The area is composed of Precambrian gneissic rocks and metamorphosed sedimentary rocks, age-unknown granite and dioritic rocks, and Jurassic granitic rocks. The modal compositions indicate that the studied granitic rocks are granodiorite, monzogranite, syeno-granite, and alkali-feldspar granite. Except for Na2O and K2O, the contents of most oxides such as P2O5, TiO2, Al2O3, CaO, MgO and Fe2O3 decrease when SiO2 increases. These granitic rocks belong to the calc-alkaline series in the TAS and AFM diagram. They also show high-K nature, indicating the rocks experienced considerable differentiations. The studied granitic rocks correspond to Peraluminous and I-type(less than 1.1) in the A/CNK diagram. Chondrite-normalized REE patterns show generally enrichment in LREE and depleted in HREE. This suggests that the magma has been largely differentiated at an early stage. REE patterns of different granitic rocks in composition are subparallel each other, suggesting cogenetic in origin. The (-) anomaly of Eu shows that the granitic rocks were generated from residual magma which had fractionated plagioclase. Furthermore, the amount of total REE of the studied granitic rocks ranges 46.93~108.84 ppm, which corresponds to the range of granitic rocks from the continental margin granite. On the N-type MORB normalized spiderdiagram, the studied rocks generally show Nb-Ta and Hf-Zr trough, indicating the subduction-related products. According to the tectonomagmatic discrimination diagram, they correspond to volcanic arc granite(VAG). The major and trace element characteristics of the granitic rocks support their emplacement at the active continental margin.

  20. The magmatic history of the Vetas-California mining district, Santander Massif, Eastern Cordillera, Colombia

    NASA Astrophysics Data System (ADS)

    Mantilla Figueroa, Luis C.; Bissig, Thomas; Valencia, Víctor; Hart, Craig J. R.

    2013-08-01

    The Vetas-California Mining District (VCMD), located in the central part of the Santander Massif (Colombian Eastern Cordillera), based on U-Pb dating of zircons, records the following principal tectono-magmatic events: (1) the Grenville Orogenic event and high grade metamorphism and migmatitization between ˜1240 and 957 Ma; (2) early Ordovician calc-alkalic magmatism, which was synchronous with the Caparonensis-Famatinian Orogeny (˜477 Ma); (3) middle to late Ordovician post-collisional calc-alkalic magmatism (˜466-436 Ma); (4) late Triassic to early Jurassic magmatism between ˜204 and 196 Ma, characterized by both S- and I-type calc-alkalic intrusions and; (5) a late Miocene shallowly emplaced intermediate calc-alkaline intrusions (10.9 ± 0.2 and 8.4 ± 0.2 Ma). The presence of even younger igneous rocks is possible, given the widespread magmatic-hydrothermal alteration affecting all rock units in the area. The igneous rocks from the late Triassic-early Jurassic magmatic episodes are the volumetrically most important igneous rocks in the study area and in the Colombian Eastern Cordillera. They can be divided into three groups based on their field relationships, whole rock geochemistry and geochronology. These are early leucogranites herein termed Alaskites-I (204-199 Ma), Intermediate rocks (199-198 Ma), and late leucogranites, herein referred to as Alaskites-II (198-196 Ma). This Mesozoic magmatism is reflecting subtle changes in the crustal stress in a setting above an oblique subduction of the Panthalassa plate beneath Pangea. The lower Cretaceous siliciclastic Tambor Formation has detrital zircons of the same age populations as the metamorphic and igneous rocks present in the study area, suggesting that the provenance is related to the erosion of these local rocks during the late Jurassic or early Cretaceous, implying a local supply of sediments to the local depositional basins.

  1. Conditions of accumulation of radioactive metals in the process of differentiation of ultrabasic alkaline-carbonatite rock associations

    NASA Astrophysics Data System (ADS)

    Kogarko, L. N.

    2014-07-01

    The distribution of radioactive elements in alkaline rocks from Polar Siberia and Ukraine shows that U and Th are markedly concentrated in carbonatite complex and nepheline syenite as final products of magma fractionation. Peralkaline nepheline syenites from Polar Siberia are characterized by very high contents of radioactive elements, which are close to the economic level. Radioactive elements are also concentrated in rocks of the carbonatite complex. For example, some soevites contain up to 294 × 10-4%U and 916 × 10-4% Th. In late dolomite carbonatites, the contents of radioactive elements are appreciably lower. The Th/U ratio in alkaline rocks of Polar Siberia is close to the chondrite value in primary high-Mg rocks and increases in late derivatives: phoscorite, calcite and dolomite carbonatites. The main amount of radioactive elements is contained in rare-metal accessory minerals: perovskite, pyrochlore, calzirtite, and apatite. Rock-forming minerals are distinguished by very low concentrations of radioactive elements. In alkaline series of the Chernigovka massif (Ukraine), U and Th also accumulate in the course of crystal fractionation, especially in phoscorites from the carbonatite complex. Mantle xenoliths and alkaline rocks from Ukraine reveal uranium specialization. Most likely, the discrepancy in fractionation of radioactive elements between Polar Siberia and Ukraine is caused by different geodynamic regimes of these provinces. The Mesozoic alkaline magmatism of Polar Siberia is a part of the Siberian superplume, whereas the Proterozoic alkaline complex in Ukraine is related to subduction of the oceanic crust.

  2. Mesoscopic faults in the Bregaglia (Bergell) massif, Central Alps

    NASA Astrophysics Data System (ADS)

    Passerini, P.; Sguazzoni, G.; Marcucci, M.

    1991-11-01

    The strike, direction of dip and pitch of the striae along mesoscopic faults in the Oligocene granodiorite-tonalite of Val Masino-Val Bregaglia (Bergell) are analysed. Most fault planes are steeply dipping, and show strike-slip or oblique-slip motion. Dominant strikes are NNW or NNE. A relative chronology of fault sets is suggested based on the presence of different minerals (chlorite and epidote) on fault planes. The pattern of mesoscopic faults in the Val Masino-Val Bregaglia massif does not follow the earlier tectonic trends of the Pennidic nappe edifice, nor even the trend of the nearby section of the Insubric Line considered at both regional and mesoscopic scales. The mesoscopic analysis of the Val Masino-Val Bregaglia massif thus reveals a fault system largely oblique to the major Alpine lineaments. The observed fault pattern does not reveal traces of thrusting referable to late Alpine orogenic phases, and can be related to subsequent deformation, dominated by strike-slip movements; this pattern does not match the traditional schemes of extensional dip-slip faulting following orogenesis. It records a stage of tectonic evolution which follows nappe emplacement, yet it precedes vertical or extensional post-orogenic tectonics.

  3. Intrusion level of granitic massifs along the Hercynian belt: balancing the eroded crust

    NASA Astrophysics Data System (ADS)

    Vigneresse, J. L.

    1999-06-01

    Hercynian granitoid intrusions form a long (3200 km) belt comparable in size to other batholiths in the world. Six massifs have been selected which encompass Cabeza de Araya (Extremadura, Spain), Guitiriz (Galicia, Spain), Pontivy and Mortagne (Brittany, France), La Marche (Massif Central, France) and Fichtelgebirge (Bavaria, Germany). Detailed gravity surveys over these massifs and subsequent inversion provide their shape at depth. Correlation of the deeper zones with internal structures determine the place of the root zones. The shape of the massifs is examined along the strike of the chain. The emplacement of individual massifs is controlled by local tectonics. Most granites are not deeply rooted, but one massif (Cabeza de Araya, Spain) shows a root zone presently as deep as 14 km. Most have about half of their volume in the first 3 km below the present surface. Estimates of the magma volume transferred result in 1500 km 3 issued from one specific feeder, yielding a total of 70,000 km 3 of magma intruded all along the chain. The depth of emplacement of the granitic massifs does not show any significant trend along the strike of the chain. The shallower massifs in the French Massif Central correspond to more deeply eroded areas in the center of the chain. Their root zone, as well as the change in the dip of the walls, are presently observed at depths ranging between 4 and 6 km in Hercynian granites. Both variations are interpreted as being related to the brittle/ductile transition at the time of emplacement. Gross thermal considerations place the transition at its former place during magma emplacement, indicating that the upper crust has not been eroded by more than 6-8 km. This estimate severely contrasts with models involving a doubled crust.

  4. Modulators of intestinal alkaline phosphatase.

    PubMed

    Bobkova, Ekaterina V; Kiffer-Moreira, Tina; Sergienko, Eduard A

    2013-01-01

    Small molecule modulators of phosphatases can lead to clinically useful drugs and serve as invaluable tools to study functional roles of various phosphatases in vivo. Here, we describe lead discovery strategies for identification of inhibitors and activators of intestinal alkaline phosphatases. To identify isozyme-selective inhibitors and activators of the human and mouse intestinal alkaline phosphatases, ultrahigh throughput chemiluminescent assays, utilizing CDP-Star as a substrate, were developed for murine intestinal alkaline phosphatase (mIAP), human intestinal alkaline phosphatase (hIAP), human placental alkaline phosphatase (PLAP), and human tissue-nonspecific alkaline phosphatase (TNAP) isozymes. Using these 1,536-well assays, concurrent HTS screens of the MLSMR library of 323,000 compounds were conducted for human and mouse IAP isozymes monitoring both inhibition and activation. This parallel screening approach led to identification of a novel inhibitory scaffold selective for murine intestinal alkaline phosphatase. SAR efforts based on parallel testing of analogs against different AP isozymes generated a potent inhibitor of the murine IAP with IC50 of 540 nM, at least 65-fold selectivity against human TNAP, and >185 selectivity against human PLAP. PMID:23860652

  5. Alkaline battery, separator therefore

    NASA Technical Reports Server (NTRS)

    Schmidt, George F. (Inventor)

    1980-01-01

    An improved battery separator for alkaline battery cells has low resistance to electrolyte ion transfer and high resistance to electrode ion transfer. The separator is formed by applying an improved coating to an electrolyte absorber. The absorber, preferably, is a flexible, fibrous, and porous substrate that is resistant to strong alkali and oxidation. The coating composition includes an admixture of a polymeric binder, a hydrolyzable polymeric ester and inert fillers. The coating composition is substantially free of reactive fillers and plasticizers commonly employed as porosity promoting agents in separator coatings. When the separator is immersed in electrolyte, the polymeric ester of the film coating reacts with the electrolyte forming a salt and an alcohol. The alcohol goes into solution with the electrolyte while the salt imbibes electrolyte into the coating composition. When the salt is formed, it expands the polymeric chains of the binder to provide a film coating substantially permeable to electrolyte ion transfer but relatively impermeable to electrode ion transfer during use.

  6. Evaluation of Alkaline Cleaner Materials

    NASA Technical Reports Server (NTRS)

    Partz, Earl

    1998-01-01

    Alkaline cleaners used to process aluminum substrates have contained chromium as the corrosion inhibitor. Chromium is a hazardous substance whose use and control are described by environmental laws. Replacement materials that have the characteristics of chromated alkaline cleaners need to be found that address both the cleaning requirements and environmental impacts. This report will review environmentally friendly candidates evaluated as non-chromium alkaline cleaner replacements and methods used to compare those candidates one versus another. The report will also list characteristics used to select candidates based on their declared contents. It will also describe and evaluate methods used to discriminate among the large number of prospective candidates.

  7. Geochronology- and Geochemistry of Late Carboniferous-Middle Permian I- and A-Type Granites and Gabro-Diorites in the Eastern Jimausi Massif, NE, China: Implications for a Tectonic Transition

    NASA Astrophysics Data System (ADS)

    Bi, Junhui; Ge, Wenchun

    2016-04-01

    The late Paleozoic magmatism in the Jiamusi Massif of northeast China, located in the eastern segment of the Central Asian Orogenic Belt (CAOB), was dominated by an active continental margin environment due to subduction of the paleo-oceanic plate. Nevertheless, what deep geodynamic processes controlled the late Paleozoic evolution of the Jiamusi Massif are still poorly constrained. In this contribution, we present zircon U-Pb ages and geochemical data of late Carboniferous-middle Permian magmatism in the Jiamusi Massif, aiming to provide constraints on the question. Precise LA-ICP-MS U-Pb zircon ages indicate that the granitoids and gabbro-diorites were emplaced in the late Carboniferous-middle Permian (302-267 Ma). The granites belong to a high-potassium calc-alkaline series, are weakly peraluminous I- and A-type granites, and show high SiO2 and K2O contents; they are depleted in high field strength elements (HFSEs), enriched in light rare earth elements (LREEs) and large ion lithophile elements (LILEs), show weakly to mildly fractionated REE patterns, and on spidergrams show arc-type affinities with strong depletions in Nb, Ta, and Ti. The combination of heterogeneous values of ɛHf(t) for magmatic zircons in all granitoids (ranging from +7.9 to -5.6) and two-stage Hf model ages (TDM2) of 0.8-1.7 Ga suggests that the granites originated from partial melting of a predominantly "old" Meso-Neoproterozoic crustal source. The gabbro-diorites of the Longtouqiao pluton are depleted in Nb, Ta, P, and Ti, and show flat distributions of most LILEs and HFSEs, except for marked large positive anomalies in Ba, K, and Pb. These features reflect limited degrees of crustal contamination associated with subduction-related magma processes. These data, together with previously reported data and the occurrence of arc magmatic rocks along the eastern part of the Jiamusi Massif, suggest that the intrusive rocks formed during westward subduction of the Paleo-Pacific Ocean lithosphere

  8. Induced seismicity in the Khibiny Massif (Kola Peninsula)

    NASA Astrophysics Data System (ADS)

    Kremenetskaya, Elena O.; Trjapitsin, Victor M.

    1995-10-01

    The topic of this paper is to review recent processes of increasing seismic activity in the Khibiny Massif in the Kcla Peninsula. It is a typical example of induced seismicity caused by rock deformation due to the extraction of more than 2·109 tons of rock mass since the mid-1960s. The dependence of seismic activity on the amount of extracted ore is demonstrated. Some of the induced earthquakes coincide with large mining explosions, thus indicating a trigger mechanism. The largest earthquake, which occurred on 16 April 1989 ( M L= 4.1) could be traced along the surface for 1200 m and observed to a depth of at least 220 m. The maximum measured displacement was 15 20 cm.

  9. Structural geology investigation on Massif Central and Parisian Basin (France)

    NASA Technical Reports Server (NTRS)

    Weecksteen, G. (Principal Investigator)

    1973-01-01

    The author has identified the following significant results. Band 5 gives the most information concerning the fracturing in the Massif Central and Parisian Basins. Band 6 and 7 show the fractures emphasized by forest boundaries and by the linear trace of water courses. The most remarkable information drawn from the preliminary investigation of two ERTS-1 images covering two different landscapes, a regular relief of shelving plateau bounded by cuestas having a sedimentary origin and a mountainous region built in crystalline and volcanic rocks, is that the deep structural elements under a thick sedimentary cover can be translated on the surface by indirect criteria. MSS imagery has permitted the Metz fault to be extended towards the west and shows clearly, through land use on the Rhone Valley fluvial deposit, the continuation towards the east of the carboniferous basin of St. Etienne.

  10. Structural investigations in the Massif-Central, France

    NASA Technical Reports Server (NTRS)

    Scanvic, J. Y.

    1974-01-01

    This survey covered the French Massif-Central (where crystalline and volcanic rocks outcrop) and its surrounding sedimentaries, Bassin de Paris, Bassin d'Aquitaine and Rhodanian valley. One objective was the mapping of fracturing and the surveying of its relationship with known ore deposits. During this survey it was found that ERTS imagery outlines lithology in some sedimentary basins. On the other hand, in a basement area, under temperature climate conditions, lithology is rarely expressed. These observations can be related to the fact that band 5 gives excellent results above sedimentary basins in France and generally band 7 is the most useful in a basement area. Several examples show clearly the value of ERTS imagery for mapping linear features and circular structures. All the main fractures are identified with the exception of new ones found both in sedimentaries and basement areas. Other interesting findings concern sun elevation which, stereoscopic effect not being possible, simulates relief in a better way under certain conditions.

  11. Geochronology and geochemistry of the Triassic volcanic rocks at the eastern margin of the Xing'an Massif, NE China: constraints on the spatial-temporal extent of the influence of the Mongol-Okhotsk tectonic regime

    NASA Astrophysics Data System (ADS)

    Yu, L.; Xu, W.; Wang, F.

    2015-12-01

    The Mongol-Okhotsk suture belt is located between the Siberian and the North China cratons and played an important role in the formation and tectonic evolution of the eastern part of the Eurasian continent during the Mesozoic. It was previously thought that subduction of the Mongol-Okhotsk oceanic plate beneath the Siberian Craton was north-directed throughout the entire period of subduction, but recent research has provided evidence of southward subduction beneath the Central Mongolia and Erguna massifs during the late Permian and early Mesozoic. However, the spatial and temporal extent of the influence of the Mongol-Okhotsk tectonic regime on NE China remains unclear. In this paper, we present new zircon U-Pb and geochemical data for Triassic volcanic rocks that crop out on the eastern margin of the Xing'an Massif to address the above-mentioned question. Zircon U-Pb dating indicates that the Triassic volcanism in the Xing'an Massif occurred in two stages during the Middle (~240 Ma) and Late (~224 Ma) Triassic. Triassic volcanism consists of a suite of calc-alkaline trachybasalt and andesite, and are enriched in light rare earth elements (LREE) and depleted in high field strength elements (HFSE; e.g., Nb, Ta, Zr, and Hf), indicating an affinity to arc-type volcanic rocks. The Triassic volcanic rocks formed in an active continental margin setting associated with southward subduction of the Mongol-Okhotsk oceanic plate. Combined with the spatial and temporal variations of late Mesozoic igneous rocks in NE China, we conclude that the spatial extent of the influence of the Mongol-Okhotsk tectonic regime reached at least the eastern margin of the Xing'an Massif, and the temporal influence of this tectonism spanned from the late Permian to the early Early Cretaceous. This research was financially supported by the National Natural Science Foundation of China (Grant 41330206) and Graduate Innovation Fund of Jilin University (Project 2015038).

  12. Petrogenesis of massif anorthosites: a perspective from St. Urbain, Quebec

    SciTech Connect

    Gromet, L.P.; Dymek, R.F.

    1985-01-01

    The St. Urbain massif is a post-orogenic anorthosite pluton (approx. 500 km/sup 2/) emplaced within the central high-grade granulite terrain of the Grenville structural province. In contrast to other Grenville anorthosites, primary magmatic features are largely preserved. The massif consists predominantly of andesine anorthosite (AA) of remarkable purity containing abundant plagioclase megacrysts. AA has high K/sub 2/O (approx. 2 wgt.%), very high Sr contents (approx. 1200 ppm) and highly fractionated, low REE contents. Features of AA provide the following insights into anorthosite origins: (1) Crystallization from anorthositic magmas, as evidenced by early crystallization of abundant antiperthitic plag, and igneous emplacement of AA dikes and veins into older, unrelated labradorite anorthosite; (2) in situ crystallization of pyroxene after plag, with no direct evidence of earlier crystallization of mafic minerals from a basaltic parent magma; (3) limited differentiation during crystallization, indicated by small variation in plag and opx and limited variations in plag Sr and REE contents; (4) the involvement of water, suggested by the late igneous crystallization of biotite and the localized grain-boundary replacement of plag by calcic myrmekite (An/sub 80/ + qtz). (5) high temperature, relatively oxidizing conditions, indicated by magmatic hemoilmenite +/- rutile and rare ferropseudobrookite in AA and associated ores. AA crystallized from highly feldspathic, relatively oxidized, somewhat hydrous parent magma with little trapped melt. The development of a hyperfeldspathic parent magma with the requisite geochemical features can be ascribed to hydrous partial melting of mafic (to intermediate) rocks at deep crustal or greater depths, leaving a garnetiferous residue.

  13. The paleoproterozoic Monchetundra mafic massif (Kola Peninsula): New geological and geochronological data

    NASA Astrophysics Data System (ADS)

    Borisenko, E. S.; Bayanova, T. B.; Nerovich, L. I.; Kunakkuzin, E. L.

    2015-11-01

    In view of the absence of an unambiguous intrusive contact between the main mafic rocks varieties in the Monchetundra massif, the latter was considered for a long time as a large complex of syngenetic mafic rocks. On the basis of data derived from study of the outcrops and drill core samples, researchers defined various numbers of zones characterized by certain rock types. The results of geological-petrographic investigations and data on the U-Pb system in zircon and baddeleyite provided grounds for revision of the views on the structure of the massif: at least four groups of different ages of mafic rocks are now definable in the Monchetundra massif. In this communication, we discuss the relations between two groups of mafic rocks and the results of their U-Pb isotopic dating, which imply a long multiphase formation of the massif.

  14. Petrology and geochemistry of primary magmas trapped in melt inclusions in scoria of Beaunit Maar (Chaîne des Puys, Massif Central, France)

    NASA Astrophysics Data System (ADS)

    Jannot, S.; Schiano, P.; Boivin, P.; Clocchiatti, R.; Chazot, G.

    2003-04-01

    The Massif Central area, characterized by a typical intraplate alkaline serie, is the largest magmatic province of the West-European Rift system. Although it has been the subject of several studies, the nature of Massif Central sources is still a matter of debate and many hypotheses are proposed, including deep-rooted continental hotspot, metasomatised spinel lherzolites and an asthenospheric flow linked to the lithospheric root of the Alpine chain. The Chaîne des Puys is the last magmatic province of the French Massif Central and is composed of hundred young well-preserved volcanoes. The present work aims to supply information on the nature and the origin of the source chemistry of alkaline serie from the Chaîne des Puys, by characterizing the trace and major element composition of minute melts preserved as quenched glass inclusions inside olivines phenocrysts in scoria from the Beaunit Maar. Heating stage experiments performed at ambient pressure on partially crystallised primary melt inclusions suggest CO_2 oversaturation of the trapped melt, and an entrapment temperature around 1200^oC±10^oC. Daughter minerals analyses point to a Ti-and Ca-rich basaltic paragenesis, in good agreement with that of erupted basalts from the Chaîne des Puys. Major element compositions show that melts trapped in inclusions evolve by limited fractional crystallization. Inclusions trapped in the more primitive olivine phenocrysts (Fo85) have alkali-basalt compositions that fall on the primitive end of the compositional trend define by the lavas of the Chaîne des Puys. Their major element chemistry rules out the hypothesis of a mantle source in the spinel stability field and requires a garnet-bearing mantle source. Analyzed for trace-element composition by LA-ICP-MS, they display homogeneous, enriched patterns, similar to those characterizing oceanic island and continental basalts. They have high concentration of LILE and LREE/HREE ratios. Such trace-element feature are typical of

  15. Growth of subcontinental lithosphere: evidence from repeated dike injections in the Balmuccia lherzolite massif, Italian Alps

    NASA Astrophysics Data System (ADS)

    Mukasa, Samuel B.; Shervais, John W.

    1999-09-01

    The Balmuccia alpine lherzolite 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 lherzolite, 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 lherzolite 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 lherzolite and websterite. The late gabbro dikes have Nd and Sr isotopic compositions similar to mid

  16. The alkaline and alkaline-carbonatite magmatism from Southern Brazil

    NASA Astrophysics Data System (ADS)

    Ruberti, E.; Gomes, C. D. B.; Comin-Chiaramonti, P.

    2015-12-01

    Early to Late Cretaceous lasting to Paleocene alkaline magmatism from southern Brazil is found associated with major extensional structural features in and around the Paraná Basin and grouped into various provinces on the basis of several data. Magmatism is variable in size, mode of occurrence and composition. The alkaline rocks are dominantly potassic, a few occurrences showing sodic affinity. The more abundant silicate rocks are evolved undersaturated to saturated in silica syenites, displaying large variation in igneous forms. Less evolved types are restricted to subvolcanic environments and outcrops of effusive suites occur rarely. Cumulatic mafic and ultramafic rock types are very common, particularly in the alkali-carbonatitic complexes. Carbonatite bodies are represented by Ca-carbonatites and Mg-carbonatites and more scarcely by Fe-carbonatites. Available radiometric ages for the alkaline rocks fit on three main chronological groups: around 130 Ma, subcoveal with the Early Cretaceous flood tholeiites of the Paraná Basin, 100-110 Ma and 80-90 Ma (Late Cretaceous). The alkaline magmatism also extends into Paleocene times, as indicated by ages from some volcanic lavas. Geochemically, alkaline potassic and sodic rock types are distinguished by their negative and positive Nb-Ta anomalies, respectively. Negative spikes in Nb-Ta are also a feature common to the associated tholeiitic rocks. Sr-Nd-Pb systematics confirm the contribution of both HIMU and EMI mantle components in the formation of the alkaline rocks. Notably, Early and Late Cretaceous carbonatites have the same isotopic Sr-Nd initial ratios of the associated alkaline rocks. C-O isotopic Sr-Nd isotopic ratios indicate typical mantle signature for some carbonatites and the influence of post-magmatic processes in others. Immiscibility of liquids of phonolitic composition, derived from mafic alkaline parental magmas, has been responsible for the origin of the carbonatites. Close association of alkaline

  17. Trace element distribution coefficients in alkaline series. [Titanites; bitite

    SciTech Connect

    Lemarchand, F.; Villemant, B.; Calas, G.

    1987-05-01

    Mineral/groundmass partition coefficients for U, Th, Zr, Hf, Ta, Rb, REE, Co and Sc have been systematically measured in olivine, clinopyroxene, amphibole, biotite, Ti-magnetites, titanite, zircon and feldspars, in basaltic to trachytic lavas from alkaline series (Velay, Chaine des Puys: Massif Central, France and Fayal: Azores). Average partition coefficients are defined within the experimental uncertainty for limited compositional ranges (basalt-hawaiite, mugearites, benmoreite-trachyte), and are useful for trace element modelling. The new results for U, Th, Ta, Zr and Hf partition coefficients show contrasting behaviour. They can thus be used as ''key elements'' for identifying fractionating mineral phases in differentiation processes (e.g. Ta and Th for amphibole and mica). Partition coefficient may be calculated using the two-lattice model suggested by NIELSEN (1985). Such values show a considerably reduced chemical dependence in natural systems, relative to weight per cent D values. The residual variations may be accounted for by temperature or volatile influence. This calculation greatly enhances modelling possibilities using trace elements for comparing differentiation series as well as for predicting the behaviour of elements during magmatic differentiation.

  18. Recent geodynamic pattern of the eastern part of the Bohemian Massif

    NASA Astrophysics Data System (ADS)

    Schenk, V.; Schenková, Z.; Grácová, M.

    2009-04-01

    The Bohemian Massif, a Precambrian cratonic terrane, had been affected by several orogeneses forming its tectonic pattern. To detect the recent geodynamic motions going on fundamental geological structures of the Massif four regional geodynamic networks were established for epoch GPS measurements and one countrywide GEONAS network for permanent GPS satellite signals monitoring. In the east part of the Bohemian Massif sinistral movements on the Sudetic NW-SE faults and as well on the NNE-SSW faults of the Moravo-Silesian tectonic system have been detected. The sinistral trends dominate on many faults situated close to the contact of the Moldanuabian and Lugian parts and the Moravo-Silesian part of the Bohemian Massif. Because of tectonic systems intersections an existence of dextral movements cannot be excluded. Additional analyses displayed that eastern part of the Massif could be under extending trends. The preliminary site velocities assessed from GPS data for the eastern part of the Bohemian Massif are discussed from a viewpoint of regional geological structure motions. The work was supported by the Grant Agency of the Academy of Sciences of the Czech Republic (Project IAA300460507), the Targeted Research Programme of the Academy of Sciences of the CR (1QS300460551) and by the Ministry of Education, Youth and Sport of the Czech Republic (Projects LC506 and 1P05ME781).

  19. Cenozoic rejuvenation events of Massif Central topography (France): Insights from cosmogenic denudation rates and river profiles

    NASA Astrophysics Data System (ADS)

    Olivetti, Valerio; Godard, Vincent; Bellier, Olivier

    2016-06-01

    The French Massif Central is a part of the Hercynian orogenic belt that currently exhibits anomalously high topography. The Alpine orogenesis, which deeply marked Western European topography, involved only marginally the Massif Central, where Cenozoic faulting and short-wavelength crustal deformation is limited to the Oligocene rifting. For this reason the French Massif Central is a key site to study short- and long-term topographic response in a framework of slow tectonic activity. In particular the origin of the Massif Central topography is a topical issue still debated, where the role of mantle upwelling is invoked by different authors. Here we present a landscape analysis using denudation rates derived from basin-averaged cosmogenic nuclide concentrations coupled with longitudinal river profile analysis. This analysis allows us to recognize that the topography of the French Massif Central is not fully equilibrated with the present base level and in transient state. Our data highlight the coexistence of out-of-equilibrium river profiles, incised valleys, and low cosmogenically derived denudation rates ranging between 40 mm/kyr and 80 mm/kyr. Addressing this apparent inconsistency requires investigating the parameters that may govern erosion processes under conditions of reduced active tectonics. The spatial distribution of denudation rates coupled with topography analysis enabled us to trace the signal of the long-term uplift history and to propose a chronology for the uplift evolution of the French Massif Central.

  20. Pyroxenites - Melting or Migration?: Evidence from the Balmuccia massif

    NASA Astrophysics Data System (ADS)

    Sossi, Paolo; O'Neill, Hugh

    2014-05-01

    The recognition of pyroxenites in the mantle, combined with their lower solidus temperatures than peridotite, have been proposed as contributors to melting (Pertermann and Hirschmann, 2003; Sobolev et al, 2005; 2007). Geochemical fingerprints of this process invoke an unspecified 'pyroxenite' as the putative source. In reality, mantle pyroxenites are diverse (Downes, 2007), requiring that their mode of origin and compositional variability be addressed. Due to the excellent preservation and exposure of the Balmuccia massif, it has become an archetype for orogenic peridotites, providing information on their composition, field relationships and metamorphic history (Shervais and Mukasa, 1991; Hartmann and Wedepohl, 1993; Rivalenti et al., 1995; Mazzucchelli et al., 2009). The Balmuccia massif consists of fertile lherzolite with subordinate harzburgite and dunite and is riddled with pyroxenite bands, which fall into two suites - Chrome-Diopside (Cr-Di) and Aluminous-Augite (Al-Aug), a pairing present in most massif peridotites. Two-pyroxene thermometry gives temperatures of 850±25°C at 1-1.5 GPa, 500°C lower than asthenospheric mantle at that pressure, meaning they do not preserve their original, high temperature mineralogy. Decimetre-sized Cr-Di bands (≡75% CPX, 25% OPX) occur as initially Ol-free and bound by refractory dunite, but, as the bands are rotated into the plane of foliation, they mechanically incorporate olivine. Al-Aug veins (60% CPX, 25% OPX, 15% Sp) discordantly cut the body, intruding lherzolites which show enrichments in Fe, Al and Ti adjacent to the dykes. Both the Cr-Di suite and the Al-Aug series have indistinguishable Sr-, Nd-isotopic compositions to the host peridotite (Mukasa and Shervais, 1999). The major element compositions of pyroxenes in the Cr-Di bands and those in the surrounding peridotites are identical. Together with isotopic evidence, this suggests a local source, not only chemically but spatially, where a very low degree melt (

  1. Typochemistry of rinkite and products of its alteration in the Khibiny Alkaline pluton, Kola Peninsula

    NASA Astrophysics Data System (ADS)

    Konopleva, N. G.; Ivanyuk, G. Yu.; Pakhomovsky, Ya. A.; Yakovenchuk, V. N.; Mikhailova, Yu. A.; Selivanova, E. A.

    2015-12-01

    The occurrence, morphology, and composition of rinkite are considered against the background of zoning in the Khibiny pluton. Accessory rinkite is mostly characteristic of foyaite in the outer part of pluton, occurs somewhat less frequently in foyaite and rischorrite in the central part of pluton, even more sparsely in foidolites and apatite-nepheline rocks, and sporadically in fenitized xenoliths of the Lovozero Formation. The largest, up to economic, accumulations of rinkite are related to the pegmatite and hydrothermal veins, which occur in nepheline syenite on both sides of the Main foidolite ring. The composition of rinkite varies throughout the pluton. The Ca, Na, and F contents in accessory rinkite and amorphous products of its alteration progressively increase from foyaite and fenitized basalt of the Lovozero Formation to foidolite, rischorrite, apatite-nepheline rocks, and pegmatite-hydrothermal veins.

  2. Low pressure granulites from the Bohemian Massif, Upper Austria

    NASA Astrophysics Data System (ADS)

    Sorger, Dominik; Daghighi, Donia; Simic, Katica; Pichler, Ruth; Schwaiger, Christian; Hauzenberger, Christoph; Linner, Manfred; Iglseder, Christoph

    2014-05-01

    Low pressure granulite facies rocks are commonly found in the Bohemian Massif in Upper Austria. They belong to the Moldanubian Unit and were metamorphosed during the last stage of the Variscan orogeny. The investigated granulites from the Donau valley (west of Linz), Lichtenberg (northwest of Linz), Sauwald (south of the river Danube) and Bad Leonfelden zone comprise mainly migmatic paragneisses. Most of these rocks underwent high degrees of melting forming meta- and diatexites (''Perlgneise)''. Al-rich metapelites with partly cm-sized garnet porphyroblasts, which are suitable for precise PT and PT-path determinations, can be found in some localities of this unit. In this study samples taken along the Danube valley between Linz and Wilhering, from Lichtenberg and from Bad Leonfelden (north of Linz) were sampled and investigated petrographically in detail. Since garnets are rare and usually consumed by cordierite, a sample with large garnets was investigated in detail. A chemical zoning profile across the c. 1cm large garnet displayed elevated Ca contents (Xgrs=0.06) in the central part which decreased discontinuously towards the rim to Xgrs=0.02. Almandine, pyrope and spessartine components do not show any pronounced zoning pattern. Most of the smaller garnet grains in other samples are also homogeneous in composition with a slight Xalm increase and Xprp decrease at the rims, typical for retrograde diffusional zoning. The cordierite-garnet-sillimanite-granulites as well as some mafic granulites were used for geothermobarometry. Metamorphic conditions of around 770°C to 850°C and 0.5-0.6 GPa could be obtained, which are similar to the values obtained by Tropper et al. (2006). P. Tropper I. Deibl F. Finger R. Kaindl (2006). P-T-t evolution of spinel-cordierite-garnet gneisses from the Sauwald Zone (Southern Bohemian Massif, Upper Austria): is there evidence for two independent late-Variscan low-P / high-T events in the Moldanubian Unit? Int J Earth Sci (Geol

  3. A key extensional metamorphic complex reviewed and restored: The Menderes Massif of western Turkey

    NASA Astrophysics Data System (ADS)

    van Hinsbergen, Douwe J. J.

    2010-09-01

    This paper provides a review of the structure and metamorphism of the Menderes Massif in western Turkey, and subsequently a map-view restoration of its Neogene unroofing history. Exhumation of this massif — among the largest continental extensional provinces in the world — is generally considered to have occurred along extensional detachments with a NE-SW stretching direction. Restoration of the early Miocene history, however, shows that these extensional detachments can only explain part of the exhumation history of the Menderes Massif, and that NE-SW stretching can only be held accountable for half, or less, of the exhumation. Restoration back to ˜ 15 Ma is relatively straightforward, and is mainly characterised by a previously reported 25-30° vertical axis rotation difference between the northern Menderes Massif, and the Southern Menderes Massif and overlying HP nappes, Lycian Nappes and Bey Dağları about a pivot point close to Denizli. To the west of this pole, the rotation was accommodated by exhumation of the Central Menderes core complex since middle Miocene times, and to the east probably by shortening. At the end of the early Miocene, the Menderes Massif formed a rectangular, NE-SW trending tectonic window of ˜ 150 × 100 km. Geochronology suggests unroofing between ˜ 25 and 15 Ma. The north-eastern Menderes Massif was exhumed along the early Miocene Simav detachment, over a distance of ≤ 50 km. The accommodation of the remainder of the exhumation is enigmatic, but penetrative NE-SW stretching lineations throughout the Menderes Massif suggest a prominent role of NE-SW extension. This, however, requires that the eastern margin of the Menderes Massif, bordering a region without significant extension, is a transform fault with an offset of ˜ 150 km, cutting through the Lycian Nappes. For this, there is no evidence. The Lycian Nappes — a non-metamorphic stack of sedimentary thrust slices and an overlying ophiolite and ophiolitic mélange

  4. Crustal structure of the northern Menderes Massif, western Turkey, imaged by joint gravity and magnetic inversion

    NASA Astrophysics Data System (ADS)

    Gessner, Klaus; Gallardo, Luis A.; Wedin, Francis; Sener, Kerim

    2016-05-01

    In western Anatolia, the Anatolide domain of the Tethyan orogen is exposed in one of the Earth's largest metamorphic core complexes, the Menderes Massif. The Menderes Massif experienced a two-stage exhumation: tectonic denudation in the footwall of a north-directed Miocene extensional detachment, followed by fragmentation by E-W and NW-SE-trending graben systems. Along the northern boundary of the core complex, the tectonic units of the Vardar-Izmir-Ankara suture zone overly the stage one footwall of the core complex, the northern Menderes Massif. In this study, we explore the structure of the upper crust in the northern Menderes Massif with cross-gradient joint inversion of gravity and aeromagnetic data along a series of 10-km-deep profiles. Our inversions, which are based on gravity and aeromagnetic measurements and require no geological and petrophysical constraints, reveal the salient features of the Earth's upper crust. We image the northern Menderes Massif as a relatively homogenous domain of low magnetization and medium to high density, with local anomalies related to the effect of interspersed igneous bodies and shallow basins. In contrast, both the northern and western boundaries of the northern Menderes Massif stand out as domains where dense mafic, metasedimentary and ultramafic domains with a weak magnetic signature alternate with low-density igneous complexes with high magnetization. With our technique, we are able to delineate Miocene basins and igneous complexes, and map the boundary between intermediate to mafic-dominated subduction-accretion units of the suture zone and the underlying felsic crust of the Menderes Massif. We demonstrate that joint gravity and magnetic inversion are not only capable of imaging local and regional changes in crustal composition, but can also be used to map discontinuities of geodynamic significance such as the Vardar-Izmir-Ankara suture and the West Anatolia Transfer Zone.

  5. The Alleret Maar lacustrine sequence (French Massif Central): a 150 ka long early-middle Pleistocene continental paleoenvironmental record.

    NASA Astrophysics Data System (ADS)

    Nomade, S.; Pastre, J.; Guillou, H.; Gauthier, A.; Scaillet, S.

    2008-12-01

    Lacustrine maar sequences of the French Massif Central are of great interest for paleoclimatic and paleoenvironmental reconstructions of mid-latitudes Quaternary continental environments. In particular, the western Velay region yields exceptional sequences spanning the last 450 ka (Reille et al., J. Quat. Sci. 2000). However, older sequences remain largely unknown despite the presence of interbedded alkaline tephras allowing precise absolute radiochronological control of many lacustrine squences. The Alleret maar is a 1500 m wide phreatomagmatic crater that provides a long lacustrine sequence (41 m). The upper part of this sequence (AL2 core, 14.6 m) was studied between 2005 and 2006 (Pastre et al., C. R. Acad Sci, 2007). A 39Ar/40Ar date (557 ± 5ka) obtained from an interbedded tephra layer located at 7m as well as the associated pollen data attribute the beginning of this sequence to the MIS 15. Thanks to the AL3 core recovered in 2005 (40.6 m, CNRS Meudon) several new tephra layers were discovered in the bottom part of this lacustrine sequence. Three new 39Ar/40Ar ages (single crystal analyses) from trachytic tephra layers were obtained at the LSCE Argon Laboratory (France). These layers are located at -30.2, -36.2 and -39.2m. Ages obtained relative to the ACR-2 flux standard (1,201Ma, Kuiper et al., Science, 2008) range from 692 ± 6 ka (MSWD: 2.3, n=18) for the youngest (-30.2m) to 726 ± 9Ka Ka (MSWD: 2.2, n=12) for the lowest tephra located at -39.2m. These new dates indicate a relatively homogeneous deposition rate of 3.5cm/ka and that the last 10 meters cover the MIS 17-MIS18 period. According to these current radiochronological data the complete lacustrine sequence last more than 150ka. Ongoing sedimentary and pollen studies will allow to extend the paleoenvironmental and paleoclimatic records of the French Massif Central towards the beginning of the early middle Pleistocene.

  6. Tephrochronology of the Mont-Dore volcanic Massif (Massif Central, France): new 40Ar/39Ar constraints on the Late Pliocene and Early Pleistocene activity

    NASA Astrophysics Data System (ADS)

    Nomade, Sébastien; Pastre, Jean-François; Nehlig, Pierre; Guillou, Hervé; Scao, Vincent; Scaillet, Stéphane

    2014-03-01

    The Mont-Dore Massif (500 km2), the youngest stratovolcano of the French Massif Central, consists of two volcanic edifices: the Guéry and the Sancy. To improve our knowledge of the oldest explosive stages of the Mont-Dore Massif, we studied 40Ar/39Ar-dated (through single-grain laser and step-heating experiments) 11 pyroclastic units from the Guéry stratovolcano. We demonstrate that the explosive history of the Guéry can be divided into four cycles of explosive eruption activity between 3.09 and 1.46 Ma (G.I to G.IV). We have also ascertained that deposits associated with the 3.1-3.0-Ma rhyolitic activity, which includes the 5-km3 "Grande Nappe" ignimbrite, are not recorded in the central part of the Mont-Dore Massif. All the pyroclastites found in the left bank of the Dordogne River belong to a later explosive phase (2.86-2.58 Ma, G.II) and were channelled down into valleys or topographic lows where they are currently nested. This later activity also gave rise to most of the volcanic products in the Perrier Plateau (30 km east of the Mont-Dore Massif); three quarters of the volcano-sedimentary sequence (up to 100 m thick) was emplaced within less than 20 ky, associated with several flank collapses in the northeastern part of the Guéry. The age of the "Fournet flora" (2.69 ± 0.01 Ma) found within an ash bed belonging to G.II suggests that temperate forests already existed in the French Massif Central before the Pliocene/Pleistocene boundary. The Guéry's third explosive eruption activity cycle (G.III) lasted between 2.36 and 1.91 Ma. It encompassed the Guéry Lake and Morangie pumice and ash deposits, as well as seven other important events recorded as centimetric ash beds some 60 to 100 km southeast of the Massif in the Velay region. We propose a general tephrochronology for the Mont-Dore stratovolcano covering the last 3.1 My. This chronology is based on 44 40Ar/39Ar-dated events belonging to eight explosive eruption cycles each lasting between 100 and 200

  7. Preliminary hydrochemical study of Ronda ultramafic massif (South Spain)

    NASA Astrophysics Data System (ADS)

    Vadillo, Iñaki; Urresti, Begoña; Jiménez, Pablo; Martos, Sergio; José Durán, Juan; Benavente, José; Carrasco, Francisco; Pedrera, Antonio

    2016-04-01

    During 2015 more than 70 springs related to the peridotite outcrops of the Ronda mountainous massif, South Spain, have been identified. The field work included "in situ" measurements of physical-chemical parameters (T, EC, pH), and water sampling for major components and stable isotopes of water and DIC. The hydrogeochemical study allowed us to characterize different flow systems: (1) springs with very low to medium electrical conductivities (200-700 μS/cm) and pH below 9.0, and (2) springs with EC above 700 μS/cm and pH above 9.0. The first group of springs are supposed to be linked with surface and subsurface flows. The hydrogeochemical reactions that determine their composition are characterized by the low solubility of minerals, atmospheric CO2 (open system) and active serpentinization reactions that supplies hundreds of ppm of Mg2+. All of them are waters of HCO3-Mg or HCO3-Mg-Na type. The second group of springs drains water with EC above 700 μS/cm and pH over 9. In general, these springs are associated to deep flows connected to regional faults or major tectonic features. Deeper flow enhances water-rock interaction and time of contact, so this system evolves towards a closed system to O2 and CO2. All these waters are old or older than the first group and show reducing features and are of Na-Cl or OH-Ca type.

  8. Deforestation Along the Maya Mountain Massif Belize-Guatemala Border

    NASA Astrophysics Data System (ADS)

    Chicas, S. D.; Omine, K.; Arevalo, B.; Ford, J. B.; Sugimura, K.

    2016-06-01

    In recent years trans-boundary incursions from Petén, Guatemala into Belize's Maya Mountain Massif (MMM) have increased. The incursions are rapidly degrading cultural and natural resources in Belize's protected areas. Given the local, regional and global importance of the MMM and the scarcity of deforestation data, our research team conducted a time series analysis 81 km by 12 km along the Belize-Guatemalan border adjacent to the protected areas of the MMM. Analysis drew on Landsat imagery from 1991 to 2014 to determine historic deforestation rates. The results indicate that the highest deforestation rates in the study area were -1.04% and -6.78% loss of forested area per year in 2012-2014 and 1995-1999 respectively. From 1991 to 2014, forested area decreased from 96.9 % to 85.72 % in Belize and 83.15 % to 31.52 % in Guatemala. During the study period, it was clear that deforestation rates fluctuated in Belize's MMM from one time-period to the next. This seems linked to either a decline in deforestation rates in Guatemala, the vertical expansion of deforestation in Guatemalan forested areas and monitoring. The results of this study urge action to reduce incursions and secure protected areas and remaining forest along the Belize-Guatemalan border.

  9. RECLAMATION OF ALKALINE ASH PILES

    EPA Science Inventory

    The objective of the study was to develop methods for reclaiming ash disposal piles for the ultimate use as agricultural or forest lands. The ashes studied were strongly alkaline and contained considerable amounts of salts and toxic boron. The ashes were produced from burning bit...

  10. Paleoproterozoic anorogenic granitoids of the Zheltav sialic massif (Southern Kazakhstan): Structural position and geochronology

    NASA Astrophysics Data System (ADS)

    Tretyakov, A. A.; Degtyarev, K. E.; Sal'nikova, E. B.; Shatagin, K. N.; Kotov, A. B.; Ryazantsev, A. V.; Pilitsyna, A. V.; Yakovleva, S. Z.; Tolmacheva, E. V.; Plotkina, Yu. V.

    2016-01-01

    The basement of the Zheltav sialic massif (Southern Kazakhstan) is composed of different metamorphic rocks united into the Anrakhai Complex. In the southeastern part of the massif, these rocks form a large antiform with the core represented by amphibole and clinopyroxene gneissic granite varieties. By their chemical composition, dominant amphibole (hastingsite) gneissic granites correspond to subalkaline granites, while their petroand geochemical properties make them close to A-type granites. The U-Pb geochronological study of accessory zircons yielded an age of 1841 ± 6 Ma, which corresponds to the crystallization age of melts parental for protoliths of amphibole gneissic granites of the Zheltav Massif. Thus, the structural-geological and geochronological data make it possible to define the Paleoproterozoic (Staterian) stage of anorogenic magmatism in the Precambrian history of the Zheltav Massif. The combined Sm-Nd isotopic—geochronological data and age estimates obtained for detrital zircons indicate the significant role of the Paleoproterozoic tectono-magmatic stage in the formation of the Precambrian continental crust of sialic massifs in Kazakhstan and northern Tien Shan.

  11. Isolation of alkaline mutagens from complex mixtures

    SciTech Connect

    Ho, C.H.; Guerin, M.R.; Clark, B.R.; Rao, T.K.; Epler, J.L.

    1981-05-01

    A method for the preparative-scale enrichment of alkaline mutagens from complex natural and anthropogenic mixtures is described. Mutagenic alkaline fractions were isolated from cigarette smoke, crude petroleum, and petroleum substitutes derived from coal and shale.

  12. A Library Response to the Massification of Higher Education: The Case of the University of Zambia Library

    ERIC Educational Resources Information Center

    Kanyengo, Christine Wamunyima

    2009-01-01

    This paper looks at the challenges that libraries in Africa face in responding to massification of higher education by discussing the University of Zambia library's response in library and information resources provision. As a result of massification of higher education, libraries have been forced not only to employ new and different strategies to…

  13. Critical Reflection on the Massification of Higher Education in Korea: Consequences for Graduate Employment and Policy Issues

    ERIC Educational Resources Information Center

    Yeom, Min-ho

    2016-01-01

    The paper critically reviews the results of Korean massification in higher education (HE) and focuses on the consequences related to graduate employment. By analysing statistical data and reviewing related articles, this study explores the process of the massification of HE, investigates major factors influencing the expansion, and analyses and…

  14. Nucleotide sequences encoding a thermostable alkaline protease

    DOEpatents

    Wilson, David B.; Lao, Guifang

    1998-01-01

    Nucleotide sequences, derived from a thermophilic actinomycete microorganism, which encode a thermostable alkaline protease are disclosed. Also disclosed are variants of the nucleotide sequences which encode a polypeptide having thermostable alkaline proteolytic activity. Recombinant thermostable alkaline protease or recombinant polypeptide may be obtained by culturing in a medium a host cell genetically engineered to contain and express a nucleotide sequence according to the present invention, and recovering the recombinant thermostable alkaline protease or recombinant polypeptide from the culture medium.

  15. Nucleotide sequences encoding a thermostable alkaline protease

    DOEpatents

    Wilson, D.B.; Lao, G.

    1998-01-06

    Nucleotide sequences, derived from a thermophilic actinomycete microorganism, which encode a thermostable alkaline protease are disclosed. Also disclosed are variants of the nucleotide sequences which encode a polypeptide having thermostable alkaline proteolytic activity. Recombinant thermostable alkaline protease or recombinant polypeptide may be obtained by culturing in a medium a host cell genetically engineered to contain and express a nucleotide sequence according to the present invention, and recovering the recombinant thermostable alkaline protease or recombinant polypeptide from the culture medium. 3 figs.

  16. A Treasure Chest of Nanogranites: the Bohemian Massif (Central Europe)

    NASA Astrophysics Data System (ADS)

    Ferrero, S.; O'Brien, P. J.; Walczak, K.; Wunder, B.; Ziemann, M. A.; Hecht, L.

    2014-12-01

    Despite 150 years of investigation of the Bohemian Massif (Central Europe), it is only recently that the investigation of old and new samples displayed the occurrence of tiny portions of crystallized anatectic melt in regional migmatites. These vestiges of magma, called "nanogranites", are natural probes of the partial melting processes in the crust. Original melt composition and water content can be directly analyzed after piston cylinder re-homogenization. When compared to classic re-melting experiments, nanogranites are ideal "natural" experimental charges of anatectic melt. They are encapsulated in peritectic garnet immediately after production - both phases are products of the same partial melting reaction. Sheltered inside garnet, they remain unaffected by the physico-chemical changes which affected the host migmatites during their slow cooling, unlike leucosomes and anatexis-related plutons. Five different case studies of nanogranite-bearing high-grade rocks have been identified so far: three in metapelites from the Moldanubian Zone, and two in metagranitoids from the Granulitgebirge and Orlica-Śnieżnik Dome. Their characterization provides insights into how the continental crust melts at different depths, from shallow levels to mantle depths, during different moments of its metamorphic history (prograde vs. decompressional melting). For example, the investigation and experimental re-melting of nanogranites from Grt+Ky leucogranulites (Orlica-Śnieżnik Dome) recently provided evidence of prograde melting of metagranitoids under eclogite-facies conditions (T≥875°C and P~2.7 GPa), close to the stability field of coesite. The melt generated is granitic, hydrous (6 wt% H2O) and metaluminous (ASI=1.03), and is at the moment the "deepest" glass obtained through re-homogenization of primary polycrystalline inclusions in natural rocks. This work confirms that nanogranites in migmatites 1) are a powerful tool to constrain anatexis in natural rocks, and 2) can

  17. Volcanoes of the Tibesti massif (Chad, northern Africa)

    NASA Astrophysics Data System (ADS)

    Permenter, Jason L.; Oppenheimer, Clive

    2007-04-01

    The Tibesti massif, one of the most prominent features of the Sahara desert, covers an area of some 100,000 km2. Though largely absent from scientific inquiry for several decades, it is one of the world’s major volcanic provinces, and a key example of continental hot spot volcanism. The intense activity of the TVP began as early as the Oligocene, though the major products that mark its surface date from Lower Miocene to Quaternary (Furon (Geology of Africa. Oliver & Boyd, Edinburgh (trans 1963, orig French 1960), pp 1-377, 1963)); Gourgaud and Vincent (J Volcanol Geotherm Res 129:261-290, 2004). We present here a new and consistent analysis of each of the main components of the Tibesti Volcanic Province (TVP), based on examination of multispectral imagery and digital elevation data acquired from the Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER). Our synthesis of these individual surveys shows that the TVP is made up of several shield volcanoes (up to 80 km diameter) with large-scale calderas, extensive lava plateaux and flow fields, widespread tephra deposits, and a highly varied structural relief. We compare morphometric characteristics of the major TVP structures with other hot spot volcanoes (the Hawaiian Islands, the Galápagos Islands, the Canary and Cape Verdes archipelagos, Jebel Marra (western Sudan), and Martian volcanoes), and consider the implications of differing tectonic setting (continental versus oceanic), the thickness and velocity of the lithosphere, the relative sizes of main volcanic features (e.g. summit calderas, steep slopes at summit regions), and the extent and diversity of volcanic features. These comparisons reveal morphologic similarities between volcanism in the Tibesti, the Galápagos, and Western Sudan but also some distinct features of the TVP. Additionally, we find that a relatively haphazard spatial development of the TVP has occurred, with volcanism initially appearing in the Central TVP and subsequently

  18. P- T- t evolution of eclogite/blueschist facies metamorphism in Alanya Massif: time and space relations with HP event in Bitlis Massif, Turkey

    NASA Astrophysics Data System (ADS)

    Çetinkaplan, Mete; Pourteau, Amaury; Candan, Osman; Koralay, O. Ersin; Oberhänsli, Roland; Okay, Aral I.; Chen, Fukun; Kozlu, Hüseyin; Şengün, Fırat

    2016-01-01

    The Alanya Massif, which is located to the south of central Taurides in Turkey, presents a typical nappe pile consisting of thrust sheets with contrasting metamorphic histories. In two thrust sheets, Sugözü and Gündoğmuş nappes, HP metamorphism under eclogite (550-567 °C/14-18 kbar) and blueschist facies (435-480 °C/11-13 kbar) conditions have been recognized, respectively. Whereas the rest of the Massif underwent MP metamorphism under greenschist to amphibolite facies (525-555 °C/6.5-7.5 kbar) conditions. Eclogite facies metamorphism in Sugözü nappe, which consists of homogeneous garnet-glaucophane-phengite schists with eclogite lenses is dated at 84.8 ± 0.8, 84.7 ± 1.5 and 82 ± 3 Ma (Santonian-Campanian) by 40Ar/39Ar phengite, U/Pb zircon and rutile dating methods, respectively. Similarly, phengites in Gündoğmuş nappe representing an accretionary complex yield 82-80 Ma (Campanian) ages for blueschist facies metamorphism. During the exhumation, the retrograde overprint of the HP units under greenschist-amphibolite facies conditions and tectonic juxtaposition with the Barrovian units occurred during Campanian (75-78 Ma). Petrological and geochronological data clearly indicate a similar Late Cretaceous tectonometamorphic evolution for both Alanya (84-75 Ma) and Bitlis (84-72 Ma) Massifs. They form part of a single continental sliver ( Alanya- Bitlis microcontinent), which was rifted from the southern part of the Anatolide-Tauride platform. The P- T- t coherence between two Massifs suggests that both Massifs have been derived from the closure of the same ocean ( Alanya- Bitlis Ocean) located to the south of the Anatolide-Tauride block by a northward subduction. The boundary separating the autochthonous Tauride platform to the north from both the Alanya and Bitlis Massifs to the south represents a suture zone, the Pamphylian- Alanya- Bitlis suture.

  19. Geomorphological and sedimentological evidences in the Western Massif of Picos de Europa since the Last Glaciation

    NASA Astrophysics Data System (ADS)

    Ruiz-Fernández, Jesus; Oliva, Marc; Cruces, Anabela; Lopes, Vera; Conceição Freitas, Maria; García-Hernández, Cristina; Nieuwendam, Alexandre; López-Sáez, José Antonio; Gallinar, David; Geraldes, Miguel

    2015-04-01

    The Western Massif of Picos de Europa includes some of the highest peaks of the Cantabrian Mountains. However, the environmental evolution in this massif since the Last Glaciation is still poorly understood. This research provides a new geochronological approach to the sequence of environmental events occurred here since the maximum expansion of glaciers during the last Pleistocene glaciation. The distribution of the glacial landforms suggests four main stages regarding the environmental evolution in the massif: maximum glacial advance, phase of second maximum glacial expansion, Late Glacial and Little Ice Age. A 5.4-m long sedimentological section retrieved from the kame terrace of Belbín, in a mid-height area of the massif, complements the geomorphological interpretation and provides a continuous paleoenvironmental sequence from this area since the Last Glaciation until nowadays. This section suggests that the maximum glacial expansion occurred at a minimum age of 37.2 ka cal BP, significantly prior to the global Last Glacial Maximum. Subsequently, a new glacial expansion occurred around 18.7-22.5 ka cal BP. The melting of the glaciers after this phase generated a shallow lake in the Belbín depression. Lake sediments do not reveal the occurrence of a cold stage during the Late Glacial, whilst, at higher locations, moraine complexes were formed suggesting a glacier readvance. The terrestrification of this lake started at 8 ka cal BP, when Belbín changed to a peaty environment. At 5 ka cal BP human occupation started at the high lands of the massif according to the existence of charcoal particles in the section. The presence of moraines in the highest northern cirques evidences the last phase with formation of small glaciers in the Western Massif of Picos de Europa, corresponding to the Little Ice Age cold event. Since then, the warming climate has led to the melting of these glaciers.

  20. Late variscan evolution of the Pelvoux Massif in the light of 3D mapping of granites

    NASA Astrophysics Data System (ADS)

    Strzerzynski, P.; Guillot, S.; Courrioux, G.; Ledru, P.

    2003-04-01

    The Pelvoux massif is a fragment of Paleozoic crustal rock involved in the alpine belt. The inner part of the massif is composed by anatectic and amphibolitic gneisses intruded by Stephanian granites. The Turbat-Lauranoure, Etages and Berarde granites have a N160 vertical magmatic foliation cross cut by N135 vertical ductile strike slip faults. A three dimensional modeling of the shape of the Turbat-Lauranoure, Etages and Berarde granites has been realized using field and cartographic data. The method based on potential field allows the integration of structural data as foliation and contact orientation measurements. The granite shapes have been modeled with three types of surface with different geological significance: The first type of surface is constrained by granite foliation measurements. They are NNW-SSE and vertical oriented. They form the eastward and westward granite-gneiss and Etages-Berarde granites boundaries. The second surface is a well known alpine structure called the Meije-Muzele Trust. This structure is oriented N50 50^oSE. The third surface is a granite-gneiss boundary in where gneisses are located on of the top the granite. The granite-gneiss contact has a northward plunge on the north and a southward plunge on the south of the massif. The NNW-SSE elongated shape of the granite associated with a left lateral ductile strike slip fault and the dome like shape of the massif are consistent with a N-S direction of extension during Stephanian time. In order to integrate this Stephanian Pelvoux Massif magmatic event in the Variscan scheme, an anticlockwise rotation occurred during Permian time. The observed N20 dextral strike slip faults are at the origin of the Permian rotation of the Pelvoux Massif.

  1. Geological structures and deformation sequence of the eastern Gyeonggi massif, central Korea

    NASA Astrophysics Data System (ADS)

    Kihm, You Hong; Hwang, Jae Ha

    2010-05-01

    The Gyeonggi massif, situated between the Nangrim and Yeongnam massifs of the Korean Peninsula, is a Precambrian terrane consists primarily of Archean to Proterozoic crystalline basement. Although the Gyeonggi massif has been suspected as an eastern extension of the Qinling-Dabie collision belt of China, a structural data about the Gyeonggi massif are very short, especially about the eastern part of the Gyeonggi massif. This study focused the deformation sequence of the eastern part of Gyeonggi massif and comparison with that of western part of Gyeonggi massif. At least, five phases of deformational events can be recognized. The first phase of deformation produced gneissic and schistose structures with intrafolial and recumbent folds. During the second phase of deformation, mylonite, mineral lineation, intrafolial recumbent folds and irregular folds were formed. The Bangsan Anticline (BSA) and its sub-order folds were produced by the third phase of deformation. SE-vergent thrust and south-vergent kink folds resulted from the forth and fifth phases of deformation, respectively. Axis of the BSA can be traced over 5km and the representative orientations of two limbs of the BSA are N17°W/32°SE, N29°E/25°NW, respectively. Interlimb angle of the BSA is measured as 128° and can be classified into open fold. Structural transect analysis of regional foliation shows that axis of the BSA is located about 4.6km toward East from longitude 127°53'45″E. If the BSA is correlated with very large-scale NS-trending folds occurred in the western part of the Gyeonggi massif based on characteristics of fold structure, the third phase of deformation can be interpreted in age from the Late Proterozoic to the Early Paleozoic (750~390 Ma). Mylonite of the study area cannot be correlated to the Gyeonggi Shear Zone, which was suggested as post-collisional top-to-the-north extensional structure. The SE-vergent thrust of the forth phase of deformation is probably correlated to the

  2. Development of alkaline fuel cells.

    SciTech Connect

    Hibbs, Michael R.; Jenkins, Janelle E.; Alam, Todd Michael; Janarthanan, Rajeswari; Horan, James L.; Caire, Benjamin R.; Ziegler, Zachary C.; Herring, Andrew M.; Yang, Yuan; Zuo, Xiaobing; Robson, Michael H.; Artyushkova, Kateryna; Patterson, Wendy; Atanassov, Plamen Borissov

    2013-09-01

    This project focuses on the development and demonstration of anion exchange membrane (AEM) fuel cells for portable power applications. Novel polymeric anion exchange membranes and ionomers with high chemical stabilities were prepared characterized by researchers at Sandia National Laboratories. Durable, non-precious metal catalysts were prepared by Dr. Plamen Atanassov's research group at the University of New Mexico by utilizing an aerosol-based process to prepare templated nano-structures. Dr. Andy Herring's group at the Colorado School of Mines combined all of these materials to fabricate and test membrane electrode assemblies for single cell testing in a methanol-fueled alkaline system. The highest power density achieved in this study was 54 mW/cm2 which was 90% of the project target and the highest reported power density for a direct methanol alkaline fuel cell.

  3. Biodiversity impact of the aeolian periglacial geomorphologic evolution of the Fontainebleau Massif (France)

    NASA Astrophysics Data System (ADS)

    Thiry, M.; Liron, M. N.

    2009-04-01

    Landscape features The geomorphology of the Fontainebleau Massif is noteworthy for its spectacular narrow ridges, up to 10 km long and 0.5 km wide, armored by tightly cemented sandstone lenses and which overhang sandy depressions of about 50m. Denudation of the sandstone pans lead to a highly contrasted landscape, with sandstone ridges ("platières") towering sandy depressions ("vallées") and limestone plateaus ("monts"). This forms the geological frame of the spectacular sceneries of the Fontainebleau Massif (Thiry & Liron, 2007). Nevertheless, there is little know about the erosive processes that have built-up these landscapes. Periglacial processes, and among them aeolian ones, appear significant in the development of the Fontainebleau Massif physiography. The periglacial aeolian geomorphology Dunes and dune fields are known since long and cover about 15% to 25% of the Fontainebleau Massif. The aeolian dunes developed as well on the higher parts of the landscape, as well as in the lower parts of the landscape. The dunes are especially well developed in the whole eastern part of the massif, whereas the western part of the massif is almost devoid of dunes. Nevertheless, detailed mapping shows that dunes can locally be found in the western district, they are of limited extension, restricted to the east facing backslope of outliers. Loamy-sand covers the limestone plateaus of the "monts". The loam cover is of variable thickness: schematically thicker in the central part of the plateaus, where it my reach 3 m; elsewhere it may thin down to 0,20-0,30 m, especially at the plateau edges. Blowout hollows are "negative" morphologies from where the sand has been withdrawed. Often these blowouts are decametric sized and well-delimited structures. Others, more complex structures, are made up of several elongated hectometric hollows relaying each other from and which outline deflation corridor more than 1 km long. A characteristic feature of these blowout hollows is the

  4. Structural geology and sedimentology of the Sermat Quartzites, Strandja Massif, NW Turkey

    NASA Astrophysics Data System (ADS)

    Yazıcı, Müge; Natal'in, Boris A.

    2015-04-01

    The Strandja Massif, NW Turkey, is the eastern continuation of the Rhodope Massif in Bulgaria. The massif is generally correlated with the Hercynian orogenic belt that was later modified by the Cimmerian orogeny. The basement of the massif is composed by various kinds of gneisses and schists, which are intruded by the metagranites. In the studied area, the Cambrian K-feldspar metagranites are unconformably overlain by metaclastics, where both units have fault contacts with volcano-sedimentary rocks. The metagranite intrusions yield Carboniferous U-Pb zircon ages (Natal'in et al., 2012a). All of them constitute the basement of the Strandja Massif. Cambrian age of metagranites and their subduction related nature as well as the subduction related nature of the Carboniferous igneous rocks suggest a prolong evolution of the Strandja Massif (Natal'in et al., 2012a). The Cambrian metagranites are unconformably overlain by a metasedimetary cover unit, which is known in the literature as the Şermat Quartzite of presumably Permo-Triassic age (Çağlayan and Yurtsever, 1998). In the studied region, detrital zircons extracted from quartzites show that their depositional age is not younger than the Ordovician (Natal'in et al., 2012a). The basement of the Strandja Massif is subjected to the epidote-amphibolite-greenschist facies of metamorphism and high strain deformation in the late Jurassic - early Cretaceous times. The Şermat Quartzite forms a transgressive sequence, which starts with metaconglomerates, metasandstones and grades up to quartz-sericite schists. The thickness of bedding changes from thin to medium with parallel bedding planes, containing lens-shaped bodies of massive quartzites. The late Jurassic - early Cretaceous foliation (S1) is generally parallel to the primary bedding plane. Foliations and lineations consistently dip to the northeast and kinematic indicators suggest a tectonic transport in the same direction. High strain in the Şermat Quartzite

  5. Relict permafrost features in Mediterranean environments: the Majella Massif

    NASA Astrophysics Data System (ADS)

    Cocco, S.; Basili, M.; Cioci, C.; di Peco, D.; Brecciaroli, G.; Agnelli, A.; Corti, G.

    2009-04-01

    The Earth's climate has warmed by about 0.74 °C over the past century and a further warming is predicted for the next decades. Climatic changes propagate downward into the ground and modify soil thermal regime inducing many transformations. It is expected that climate warming will cause increased permafrost melting in high latitude environments and even to total permafrost degradation in regions of lower latitude. In fact, direct observations in the tundra region have shown recent increases in surface and soil temperatures and permafrost melting while in many European mountains recent micro-climatologic studies have identified only small alpine enclaves of screes with permafrost. However, in the literature no reports exist on relict permafrost in the Apennines, except for few observations about the presence of periglacial features such as rock glaciers. Some authors indicated in the past the presence of favourable conditions for preserving sporadic mountain permafrost in the Majella Massif (Central Apennines, Italy), especially in the upper Cannella Valley, where sun irradiation is particularly reduced and winds blow very energetically during the cold period. In the same valley, we monitored soil temperatures at different depths since 2006, in order to study the effects of climate change on pedogenesis and to evaluate the resilience of soils to change. The temperature data referred to the 2006-2007 and those of 2007-2008 showed different trends. The temperatures of the first year were relatively mild and soil freezing was progressively induced from top to down soil. In contrast, during the winter of the second year the temperatures assumed the lowest values (minus 2-3°C) atop the soil, increased down soil (plus 0.5-1.5°C) till he depth of 30-40 cm and decrease to minus 1-2°C more in depth (60 cm); in addition, in depth, the temperature below 0°C were reached before than at surface. This behaviour was evidently due to a deep cold source and interpreted as a

  6. Two Lithologies in Lithospheric Mantle Beneath Nothern Margin of the Bohemian Massif (e Germany and SW Poland).

    NASA Astrophysics Data System (ADS)

    Matusiak-Małek, Magdalena; Puziewicz, Jacek; Ntaflos, Theodoros; Kukuła, Anna; Ćwiek, Mateusz

    2014-05-01

    The subcontinental lithospheric mantle (SCLM) occurring beneath Bohemian Massif in Central Europe has been sampled in Cenozoic times by numerous lavas. Recent studies (Puziewicz et al. 2011 and references therein) show that mantle in this region is mostly anhydrous, harzburgitic, and was subjected to various kinds of metasomatic events. Two major mantle lithologies characterized by different major element composition of peridotite- forming minerals occur in the SCLM Lower Silesia and Lusatia (op. cit. and unpublished results, 9 sites). Lithology "A" (minimal temperatures from 900 to 1000ºC or no equilibrium between cpx and opx) contains olivine Fo90.5 -92.0. Part of the population "A" peridotites contain clinopyroxene of mg# 94 - 95, typical for low temperatures of equilibration. The lithology "B" (equilibration temperatures close to 900 ºC) contains olivine Fo87.5-90.0. Elevated contents of LREE in clinopyroxene from both the lithologies "A" and "B" suggest their equilibration with one of the two metasomatic agents stated in this area: anhydrous silicate alkaline melt or carbonatite-silicate melt. Action of hydrous alkaline melts in the mantle in the region is recorded only locally (e.g. Wilcza Góra). In some sites (e.g. Krzeniów) the trace element patterns show that decreasing mg# of clinopyroxene in the "A" peridotites is due to gradual replacement of primary lower-temperature mineral assemblage by the later higher-temperature one. This suggests that the variation of mineral chemistry is rather due to chromatographic fractionation of metasomatic agents than due to vertical variation in lithospheric mantle temperatures (Christensen et al.,2001). The "B" peridotites originated due to "Fe-metasomatism" of more magnesian peridotites by silicate melts percolating through lithospheric mantle. The peridotites belonging to lithology "A" might have been partly the protolith of the lithology "B". The data on Central European lithospheric mantle are equivocal and thus

  7. Teaching Quality after the Massification of Higher Education in Taiwan: A Student Perspective

    ERIC Educational Resources Information Center

    Dian-Fu, Chang; Yeh, Chao-Chi

    2012-01-01

    To explore whether teaching quality was improved by the Taiwan Ministry of Education's implementation of the Teaching Excellence Program after the massification of higher education, the authors used data from a 2007 student survey to build a Teaching Quality Assessment Model to analyze university students' views of the Teaching Excellence…

  8. Massification of University Education in Nigeria: Private Participation and Cost Challenges

    ERIC Educational Resources Information Center

    Ahunanya, S.; Chineze, U.; Nnennaya, I.

    2013-01-01

    This study investigated the massification of university education in Nigeria as a result of the reforms in the education subsector that led to private participation in the provision of university education from 1999. The question of the study hinges on the percentage of access and if the increased number of universities has led to increased…

  9. Reforming Higher Education in Hong Kong towards Post-Massification: The First Decade and Challenges Ahead

    ERIC Educational Resources Information Center

    Wan, Calvin

    2011-01-01

    The process of reforming Hong Kong's higher education sector commenced in 2001, and the system moved into the post-massification era. Within five years, the post-secondary participation rate for the 17-20 age cohort had increased to 66 per cent. This target was achieved much earlier than the Government had planned. More educational opportunities…

  10. Unique paragenesis of cerium and yttrium allanites in tourmalinite of the Severny massif (Chukotka)

    NASA Astrophysics Data System (ADS)

    Alekseev, V. I.; Marin, Yu. B.

    2016-07-01

    A description of hydrothermal allanite-(Y) and its unique association with allanite-(Ce) from tourmaline metasomatic rock of the Severny granite massif in Chukotka is presented in the article. Examination of the composition of metasomatic rims in allanite-(Y) allowed us to estimate the limit of isomorphic replacement in allanite of Y and heavy lanthanides by LREE, reaching 25%.

  11. Occurrence of springs in massifs of crystalline rocks, northern Portugal

    NASA Astrophysics Data System (ADS)

    Pacheco, Fernando António Leal; Alencoão, Ana Maria Pires

    2002-02-01

    An inventory of artesian springs emerging from fractures (fracture springs) was conducted in the Pinhão River Basin and Morais Massif, northern Portugal, comprising an area of approximately 650 km2. Over 1,500 springs were identified and associated with geological domains and fracture sets. Using cross-tabulation analysis, spring distributions by fracture sets were compared among geological environments, and the deviations related to differences in rock structure and, presumably, to differences in deformational histories. The relation between spring frequencies and rock structures was further investigated by spectral determination, the model introduced in this study. Input data are the spring frequencies and fracture lengths in each geological domain, in addition to the angles between fracture strikes and present-day stress-field orientation (θ). The model's output includes the so-called intrinsic densities, a parameter indexing spring occurrence to factors such as fracture type and associated deformational regime and age. The highest densities (12.2 springs/km of lineament) were associated with young shear fractures produced by brittle deformation, and the lowest (0.1) with old tensional and ductile fractures. Spectral determination also relates each orientation class to a dominant structural parameter: where spring occurrence is controlled by θ, the class is parallel to the present-day stress-field orientation; where the control is attributed to the length of fractures, the spring occurrence follows the strike of large-scale normal faults crossing the region. Résumé. Un inventaire des sources artésiennes émergeant de fractures (sources de fractures) a été réalisé dans le bassin de la rivière Pinhão et dans le massif de Morais, dans le nord du Portugal, dans une région couvrant environ 650 km2. Plus de 1,500 sources ont été identifiées et associées à des domaines géologiques et à des ensembles de fractures. Grâce à une analyse de tableaux

  12. Niklas - a Hitherto Unknown Deep Magmatic Massif in the Eastern Mediterranean

    NASA Astrophysics Data System (ADS)

    Rybakov, M.; Voznesensky, V.; Ben-Avraham, Z.

    2004-12-01

    A Niklas massif was discovered recompiling the gravity and magnetic maps and interpreting in 3-D mode all the available data in the area around Eratosthenes Seamount (ESM). The updated datasets clearly show two partially superimposed magnetic dipoles, which also correspond well to disturbances in the gravity field. The pronounced Eratosthenes magnetic anomaly (EMA) is only the positive part of the southeastern dipole. There is no large gravity anomaly here, however the specific gravity pattern corresponds to the magnetic body. The northwestern `magnetic dipole coincides with a prominent (about of 100mGal) gravity high that was recently delineated by Russian geophysicists. Such grav/mag combination allowed us to interpret the anomalies as being caused by a hitherto unknown dense and magnetic body which we have named the Niklas massif. The parameters and depth of causative bodies were calculated by inverse programs and forward modeling using the seismic refraction and reflection constraints. The reliability of the final model was verified using forward modeling. The magnetic data were interpreted by assuming an induced magnetization as the main magnetizing factor. The final model consists of two large compact features oriented NE-SW and located south of the Cyprian arc,as the Eratosthenes and Niklas bodies. The gravity and magnetic pattern of the Niklas is typical for the ophiolite massifs of the Eastern Mediterranean and Southern Turkey (Troodos, Hatay, Antalya). Based on this likeness we assume the Niklas composed by dense and magnetic ophyolites. This large (~100*75km) deep-seated (~7km) thick (~7km) massif is located ~95km southwest of Cyprus. We consider the Niklas as the south-most fragment of the large allochthonous ophiolite thrust slab including the Troodos massif. The tectonic situations of the Niklas area and the central segment of the Cyprian Arc are similar to that of the Eastern Taurus, Bayer-Bassit and Hatay areas. Interaction of the large Late

  13. Crustal structure of the Bohemian Massif in the light of seismic refraction data

    NASA Astrophysics Data System (ADS)

    Hrubcova, Pavla

    2010-05-01

    The Bohemian Massif is one of the largest stable outcrops of pre-Permian rocks in Central and Western Europe. It forms the easternmost part of the Variscan Belt, which developed approximately between 500 and 250 Ma during a stage of large-scale crustal convergence, collision of continental plates and microplates, and possibly also subduction. It consists mainly of low- to high-grade metamorphic and plutonic Palaeozoic rocks. The area of the Bohemian Massif can be subdivided into various tectonostratigraphic units separated by faults, shear zones or thrusts trending roughly in a SW-NE direction, and reflecting varying influence of the Cadomian and Variscan orogenies: the Saxothuringian, Teplá-Barrandian, Moldanubian and Moravo-Silesian. Geographically, it comprises the area of the Czech Republic, partly Austria, Germany and Poland. While the post-collisional history of the Variscan Bohemian Massif is relatively clear, the kinematics of plate movements before and during collision is still subject of debates. To investigate such a complex structure, the Bohemian Massif has been covered by a network of seismic experiments as a result of a massive international cooperative effort in central Europe. Detailed analyses of the data from the main profiles of the CELEBRATION 2000, ALP 2002, and SUDETES 2003 refraction and wide-angle reflection seismic experiments show crustal and uppermost mantle structure of the massif and delimit the continuation of various tectonic units in depth. The differences in seismic velocities reflect, to some extent, the structural variances and give some indications for tracing of crust-forming processes during individual tectonic events. Lower crust in the Saxothuringian exhibits complicated structure, ranging from a highly reflective lower crustal layer above Moho with a strong velocity contrast at the top of this layer. Another possible explanation can be a double Moho or the Moho with some lateral topography. This complicated lower crust

  14. Anode conductor for alkaline cells

    SciTech Connect

    Schrenk, D.J.; Murphy, P.E.

    1988-12-13

    This patent describes an electrochemical cell comprised of an anode comprised of zinc; a cathode; and alkaline electrolyte; and a current collector comprised of a silicon bronze alloy that is comprised of 85-98% by weight copper and 1-5% by weight silicon with the remainder being comprised of at least one of manganese, iron, zinc, aluminum, tin, lead, or mixtures thereof; and a strip of metal tab stock welded to the current collector, the tab stock being a metal other than silicon bronze alloy.

  15. Alkaline fuel cell performance investigation

    NASA Technical Reports Server (NTRS)

    Martin, R. E.; Manzo, M. A.

    1988-01-01

    An exploratory experimental fuel cell test program was conducted to investigate the performance characteristics of alkaline laboratory research electrodes. The objective of this work was to establish the effect of temperature, pressure, and concentration upon performance and evaluate candidate cathode configurations having the potential for improved performance. The performance characterization tests provided data to empirically establish the effect of temperature, pressure, and concentration upon performance for cell temperatures up to 300 F and reactant pressures up to 200 psia. Evaluation of five gold alloy cathode catalysts revealed that three doped gold alloys had more than two times the surface areas of reference cathodes and therefore offered the best potential for improved performance.

  16. Alkaline fuel cell performance investigation

    NASA Technical Reports Server (NTRS)

    Martin, R. E.; Manzo, M. A.

    1988-01-01

    An exploratory experimental fuel cell test program was conducted to investigate the performance characteristics of alkaline laboratory research electrodes. The objective of this work was to establish the effect of temperature, pressure, and concentration upon performance and evaluate candidate cathode configurations having the potential for improved performance. The performance characterization tests provided data to empirically establish the effect of temperature, pressure, and concentration upon performance for cell temperatures up to 300 F and reactant pressures up to 200 psia. Evaluation of five gold alloy cathode catalysts revealed that three doped gold alloys had more that two times the surface areas of reference cathodes and therefore offered the best potential for improved performance.

  17. PGE mineralization of dunite-wehrlite massifs at the Gutara-Uda interfluve, Eastern Sayan

    NASA Astrophysics Data System (ADS)

    Mekhonoshin, A. S.; Tolstykh, N. D.; Podlipsky, M. Yu.; Kolotilina, T. B.; Vishnevsky, A. V.; Benedyuk, Yu. P.

    2013-05-01

    The Pt-Pd and Au-Ag mineralization hosted in both wehrlite without visible links to sulfide mineralization (dispersed assemblage of the Tartai massif) and disseminated Cu-Ni sulfide ore (ore assemblage of the Ognit massif) was found in dunite-wehrlite massifs localized in the fold framework of the Siberian Craton. The Pt minerals in both assemblages comprise sperrylite (PtAs2) and secondary Pt-Fe-Ni alloys in the Ognit massif and Pt-Fe-Cu and Pt-Cu alloys in the Tartai massif. The Pd minerals are widespread in the ore assemblages as compounds with Te, Sb, and Bi, whereas in the dispersed assemblage Pd is concentrated primarily in Pd-Cu-Sb compounds. Both assemblages are characterized by similar substitution of sperrylite with orcelite (Ni5 - xAs2) and then with secondary Pt-Fe-Ni or Pt-Fe-Cu and Pt-Cu alloys; the occurrence of Au-Ag alloys with prevalence of Ag over Au; and replacement of them with auricupride (Cu3Au) at the late stage. Sperrylite in both assemblages contains Ir impurities, while the Pd minerals contain Cu and Ni admixtures, which are typical of mineral assemblages related to the ultramafic intrusions with nickel specialization. PGM were formed under a low sulfur fugacity and high As, Bi, and Sb activities. The postmagmatic fluids affected the primary mineral assemblages under reductive conditions, and this effect resulted in replacement of sperrylite with Ni arsenide (orcelite) and Pt-Fe-Ni and Pt-Fe-Cu alloys; Ni and Cu sulfides were replaced with awaruite and native copper.

  18. Evolution of stocks and massifs from burial of salt sheets, continental slope, northern Gulf of Mexico

    SciTech Connect

    Seni, S.J. )

    1991-03-01

    Salt structures in a 4000-km{sup 2} region of the continental slope, the northeast Green Canyon area, include stocks, massifs, remnant structures, and an allochthonous sheet. Salt-withdrawal basins include typical semicircular basins and an extensive linear trough that is largely salt-free. Counterregional growth faults truncate the landward margin of salt sheets that extend 30-50 km to the Sigsbee Escarpment. The withdrawal basins, stocks, and massifs occur within a large graben between an east-northeast-trending landward zone of shelf-margin growth faults and a parallel trend of counterregional growth faults located 48-64 km basinward. The graben formed by extension and subsidence as burial of the updip portion of a thick salt sheet produced massifs and stocks by downbuilding. Differential loading segmented the updip margin of the salt sheet into stocks and massifs separated by salt-withdrawal basins. Initially, low-relief structures evolved by trap-door growth as half-graben basins buried the salt sheet. Remnant-salt structures and a turtle-structure anticline overlay a salt-weld disconformity in sediments formerly separated by a salt sheet. Age of sediments below the weld is inferred to be be late Miocene to early Pliocene (4.6-5.3 Ma); age of sediments above the weld is late Pliocene (2.8-3.5 Ma). The missing interval of time (1-2.5 Ma) is the duration between emplacement of the salt sheet and burial of the sheet. Sheet extrusion began in the late Miocene to early Pliocene, and sheet burial began in the late Pliocene in the area of the submarine trough to early Pleistocene in the area of the massifs.

  19. Syntectonic Variscan magmatism in the Aguiar da Beira region (Iberian Massif, Portugal)

    NASA Astrophysics Data System (ADS)

    Mafalda Costa, Maria; Margarida Neiva, Ana; do Rosario Azevedo, Maria; Corfu, Fernando

    2014-05-01

    The Aguiar da Beira region (Portugal) is located in the core of the Iberian Massif, more precisely in the Central-Iberian Zone, which is dominantly composed by abundant volumes of plutonic rocks, emplaced into Late Proterozoic - Early Cambrian and Palaeozoic metasediments, mainly during or slightly after the third deformation phase of the Variscan Orogeny (D3). A considerable amount of these granites are syntectonic, intruded during the peak of this deformation event (D3). In particular, at the Aguiar da Beira region, two suites of syntectonic granitoids represent distinct magmatic series: a medium- to coarse-grained porphyritic biotite granodiorite-granite (322 Ma), which belongs to the early granodiorite series, and a medium-grained muscovite-biotite granite (317 Ma) that is part of the two-mica peraluminous leucogranites suite. The petrographic, geochemical (whole-rock and mineral compositions) and isotopic (Sr-Nd, δ18O-wr and δ18O-zr) study of the two intrusions reveals their remarkably different character. It is concluded that they correspond to two independent magma pulses, derived from distinct sources and/or petrogenetic processes. The biotite granodiorite-granite is a weakly peraluminous intrusion, characterized by intermediate to felsic SiO2 contents (66 - 68 %), high Ba, Sr and REE, and biotite with high Al and Mg contents, typical of the calc-alkaline associations. The Sr-Nd initial ratios are homogeneous (87Sr-86Sr322: 0.7070 - 0.7074; ɛNd322: -3.9 to -4.6) and overlap the isotopic signatures of lower crustal felsic metaigneous granulites (Villaseca et al. 1999). This similarity, which is further supported by δ18O-wr and δ18O-zr data, may indicate an origin by anatexis of lower felsic metaigneous rocks. Alternatively, the same data, allied to the presence of microgranular enclaves seen in this intrusion, can also be explained by the mixing of lower crustal derived magmas and mantle melts. By contrast, the muscovite-biotite granite has an entirely

  20. Alkaline detergent recycling via ultrafiltration

    SciTech Connect

    Steffani, C.; Meltzer, M.

    1995-06-01

    The metal finishing industry uses alkaline cleaners and detergents to remove oils and dirt from manufactured parts, often before they are painted or plated. The use of these cleaners has grown because environmental regulations are phasing out ozone depleting substances and placing restrictions on the use and disposal of many hazardous solvents. Lawrence Livermore National Laboratory is examining ultrafiltration as a cleaning approach that reclaims the cleaning solutions and minimizes wastes. The ultrafiltration membrane is made from sheets of polymerized organic film. The sheets are rolled onto a supporting frame and installed in a tube. Spent cleaning solution is pumped into a filter chamber and filtered through the membrane that captures oils and dirt and allows water and detergent to pass. The membrane is monitored and when pressure builds from oil and dirt, an automatic system cleans the surface to maintain solution flow and filtration quality. The results show that the ultrafiltration does not disturb the detergent concentration or alkalinity but removed almost all the oils and dirt leaving the solution in condition to be reused.

  1. Grace DAKASEP alkaline battery separator

    NASA Technical Reports Server (NTRS)

    Giovannoni, R. T.; Lundquist, J. T.; Choi, W. M.

    1987-01-01

    The Grace DAKASEP separator was originally developed as a wicking layer for nickel-zinc alkaline batteries. The DAKASEP is a filled non-woven separator which is flexible and heat sealable. Through modification of formulation and processing variables, products with a variety of properties can be produced. Variations of DAKASEP were tested in Ni-H2, Ni-Zn, Ni-Cd, and primary alkaline batteries with good results. The properties of DAKASEP which are optimized for Hg-Zn primary batteries are shown in tabular form. This separator has high tensile strength, 12 micron average pore size, relatively low porosity at 46-48 percent, and consequently moderately high resistivity. Versions were produced with greater than 70 percent porosity and resistivities in 33 wt percent KOH as low as 3 ohm cm. Performance data for Hg-Zn E-1 size cells containing DAKASEP with the properties shown in tabular form, are more reproducible than data obtained with a competitive polypropylene non-woven separator. In addition, utilization of active material is in general considerably improved.

  2. 40Ar/ 39Ar ages for the alkaline volcanism and the basement of Gorringe Bank, North Atlantic ocean

    NASA Astrophysics Data System (ADS)

    Féraud, Gilbert; Gastaud, Janine; Auzende, Jean-Marie; Olivet, Jean-Louis; Cornen, Guy

    1982-01-01

    Gorringe Bank is situated on the Europe-Africa plate boundary at the eastern end of the Azores-Gibraltar fracture zone. It has two summits, Gettysburg Bank to the Southwest and Ormonde Bank to the northeast. We applied the 40Ar/ 39Ar stepwise heating method to date six samples of the alkaline volcanic rocks, two gabbros from the Ormonde Bank and a dolerite from the Gettysburg Bank. The results that the alkaline volcanism lasted probably for less than 6 Ma(66-60 Ma). Although the nature of this volcanism precludes any subduction feature during its setting, the alkaline volcanism of Ormonde is probably linked to Upper Cretaceous/Eocene compressive tectonic events. The basement rocks of Gorringe Bank reveal distrubed 40Ar/ 39Ar age spectra. One plagioclase and one biotite from a gabbro give evidence for a thermic event whose age is tentatively estimated at about 75 Ma, and related to a variation in the direction of the relative movement between Europe and Africa. The more probable age given by a plagioclase of another gabbro and by a dolerite (110 Ma) corresponds to tilting northeastward of the Gorringe massif.

  3. Paleostress Analysis Using Calcite Twins in Carbonates - A key study on the Cretaceous Sava-Klepa Massif, Former Yugoslav Republic of Macedonia

    NASA Astrophysics Data System (ADS)

    Köpping, Jonas; Peternell, Mark; Prelević, Dejan; Altmeyer, Tobias

    2016-04-01

    The Geological composition of the Balkan region has been predominantly shaped by the existence of two ophiolite belts originated after the closure of the Tethyan ocean(s) which are the Dinaride-Hellenide ophiolite belt in the south-west and the Vardar belt in the north-east. These two ophiolite belts are either relics of two separate major branches of the Neotethys ocean with intervening continental terranes (Karamata, 2006), or may represent a single thrust from the Triassic-Jurassic Vardar oceanic sequence onto the Adria passive (Schmid et al., 2008). A bulk of Balkan ophiolites are of Jurassic age, and available data on the metamorphic sole indicate that the major episode of convergence and the ocean closure happened not later than in the Upper Jurassic. Recently, the Sava-zone ophiolite of late Cretaceous age was differentiated in the northern Bosnia-Kozara ophiolite and more southerly in the Klepa Massif of Macedonia. Geochemistry of the lavas occurring within the Sava-zone ophiolites show an alkaline character similar to intracontinental rift zones, with no similarities to arc or MORB attributes. This may imply a re-opening of the Tethys during the Early Cretaceous until the Late Cretaceous and thus challenges the widely accepted model of a terminated Upper Jurassic ocean closure (Schmid et al., 2008). This study focuses on the basement sequences surrounding Klepa Massif in Macedonia. Our aim is to test the hypothesis that the Klepa Massif could represent a new ocean that rifted after the collision of Europe and Adria. Detailed structural mapping and paleostress reconstructions from calcite twins within Jurassic as well as Cretaceous carbonates were performed to constrain the evolution of the Cretaceous Sava-Klepa Massif. We use the Turbo Pascal program package of calcite paleostress analysis (Sperner & Ratschbacher, 1994) based on the P-B-T method, together with the numerical dynamic analysis method. Orientation of twin planes and c-axis orientations are

  4. Alkaline and alkaline earth metal phosphate halides and phosphors

    SciTech Connect

    Lyons, Robert Joseph; Setlur, Anant Achyut; Cleaver, Robert John

    2012-11-13

    Compounds, phosphor materials and apparatus related to nacaphite family of materials are presented. Potassium and rubidium based nacaphite family compounds and phosphors designed by doping divalent rare earth elements in the sites of alkaline earth metals in the nacaphite material families are descried. An apparatus comprising the phosphors based on the nacaphite family materials are presented herein. The compounds presented is of formula A.sub.2B.sub.1-yR.sub.yPO.sub.4X where the elements A, B, R, X and suffix y are defined such that A is potassium, rubidium, or a combination of potassium and rubidium and B is calcium, strontium, barium, or a combination of any of calcium, strontium and barium. X is fluorine, chlorine, or a combination of fluorine and chlorine, R is europium, samarium, ytterbium, or a combination of any of europium, samarium, and ytterbium, and y ranges from 0 to about 0.1.

  5. Research of dynamical Characteristics of slow deformation Waves as Massif Responses on Explosions

    NASA Astrophysics Data System (ADS)

    Hachay, Olga; Khachay, Oleg; Shipeev, Oleg

    2013-04-01

    The research of massif state with use of approaches of open system theory [1-3] was developed for investigation the criterions of dissipation regimes for real rock massifs, which are under heavy man-caused influence. For realization of that research we used the data of seismic catalogue of Tashtagol mine. As a result of the analyze of that data we defined character morphology of phase trajectories of massif response, which was locally in time in a stable state: on the phase plane with coordinates released by the massif during the dynamic event energy E and lg(dE/dt) there is a local area as a ball of twisted trajectories and some not great bursts from that ball, which are not greater than 105 joules. In some time intervals that burst can be larger, than 105 joules, achieving 106 joules and yet 109 joules. [3]. Evidently there are two reciprocal depend processes: the energy accumulation in the attracted phase trajectories area and resonance fault of the accumulated energy. But after the fault the system returns again to the same attracted phase trajectories area. For analyzing of the thin structure of the chaotic area we decided to add the method of processing of the seismic monitoring data by new parameters. We shall consider each point of explosion as a source of seismic or deformation waves. Using the kinematic approach of seismic information processing we shall each point of the massif response use as a time point of the first arrival of the deformation wave for calculation of the wave velocity, because additionally we know the coordinates of the fixed response and the coordinates of explosion. The use of additional parameter-velocity of slow deformation wave propagation allowed us with use method of phase diagrams identify their hierarchic structure, which allow us to use that information for modeling and interpretation the propagation seismic and deformation waves in hierarchic structures. It is researched with use of that suggested processing method the thin

  6. Long lasting paleolandscapes stability of the French Massif Central during the Mesozoic

    NASA Astrophysics Data System (ADS)

    Ricordel-Prognon, C.; Thiry, M.; Theveniaut, H.; Lagroix, F.

    2009-04-01

    Regional geodynamical evolution is mainly constrained by the sedimentary record in the basins. Usually, little is known about geodynamics of the peripheral areas and even less on the evolution of the basement areas. Continental unconformities are essential to estimate erosion rates of basement and to model the crustal dynamics that control subsidence of surrounding sedimentary basins but also uplift and erosion on their edges. Dating such unconformities has always been the stumbling block while it is a prerequisite to constrain geodynamical models. Paleomagnetism has been proven as a suitable tool to date ferrugineous paleoweathering features. The method has been applied to paleoweathering occurrences resting on the Massif Central crystalline basement as well as to paleoweathering features affecting the crystalline basement itself. The remanence measurements were obtained at the Paleomagnetic Laboratory of the Institut Physique du Globe de Paris and data analyses were carried out using PaleoMac 5 software (Cogné, 2003). Relative dating of the paleoweathering profiles have been acquired by comparing the recorded paleomagnetic poles from the analysed samples to the apparent polar wandering path of the Eurasian plate (Edel et Duringer, 1997 ; Besse and Courtillot, 2003). Thick red kaolinitic formations rest locally on the Massif Central basement. They are generally bounded by the Tertiary grabens and buried by the Oligocene formations. Thus these azoic red formations have classically been ascribed to the "Siderolithic" formations of Eocene-Oligocene age. They show many pedogenic features (termites burrows, illuviation and hydromorphic features and nodules) and strong relationships with paleolandscape organisation (leaned against fault scarps, infilling paleovalleys, etc.). Macro and micromorphological arrangements show that these formations are in situ paleosols. Paleomagnetic ages range from 160 Ma (Late Jurassic) in the centre of the Massif Central to 140 Ma (Early

  7. Long lasting paleolandscapes stability of the French Massif Central during the Mesozoic

    NASA Astrophysics Data System (ADS)

    Ricordel-Prognon, C.; Thiry, M.; Theveniaut, H.; Lagroix, F.

    2009-04-01

    Regional geodynamical evolution is mainly constrained by the sedimentary record in the basins. Usually, little is known about geodynamics of the peripheral areas and even less on the evolution of the basement areas. Continental unconformities are essential to estimate erosion rates of basement and to model the crustal dynamics that control subsidence of surrounding sedimentary basins but also uplift and erosion on their edges. Dating such unconformities has always been the stumbling block while it is a prerequisite to constrain geodynamical models. Paleomagnetism has been proven as a suitable tool to date ferrugineous paleoweathering features. The method has been applied to paleoweathering occurrences resting on the Massif Central crystalline basement as well as to paleoweathering features affecting the crystalline basement itself. The remanence measurements were obtained at the Paleomagnetic Laboratory of the Institut Physique du Globe de Paris and data analyses were carried out using PaleoMac 5 software (Cogné, 2003). Relative dating of the paleoweathering profiles have been acquired by comparing the recorded paleomagnetic poles from the analysed samples to the apparent polar wandering path of the Eurasian plate (Edel et Duringer, 1997 ; Besse and Courtillot, 2003). Thick red kaolinitic formations rest locally on the Massif Central basement. They are generally bounded by the Tertiary grabens and buried by the Oligocene formations. Thus these azoic red formations have classically been ascribed to the "Siderolithic" formations of Eocene-Oligocene age. They show many pedogenic features (termites burrows, illuviation and hydromorphic features and nodules) and strong relationships with paleolandscape organisation (leaned against fault scarps, infilling paleovalleys, etc.). Macro and micromorphological arrangements show that these formations are in situ paleosols. Paleomagnetic ages range from 160 Ma (Late Jurassic) in the centre of the Massif Central to 140 Ma (Early

  8. Petrological and geochemical evolution of the Tolbachik volcanic massif, Kamchatka, Russia

    NASA Astrophysics Data System (ADS)

    Churikova, Tatiana G.; Gordeychik, Boris N.; Iwamori, Hikaru; Nakamura, Hitomi; Ishizuka, Osamu; Nishizawa, Tatsuji; Haraguchi, Satoru; Miyazaki, Takashi; Vaglarov, Bogdan S.

    2015-12-01

    Data on the geology, petrography, and geochemistry of Middle-Late-Pleistocene rocks from the Tolbachik volcanic massif (Kamchatka, Klyuchevskaya group of volcanoes) are presented and compared with rocks from the neighboring Mount Povorotnaya, Klyuchevskaya group basement, and Holocene-historical Tolbachik monogenetic cones. Two volcanic series of lavas, middle-K and high-K, are found in the Tolbachik massif. The results of our data analysis and computer modeling of crystallization at different P-T-H2O-fO2 conditions allow us to reconstruct the geochemical history of the massif. The Tolbachik volcanic massif started to form earlier than 86 ka based on K-Ar dating. During the formation of the pedestal and the lower parts of the stratovolcanoes, the middle-K melts, depleted relative to NMORB, fractionated in water-rich conditions (about 3% of H2O). At the Late Pleistocene-Holocene boundary, a large fissure zone was initiated and the geodynamical regime changed. Upwelling associated with intra-arc rifting generated melting from the same mantle source that produced magmas more enriched in incompatible trace elements and subduction components; these magmas are high-K, not depleted relative to N-MORB melts with island arc signatures and rift-like characteristics. The fissure opening caused degassing during magma ascent, and the high-K melts fractionated at anhydrous conditions. These high-K rocks contributed to the formation of the upper parts of stratovolcanoes. At the beginning of Holocene, the high-K rocks became prevalent and formed cinder cones and associated lava fields along the fissure zone. However, some features, including 1975-1976 Northern Breakthrough, are represented by middle-K high-Mg rocks, suggesting that both middle-K and high-K melts still exist in the Tolbachik system. Our results show that fractional crystallization at different water conditions and a variably depleted upper mantle source are responsible for all observed variations in rocks within

  9. Micas from mariupolite of the Oktiabrski massif (SE Ukraine): an insight into the host rock evolution--geochemical data supported by Raman microspectroscopy.

    PubMed

    Dumańska-Słowik, Magdalena; Wesełucha-Birczyńska, Aleksandra; Pieczka, Adam

    2015-02-25

    Muscovite and two dark mica varieties (the coarse-crystalline, pegmatitic, and fine-crystalline with signs of early weathering) representing members of the biotite series, originating from mariupolite of the Oktiabrski massif, (Ukraine), were investigated along with their solid inclusions using electron microprobe and Raman micro-spectroscopy to discuss their genesis and relationship to the parental magma. The coarse-crystalline, pegmatitic biotite, (K1.90Rb0.02Na0.01)(Fe3.56(2+)Mg1.34Ti0.36Fe0.34(3+)Mn0.03)[(Si5.73Al2.10Fe0.17(3+))O20](OH3.24 F0.76) represents the primary, magmatic annite that crystallized from an alkaline, Fe-rich and Mg-depleted host magma, whereas the fine-crystalline biotite, partly altered to vermiculite, (K1.75Rb0.03Na0.03)(Fe3.23(3+)Fe1.16(2+)Mg0.26Mn0.04Ti0.10)[(Si5.16 Al2.84)O20](OH)4.00, devoid of F, represents a re-equilibrated or secondary, post-magmatic Fe(3+)-bearing mica crystallized from alkaline to the subalkaline host magma. Muscovite, (K1.96Na0.06)(Al3.97Fe0.06(2+))[(Si5.99Al2.01)O20](OH)4, with low Na/(Na+K) ratio, low Fe and devoid of Ti and also F, forms only tiny, subhedral flakes formed in the post-magmatic, hydrothermal stage. The primary, unaltered biotite contains numerous solid inclusions of primary origin (albite, aegirine, zircon, K-feldspar, nepheline, pyrochlore, magnetite) and secondary origin (natrolite, hematite, Ti-Mn oxides/hydroxides); most of them are accompanied by a carbonaceous substance, all confirmed by scanning electron microscopy and Raman microspectroscopy. PMID:25277630

  10. Cambrian rift-related magmatism in the Ossa-Morena Zone (Iberian Massif): Geochemical and geophysical evidence of Gondwana break-up

    NASA Astrophysics Data System (ADS)

    Sarrionandia, F.; Carracedo Sánchez, M.; Eguiluz, L.; Ábalos, B.; Rodríguez, J.; Pin, C.; Gil Ibarguchi, J. I.

    2012-10-01

    Volcanic rocks of Cambrian age from Zafra (Ossa-Morena Zone, Iberian Massif) are the result of rift processes that affected Cadomian arc units accreted to the NW edge of Gondwana during the Neoproterozoic-Early Cambrian transition. Tephrite to rhyolite volcanics define an alkaline transitional association (Coombs type). Basic-ultrabasic rocks exhibit typical alkaline REE-patterns, strongly enriched in LREE with respect to HREE. Two parental magmas are identified, one with a mantle signature, lack of Nb negative anomaly and εNd500Ma + 3.8 to + 4.2; another with crustal contribution, minor Nb negative anomaly and εNd500Ma + 0.8 to + 1.8. Intermediate-acid rocks show variable REE fractionation and share geochemical characteristics of both basic-ultrabasic groups with restricted εNd500Ma + 2.2 to 3.1 and general absence of Nb negative anomaly. Basic-ultrabasic melts resulted from different amounts of partial melting of a homogeneous source and segregation at the garnet-spinel transition zone. We argue that the "Hales transition" recently recognized in reflection seismic experiments of SW Iberia might image such a source region. Mantle-derived magmas ponded at the base of the crust and weakly interacted with crustal rocks/melts, whilst intermediate-acid rocks were generated by plagioclase ± clinopyroxene ± amphibole fractionation. Melt ascent took place through fractures, with limited crustal interaction. Based upon the new geochemical results and complementary cartographic and geophysical data, a model is presented for the Cambrian break-up of North Gondwana due to magma ascent from the mantle.

  11. Micas from mariupolite of the Oktiabrski massif (SE Ukraine): An insight into the host rock evolution - Geochemical data supported by Raman microspectroscopy

    NASA Astrophysics Data System (ADS)

    Dumańska-Słowik, Magdalena; Wesełucha-Birczyńska, Aleksandra; Pieczka, Adam

    2015-02-01

    Muscovite and two dark mica varieties (the coarse-crystalline, pegmatitic, and fine-crystalline with signs of early weathering) representing members of the biotite series, originating from mariupolite of the Oktiabrski massif, (Ukraine), were investigated along with their solid inclusions using electron microprobe and Raman micro-spectroscopy to discuss their genesis and relationship to the parental magma. The coarse-crystalline, pegmatitic biotite, (K1.90Rb0.02Na0.01)(Fe2+3.56Mg1.34Ti0.36Fe3+0.34Mn0.03)[(Si5.73Al2.10Fe3+0.17)O20](OH3.24 F0.76) represents the primary, magmatic annite that crystallized from an alkaline, Fe-rich and Mg-depleted host magma, whereas the fine-crystalline biotite, partly altered to vermiculite, (K1.75Rb0.03Na0.03)(Fe3+3.23Fe2+1.16Mg0.26Mn0.04Ti0.10)[(Si5.16 Al2.84)O20](OH)4.00, devoid of F, represents a re-equilibrated or secondary, post-magmatic Fe3+-bearing mica crystallized from alkaline to the subalkaline host magma. Muscovite, (K1.96Na0.06)(Al3.97Fe2+0.06)[(Si5.99Al2.01)O20](OH)4, with low Na/(Na + K) ratio, low Fe and devoid of Ti and also F, forms only tiny, subhedral flakes formed in the post-magmatic, hydrothermal stage. The primary, unaltered biotite contains numerous solid inclusions of primary origin (albite, aegirine, zircon, K-feldspar, nepheline, pyrochlore, magnetite) and secondary origin (natrolite, hematite, Ti-Mn oxides/hydroxides); most of them are accompanied by a carbonaceous substance, all confirmed by scanning electron microscopy and Raman microspectroscopy.

  12. Scorpions from the Mitaraka Massif in French Guiana. II. Description of a new species of Ananteris Thorell, 1891 (Scorpiones: Buthidae).

    PubMed

    Lourenço, Wilson R

    2016-01-01

    A new remarkable species belonging to the genus Ananteris Thorell, 1891 (Buthidae) is described from the Mitaraka Massif in French Guiana, a site located near the borders of French Guiana, Brazil, and Suriname. The description of this new species brings further evidence about the biogeographic patterns of distribution presented by most species of the genus Ananteris, which are highly endemic in most biogeographic realms of South America, including the Tepuys and Inselberg Massifs. PMID:27156170

  13. New evidence of effusive and explosive volcanism in the Lower Carboniferous formations of the Moroccan Central Hercynian Massif: Geochemical data and geodynamic significance

    NASA Astrophysics Data System (ADS)

    Ntarmouchant, A.; Smaili, H.; Bento dos Santos, T.; Dahire, M.; Sabri, K.; Ribeiro, M. L.; Driouch, Y.; Santos, R.; Calvo, R.

    2016-03-01

    The Azrou-Khénifra basin, located in the SE sector of the Moroccan Central Hercynian Massif of the Western Meseta of Morocco comprises volcanic and volcanoclastic rocks where two magmatic sequences can be distinguished: i) the Dhar Lahmar Sequence, composed of Upper Visean basaltic lava flows and pyroclastic deposits; and ii) the Kef Al Asri Sequence, composed of Visean - Serpukhovian intermediate to acid rocks. A continuous spatial and temporal evolution between the two volcano-sedimentary sequences was observed during the detailed geological work performed in the studied area. Petrography and geochemical studies additionally suggest a continuous compositional evolution from the more basic magmatic rocks to the intermediate/acid rocks, which implies a cogenetic magmatic differentiation controlled by crystal fractionation (with minor crustal assimilation) of a calc-alkaline trend magmatic suite. The inferred magmatic evolution is consistent with a geodynamic environment of an orogenic zone within an active continental margin setting. This partly explosive Visean - Serpukhovian volcanism, identified for the first time in the Western Meseta of Morocco, displays very similar petrographic and geochemical characteristics to its Eastern Meseta analogues, which implies that the emplacement of these magmatic rocks must have occurred in similar collisional geodynamic settings for both major geological domains, further constraining the evolution of this major crustal segment within the Carboniferous events that shaped the Hercynian Orogeny.

  14. Process for extracting technetium from alkaline solutions

    SciTech Connect

    Moyer, B.A.; Sachleben, R.A.; Bonnesen, P.V.

    1994-12-31

    This invention relates generally to a process for extracting technetium from nuclear wastes and more particularly to a process for extracting technetium from alkaline waste solutions containing technetium and high concentrations of alkali metal nitrates. A process for extracting technetium values from an aqueous alkaline solution containing at least one alkali metal hydroxide and at least one alkali metal nitrate comprises the steps of: contacting the aqueous alkaline solution with a solvent consisting of a crown ether in a diluent, the diluent being a water-immiscible organic liquid in which the crown ether is soluble, for a period of time sufficient to selectively extract the technetium values from the aqueous alkaline solution into the solvent; separating the solvent containing the technetium values from the aqueous alkaline solution; and stripping the technetium values from the solvent by contacting the solvent with water.

  15. Alkaline-resistance model of subtilisin ALP I, a novel alkaline subtilisin.

    PubMed

    Maeda, H; Mizutani, O; Yamagata, Y; Ichishima, E; Nakajima, T

    2001-05-01

    The alkaline-resistance mechanism of the alkaline-stable enzymes is not yet known. To clarify the mechanism of alkaline-resistance of alkaline subtilisin, structural changes of two typical subtilisins, subtilisin ALP I (ALP I) and subtilisin Sendai (Sendai), were studied by means of physicochemical methods. Subtilisin NAT (NAT), which exhibits no alkaline resistance, was examined as a control. ALP I gradually lost its activity, accompanied by protein degradation, but, on the contrary, Sendai was stable under alkaline conditions. CD spectral measurements at neutral and alkaline pH indicated no apparent differences between ALP I and Sendai. A significant difference was observed on measurement of fluorescence emission spectra of the tryptophan residues of ALP I that were exposed on the enzyme surface. The fluorescence intensity of ALP I was greatly reduced under alkaline conditions; moreover, the reduction was reversed when alkaline-treated ALP I was neutralized. The fluorescence spectrum of Sendai remained unchanged. The enzymatic and optical activities of NAT were lost at high pH, indicating a lack of functional and structural stability in an alkaline environment. Judging from these results, the alkaline resistance is closely related to the surface structure of the enzyme molecule. PMID:11328588

  16. Œdème vulvaire massif pendant la grossesse: à propos d'un cas

    PubMed Central

    El Hassani, Moulay Elmehdi; Kassidi, Farid; Benabdejlil, Youssef; Kouach, Jaouad; Moussaoui, Driss Rahali; Dehayni, Mohammed

    2014-01-01

    L’œdème vulvaire massif est rare pendant la grossesse, mais requiert une attention particulière car il peut se greffer de complications maternelles et fœtales. Il peut être associé à plusieurs pathologies spécifiques ou non spécifiques à la grossesse dont le diagnostic fait appel obligatoirement à un interrogatoire et un examen clinique minutieux, puis à un bilan biologique standard. Le traitement doit être étiologique chaque fois que possible à coté du traitement symptomatique. Cette situation peut nécessiter un accouchement par césarienne. En dehors du risque potentiel de nécrose tissulaire et du risque exceptionnel de décès maternel associé à l’œdème vulvaire massif du post-partum l’évolution est favorable sous traitement bien conduit. PMID:25922627

  17. Seismic characterization of an active metamorphic massif, Nanga Parbat, Pakistan Himalaya

    NASA Astrophysics Data System (ADS)

    Meltzer, Anne; Sarker, Golam; Beaudoin, Bruce; Seeber, Leonardo; Armbruster, John

    2001-07-01

    Earthquakes recorded by a dense seismic array at Nanga Parbat, Pakistan, provide new insight into synorogenic metamorphism and mass flow during mountain building. Microseismicity beneath the massif drops off sharply with depth and defines a shallow transition between brittle failure and ductile flow. The base of seismicity bows upward, mapping a thermal boundary with 3 km of structural relief over a lateral distance of 12 km. Anomalously low seismic velocities are observed at the core of the massif and extend to depth through the crust. The main locus of seismicity and low velocities correlates with a region of high topography, rapid exhumation, high geothermal gradients, young metamorphic and igneous ages, and crustal fluid flow. We suggest a genetic link between these phenomena in which hot rocks, rapidly advected from depth, are pervasively modified at relatively shallow levels in the crust.

  18. Two types of noble metal mineralization in the Kaalamo massif (Karelia)

    NASA Astrophysics Data System (ADS)

    Ivashchenko, V. I.; Ruchyev, A. M.; Golubev, A. I.

    2016-05-01

    Noble metal mineralization of the syngenetic (Southern Kaalamo) and epigenetic (Surisuo) types are defined in the Kaalamo massif. The ƩPt, Pd, Au content is as high as 0.9-1.1 g/t. Syngenetic mineralization started at the late magmatic stage (at around 800°C) gradually evolving to cease during the hydrothermal-metasomatic stage (<271°C). Epigenetic mineralization was formed at temperatures ranging from 500 to <230°C in zones of intense shear deformations and low-temperature metasomatosis during the collisional stage of the Svecofennian tectono-magmatic cycle (approximately 1.85 Ga ago). Taking into consideration the geological position of the Kaalamo massif in the Raakhe-Ladoga metallogenic zone with widely developed intense shear dislocations, the epigenetic mineralization type seems to be more promising with respect to noble metals.

  19. Mineralogy and geochemistry of the Tartai massif, East Siberian metallogenic province

    NASA Astrophysics Data System (ADS)

    Podlipsky, M. Yu.; Mekhonoshin, A. S.; Tolstykh, N. D.; Vishnevskiy, A. V.; Polyakov, G. V.

    2015-05-01

    The Tartai ultramafic-mafic massif is located in the central part of the East Siberian metallogenic (PGE-Cu-Ni) province (728-712 Ma), which constitutes part of the southern margin of the Siberian craton. This dunite-peridotite-pyroxenite-gabbro massif is the host to low-sulfide PGE-Cu-Ni mineralization. The massif was formed by fractional crystallization of picritic magmas and is composed of wehrlite, dunite, plagiowehrlite, and olivine melanogabbro. The composition of olivine varies from Fo89.9 in dunite to Fo83 in melanocratic olivine gabbro; clinopyroxene is esentially augite. Chrome-spinels crystallized at a low degree of oxidation and have a high iron content. Disseminated sulfide mineralization (pentlandite and heazlewoodite) with high PGE concentrations was identified in wehrlites. Pentlandite is enriched in Fe and Co and depleted in S. These features and the association pentlandite with heazlewoodite suggest that the sulfide mineralization was formed over a wide temperature range (600-400°C) at low sulfur activity (log fS2 from -16 to -9). PGM are represented by Ir-bearing sperrylite, Pd-Cu-Sb panning compounds of variable compositions, Pt-Fe-Cu and Pt-Cu alloys. The evolutionary trend of the ore system was from essentially Ni compositions at the early magmatic stage during formation of disseminated mineralization toward Cu-rich composition at the post-magmatic stage. The PGM assemblage from heavy concentrate haloes differs from bedrock-hosted mineralization in its wider variety of mineral species and the presence of refractory platinoids. Sperrylite from heavy concentrate haloes of the Tartai massif serves as a reliable prospecting guide for bedrock-hosted sulfide Cu-Ni deposits.

  20. Origin and significance of tourmalinites and tourmaline-bearing rocks of Menderes Massif, western Anatolia, Turkey

    NASA Astrophysics Data System (ADS)

    Yücel-Öztürk, Yeşim; Helvacı, Cahit; Palmer, Martin R.; Ersoy, E. Yalçın; Freslon, Nicolas

    2015-03-01

    In the western central portion of Anatolia lies the Menderes Massif - a large metamorphic crystalline complex made of Neoproterozoic to Precambrian basement rocks overlain by Palaeozoic to early Tertiary metasedimentary rocks, and with a multistage metamorphic evolution developed from the late Neo-Proterozoic to Eocene. We have undertaken a study of the petrology, geochemistry and boron isotope composition of these tourmaline occurrences aiming to constrain the processes responsible for the enrichment of boron and other fluid mobile elements in the Menderes Massif. The dispersed tourmaline has chemical and boron isotope compositions typical of a continental crust setting, but while some of the tourmalinites display similar signatures, others have heavier boron isotope compositions (up to + 7.5‰). We suggest that the tourmalinites with continental characteristics formed part of the original Pan African basement rocks, whereas those with heavier δ11B signatures formed by later metamorphism during the Alpine orogeny, possibly through interaction with subduction-like fluids. This proposed process may also have been coincident with metasomatism of the lithospheric mantle beneath the massif, which is known to have experienced multistage metasomatism and enrichment history up to Neogene time.

  1. Significance of Geological Units of the Bohemian Massif, Czech Republic, as Seen by Ambient Noise Interferometry

    NASA Astrophysics Data System (ADS)

    Růžek, Bohuslav; Valentová, Lubica; Gallovič, František

    2016-05-01

    Broadband recordings of 88 seismic stations distributed in the Bohemian Massif, Czech Republic, and covering the time period of up to 12 years were processed by a cross-correlation technique. All correlograms were analyzed by a novel approach to get both group and phase dispersion of Rayleigh and Love waves. Individual dispersion curves were averaged in five distinct geological units which constitute the Bohemian Massif (Saxothuringian, Teplá-Barrandean, Sudetes, Moravo-Silesian, and Moldanubian). Estimated error of the averaged dispersion curves are by an order smaller than the inherent variability due to the 3D distribution of seismic velocities within the units. The averaged dispersion data were inverted for 1D layered velocity models including their uncertainty, which are characteristic for each of the geological unit. We found that, overall, the differences between the inverted velocity models are of similar order as the variability inside the geological units, suggesting that the geological specification of the units is not fully reflected into the S-wave propagation velocities on a regional scale. Nevertheless, careful treatment of the dispersion data allowed us to identify some robust characteristics of the area. The vp to vs ratio is anomalously low (~1.6) for all the units. The Moldanubian is the most rigid and most homogeneous part of the Bohemian Massif. Middle crust in the depth range of ~3-15 km is relatively homogeneous across the investigated region, while both uppermost horizon (0-3 km) and lower crust (>15 km) exhibit lower degree of homogeneity.

  2. Age and sources of Precambrian zircon-rutile deposits in the Kokchetav sialic massif (northern Kazakhstan)

    NASA Astrophysics Data System (ADS)

    Degtyarev, K. E.; Kovach, V. P.; Tret'yakov, A. A.; Kotov, A. B.; Wang, Kuo-Lun

    2015-10-01

    The U-Pb geochronological data on detrital zircons from placers confined to Neoproterozoic quartzite-schist sequences, which are widespread in the Kokchetav massif of northern Kazakhstan, are discussed. Detrital zircons (332 grains in total) originate from the ore occurrences in the central, northern, and western parts of the massif. The concordant ages of detrital zircons from all the examined occurrences largely correspond to intervals of 1017-1528, 1628-1946, and 2653-2739 Ma. The obtained data imply that material of quartzite-schist sequences of the Kokchetav massif was provided by Mesoproterozoic, Paleoproterozoic, and Neoarchean rock complexes. The lower age limit determined for these sequences is approximately 1.06 Ga. The dates obtained for detrital zircons are most consistent with events that took place in Laurentia. They correspond to the formation and breakup of the Columbia/Nuna supercontinent (approximately 1650-1580 and 1450-1380 Ma ago, respectively) and formation of the Rodinia supercontinent in the period of 1300-900 Ma ago.

  3. Chain Lakes massif, west central Maine: northern Appalachian basement or suspect terrane

    SciTech Connect

    Cheatham, M.M.; Olszewski, W.J. Jr.; Gaudette, H.E.

    1985-01-01

    The Chain Lakes massif of west-central Main is a 3 km thick sequence of diamictite and aquagene metavolcanics and metasediments, which contrasts strikingly with its surrounding Paleozoic rocks in lithology, structural style and metamorphic grade. The rocks of the massif are characterized by mineral assemblages developed during two separate metamorphic events. The first, of second sillimanite grade, is reflected by qtz-oligoclase-Kspar-sillimanite-biotite and muscovite. The second metamorphism is a retrograde event of greenschist facies, and chlorite grade. Isotopic Rb-Sr and Sm-Nd whole rock, and Rb-Sr mineral analyses of samples of the diamictite members, now gneiss and granofels, indicate that the first prograde metamorphism occurred at 770 Ma. with the retrograde event at approximately 405 Ma. Due to the restricted range of /sup 147/Sm//sup 144/Nd, no Sm-Nd isochron age could be determined. However, model ages for both Sr and Nd are approximately 1500 Ma for derivation of the Chain Lakes protolith material from depleted mantle. Lithology, bounding formations, complexes and plutons, and the isotopic data support previous contentions that the Chain Lakes massif is a suspect terrane. However, similarities with Proterozoic rocks along the Eastern Margin, as well as recent suggestions of similar rocks underlying the Kearsarge-Central Main synclinorium may suggest the possible widespread occurrence of dismembered masses of a perhaps once coherent, Precambrian terrane underlying the Northern Appalachians.

  4. Re-Os isotopic evidence for a lower crustal origin of massif-type anorthosites

    PubMed

    Schiellerup; Lambert; Prestvik; Robins; McBride; Larsen

    2000-06-15

    Massif-type anorthosites are large igneous complexes of Proterozoic age. They are almost monomineralic, representing vast accumulations of plagioclase with subordinate pyroxene or olivine and Fe-Ti oxides--the 930-Myr-old Rogaland anorthosite province in southwest Norway represents one of the youngest known expressions of such magmatism. The source of the magma and geodynamic setting of massif-type anorthosites remain long-standing controversies in Precambrian geology, with no consensus existing as to the nature of the parental magmas or whether these magmas primarily originate in the Earth's mantle or crust. At present, massif-type anorthosites are believed to have crystallized from either crustally contaminated mantle-derived melts that have fractionated olivine and pyroxenes at depth or primary aluminous gabbroic to jotunitic melts derived from the lower continental crust. Here we report rhenium and osmium isotopic data from the Rogaland anorthosite province that strongly support a lower crustal source for the parental magmas. There is no evidence of significantly older crust in southwest Scandinavia and models invoking crustal contamination of mantle-derived magmas fail to account for the isotopic data from the Rogaland province. Initial osmium and neodymium isotopic values testify to the melting of mafic source rocks in the lower crust with an age of 1,400-1,550 Myr. PMID:10866196

  5. First SHRIMP U Pb zircon dating of granulites from the Kontum massif (Vietnam) and tectonothermal implications

    NASA Astrophysics Data System (ADS)

    Nam, Tran Ngoc; Sano, Yuji; Terada, Kentaro; Toriumi, Mitsuhiro; Van Quynh, Phan; Dung, Le Tien

    2001-02-01

    The Kontum massif in Central Vietnam represents the largest continuous exposure of crystalline basement of the Indochina craton. The central Kontum massif is chiefly made of orthopyroxene granulites (enderbite, charnockite) and associated rocks of the Kannack complex. Mineral assemblages and geothermobarometric studies have shown that the Kannack complex has severely metamorphosed under granulite facies corresponding to P-T conditions of 800-850°C and 8±1 kbars. Twenty-three SHRIMP II U-Pb analyses of eighteen zircon grains separated from a granulite sample of the Kannack complex yield ca 254 Ma, and one analysis gives ca 1400 Ma concordant age for a zoned zircon core. This result shows that granulites of the Kannack complex in the Kontum massif have formed from a high-grade granulite facies tectonothermal event of Indosinian age (Triassic). The cooling history and subsequent exhumation of the Kannack complex during Indosinian times ranged from ˜850°C at ca 254 Ma to ˜300°C at 242 Ma, with an average cooling rate of ˜45°C/Ma.

  6. Early differentiation of the Moon: Experimental and modeling studies and experimental and modeling studies of massif anorthosites

    NASA Technical Reports Server (NTRS)

    Longhi, John

    1994-01-01

    NASA grant NAG9-329 was in effect from 3/1/89 to 8/31/94, the last 18 months being a no-cost extension. While the grant was in effect, the P.I., coworkers, and students gave 22 talks and poster sessions at professional meetings, published 12 articles in referred journals (one more is in press, and another is in review), and edited 2 workshop reports relevant to this project. Copies of all the publications are appended to this report. The major accomplishments during the grant period have derived from three quarters: 1) the application of quantitative models of fractional crystallization and partial melting to various problems in planetary science, such as the petrogenesis of picritic glasses and mare basalts and the implications of the SNC meteorites for martian evolution; 2) an experimental study of silicate liquid immiscibility relevant to early lunar differentiation and the petrogenesis of evolved highlands rocks; and 3) experimental studies of massif anorthosites and related rocks that provide terrestrial analogs for the proposed origin of lunar anorthosites by multistage processes. The low-pressure aspects of the quantitative models were developed by the P.I. in the 1980s with NASA support and culminated with a paper comparing the crystallization of terrestrial and lunar lavas. The basis for the high-pressure modifications to the quantitative models is a data set gleaned from high pressure melting experiments done at Lamont and is supplemented by published data from other labs that constrain the baric and compositional dependences of various liquidus phase boundaries such as olivine/orthopyroxene, relevant to the melting of the mantles of the terrestrial planets. With these models it is possible to predict not only the thermal and compositional evolution of magmatic liquids ranging in composition from lumar mare basalt to terrestrial calc-alkaline basalts, but also the small increments of fractional melting that are produced when mantle rises adiabatically

  7. The quartz-dioritic Hospitais intrusion (SW Iberian Massif) and its mafic microgranular enclaves - Evidence for mineral clustering

    NASA Astrophysics Data System (ADS)

    Moita, P.; Santos, J. F.; Pereira, M. F.; Costa, M. M.; Corfu, F.

    2015-05-01

    The Hospitais pluton is an elliptical body, with its long axis oriented WNW-ESE, that belongs to the Évora Massif (Iberian Variscan belt). This intrusion has a quartz-dioritic composition, with plagioclase, quartz, amphibole (hornblende, but locally also cummingtonite) and biotite as the main mineral phases. Mafic microgranular enclaves in the quartz-diorite show the same minerals as the host, but with a greater abundance of amphibole and lower proportions of felsic minerals, especially quartz. U-Pb zircon ages obtained in one sample of the quartz-diorite and one sample of a mafic microgranular enclave gave identical ages, within error, of ca. 337 Ma. Geochemical data show that the quartz-diorite has a calc-alkaline signature with moderate enrichment in LILE/HFSE ratio (ThN/YN: 2.71-11.43) and clear negative Ti and Nb-Ta anomalies (ThN/NbN: 1.33-6.22). The composition of the enclaves shows that they do not represent direct melt compositions. Instead, their geochemical features (namely the abundances of Fe and Mn in variation diagrams and REE patterns in primitive mantle normalized diagrams) suggest that they correspond to mineral clustering formed during the previous crystallization stage of quartz-dioritic magma. Overlapping of mineral chemistry and Sr-Nd isotope compositions in the quartz-diorite and the enclaves provides further support to that conclusion. The values for [87Sr/86Sr]i and εNdi (calculated for 337 Ma) in the quartz-diorite vary from 0.706147 to 0.706491 and from - 1.87 to - 3.22, respectively. This isotope composition may be explained either by differentiation of a mafic magma extracted from a mantle wedge enriched by long lasting subduction processes, or by mixing between a mafic magma from a depleted mantle source and a crustal melt. In the second case, the most likely source for the felsic component should be meta-igneous rocks, like the Lower Cambrian Alcáçovas orthogneisses that outcrop in neighbouring areas.

  8. Alkaline sorbent injection for mercury control

    DOEpatents

    Madden, Deborah A.; Holmes, Michael J.

    2002-01-01

    A mercury removal system for removing mercury from combustion flue gases is provided in which alkaline sorbents at generally extremely low stoichiometric molar ratios of alkaline earth or an alkali metal to sulfur of less than 1.0 are injected into a power plant system at one or more locations to remove at least between about 40% and 60% of the mercury content from combustion flue gases. Small amounts of alkaline sorbents are injected into the flue gas stream at a relatively low rate. A particulate filter is used to remove mercury-containing particles downstream of each injection point used in the power plant system.

  9. Alkaline sorbent injection for mercury control

    DOEpatents

    Madden, Deborah A.; Holmes, Michael J.

    2003-01-01

    A mercury removal system for removing mercury from combustion flue gases is provided in which alkaline sorbents at generally extremely low stoichiometric molar ratios of alkaline earth or an alkali metal to sulfur of less than 1.0 are injected into a power plant system at one or more locations to remove at least between about 40% and 60% of the mercury content from combustion flue gases. Small amounts of alkaline sorbents are injected into the flue gas stream at a relatively low rate. A particulate filter is used to remove mercury-containing particles downstream of each injection point used in the power plant system.

  10. Inorganic-organic separators for alkaline batteries

    NASA Technical Reports Server (NTRS)

    Sheibley, D. W. (Inventor)

    1978-01-01

    A flexible separator is reported for use between the electrodes of Ni-Cd and Ni-Zn batteries using alkaline electrolytes. The separator was made by coating a porous substrate with a battery separator composition. The coating material included a rubber-based resin copolymer, a plasticizer and inorganic and organic fillers which comprised 55% by volume or less of the coating as finally dried. One or more of the filler materials, whether organic or inorganic, is preferably active with the alkaline electrolyte to produce pores in the separator coating. The plasticizer was an organic material which is hydrolyzed by the alkaline electrolyte to improve conductivity of the separator coating.

  11. Process for extracting technetium from alkaline solutions

    DOEpatents

    Moyer, Bruce A.; Sachleben, Richard A.; Bonnesen, Peter V.

    1995-01-01

    A process for extracting technetium values from an aqueous alkaline solution containing at least one alkali metal hydroxide and at least one alkali metal nitrate, the at least one alkali metal nitrate having a concentration of from about 0.1 to 6 molar. The solution is contacted with a solvent consisting of a crown ether in a diluent for a period of time sufficient to selectively extract the technetium values from the aqueous alkaline solution. The solvent containing the technetium values is separated from the aqueous alkaline solution and the technetium values are stripped from the solvent.

  12. Layered granitoids: Interaction between continental crust recycling processes and mantle-derived magmatism: Examples from the Évora Massif (Ossa-Morena Zone, southwest Iberia, Portugal)

    NASA Astrophysics Data System (ADS)

    Moita, Patrícia; Santos, José F.; Pereira, M. Francisco

    2009-08-01

    In this paper, field, petrographic, mineralogical, geochemical and isotopic (Rb-Sr and Sm-Nd) information from three areas within the Évora Massif (Iberian Variscan Orogen) is presented and discussed aiming at to unravel the relationships between granitoids and units mapped as migmatites and also to evaluate the interplay between mantle and crustal derived magmas. One of the areas - Almansor - displays a well-developed compositional layering (concordant with the regional Variscan structure) which was considered, in previous works, as an alternation of leucosome and melanosome. In this study, the layering is described as intercalation of diatexites, weakly foliated granitoids and trondhjemitic veins. Diatexites have characteristics of crustal melts plus restitic material and, according to geochemical and isotopic evidence, result from anatexis of Ediacaran metasediments. Weakly foliated granitoids and trondhjemitic veins from Almansor have calc-alkaline signatures and may be related to each other by crystal fractionation processes; however, the mixing between mafic (mantle-derived) and felsic (diatexitic melt) magmas revealed by the isotopic data may also explain their genesis. In the Alto de São Bento area, several igneous lithologies (tonalites, granodiorites, porphyritic granites and leucogranites) are present and show typical isotropic igneous textures. Despite structural and textural differences, geochemical data support, for most rocks, an origin from the same calk-alkaline suite, also present at Almansor. The Alto de São Bento leucogranites have an isotopic signature that, although different from that obtained in the Almansor diatexites, is still compatible with an origin involving melting of Ediacaran metasediments; compositions, with very low contents of usually incompatible elements, flat normalized REE patterns and strong negative Eu anomalies, suggest that the anatectic melt has undergone crystal fractionation processes before reaching the composition

  13. Jurassic hot spring deposits of the Deseado Massif (Patagonia, Argentina): Characteristics and controls on regional distribution

    NASA Astrophysics Data System (ADS)

    Guido, Diego M.; Campbell, Kathleen A.

    2011-06-01

    The Deseado Massif, Santa Cruz Province, Argentinean Patagonia, hosts numerous Middle to Late Jurassic age geothermal and epithermal features represented by siliceous and calcareous chemical precipitates from hot springs (sinters and travertines, respectively), hydrothermal breccias, quartz veins, and widespread hydrothermal silicification. They indicate pauses in explosive volcanic activity, marking the final stages in the evolution of an extensive Jurassic (ca. 178-151 Ma) volcanic complex set in a diffuse extensional back-arc setting heralding the opening of the Atlantic Ocean. Published paleo-hot spring sites for the Deseado Massif, plus additional sites identified during our recent field studies, reveal a total of 23 locations, five of which were studied in detail to determine their geologic and facies associations. They show structural, lithologic, textural and biotic similarities with Miocene to Recent hot spring systems from the Taupo and Coromandel volcanic zones, New Zealand, as well as with modern examples from Yellowstone National Park, U.S.A. These comparisons aid in the definition of facies assemblages for Deseado Massif deposits - proximal, middle apron and distal siliceous sinter and travertine terraces and mounds, with preservation of many types of stromatolitic fabrics - that likely were controlled by formation temperature, pH, hydrodynamics and fluid compositions. Locally the mapped hot spring deposits largely occur in association with reworked volcaniclastic lacustrine and/or fluvial sediments, silicic to intermediate lava domes, and hydrothermal mineralization, all of which are related to local and regional structural lineaments. Moreover, the numerous geothermal and significant epithermal (those with published minable resources) deposits of the Deseado Massif geological province mostly occur in four regional NNW and WNW hydrothermal-structural belts (Northwestern, Northern, Central, and Southern), defined here by alignment of five or more hot

  14. Geological mapping of the Rainbow Massif, Mid-Atlantic Ridge, 36°14'N

    NASA Astrophysics Data System (ADS)

    Ildefonse, B.; Fouquet, Y.; Hoisé, E.; Dyment, J.; Gente, P.; Thibaud, R.; Bissessur, D.; Yatheesh, V.; Momardream 2008 Scientific Party*, T.

    2008-12-01

    The Rainbow hydrothermal field at 36°14'N on the Mid-Atlantic Ridge is one of the few known sites hosted in ultramafic basement. The Rainbow Massif is located along the non-transform offset between the AMAR and South AMAR second-order ridge segments, and presents the characteristic dome morphology of oceanic core complexes, although no corrugated surface has been observed so far. One of the objectives of Cruises MOMAR DREAM (July 2007, R/V Pourquoi Pas ?; Aug-Sept 2008, R/V Atalante) was to study the petrological and structural context of the hydrothermal system at the scale of the Rainbow Massif. Our geological sampling complements previous ones achieved during Cruises FLORES (1997) and IRIS (2001), and consisted in dredge hauls, and submersible dives by manned submersible Nautile and ROV Victor. The tectonics of the Rainbow Massif is dominated by a N-S trending fault pattern on the western flank of the massif, and a series of SW-NW ridges on its northeastern side. The active hydrothermal site is located in the area were these two systems crosscut. The most abundant recovered rock type is peridotite (harzburgite and dunite) that presents a variety of serpentinization styles and intensity, and a variety of deformation styles (commonly undeformed, sometimes displaying ductile or brittle foliations). Serpentinites are frequently oxidized. Some peridotite samples have melt impregnation textures. Massive chromitite was recovered in one dredge haul. Variously evolved gabbroic rocks were collected as discrete samples or as centimeter to decimeter-thick dikes in peridotites. Basalts and fresh basaltic glass were also sampled in talus and sediments on the southwestern and northeastern flanks of the massif. Our sampling is consistent with the lithological variability encountered in oceanic core complexes along the Mid-Atlantic Ridge and Southwest Indian Ridge. The stockwork of the hydrothermal system has been sampled on the western side of the present-day hydrothermal

  15. Mapping of the Ronda peridotite massif (Spain) from AVIRIS spectro-imaging survey: A first attempt

    NASA Technical Reports Server (NTRS)

    Pinet, P. C.; Chabrillat, S.; Ceuleneer, G.

    1993-01-01

    In both AVIRIS and ISM data, through the use of mixing models, geological boundaries of the Ronda massif are identified with respect to the surrounding rocks. We can also yield first-order vegetation maps. ISM and AVIRIS instruments give consistent results. On the basis of endmember fraction images, it is then possible to discard areas highly vegetated or not belonging to the peridotite massif. Within the remaining part of the mosaic, spectro-mixing analysis reveals spectral variations in the peridotite massif between the well-exposed areas. Spatially organized units are depicted, related to differences in the relative depth of the absorption band at 1 micron, and it may be due to a different pyroxene content. At this stage, it is worth noting that, although mineralogical variations observed in the rocks are at a sub-pixel scale for the airborne analysis, we see an emerging spatial pattern in the distribution of spectral variations across the massif which might be prevailingly related to mineralogy. Although it is known from fieldwork that the Ronda peridotite massif exhibits mineralogical variations at local scale in the content of pyroxene, and at regional scale in different mineral facies, ranging from garnet-, to spinel- to plagioclase-lherzolites, no attempt has been done yet to produce a synoptic map relating the two scales of analysis. The present work is a first attempt to reach this objective, though a lot more work is still required. In particular, for the purpose of mineralogical interpretation, it is critical to relate the airborne observation to field work and laboratory spectra of Ronda rocks already obtained, with the use of image endmembers and associated reference endmembers. Also, the pretty rough linear mixing model used here is taken as a 'black-box' process which does not necessarily apply correctly to the physical situation at the sub-pixel level. One may think of using the ground-truth observations bearing on the sub-pixel statistical

  16. Conditions of crystallization of the Ural platinum-bearing ultrabasic massifs: evidence from melt inclusions

    NASA Astrophysics Data System (ADS)

    Simonov, Vladimir; Puchkov, Victor; Prikhod'ko, Vladimir; Stupakov, Sergey; Kotlyarov, Alexey

    2013-04-01

    Conditions of the Ural platinum-bearing ultramafic massifs formation attract attention of numerous researchers. A most important peculiarity of such plutons is their dunite cores, to which commercial Pt deposits are related. There are a different opinions about genesis of these massifs and usual methods not always can solve this question. As a result of melt inclusions study in the Cr-spinel the new data on physical and chemical parameters of dunite crystallization of the Nizhnii Tagil platinum-bearing ulrabasic massif (Ural) was obtained. The comparative analysis of Cr-spinels, containing melt inclusions, has shown essential differences of these minerals from chromites of the ultrabasic ophiolite complexes and of modern oceanic crust. Contents of major chemical components in the heated and quenched melt inclusions are close to those in the picrite and this testifies dunite crystallization from ultrabasic (to 24 wt.% MgO) magma. On the variation diagrams for inclusions in Cr-spinel the following changes of chemical compositions are established: during SiO2 growth there is falling of FeO, MgO, and increase of CaO, Na2O contents. Values of TiO2, Al2O3, K2O and P2O5 remain as a whole constant. Comparing to the data on the melt inclusions in Cr-spinel from the Konder massif, we see that values of the most part of chemical components (SiO2, TiO2, K2O, P2O5) are actually overlapped. At the same time, for the Nizhnii Tagil platinum-bearing massif the big maintenances of FeO and CaO in inclusions are marked. Distinct dependence of the majority of components from the MgO content in inclusions is observed: values TiO2, Al2O3 FeO, CaO and Na2O fall at transition to more magnesia melts. On the peculiarities of distribution of petrochemical characteristics melt inclusions in considered Cr-spinels are co-ordinated with the data on evolution of compositions of melts and rocks of model stratified ultramafic plutons during their crystallization in the magmatic chambers. On the

  17. Garzon Massif basement tectonics: A geopyhysical study, Upper Magdalena Valley, Colombia

    NASA Astrophysics Data System (ADS)

    Bakioglu, Kadir Baris

    The mechanics and kinematics of basement tectonic uplifts, such as the Laramide Rocky Mountain orogeny, remain poorly understood and controversial. The debate continues in part because of the limited number of well-documented present day analogs. The Garzon Massif rising between the Upper Magdalena Valley and the Llanos Basin of Colombia is an active basement uplift with well, seismic, gravity, and magnetic data available. In the past 10 Ma, PreCambrian age granitic rocks of the Garzon Massif have been uplifted and displaced against Cretaceous and Tertiary sediments of the Upper Magdalena Valley along the Garzon fault. Aerogravimetric data calibrated by well data and 2D seismic data were used to model the geometry of the Garzon fault and the top of basement (Saldana Fm) in 2 dimensions. The density models provide an independent estimate of fault orientation. A high density airborne gravity and magnetic survey were flown over the Garzon fault in 2000, including 2,663 line km along 1 x 5 and 1 x 4 km flight lines at elevations of 2564 and 4589 m above mean sea level. An initial depth model was derived from the well logs, seismic reflection profile, and down-hole velocity surveys. Airborne gravity data was used to produce a Bouguer anomaly gravity map. Average rock densities were estimated from density logs, seismic velocities, and formation rock types. The regional gravity field was estimated and 2-dimensional forward models were constructed with average densities from the wells, seismic velocities, and rock types, and the initial depth model. Since the model fit is dependent on the density assumed for the Garzon Massif rocks, multiple densities and dip angles were tested. The gravity analysis indicates that the Garzon fault is a basement thrust fault dipping at a shallow angle under the Massif. Best-fit models show a true dip of 12 to 17 degrees to the southeast. A regional density and magnetic susceptibility model of the entire Massif is consistent with dense

  18. Composite seal reduces alkaline battery leakage

    NASA Technical Reports Server (NTRS)

    Clatterbuck, C. H.; Plitt, K. F.

    1965-01-01

    Composite seal consisting of rubber or plastic washers and a metal washer reduces alkaline battery leakage. Adhesive is applied to each washer interface, and the washers are held together mechanically.

  19. Technetium recovery from high alkaline solution

    DOEpatents

    Nash, Charles A.

    2016-07-12

    Disclosed are methods for recovering technetium from a highly alkaline solution. The highly alkaline solution can be a liquid waste solution from a nuclear waste processing system. Methods can include combining the solution with a reductant capable of reducing technetium at the high pH of the solution and adding to or forming in the solution an adsorbent capable of adsorbing the precipitated technetium at the high pH of the solution.

  20. Alkaline tolerant dextranase from streptomyces anulatus

    DOEpatents

    Decker, Stephen R.; Adney, William S.; Vinzant, Todd B.; Himmel, Michael E.

    2003-01-01

    A process for production of an alkaline tolerant dextranase enzyme comprises culturing a dextran-producing microorganism Streptomyces anulatus having accession no. ATCC PTA-3866 to produce an alkaline tolerant dextranase, Dex 1 wherein the protein in said enzyme is characterized by a MW of 63.3 kDa and Dex 2 wherein its protein is characterized by a MW of 81.8 kDa.

  1. Evaluation of the alkaline electrolysis of zinc

    SciTech Connect

    Meisenhelder, J.H.; Brown, A.P.; Loutfy, R.O.; Yao, N.P.

    1981-05-01

    The alkaline leach and electrolysis process for zinc production is compared to the conventional acid-sulfate process in terms of both energy saving and technical merit. In addition, the potential for industrial application of the alkaline process is discussed on the basis of present market conditions, possible future zinc market scenarios, and the probability of increased secondary zinc recovery. In primary zinc production, the energy-saving potential for the alkaline process was estimated to be greater than 10%, even when significantly larger electrolysis current densities than those required for the sulfate process are used. The principal technical advantages of the alkaline process are that it can handle low-grade, high-iron-content or oxidized ores (like most of those found in the US) in a more cost- and energy-efficient manner than can the sulfate process. Additionally, in the electrowinning operation, the alkaline process should be technically superior because a dendritic or sponge deposit is formed that is amenable to automated collection without interruption of the electrolysis. Also, use of the higher current densities would result in significant capital cost reductions. Alkaline-based electrolytic recovery processes were considered for the recycling of zinc from smelter baghouse dusts and from the potential source of nickel/zinc electric-vehicle batteries. In all comparisons, an alkaline process was shown to be technically superior and, particularly for the baghouse dusts, energetically and economically superior to alternatively proposed recovery methods based on sulfate electrolysis. It is concluded that the alkaline zinc method is an important alternative technology to the conventional acid zinc process. (WHK)

  2. Alkaline Water and Longevity: A Murine Study

    PubMed Central

    Magro, Massimiliano; Corain, Livio; Ferro, Silvia; Baratella, Davide; Bonaiuto, Emanuela; Terzo, Milo; Corraducci, Vittorino; Salmaso, Luigi; Vianello, Fabio

    2016-01-01

    The biological effect of alkaline water consumption is object of controversy. The present paper presents a 3-year survival study on a population of 150 mice, and the data were analyzed with accelerated failure time (AFT) model. Starting from the second year of life, nonparametric survival plots suggest that mice watered with alkaline water showed a better survival than control mice. Interestingly, statistical analysis revealed that alkaline water provides higher longevity in terms of “deceleration aging factor” as it increases the survival functions when compared with control group; namely, animals belonging to the population treated with alkaline water resulted in a longer lifespan. Histological examination of mice kidneys, intestine, heart, liver, and brain revealed that no significant differences emerged among the three groups indicating that no specific pathology resulted correlated with the consumption of alkaline water. These results provide an informative and quantitative summary of survival data as a function of watering with alkaline water of long-lived mouse models. PMID:27340414

  3. Performed surfactant-optimized aqueous alkaline flood

    SciTech Connect

    Thigpen, D.R.; Lawson, J.B.; Nelson, R.C.

    1991-11-26

    This paper describes improvement in a process for recovering oil from an acidic oil reservoir by injecting an aqueous alkaline solution comprising water, sodium chloride, and alkaline material for reacting with the reservoir oil forming a petroleum acid soap to form an in-situ surfactant system. The improvement comprises: selecting a preformed cosurfactant which is soluble in both the aqueous solution and the reservoir oil and has a solubility ratio which is grater than the solubility ratio of the petroleum acid soap where the solubility ratio is the ratio of solubility in the aqueous alkaline solution to the solubility in the reservoir oil; combining with the alkaline solution an amount of the preformed cosurfactant which will result in the in-situ surfacant system having a salinity about equal to a salinity which results in minimal interfacial tension between the oil in the reservoir and the in-situ surfactant system at reservoir temperature, wherein the amount of the preformed cosurfactant is about 0.3 percent by weight in the aqueous alkaline solution; and injecting the cosurfactant-aqueous alkaline solution mixture into the reservoir to displace oil toward a fluid production location.

  4. New Isotopic age data for understanding the resetting radioactive clock of the Kazdaǧı Massif (Western Anatolia, Turkey)

    NASA Astrophysics Data System (ADS)

    Hasözbek, Altug; Akay, Erhan; Sherlock, Sarah Christine

    2016-04-01

    The Kazdaǧı Massif comprises one of the well-known high-grade metamorphic complexes in the western Anatolia (Turkey). This high-grade succession is subdivided into two units, which is separated by regionally defined unconformity. The lower unit defines a typical oceanic crust package including ultramafic rocks and cumulate gabbros (Tozlu metaophiolite unit). The upper unit comprises of a thick platform succession of detritals and carbonates with mafic volcanic intercalations. Carbonates of this succession are now found as white coarse-crystalline marbles, detritals are schists, metagranites and migmatites and mafic volcanic intercalations are as amphibolites (Sarikiz unit). The whole sequence is cut by shallow-seated Late Oligocene-Early Miocene non-metamorphic granites (Evciler, Eybek granites). New 40Ar-39Ar amphibole ages of 22-19.7 Ma state that both associations of the Tozlu metaophiolite and Sarıkız units experienced almost the same age era as the youngest granites (Evciler, Eybek granites) in the study area. In addition to that, previous U-Pb zircon age results indicate a peak metamorphism age of the Kazdaǧı Massif is around 30-35 Ma. Such young Ar-Ar ages from the Kazdaǧı Massif, which gather close to the granite intrusion crystallization ages, are likely indicators of the resetting radioactive clock of the Kazdaǧı Massif. This data is also in agreement of a single stage migmatization of the massif during the Alpine Orogeny.

  5. PGE distribution in sulfide ores from ultramafic massifs of the central East Sayan Mountains, Southern Siberia, Russia

    NASA Astrophysics Data System (ADS)

    Kolotilina, T. B.; Mekhonoshin, A. S.; Orsoev, D. A.

    2016-01-01

    Data on the composition of sulfide ores from ultramafic massifs in the central East Sayan Mountains and on the regularities of platinum group elements (PGE) in these ores are presented. It is found that the highest PGE contents are characteristic for net-textured and massive ores from the Zhelos massif: total PGE content there is up to 15 ppm, with Pd/Pt = 3-8, for Ni and Cu contents of 1.5-2.8 and 0.5-2.7 wt%, respectively. In the disseminated ores of the Zhelos massif, PGE contents vary from 1 to 7 ppm, at Ni and Cu contents varying in the ranges of 0.5-1.0 and 0.2-0.4 wt %, respectively. In the Tokty-Oi massif, disseminated ores are characterized by higher absolute PGE contents (1.6 to 3.3 ppm) at similar Ni content. PGE tenor of disseminated ores is higher compared to that of massive and net-textured ones. In the cross-sections of both massifs, net-textured and massive ores of an essentially pyrrhotine composition are found at the contact between ultramafic and host rocks. Total PGE in these ores is up to 12 ppm. The obtained data on sulfur isotopes indicate the common, well-homogenized sources, and close physical-chemical depositional conditions of all ore types.

  6. Biodiversity impact of the aeolian periglacial geomorphologic evolution of the Fontainebleau Massif (France)

    NASA Astrophysics Data System (ADS)

    Thiry, M.; Liron, M. N.

    2009-04-01

    Landscape features The geomorphology of the Fontainebleau Massif is noteworthy for its spectacular narrow ridges, up to 10 km long and 0.5 km wide, armored by tightly cemented sandstone lenses and which overhang sandy depressions of about 50m. Denudation of the sandstone pans lead to a highly contrasted landscape, with sandstone ridges ("platières") towering sandy depressions ("vallées") and limestone plateaus ("monts"). This forms the geological frame of the spectacular sceneries of the Fontainebleau Massif (Thiry & Liron, 2007). Nevertheless, there is little know about the erosive processes that have built-up these landscapes. Periglacial processes, and among them aeolian ones, appear significant in the development of the Fontainebleau Massif physiography. The periglacial aeolian geomorphology Dunes and dune fields are known since long and cover about 15% to 25% of the Fontainebleau Massif. The aeolian dunes developed as well on the higher parts of the landscape, as well as in the lower parts of the landscape. The dunes are especially well developed in the whole eastern part of the massif, whereas the western part of the massif is almost devoid of dunes. Nevertheless, detailed mapping shows that dunes can locally be found in the western district, they are of limited extension, restricted to the east facing backslope of outliers. Loamy-sand covers the limestone plateaus of the "monts". The loam cover is of variable thickness: schematically thicker in the central part of the plateaus, where it my reach 3 m; elsewhere it may thin down to 0,20-0,30 m, especially at the plateau edges. Blowout hollows are "negative" morphologies from where the sand has been withdrawed. Often these blowouts are decametric sized and well-delimited structures. Others, more complex structures, are made up of several elongated hectometric hollows relaying each other from and which outline deflation corridor more than 1 km long. A characteristic feature of these blowout hollows is the

  7. 21 CFR 864.7660 - Leukocyte alkaline phosphatase test.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 8 2011-04-01 2011-04-01 false Leukocyte alkaline phosphatase test. 864.7660... Leukocyte alkaline phosphatase test. (a) Identification. A leukocyte alkaline phosphatase test is a device used to identify the enzyme leukocyte alkaline phosphatase in neutrophilic granulocytes...

  8. 21 CFR 864.7660 - Leukocyte alkaline phosphatase test.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Leukocyte alkaline phosphatase test. 864.7660... Leukocyte alkaline phosphatase test. (a) Identification. A leukocyte alkaline phosphatase test is a device used to identify the enzyme leukocyte alkaline phosphatase in neutrophilic granulocytes...

  9. Thermal and structural evolution of the external Western Alps: Insights from (U-Th-Sm)/He thermochronology and RSCM thermometry in the Aiguilles Rouges/Mont Blanc massifs

    NASA Astrophysics Data System (ADS)

    Boutoux, A.; Bellahsen, N.; Nanni, U.; Pik, R.; Verlaguet, A.; Rolland, Y.; Lacombe, O.

    2016-06-01

    In the Western Alps, the External Crystalline Massifs (ECM) are key places to investigate the kinematics and thermal structure of a collisional crustal wedge, as their paleo-brittle/ductile transition is now exhumed at the surface. New (U-Th-Sm)/He data on zircon and new Raman Spectroscopy on Carbonaceous Material (RSCM) data from the Aiguilles Rouges and the Mont Blanc massifs, coupled to HeFTy thermal modeling, constrain the thermal evolution and exhumation of the massifs. In the cover of the Aiguilles Rouges massif, we found that the maximal temperature was about 320 °C (+/- 25 °C), close to the maximal temperature reached in the cover of the Mont Blanc massif (~ 350 °C +/- 25 °C). We show that, after a fast heating period, the thermal peak lasted 10-15 Myrs in the Mont Blanc massif, and probably 5-10 Myrs in the Aiguilles Rouges massif. This thermal peak is synchronous with crustal shortening documented in the basement. (U-Th-Sm)/He data and thermal modeling point toward a coeval cooling of both massifs, like other ECM, at around 18 Ma +/- 1 Ma. This cooling was related to an exhumation due to the initiation of frontal crustal ramps below the ECM, quite synchronously along the Western Alps arc.

  10. Geological structures and geochronology of the Gonam Complex in the Gyeonggi Massif, South Korea

    NASA Astrophysics Data System (ADS)

    Kihm, You Hong; Kim, Sung Won

    2013-04-01

    Geological structures and geochronology of the Gonam Complex in the Gyeonggi Massif, South Korea You Hong Kihm and Sung Won Kim The Gonam complex is exposed in the westernmost part of the Gyeonggi Massif, which is recently thought be related with Triassic collision of China. This complex consists of various lithologies such as quartz schist, mica schist, quartzite, marble, leucocratic granite, mafic dyke and alkali granite. The Gonam complex can be divided into three units from south to north. The first is dominated by alternation of quartz schist and mica schist, which are intruded by leucocratic granites and mafic dykes. The second unit is highly sheared and folded quartzite. The last unit is composed of schists and marble intruded by acidic dykes, mafic dykes and foliated syenite. The deformation of the Gonam complex is characterized by one ductile shearing, two generations of folding, and four generations of faulting. The most prominent geological structures developed in the Gonam Complex are ductile structures, such as mylonitic foliations, mineral stretching lineations, sheath folds and oblique folds. At most outcrops the Gonam Complex was strongly sheared and intruded by amphibolitic dykes and leucocratic granites, which are also sheared. Widely developed mylonite indicates the ductile shearing occurred in high temperature metamorphic condition. SHRIMP zircon ages of detrital zircons obtained from schist and quartzite range from 3313 to 1819 Ma indicating the Gonam Complex deposited after Paleoproterozoic. Intrusion ages of foliated leucocratic granite, mafic dyke and foliated syenite are 821 Ma, 812 Ma and 751 Ma, respectively. And massive mafic dyke, syenite and two-mica granite (232~228 Ma) are interpreted as post-collisional igneous activity. These events are similar to those of Qinling-Dabie Belt and suggest that the Gyeonggi Massif is probably correlated to the Qinling-Dabie Belt.

  11. Constraining the deformation and exhumation history of the Ronda Massif, Southern Spain

    NASA Astrophysics Data System (ADS)

    Myall, Jack; Donaldson, Colin

    2016-04-01

    The Ronda peridotite, southern Spain is comprised of four peridotite units hosted within metasedimentary units of the Betic Cordillera, Western Alps. These four areas of differing mineral facies are termed: the Garnet Mylonite , the Foliated Spinel Peridotite, the Granular Spinel Peridotite and the Foliated Plagioclase Peridotite. Whilst two of these units show a strong NE-SW foliation, the granular unit has no foliation and the Plagioclase facies shows a NW-SE foliation. The massif is separated from the metasedimentary host through a mylonite shear zone to the NW and thrust faults to the SE. The Garnets contain rims of Kelyphite which when combined with the rims of Spinel on the Plagioclase crystals illustrate the complicated exhumation of this massif. The Kelyphite shows the breakdown of garnet back to spinel and pyroxene showing the deeper high pressure high temperature mineral is under shallowing conditions whereas in contrast to this the low pressure low temperature plagioclase crystals have spinel rims showing that they have been moved into deeper conditions. The P-T-t pathway of the massif suggests slow exhumation to allow for partial recrystallisation of not only the garnets and plagioclases but of a 100m band of peridotite between the Foliated Spinel Peridotite and the Granular Spinel Peridotite facies. The tectonic model for the Ronda Peridotite that best describes the field data and subsequent lab work of this study is Mantle Core complex and slab roll back models. These models support mantle uprising during an extensional event that whereby slab roll back of the subducting lithosphere provides uplift into a void and emplacement into the crust. Further extension and final exhumation causes rotation of a mantle wedge into its present day position.

  12. Catalog of Apollo 17 rocks. Volume 1: Stations 2 and 3 (South Massif)

    NASA Technical Reports Server (NTRS)

    Ryder, Graham

    1993-01-01

    The Catalog of Apollo 17 Rocks is a set of volumes that characterize each of 334 individually numbered rock samples (79 larger than 100 g) in the Apollo 17 collection, showing what each sample is and what is known about it. Unconsolidated regolith samples are not included. The catalog is intended to be used by both researchers requiring sample allocations and a broad audience interested in Apollo 17 rocks. The volumes are arranged geographically, with separate volumes for the South Massif and Light Mantle, the North Massif, and two volumes for the mare plains. Within each volume, the samples are arranged in numerical order, closely corresponding with the sample collection stations. The present volume, for the South Massif and Light Mantle, describes the 55 individual rock fragments collected at Stations two, two-A, three, and LRV-five. Some were chipped from boulders, others collected as individual rocks, some by raking, and a few by picking from the soil in the processing laboratory. Information on sample collection, petrography, chemistry, stable and radiogenic isotopes, rock surface characteristics, physical properties, and curatorial processing is summarized and referenced as far as it is known up to early 1992. The intention has been to be comprehensive: to include all published studies of any kind that provide information on the sample, as well as some unpublished information. References which are primarily bulk interpretations of existing data or mere lists of samples are not generally included. Foreign language journals were not scrutinized, but little data appears to have been published only in such journals. We have attempted to be consistent in format across all of the volumes, and have used a common reference list that appears in all volumes. Where possible, ages based on Sr and Ar isotopes have been recalculated using the 'new' decay constants recommended by Steiger and Jager; however, in many of the reproduced diagrams the ages correspond with the

  13. The pre-oceanic evolution of the Erro-Tobbio peridotite (Voltri Massif, Ligurian Alps, Italy)

    NASA Astrophysics Data System (ADS)

    Piccardo, G. B.; Vissers, R. L. M.

    2007-05-01

    This paper presents the results of field, structural, petrologic and geochemical investigations on the Erro-Tobbio (E-T) ophiolitic peridotite (Voltri Massif, Ligurian Alps, Italy). This massif represents a mantle section equilibrated at spinel-facies conditions in the subcontinental lithosphere of the Europe-Adria system prior to the Early Jurassic that has been exhumed and emplaced at the sea-floor during rifting and opening of an ocean basin. The E-T massif comprises km-scale volumes of peridotites with structural and compositional characteristics pointing to melt-peridotite interaction. Their formation is thought to result from the interaction of pristine lithospheric peridotites with MORB-type melts ascending by porous flow, leading to the development of reactive spinel harzburgites, impregnated plagioclase peridotites and replacive spinel dunites. The melt-related events were followed by MORB melt intrusion. Field relationships between sheared lithospheric peridotites, including coarse tectonites as well as fine-grained mylonites developed during lithosphere extension, and melt-modified peridotites suggest that melt-related processes occurred during exhumation of the E-T mantle. These melt-related processes likely included both diffuse percolation and focused intrusion and are considered to be a consequence of MORB-forming partial melting of the asthenosphere induced by near-adiabatic decompressional upwelling related to lithosphere extension and thinning. Field, structural and petrological data allow us to conclude that the entire pre-oceanic evolution of deformation, metamorphism and magmatism recorded by the E-T mantle started during the Early-Middle Jurassic and was related to lithospheric extension leading to the Late Jurassic opening of the Ligurian Tethys ocean.

  14. Metamorphic evolution of pelitic-semipelitic granulites in the Kon Tum massif (south-central Vietnam)

    NASA Astrophysics Data System (ADS)

    Tích, Vu Van; Leyreloup, Andrey; Maluski, Henry; Lepvrier, Claude; Lo, Chinh-hua; Vượng, Nguyễn V.

    2013-09-01

    Pelitic and semipelitic anatectic granulites form one of the major lithological units in Kan Nack complex of the Kon Tum massif (in south-central Vietnam), which comprises HT metamorphic and magmatic rocks including granulites and charnockites is classically regarded as the older part of the Gondwana-derived Indosinia terrain. Metamorphic evolution study of pelitic granulite, the most abundant among granulites exposed in this massif, facilitates to understand that tectonic setting take place during the Indosinian time. The paragenetic assemblages, mineral chemistry, thermobarometry and P-T evolution path of pelitic-semipelitic granulites from Kon Tum massif has been studied in detail. Petrographic feature demonstrates that the pelitic granulite experienced prograde history, from pregranulitic conditions in the amphibolite facies up to the peak granulitic assemblages. Successive prograde reactions led to the temperature-climax giving rise to assemblages with cordierite-hercynite and cordierite-hercynite-K-feldspar. Then, as attested by the mineralogic association occurring in cordieritic coronas, these rocks have been affected by retrograde conditions coeval with a decrease of the pressure. Thermobarometic results show that the highest temperature obtained by ksp/pl thermometry is 850 °C and the highest pressure obtained by GASP (Garnet Alumino-Silicate Plagioclase) is 7.8 kbar. The obtained clockwise P-T evolution path involving heating decompression, then nearly isothermal decompression and nearly isobar cooling conditions shows that high temperature-low pressure metamorphism of the studied pelitic anatectic granulites of Kan Nack complex occurred possibly in extensional setting during the Indosinian orogeny of 260-240 Ma in age.

  15. Microstructure and texture in lherzolites of the Balmuccia massif and their significance regarding the thermomechanical history

    NASA Astrophysics Data System (ADS)

    Skrotzki, W.; Wedel, A.; Weber, K.; Müller, W. F.

    1990-07-01

    The microstructure and crystallographic preferred orientation (here referred to as texture) in lherzolites of the Balmuccia massif have been investigated in order to unravel the thermomechanical history of this massif. Two deformation events may be recognized in the microstructure. In olivine the first deformation led to a coarse-grained dynamic recrystallization. The second deformation produced the subgrain and dislocation structure and a fine-grained dynamically recrystallized rim around the matrix grains. The subgrain boundaries are (100) and occasionally (001) tilt boundaries with variable tilt axis. The free dislocations are mainly screw dislocations with an [001] Burgers vector. An analysis of the dislocations bound in subgrain boundaries and the free dislocations yields {0 kl}[100] and { hk0}[001] as main activated slip systems. The orthopyroxenes are not recrystaUized and show deformation-induced clinoenstatite lamellae. The texture of olivine is characterized by [010] perpendicular to the foliation and [100] parallel to the lineation. In the orthopyroxene [100] is normal to the foliation and [001] normal to the lineation. The results are comparable with those found in similar massifs except the texture in the orthopyroxene. Stress and temperature estimates based on the dislocation density, subgrain size, dynamically recrystaUized grain sizes and the ortho-clinoenstatite transformation yield ≈ 20 MPa and ≈ 1000°C for deformation event I and 300 MPa and 650°C for deformation event II. The first and second deformation events are interpreted as intrusion of mantle material into the lower crust and the tilting of the Ivrea zone, respectively. From the correlation of the texture and microstructure it is concluded that the texture in the olivine reflects the first deformation event. The texture of the relatively hard and therefore only weakly deformed orthopyroxene may be explained by external rotation in the ductile olivine matrix.

  16. Formation of the Red Hills Ultramafic Massif during Subduction Initiation along an Oceanic Transform Fault

    NASA Astrophysics Data System (ADS)

    Tikoff, B.; Stewart, E. D.; Newman, J.; Lamb, W. M.

    2015-12-01

    The Red Hills ultramafic massif in the South Island, New Zealand, is part of the Dun Mountain Ophiolite Belt (DMOB). The DMOB was created at the onset of subduction in a forearc setting in the Middle Permian, and it likely formed immediately prior to the establishment of a magmatic arc along the New Zealand and Australian portions of the Gondwanan margin. The Red Hills ultramafic massif records a two-stage history of high temperature mantle flow during subduction initiation along the Gondwanan margin. Initial deformation was homogeneous and fabrics are constrictional. Kilometer-scale deformation zones, part of the second stage of deformation, overprinted the early homogeneous fabric throughout the western portion of the massif. Timing of all high-temperature mantle deformation in the Red Hills was between 285 and 274 Ma during subduction initiation based on the earliest ages of igneous activity in adjacent volcanic rocks, and a new U-Pb zircon age of 274.55±0.43 Ma from a cross-cutting dike. We present a kinematic model to explain the occurrence of the constructional fabrics during subduction initiation, and find that the three-dimensional boundary conditions for deformation in the incipient mantle wedge must have been transtensional, with a dominant trench-parallel component of motion. Such a scenario indicates subduction likely initiated along an active oceanic transform fault. We test this model by kinematically restoring the Red Hills ultramafics to their Permian orientation, and find the consistent elongation direction of the constructional fabrics was oriented nearly parallel to the trench. Stage 2 deformation zones were variably oriented, but all accommodated normal motion. These results support a model where the incipient mantle wedge was undergoing highly oblique transtension, and the lack of evidence for contraction suggests the onset of subduction along the Permian margin of New Zealand occurred along a transform fault due to spontaneous, density driven

  17. Subsurface Implications of Spatially Variable Seafloor Character on the Atlantis Massif

    NASA Astrophysics Data System (ADS)

    Greene, J. A.; Tominaga, M.; Blackman, D. K.

    2014-12-01

    We documented and mapped the characteristics of the seafloor on the Atlantis Massif, an ocean core complex located at 30°N on the Mid-Atlantic Ridge. Our goal is to investigate the implications of these surficial features, particularly whether their spatial variations might reflect subsurface lithology and geological processes. We utilized data collected during the MARVEL 2000 cruise AT3-60, specifically Alvin videos and rock samples, Argo II digital still photos, and TOBI/DSL-120 side-scan sonar mosaic. The Alvin dives studied occurred over the Central Dome and Eastern Block, which is interpreted as the hanging wall to the detachment that unroofed the dome. We also studied two Argo II dives located over the Central Dome, one over the Eastern Block, and one over the Western Shoulder of the southern dome. The TOBI/DSL-120 side-scan sonar followed a widespread, looped track providing near total coverage of the massif. We classified the character of the seafloor based on imagery, the acoustic reflectivity, and the basic composition of rock samples. To aid in our classification, we merged Argo II still images to produce photo-mosaics displaying tens of meters long transects. We then classified the seafloor as unconsolidated sediment, lithified sediment (a carbonate crust or cap), exposed bedrock, or rubble. To obtain a broader understanding of the Atlantis Massif, we analyzed the distribution of these classes of seafloor. Over the Central Dome and Western Shoulder, we found most seafloor classes present in notable amounts, with many individual areas dominated by a particular type.

  18. Types Of The Focal Mechanisms Of Seismic Events In The Khibiny Massif

    NASA Astrophysics Data System (ADS)

    Fedotova, I. V.; Yunga, S. L.

    The stress-strain state of Khibiny massif and the focal mechanisms of microseismic events (magnitudes as many M=1) were investigated. This analysis was based on seis- mical data registered by automized monitoring system of in the ore mines "Apatite" as well as on the catalogue of earthquakes registered by Kola regional seismological centre. The main goal of this study is the estimation of applicability of methods of quantitative seismology for a solution of local tasks of prognosis of the dynamic phe- nomena in the ore mines of Khibiny massif during widescale mining operations. On the basis of the existing methods original computer programs were developed. Taking into account features of local monitoring systems of seismicity and collection of the obtained data on focal mechanisms, calculations of matrix of mean "composite" focal mechanisms of the registered seismic events were carried out. The process of grouping of events was based on revealing of similar focal mechanisms. Eigen value analysis of average matrix was performed and the directions of main stresses and tendency of principal deformation directions in the massif are revealed. Thus schema of relative blocks movements is created. As a result of this study 5 basic groups with different types of focal mechanisms of seismic events are selected: normal fault; strike-slip fault (with contraction along the strike of ore bodies), thrust fault, and two interme- diate types - strike-slip with normal movement and strike-slip with upthrust move- ment. Specific structural blocks are revealed on the basis of schema of fault zones and zones of tectonic weakness and analysis of seismic events with the particular focal mechanisms. The directions of main stresses based on the composite focal mecha- nisms well correlates with the directions obtained by other methods. Composite focal mechanisms determined for low magnitude seismic events may be effectively used to control stress-strain state in rock massif, to select

  19. Accelerated glacier shrinkage in the Ak-Shyirak massif, Inner Tien Shan, during 2003-2013.

    PubMed

    Petrakov, Dmitry; Shpuntova, Alyona; Aleinikov, Alexandr; Kääb, Andreas; Kutuzov, Stanislav; Lavrentiev, Ivan; Stoffel, Markus; Tutubalina, Olga; Usubaliev, Ryskul

    2016-08-15

    The observed increase in summer temperatures and the related glacier downwasting has led to a noticeable decrease of frozen water resources in Central Asia, with possible future impacts on the economy of all downstream countries in the region. Glaciers in the Ak-Shyirak massif, located in the Inner Tien Shan, are not only affected by climate change, but also impacted by the open pit gold mining of the Kumtor Gold Company. In this study, glacier inventories referring to the years 2003 and 2013 were created for the Ak-Shyirak massif based on satellite imagery. The 193 glaciers had a total area of 351.2±5.6km(2) in 2013. Compared to 2003, the total glacier area decreased by 5.9±3.4%. During 2003-2013, the shrinkage rate of Ak-Shyirak glaciers was twice than that in 1977-2003 and similar to shrinkage rates in Tien Shan frontier ranges. We assessed glacier volume in 2013 using volume-area (VA) scaling and GlabTop modelling approaches. Resulting values for the whole massif differ strongly, the VA scaling derived volume is 30.0-26.4km(3) whereas the GlabTop derived volume accounts for 18.8-13.2km(3). Ice losses obtained from both approaches were compared to geodetically-derived volume change. VA scaling underestimates ice losses between 1943 and 2003 whereas GlabTop reveals a good match for eight glaciers for the period 2003-2012. In comparison to radio-echo soundings from three glaciers, the GlabTop model reveals a systematic underestimation of glacier thickness with a mean deviation of 16%. GlabTop tends to significantly underestimate ice thickness in accumulation areas, but tends to overestimate ice thickness in the lowermost parts of glacier snouts. Direct technogenic impact is responsible for about 7% of area and 5% of mass loss for glaciers in the Ak-Shyirak massif during 2003-2013. Therefore the increase of summer temperature seems to be the main driver of accelerated glacier shrinkage in the area. PMID:27100016

  20. Recycled gabbro signature in Upper Cretaceous Magma within Strandja Massif: NW Turkey

    NASA Astrophysics Data System (ADS)

    Ulusoy, Ezgi; Kagan Kadioglu, Yusuf

    2016-04-01

    Basic magma intrusions within plate interiors upwelling mantle plumes have chemical signatures that are distinct from mid-ocean ridge magmas. When a basic magma interact with continental crust or with the felsic magma, the compositions of both magma changes, but there is no consensus as to how this interaction occurs. Here we analyse the mineral behavior and trace element signature of gabbroic rocks of the samples collected from the Strandja Massif. Srednogorie magmatic arc is a part of Apuseni- Banat-Timok-Srednogorie magmatic belt and formed by subduction and closure of the Tethys Ocean during Upper Cretaceous times. Upper Cretaceous magmatic rocks cutting Strandja Massif in NW Turkey belong to eastern edge of Srednogorie Magmatic arc. Upper Cretacous magmatic rocks divided into four subgroup in Turkey part of Strandja massif: (I) granitic rocks, (II) monzonitic rock, (III) syenitic rocks and (IV) gabbroic rocks. Gabbroic rocks outcropped around study area in phaneritic - equigranular texture. According to mineralogic - petrographic studies gabbros have mainly holocrystalline texture and ophitic to subophitic texture composed of plagioclase, amphibole, pyroxene, and rarely olivine and opaque minerals. Also because of special conditions there have been pegmatitic texture on mafic minerals with euhedral form up to 3 cm in size and orbicular texture which reach 15cm in size and rounded - elliptical form. Confocal Raman Spectroscopy studies reveals that plagioclase are ranging in composition from labradorite to bytownite, the pyroxene are ranging in composition from diopside to augite acting with uralitization processes and the olivine are generally in the composition of forsterite. Petrographic and mineralogical determination reveals some metasomatic magmatic epidote presence. Confocal Raman Spectroscopy studies on anhydrous minerals within gabbroic rocks shows affect of hydrous process because of magma mixing. The gabbroic rocks have tholeiitic and changed towards

  1. Isotopic age and heterogeneous sources of gabbro‒anorthosites from the Patchemvarek massif, Kola Peninsula

    NASA Astrophysics Data System (ADS)

    Vrevsky, A. B.; Lvov, A. P.

    2016-07-01

    New U‒Pb (SHRIMP II) data on the age (2661.8 ± 7.1 Ma) and isotopic (Sm‒Nd) composition of the Patchemvarek gabbro‒anorthosite massif located in the junction zone between the Neoarchean Kolmozero-Voron'ya greenstone belt and Keivy paragneiss structure are discussed. The established age and geological‒tectonic position of gabbro‒anorthosites allow the prognostic metallogenic estimate of Ti‒V‒Fe mineralization to be extended to the entire Kolmozero-Voron'ya‒Keivy infrastructural zone of the Kola‒Norwegian province of the Fennoscandian shield.

  2. Deglaciation and post-glacial environmental evolution in the Western Massif of Picos de Europa

    NASA Astrophysics Data System (ADS)

    Ruiz-Fernández, Jesús; Oliva, Marc; García, Cristina; López-Sáez, José Antonio; Gallinar, David; Geraldes, Miguel

    2014-05-01

    This study examines the process of deglaciation of the Western Massif of Picos de Europa through field work, geomorphological mapping, sedimentary records and absolute datings of 14C. This massif has several peaks over 2,400 m a.s.l. (Peña Santa de Castilla, 2,596 m; Torre Santa María, 2,486 m; Torre del Mediu, 2,467 m). It is composed mainly by Carboniferous limestones. This area has been intensively affected by karstic dissolution, Quaternary glaciers and fluvio-torrential processes (Miotke, 1968; Moreno et al, 2010; Ruiz-Fernández et al, 2009; Ruiz-Fernández, 2013). At present day, periglacial processes are active at the highest elevations (Ruiz-Fernández, 2013). We have identified four main glacial stages regarding the deglaciation of the massif: (i) maximum advance corresponding to the Last Glaciation, (ii) retreat and stabilization after the maximum advance, (iii) Late Glacial, and (iv) Little Ice Age. Sedimentological studies also contribute data to the understanding of the chronological framework of these environmental changes. The datings of the bottom sediments in two long sequences (8 and 5.4 m) provided a minimum age of 18,075 ± 425 cal BP for the maximum advance stage and 11,150 ± 900 cal BP for retreat and stabilization in the phase following the maximum advance. The ongoing analyses of these sequences at very high resolution will provide new knowledge about the environmental conditions prevailing since the deglaciation of the massif. References Miotke, F.D. (1968). Karstmorphologische studien in der glazial-überformten Höhenstufe der Picos de Europa, Nordspanien. Hannover, Selbtverlag der Geografischen Gessellschaft, 161 pp. Moreno, A., Valero, B.L., Jiménez, M., Domínguez, M.J., Mata, M.P., Navas, A., González, P., Stoll, H., Farias, P., Morellón, M., Corella, J.P. & Rico, M. (2010). The last deglaciation in the Picos de Europa National Park (Cantabrian Mountains, Northern Spain). Journal of Quaternary Science, 25 (7), 1076-1091. Ruiz

  3. MASSIF-1: a beamline dedicated to the fully automatic characterization and data collection from crystals of biological macromolecules.

    PubMed

    Bowler, Matthew W; Nurizzo, Didier; Barrett, Ray; Beteva, Antonia; Bodin, Marjolaine; Caserotto, Hugo; Delagenière, Solange; Dobias, Fabian; Flot, David; Giraud, Thierry; Guichard, Nicolas; Guijarro, Mattias; Lentini, Mario; Leonard, Gordon A; McSweeney, Sean; Oskarsson, Marcus; Schmidt, Werner; Snigirev, Anatoli; von Stetten, David; Surr, John; Svensson, Olof; Theveneau, Pascal; Mueller-Dieckmann, Christoph

    2015-11-01

    MASSIF-1 (ID30A-1) is an ESRF undulator beamline operating at a fixed wavelength of 0.969 Å (12.8 keV) that is dedicated to the completely automatic characterization of and data collection from crystals of biological macromolecules. The first of the ESRF Upgrade MASSIF beamlines to be commissioned, it has been open since September 2014, providing a unique automated data collection service to academic and industrial users. Here, the beamline characteristics and details of the new service are outlined. PMID:26524320

  4. Utilization of digital LANDSAT imagery for the study of granitoid bodies in Rondonia: Case example of the Pedra Branca massif

    NASA Technical Reports Server (NTRS)

    Parada, N. D. J. (Principal Investigator); Almeidafilho, R.; Payolla, B. L.; Depinho, O. G.; Bettencourt, J. S.

    1984-01-01

    Analysis of digital multispectral MSS-LANDSAT images enhanced through computer techniques and enlarged to a video scale of 1:100.000, show the main geological and structura features of the Pedra Branca granitic massif in Rondonia. These are not observed in aerial photographs or adar images. Field work shows that LANDSAT photogeological units correspond to different facies of granitic rocks in the Pedra Branca massif. Even under the particular characteristics of Amazonia (Tropical Forest, deep weathering, and Quaternary sedimentary covers), an adequate utilization of orbital remote sensing images can be important tools for the orientation of field works.

  5. MASSIF-1: a beamline dedicated to the fully automatic characterization and data collection from crystals of biological macromolecules

    PubMed Central

    Bowler, Matthew W.; Nurizzo, Didier; Barrett, Ray; Beteva, Antonia; Bodin, Marjolaine; Caserotto, Hugo; Delagenière, Solange; Dobias, Fabian; Flot, David; Giraud, Thierry; Guichard, Nicolas; Guijarro, Mattias; Lentini, Mario; Leonard, Gordon A.; McSweeney, Sean; Oskarsson, Marcus; Schmidt, Werner; Snigirev, Anatoli; von Stetten, David; Surr, John; Svensson, Olof; Theveneau, Pascal; Mueller-Dieckmann, Christoph

    2015-01-01

    MASSIF-1 (ID30A-1) is an ESRF undulator beamline operating at a fixed wavelength of 0.969 Å (12.8 keV) that is dedicated to the completely automatic characterization of and data collection from crystals of biological macromolecules. The first of the ESRF Upgrade MASSIF beamlines to be commissioned, it has been open since September 2014, providing a unique automated data collection service to academic and industrial users. Here, the beamline characteristics and details of the new service are outlined. PMID:26524320

  6. Système hydrogéologique d'un massif minier ultrabasique de Nouvelle-Calédonie

    NASA Astrophysics Data System (ADS)

    Join, Jean-Lambert; Robineau, Bernard; Ambrosi, Jean-Paul; Costis, Claire; Colin, Fabrice

    2005-12-01

    Ultramafic rocks outcrop over more than one third of New Caledonia's main island. Under tropical conditions, thick lateritic mantles with nickel concentrations developed on these rocks by geochemical weathering. Groundwater in ultramafic mined massifs represents a valuable resource, but also a severe constrain for mining engineering. Previous works describe several water tables in the various layers of the weathering mantle. From a hydrologic study of the Tiebaghi massif, the hydraulic continuity across the weathering layers down to the bedrock is proposed. To cite this article: J.-L. Join et al., C. R. Geoscience 337 (2005).

  7. Intermediate range order in alkaline borate glasses

    NASA Astrophysics Data System (ADS)

    Crupi, C.; Carini, G.; Ruello, G.; D'Angelo, G.

    2016-03-01

    We describe the neutron diffraction patterns of a series of alkaline borate glasses at different metal oxide content. Strong differences are observed in the intermediate range order as a function of the specific alkaline ion and of its concentration. On these results, we propose that the first sharp diffraction peak arises from correlations of atoms of voids and show that the compositional variation of this peak intensity in alkaline borate glasses is due to changes in the distribution of void sizes within the three-dimensional network. We argue that our interpretation in terms of interstitial (empty and/or filled) voids, having different sizes, provides a general explanation for all anomalous behaviours revealed for the first sharp diffraction peak.

  8. Reconstructing subduction polarity through the geochemistry of mafic rocks in a Cambrian magmatic arc along the Gondwana margin (Órdenes Complex, NW Iberian Massif)

    NASA Astrophysics Data System (ADS)

    Andonaegui, P.; Sánchez-Martínez, S.; Castiñeiras, P.; Abati, J.; Arenas, R.

    2016-04-01

    In the allochthonous complexes of the NW Iberian Massif, the Upper Units have been interpreted as a section of a peri-Gondwanan magmatic arc active from Middle Cambrian to Early Ordovician times. The main plutonic bodies intruding the arc metasediments are the Monte Castelo gabbronorites and the Corredoiras orthogneisses, which include minor metagabbronorite bodies, both dated at ca 500 Ma. The geochemical features of Monte Castelo metagabbronorites indicate a tholeiitic affinity, with negative Nb anomaly; its 143Nd/144Nd ratios are high (0.5143119-0.513019), whereas initial 87Sr/86Sr ratios are low (0.702562-0.703174), with positive ɛNdi values (+7.8 to +5.4). The geochemistry of Corredoiras metagabbronorites indicates a calc-alkaline affinity, also with negative Nb anomaly, low 143Nd/144Nd (0.512575-0.512436) and high initial 87Sr/86Sr (0.705082-0.706684), ɛNdi values ranging between -0.65 and +1.83. In the ɛNd versus age diagram, Monte Castelo samples show compositions equivalent to the contemporaneous depleted mantle. Corredoiras metagabbros have much lower ɛNdi values compared with Monte Castelo samples, with older model ages ranging between 1165 and 1291 Ma, suggesting contamination of the original mafic mantle-derived magmas with an older continental crust. These geochemical features can be linked to the setting of a mature volcanic arc, in which Monte Castelo metagabbros were located close to the trench, while Corredoiras metagabbros would be in a relatively distant position from the trench, thus indicating subduction polarity.

  9. Geochronology and geochemistry of a dyke host rock association and implications for the formation of the Bavarian Pfahl shear zone, Bohemian Massif

    NASA Astrophysics Data System (ADS)

    Siebel, Wolfgang; Blaha, Ulrich; Chen, Fukun; Rohrmüller, Johann

    2005-02-01

    To place constraints on the formation and deformation history of the major Variscan shear zone in the Bavarian Forest, Bavarian Pfahl zone, SW Bohemian Massif, granitic dykes and their feldspar-phyric massive host rock (so-called “palite”), zircons were dated by the U Pb isotope dilution and Pb-evaporation methods. The dated samples comprise two host rocks and four dykes from a K-rich calc-alkaline complex adjoining the SW part of the Bavarian Pfahl shear zone. The palites, which appear to be the oldest magmatic rocks emplaced in the shear zone, yield ages of 334±3, 334.5±1.1 Ma (average 207Pb/206Pb-evaporation zircon ages) and 327 342 Ma (range of U/Pb zircon ages) suggesting a Lower Carboniferous age for the initiation of the Pfahl zone. Absence of inherited older cores in all investigated zircons indicates that incorporation of crustal zircon material has played virtually no role or that the melting temperature was very high. Determination of the dyke emplacement age is complicated by partial Pb-loss in most of the fractions analysed. This Pb-loss can be ascribed to higher U content of the dyke zircons compared to those from host rock. Upper discordia intercept ages of the different dykes range from 322±5 to 331±9 Ma. The dykes are pre- to synkinematic with respect to penetrative regional mylonitisation along the Pfahl zone, and the upper intercept ages provide a maximum age for this tectonic event.

  10. Alkaline Band Formation in Chara corallina

    PubMed Central

    Lucas, William J.

    1979-01-01

    The nature of the transport system responsible for the establishment of alkaline bands on cells of Chara corallina was investigated. The transport process was found to be insensitive to external pH, provided the value was above a certain threshold. At this threshold (pH 5.1 to 4.8) the transport process was inactivated. Transport function could be recovered by raising the pH value of the external solution. The fastest rate of recovery was always obtained in the presence of exogenous HCO3−. Experiments in which plasmalemma integrity was modified using 10 millimolar K+ treatment were also performed. Alkaline band transport was significantly reduced in the presence of 10 millimolar K+, but the system did not recover, following return to 0.2 millimolar K+ solutions, until the transport site was reexposed to exogenous HCO3−. The influence of presence and absence of various cations on both alkaline band transport and total H14CO3− assimilation was examined. No specific cation requirement (mono- or divalent) was found for either process, except the previously established role of Ca2+ at the HCO3− transport site. The alkaline band transport process exhibited a general requirement for cations. This transport system could be partially or completely stalled in low cation solutions, or glass-distilled water, respectively. The results indicate that no cationic flux occurs across the plasmalemma in direct association with either the alkaline band or HCO3− transport systems. It is felt that the present results offer support for the hypothesis that an OH− efflux transport system (rather than a H+ influx system) is responsible for alkaline band development in C. corallina. The results support the hypothesis that OH− efflux is an electrogenic process. This OH− transport system also appears to contain two allosteric effector sites, involving an acidic group and a HCO3− ion. PMID:16660706

  11. Degradation of halogenated carbons in alkaline alcohol

    NASA Astrophysics Data System (ADS)

    Nakagawa, Seiko; Shimokawa, Toshinari

    2002-02-01

    1,1,2-Trichloro-trifluoroethane, 1,2-dibromo-tetrafluoroethane, 2,3,4,6-tetrachlorophenol, 1,2,4-trichlorobenzene, and 2,4,6-trichloroanisole were dissolved in alkaline isopropyl alcohol and irradiated with 60Co gamma rays after purged with pure nitrogen gas. The concentration of the hydroxide ions and the parent molecules decreased with the dose, while that of the halide ions and the organic products, with less halogen atoms than the parent, increased. Chain degradation will occur in alkaline isopropyl alcohol.

  12. Alkaline earth filled nickel skutterudite antimonide thermoelectrics

    DOEpatents

    Singh, David Joseph

    2013-07-16

    A thermoelectric material including a body centered cubic filled skutterudite having the formula A.sub.xFe.sub.yNi.sub.zSb.sub.12, where A is an alkaline earth element, x is no more than approximately 1.0, and the sum of y and z is approximately equal to 4.0. The alkaline earth element includes guest atoms selected from the group consisting of Be, Mb, Ca, Sr, Ba, Ra and combinations thereof. The filled skutterudite is shown to have properties suitable for a wide variety of thermoelectric applications.

  13. Laser direct write of planar alkaline microbatteries

    NASA Astrophysics Data System (ADS)

    Arnold, C. B.; Kim, H.; Piqué, A.

    We are developing a laser engineering approach to fabricate and optimize alkaline microbatteries in planar geometries. The laser direct-write technique enables multicapability for adding, removing and processing material and provides the ability to pattern complicated structures needed for fabricating complete microbattery assemblies. In this paper, we demonstrate the production of planar zinc-silver oxide alkaline cells under ambient conditions. The microbattery cells exhibit 1.55-V open-circuit potentials, as expected for the battery chemistry, and show a flat discharge behavior under constant-current loads. High capacities of over 450 μAhcm-2 are obtained for 5-mm2 microbatteries.

  14. Alkaline Capacitors Based on Nitride Nanoparticles

    NASA Technical Reports Server (NTRS)

    Aldissi, Matt

    2003-01-01

    High-energy-density alkaline electrochemical capacitors based on electrodes made of transition-metal nitride nanoparticles are undergoing development. Transition- metal nitrides (in particular, Fe3N and TiN) offer a desirable combination of high electrical conductivity and electrochemical stability in aqueous alkaline electrolytes like KOH. The high energy densities of these capacitors are attributable mainly to their high capacitance densities, which, in turn, are attributable mainly to the large specific surface areas of the electrode nanoparticles. Capacitors of this type could be useful as energy-storage components in such diverse equipment as digital communication systems, implanted medical devices, computers, portable consumer electronic devices, and electric vehicles.

  15. Oriented feldspar-feldspathoid intergrowths in rocks of the Khibiny massif: genetic implications

    NASA Astrophysics Data System (ADS)

    Ageeva, Olga A.; Abart, Rainer; Habler, Gerlinde; Ye. Borutzky, Boris; Trubkin, Nikolay V.

    2012-09-01

    Poikilitic megacrysts of alkali feldspar with abundant inclusions of feldspar-nepheline and feldspar-kalsilite micrographic or lamellar intergrowths are characteristic for the rischorrites of the Khibiny massif. Strict crystallographic orientation relations were identified among the intergrowth phases based on optical investigation using a 4-axes universal stage and crystal orientation imaging using electron back scatter diffraction. The most frequently observed orientation relation is the parallel orientation of the kalsilite and nepheline [001] directions with the [010] direction of the alkali feldspar host and concomitant coincidence of the feldspathoid [100] directions with the [100]-, [101]- and [001] directions of the alkali feldspar. The presence of relic nepheline within intergrowth domains and the successive replacement of precursor nepheline by alkali feldspar and associated formation of feldspar-feldspathoid intergrowth suggest development of the rischorrites from feldspar urtites, in which nepheline is the dominant felsic phase. The metasomatic nature of the transformation of urtites to rischorrites is identified from massive introduction of potassium and silica and removal of sodium. Metasomatism occurred at high temperature; the gigantic apatite deposits of the Khibiny massif seem to be related to this metasomatic event.

  16. The topographic signature of Quaternary tectonic uplift in the Ardennes massif (Western Europe)

    NASA Astrophysics Data System (ADS)

    Sougnez, N.; Vanacker, V.

    2011-04-01

    Geomorphic processes that produce and transport sediment, and incise river valleys are complex; and often difficult to quantify over longer timescales of 103 to 105 y. Morphometric indices that describe the topography of hill slopes, valleys and river channels have commonly been used to compare morphological characteristics between catchments and to relate them to hydrological and erosion processes. This study aims to analyze the link between tectonic uplift rates and landscape morphology based on slope and channel morphometric indexes. To achieve this objective, we selected 10 catchments of about 150 to 250 km2 across the Ardennes Massif (a Palaeozoic massif of NW Europe, principally located in Belgium) that cover various tectonic domains with uplift rates ranging from about 0.06 to 0.20 mm yr-1 since mid-Pleistocene times. The morphometric analysis indicates that the slope and channel morphology of third-order catchments is not yet in topographic steady-state, and exhibits clear convexities in slope and river profiles. Our analysis indicates that the fluvial system is the main driver of topographic evolution and that the spatial pattern of uplift rates is reflected in the distribution of channel steepness and convexity. The spatial variation that we observe in slope and channel morphology between the 10 third-order catchments suggests that the response of the fluvial system was strongly diachronic, and that a transient signal of adjustment is migrating from the Meuse valley towards the Ardennian headwaters.

  17. New radiocarbon chronology of a late Holocene landslide event in the Mont Blanc massif, Italy

    NASA Astrophysics Data System (ADS)

    Hajdas, Irka; Sojc, Ursula; Ivy-Ochs, Susan; Akçar, Naki; Deline, Philip

    2016-04-01

    The Ferret valley Arp Nouva peat bog located in the Mont Blanc massif was critically evaluated since previously published radiocarbon dates have led to controversial conclusions on the formation of the swamp. Radiocarbon dating of roots from three pits of up to 1 m depth was applied to discuss the question whether the historical documented rock avalanche occurring in AD 1717 overran the peat bog or formed it at a later stage. Our results indicate that the rock avalanche formed the Arp Nouva peat bog by downstream blockage of the Bellecombe torrent. Furthermore, careful sample preparation with consequent separation of roots from the bulk peat sample provides possible explanation for the too old 14C ages of bulk peat samples dated previously (Deline and Kirkbride, 2009 and references therein). This work demonstrates that a combined geomorphological and geochronological approach is the most reliable way to reconstruct landscape evolution, especially in light of apparent chronological problems. The key to successful 14C dating is a careful sample selection and the identification of material that might be not ideal for chronological reconstructions. References Deline, Philip, and Martin P. Kirkbride. "Rock avalanches on a glacier and morainic complex in Haut Val Ferret (Mont Blanc Massif, Italy)".Geomorphology 103 (2009): 80-92.

  18. Thermochronology and tectonics of the Mérida Andes and the Santander Massif, NW South America

    NASA Astrophysics Data System (ADS)

    van der Lelij, Roelant; Spikings, Richard; Mora, Andrés

    2016-04-01

    New apatite U-Pb and multiphase 40Ar/39Ar data constrain the high to medium temperature (~ 500 °C-~ 300 °C) thermal histories of igneous and metamorphic rocks exposed in the Mérida Andes of Venezuela, and new apatite and zircon fission track data constrain the ~ 500 °C-~ 60 °C thermal histories of pre-Jurassic igneous and metamorphic rocks of the adjacent Santander Massif of Colombia. Computed thermal history envelopes using apatite U-Pb dates and grain size information from an Early Palaeozoic granodiorite in the Mérida Andes suggest that it cooled from > 500 °C to < 350 °C between ~ 266 Ma and ~ 225 Ma. Late Permian to Triassic cooling is also recorded in Early Palaeozoic granitoids and metasedimentary rocks in the Mérida Andes by numerous new muscovite and biotite 40Ar/39Ar plateau dates spanning 257.1 ± 1.0 Ma to 205.1 ± 0.8 Ma. This episode of cooling is not recognised in the Santander Massif, where 40Ar/39Ar data suggest that some Early Palaeozoic rocks cooled below ~ 320 °C in the Early Palaeozoic. However, most data from pre-Jurassic rocks reveal a regional heat pulse at ~ 200 Ma during the intrusion of numerous shallow granitoids, resulting in temperatures in excess of ~ 520 °C, obscuring late Palaeozoic histories. The generally accepted timing of amalgamation of Pangaea along the Ouachita-Marathon suture pre-dates Late Permian to Triassic cooling recorded in basement rocks of the Mérida Andes by > 30 Ma, and its effect on rocks preserved in north-western South America is unknown. We interpret late Permian to Triassic cooling in the Mérida Andes to be driven by exhumation. Previous studies have suggested that a short phase of shortening and anatexis is recorded at ~ 253 Ma in the Maya Block, which may have been adjacent to the basement rocks of the Mérida Andes in the Late Permian. The coeval onset of exhumation in the Mérida Andes may be a result of increased coupling in the magmatic arc, which was located along the western margin of

  19. The Alkaline Diet: Is There Evidence That an Alkaline pH Diet Benefits Health?

    PubMed Central

    Schwalfenberg, Gerry K.

    2012-01-01

    This review looks at the role of an alkaline diet in health. Pubmed was searched looking for articles on pH, potential renal acid loads, bone health, muscle, growth hormone, back pain, vitamin D and chemotherapy. Many books written in the lay literature on the alkaline diet were also reviewed and evaluated in light of the published medical literature. There may be some value in considering an alkaline diet in reducing morbidity and mortality from chronic diseases and further studies are warranted in this area of medicine. PMID:22013455

  20. A Paleozoic anorthosite massif related to rutile-bearing ilmenite ore deposits, south of the Polochic fault, Chiapas Massif Complex, Mexico

    NASA Astrophysics Data System (ADS)

    Cisneros, A.; Ortega-Gutiérrez, F.; Weber, B.; Solari, L.; Schaaf, P. E.; Maldonado, R.

    2013-12-01

    The Chiapas Massif Complex in the southern Maya terrane is mostly composed of late Permian igneous and meta-igneous rocks. Within this complex in southern Mexico and in the adjacent San Marcos Department of Guatemala, south of the Polochic fault, several small outcrops (~10 km2) of a Phanerozoic andesine anorthosite massif were found following an E-W trend similar to the Polochic-Motagua Fault System. Such anorthosites are related to rutile-bearing ilmenite ore deposits and hornblendite-amphibolite bands (0.1-3 meters thick). The anorthosites show recrystallization and metamorphic retrogression (rutile with titanite rims), but no relicts of high-grade metamorphic minerals such as pyroxene or garnet have been found. In Acacoyagua, Chiapas, anorthosites are spatially related to oxide-apatite rich mafic rocks; in contrast, further to the west in Motozintla, they are related to monzonites. Zircons from these monzonites yield a Permian U-Pb age (271.2×1.4 Ma) by LA-MC-ICPMS. Primary mineral assemblage of the anorthosites include mostly medium to fine-grained plagioclase (>90%) with rutile and apatite as accessory minerals, occasionally with very low amounts of quartz. Massive Fe-Ti oxide lenses up to tens of meters in length and few meters thick are an ubiquitous constituent of these anorthosites and their mineralogy include ilmenite (with exsolution lamellae of Ti-magnetite), rutile, magnetite, clinochlore, ×spinel, ×apatite, ×zircon and srilankite (Ti2ZrO6, first finding of this phase in Mexico). Rutile occurs within the massive ilmenite in two morphological types: (1) fine-grained (5-40 μm) rutile along ilmenite grain boundaries or fractures, and (2) coarse-grained rutile (<5 mm) as discrete grains, whereas magnetite and srilankite only appear as small grains along ilmenite boundaries. Zircon is present as discontinuously aligned small grains (10-40 μm) forming rims around many rutile and ilmenite grains. Attempts to date zircon rims by U-Pb using LA

  1. Possible petrogenetic associations among igneous components in North Massif soils: Evidence in 2-4 mm soil particles from 76503

    NASA Technical Reports Server (NTRS)

    Jolliff, Bradley L.; Bishop, Kaylynn M.; Haskin, Larry A.

    1992-01-01

    Studies of Apollo 17 highland igneous rocks and clasts in breccias from the North and South Massifs have described magnesian troctolite, norite, anorthositic gabbro, dunite, spinel cataclasites, and granulitic lithologies that may have noritic anothosite or anorthositic norite/gabbro as igneous precursors, and have speculated on possible petrogenetic relationships among these rock types. Mineral compositions and relative proportions of plagioclase and plagioclase-olivine particles in samples 76503 indicate that the precursor lithology of those particles were troctolitic anorthosite, not troctolite. Mineral and chemical compositions of more pyroxene-rich, magnesian breccias and granulites in 76503 indicate that their precursor lithology was anorthositic norite/gabbro. The combination of mineral compositions and whole-rock trace-element compositional trends supports a genetic relationship among these two groups as would result from differentiation of a single pluton. Although highland igneous lithologies in Apollo 17 materials have been described previously, the proportions of different igneous lithologies present in the massifs, their frequency of association, and how they are related are not well known. We consider the proportions of, and associations among, the igneous lithologies found in a North Massif soil, which may represent those of the North Massif or a major part of it.

  2. Comprenhensive Program of Engineering and Geologic Surveys for Designing and Constructing Radioactive Waste Storage Facilities in Hard Rock Massifs

    SciTech Connect

    Gupalo, T; Milovidov, V; Prokopoca, O; Jardine, L

    2002-12-27

    Geological, geophysical, and engineering-geological research conducted at the 'Yeniseisky' site obtained data on climatic, geomorphologic, geological conditions, structure and properties of composing rock, and conditions of underground water recharge and discharge. These results provide sufficient information to make an estimate of the suitability of locating a radioactive waste (R W) underground isolation facility at the Nizhnekansky granitoid massif

  3. Massification, Bureaucratization and Questing for "World-Class" Status: Higher Education in China since the Mid-1990s

    ERIC Educational Resources Information Center

    Ngok, Kinglun

    2008-01-01

    Purpose: This article aims to review the latest developments of the higher education sector in China since the mid-1990s by focusing on the expansion of university education. Design/methodology/approach: It is argued that while massification of higher education is an important indication of the progress in China's higher education system, the…

  4. Has Massification of Higher Education Led to More Equity? Clues to a Reflection on Portuguese Education Arena

    ERIC Educational Resources Information Center

    Dias, Diana

    2015-01-01

    Massification is an undeniable phenomenon in the higher education arena. However, there have been questions raised regarding the extent to which a mass system really corresponds to an effective democratisation not only of access, but also of success. With regards to access, this article intends, through a brief analysis of the expansion of higher…

  5. Cenozoic remagnetization of the Paleozoic rocks in the Kitakami massif of northeast Japan, and its tectonic implications

    NASA Astrophysics Data System (ADS)

    Otofuji, Yo-ichiro; Takemoto, Kazuhiro; Zaman, Haider; Nishimitsu, Yoshitomo; Wada, Yutaka

    2003-05-01

    Secondary remanent magnetization is identified in the Paleozoic igneous and sedimentary rocks of the Kitakami massif. The secondary nature is shown by a negative fold test for the Permo-Carboniferous sedimentary rocks. The northwesterly paleomagnetic declination with moderate inclination ( D=321.2°, I=56.5°, α95=5.2°, N=18) of this secondary remanent magnetization is almost parallel to the primary magnetization reported for the Cenozoic welded tuffs of northeast Japan, indicating that the Paleozoic rocks were subjected to remagnetization at any period between 62 and 16 Ma. The secondary magnetization of the serpentinized ultramafic rocks is carried by magnetite, which grew in veins and mesh rims of serpentine, whereas the carrier of the magnetization in limestones is fine-grained pyrrhotite. Combining this with the previously reported remagnetization of the Kitakami granitic rocks, it is suggested that rocks in the Kitakami massif were subjected to crystallization remanent magnetization at low-temperature conditions. Since serpentinization requires fluid migration, one of the most likely events is the eastward lateral migration of water into the Kitakami massif. We postulate a Cenozoic suturing of the Kitakami massif with the Asian continent as a plausible tectonic event for this fluid migration.

  6. MERCURIC CHLORIDE CAPTURE BY ALKALINE SORBENTS

    EPA Science Inventory

    The paper gives results of bench-scale mechanistic studies of mercury/sorbent reactions that showed that mercuric chloride (HgC12) is readily adsorbed by alkaline sorbents, which may offers a less expensive alternative to the use of activated carbons. A laboratory-scale, fixed-b...

  7. Negative Electrode For An Alkaline Cell

    DOEpatents

    Coco, Isabelle; Cocciantelli, Jean-Michel; Villenave, Jean-Jacques

    1998-07-14

    The present invention concerns a negative electrode for an alkaline cell, comprising a current collector supporting a paste containing an electrochemically active material and a binder, characterized in that said binder is a polymer containing hydrophilic and hydrophobic groups, said polymer being selected from an acrylic homopolymer, copolymer and terpolymer, an unsaturated organic acid copolymer and an unsaturated acid anhydride copolymer.

  8. Kinetics of the alkaline hydrolysis of nitrocellulose.

    PubMed

    Christodoulatos, C; Su, T L; Koutsospyros, A

    2001-01-01

    Cellulose nitrate (nitrocellulose) is an explosive solid substance used in large quantities in various formulations of rocket and gun propellants. Safe destruction of nitrocellulose can be achieved by alkaline hydrolysis, which converts it to biodegradable products that can then be treated by conventional biological processes. The kinetics of the alkaline hydrolysis of munitions-grade nitrocellulose in sodium hydroxide solutions were investigated in completely mixed batch reactors. Experiments were conducted using solutions of alkaline strength ranging from 0.1 to 15% by mass and temperatures in the range of 30 to 90 degrees C. Regression analysis of the kinetic data revealed that alkaline hydrolysis of nitrocellulose is of the order 1.0 and 1.5 with respect to nitrocellulose and hydroxide concentration, respectively. The activation energy of the hydrolysis reaction was found to be 100.9 kJ/mol with a preexponential Arrhenius constant of 4.73 x 10(13). Nitrite and nitrate, in a 3:1 ratio, were the primary nitrogen species present in the posthydrolysis solution. The kinetic information is pertinent to the development and optimization of nitrocellulose chemical-biological treatment systems. PMID:11563378

  9. Use Alkalinity Monitoring to Optimize Bioreactor Performance.

    PubMed

    Jones, Christopher S; Kult, Keegan J

    2016-05-01

    In recent years, the agricultural community has reduced flow of nitrogen from farmed landscapes to stream networks through the use of woodchip denitrification bioreactors. Although deployment of this practice is becoming more common to treat high-nitrate water from agricultural drainage pipes, information about bioreactor management strategies is sparse. This study focuses on the use of water monitoring, and especially the use of alkalinity monitoring, in five Iowa woodchip bioreactors to provide insights into and to help manage bioreactor chemistry in ways that will produce desirable outcomes. Results reported here for the five bioreactors show average annual nitrate load reductions between 50 and 80%, which is acceptable according to established practice standards. Alkalinity data, however, imply that nitrous oxide formation may have regularly occurred in at least three of the bioreactors that are considered to be closed systems. Nitrous oxide measurements of influent and effluent water provide evidence that alkalinity may be an important indicator of bioreactor performance. Bioreactor chemistry can be managed by manipulation of water throughput in ways that produce adequate nitrate removal while preventing undesirable side effects. We conclude that (i) water should be retained for longer periods of time in bioreactors where nitrous oxide formation is indicated, (ii) measuring only nitrate and sulfate concentrations is insufficient for proper bioreactor operation, and (iii) alkalinity monitoring should be implemented into protocols for bioreactor management. PMID:27136151

  10. ISSUES WITH ALKALINE TREATMENT OF SLUDGE

    EPA Science Inventory

    This presentation begins with a discussion of the use of lime and other alkaline materials from the very earliest times to the present for killing bacteria, viruses and parasites and for controlling odors in wastewaters and sludge. It answers the question "How did EPA arrive at i...

  11. Alkaline electrochemical cells and method of making

    NASA Technical Reports Server (NTRS)

    Hoyt, H. E.; Pfluger, H. L. (Inventor)

    1970-01-01

    Equilibrated cellulose ether membranes of increased electrolytic conductivity for use as separators in concentrated alkaline electrochemical cells are investigated. The method of making such membranes by equilibration to the degree desired in an aqueous alkali solution mantained at a temperature below about 10 C is described.

  12. Seismic imaging of the western Iberian crust using ambient noise: Boundaries and internal structure of the Iberian Massif

    NASA Astrophysics Data System (ADS)

    Silveira, Graça; Dias, Nuno; Villaseñor, Antonio

    2013-04-01

    The Iberian Massif one of the major structural units of the Iberian Peninsula is composed by rocks with ages ranging from the Upper Precambrian to Upper Carboniferous. The massif outcrops in Central and Western Iberia and the location of its limits, as well as the relationship between its shallow and deeper structures are still a matter of debate. Several problems like source-receiver geometry, irregular seismicity distribution or, for some methods, low seismicity occurrence did not allow obtaining high-resolution models of Iberian structure using traditional imaging methods. Seismic interferometry/ambient noise surface-waves tomography allows imaging regions with a resolution that mainly depends on the seismic network coverage. This study aims to map the boundaries of the Iberian Massif particularly those that are covered or in contact with recent (Cenozoic) and older (Mesozoic) basins. Whenever possible, we intend to characterize second-order structures inside the Massif. We present new Rayleigh-wave dispersion maps of the western Iberian Peninsula for periods between 8 and 30 seconds, obtained from correlations of seismic ambient noise, following the recent increase in seismic broadband network density in Portugal and Spain. Group velocities have been computed for each station pair using the empirical Green's functions generated by cross-correlating one-day-length seismic ambient-noise records. The resulting high-path density allows us to obtain lateral variations of the group velocities as a function of period in cells of 0.5° x 0.5° with an unprecedented resolution. As a result we were able to address some of the unknowns regarding the lithospheric structure beneath SW Iberia. The dispersion maps allow the imaging of the major structural units, namely the Iberian Massif, and the Lusitanian and Algarve Meso-Cenozoic basins. The Cadiz Gulf/Gibraltar Strait area corresponds to a strong low-velocity anomaly, which can be followed to the largest period inverted

  13. Titanium corrosion in alkaline hydrogen peroxide environments

    NASA Astrophysics Data System (ADS)

    Been, Jantje

    1998-12-01

    The corrosion of Grade 2 titanium in alkaline hydrogen peroxide environments has been studied by weight loss corrosion tests, electrochemical impedance spectroscopy (EIS), linear polarization resistance (LPR) measurements and potentiodynamic polarography. Calcium ions and wood pulp were investigated as corrosion inhibitors. In alkaline peroxide, the titanium corrosion rate increased with increasing pH, temperature, and hydrogen peroxide concentration. The corrosion controlling mechanism is thought to be the reaction of the oxide with the perhydroxyl ion. No evidence of thermodynamically stable calcium titanate was found in the surface film of test coupons exposed to calcium-inhibited alkaline peroxide solutions. Calcium inhibition is probably the result of low local alkali and peroxide concentrations at the metal surface produced by reaction of adsorbed calcium with hydrogen peroxide. It has been shown that the inhibiting effect of calcium is temporary, possibly through an effect of calcium on the chemical and/or physical stability of the surface oxide. Pulp is an effective and stable corrosion inhibitor. Raising the pulp concentration decreased the corrosion rate. The inhibiting effect of pulp may be related to the adsorption and interaction of the pulp fibers with H 2O2, thereby decreasing the peroxide concentration and rendering the solution less corrosive. The presence of both pulp and calcium led to higher corrosion rates than obtained by either one inhibitor alone. Replacement of hydrofluoric acid with alkaline peroxide for pickling of titanium was investigated. Titanium corrosion rates in alkaline peroxide exceeded those obtained in the conventional hydrofluoric acid bath. General corrosion was observed with extensive roughening of the surface giving a dull gray appearance. Preferred dissolution of certain crystallographic planes was investigated through the corrosion of a titanium single crystal. Whereas the overall effect on the corrosion rate was small

  14. Cambrian to Lower Ordovician complexes of the Kokchetav Massif and its fringing (Northern Kazakhstan): Structure, age, and tectonic settings

    NASA Astrophysics Data System (ADS)

    Degtyarev, K. E.; Tolmacheva, T. Yu.; Tretyakov, A. A.; Kotov, A. B.; Shatagin, K. N.

    2016-01-01

    A comprehensive study of the Lower Palaeozoic complexes of the Kokchetav Massif and its fringing has been carried out. It has allowed for the first time to discover and investigate in detail the stratified and intrusive complexes of the Cambrian-Early Ordovician. Fossil findings and isotope geochronology permitted the determination of their ages. The tectonic position and internal structures of those complexes have also been defined and their chemical features have been analyzed as well. The obtained data allowed us to put forward a model of the geodynamic evolution of Northern Kazakhstan in the Late Ediacaran-Earliest Ordovician. The accumulation of the oldest Ediacaran to Earliest Cambrian siliciclastics and carbonates confined to the Kokchetav Massif and its fringing occurred in a shallow shelf environment prior to its collision with the Neoproterozoic Daut island arc: complexes of the latter have been found in the northeast of the studied area. The Early Cambrian subduction of the Kokchetav Massif under the Daut island arc, their following collision and exhumation of HP complexes led to the formation of rugged ground topography, promoting deposition of siliceous-clastic and coarse clastic units during the Middle to early Late Cambrian. Those sediments were mainly sourced from eroded metamorphic complexes of the Kokchetav Massif basement. At the end of the Late Cambrian to the Early Ordovician within the boundaries of the massif with the Precambrian crust, volcanogenic and volcano-sedimentary units along with gabbros and granites with intraplate affinities were formed. Simultaneously in the surrounding zones, which represent relics of basins with oceanic crust, N-MORB- and E-MORB-type ophiolites were developed. These complexes originated under extensional settings occurred in the majority of the Caledonides of Kazakhstan and Northern Tian Shan. In the Early Floian Stage (Early Ordovician) older heterogeneous complexes were overlain by relatively monotonous

  15. Detachment shear zone of the Atlantis Massif core complex, Mid-Atlantic Ridge, 30°N

    NASA Astrophysics Data System (ADS)

    Karson, J. A.; Früh-Green, G. L.; Kelley, D. S.; Williams, E. A.; Yoerger, D. R.; Jakuba, M.

    2006-06-01

    Near-bottom investigations of the cross section of the Atlantis Massif exposed in a major tectonic escarpment provide an unprecedented view of the internal structure of the footwall domain of this oceanic core complex. Integrated direct observations, sampling, photogeology, and imaging define a mylonitic, low-angle detachment shear zone (DSZ) along the crest of the massif. The shear zone may project beneath the nearby, corrugated upper surface of the massif. The DSZ and related structures are inferred to be responsible for the unroofing of upper mantle peridotites and lower crustal gabbroic rocks by extreme, localized tectonic extension during seafloor spreading over the past 2 m.y. The DSZ is characterized by strongly foliated to mylonitic serpentinites and talc-amphibole schists. It is about 100 m thick and can be traced continuously for at least 3 km in the tectonic transport direction. The DSZ foliation arches over the top of the massif in a convex-upward trajectory mimicking the morphology of the top of the massif. Kinematic indicators show consistent top-to-east (toward the MAR axis) tectonic transport directions. Foliated DSZ rocks grade structurally downward into more massive basement rocks that lack a pervasive outcrop-scale foliation. The DSZ and underlying basement rocks are cut by discrete, anastomosing, normal-slip, shear zones. Widely spaced, steeply dipping, normal faults cut all the older structures and localize serpentinization-driven hydrothermal outflow at the Lost City Hydrothermal Field. A thin (few meters) sequence of sedimentary breccias grading upward into pelagic limestones directly overlies the DSZ and may record a history of progressive rotation of the shear zone from a moderately dipping attitude into its present, gently dipping orientation during lateral spreading and uplift.

  16. Thematic mapping of likely target areas for the occurence of cassiterite in the Serra do Mocambo (GO) granitic massifs using LANDSAT 2 digital imaging

    NASA Technical Reports Server (NTRS)

    Almeidofilho, R. (Principal Investigator)

    1984-01-01

    The applicability of LANDSAT/MSS images, enhanced by computer derived techniques, as essential tools in mineral research was investigated and the Serra do Mocambo granitic massif was used as illustration. Given the peculiar factors founded in this area, orbital imagery permitted the delineation of potential target areas of mineralization occurrences, associated to albitized/greisenized types. Follow up prospection for primary tin deposits in this granitic massif should be restricted to the delineated areas which are less than 5% of the total superficial area of the massif.

  17. ACTINIDE-ALUMINATE SPECIATION IN ALKALINE RADIOACTIVE WASTE

    EPA Science Inventory

    Highly alkaline radioactive waste tanks contain a number of transuranic species, in particular U, Np, Pu, and Am - the exact forms of which are currently unknown. Knowledge of actinide speciation under highly alkaline conditions is essential towards understanding and predicting ...

  18. A method for making an alkaline battery electrode plate

    NASA Technical Reports Server (NTRS)

    Chida, K.; Ezaki, T.

    1983-01-01

    A method is described for making an alkaline battery electrode plate where the desired active substances are filled into a nickel foam substrate. In this substrate an electrolytic oxidation reduction occurs in an alkaline solution containing lithium hydroxide.

  19. The seismotectonic significance of the 2008-2010 seismic swarm in the Brabant Massif (Belgium)

    NASA Astrophysics Data System (ADS)

    Van Noten, Koen; Lecocq, Thomas; Shah, Anjana K.; Camelbeeck, Thierry

    2015-04-01

    Structural interpretations of the tectonic grain of orogenic mountain belts have often been based on the study of potential field data. The steep architecture of mountain belts can be highlighted by the inclination of the magnetic field and by the persistence of aeromagnetic lineaments with depth. With respect to seismology, matched filtering has proven to be very useful for linking seismicity with deep-seated tectonic structures by separating short-wavelength anomalies, that originate from shallow depths, from long-wavelength anomalies that generally originate at greater depths. Between 2008 and 2010 more than 300 low-magnitude earthquakes occurred 20 km SE of Brussels (Belgium). Thanks to a locally deployed temporary seismic network covering the epicentral area, very small events could be detected (magnitude variation between ML -0.7 and ML 3.2). The spatial distribution of the hypocenter locations show a dense spatial cluster displaying a narrow, 1.5-km long, NW-SE oriented fault zone at a depth range between 5 and 7 km, located in the Cambrian basement rocks of the Lower Palaeozoic Anglo-Brabant Massif. Its NW-SE orientation is in agreement with the structural grain in this part of the Brabant Massif. In order to find a relevant tectonic structure that could correspond to the 2008-2010 seismic swarm, we present a full seismotectonic analysis linking local geology to the seismic swarm. A systematic filtering approach was applied in which the magnetic field was carefully bandpass filtered to generate different aeromagnetic maps that highlight sources near the hypocenter depths. Filtering demonstrates that the structure responsible for the seismic swarm is limited in length as it is bordered at both ends by magnetic lineaments with different orientations than the seismic swarm. These observations explain the rather limited spatial distribution of the swarm, both in a vertical and horizontal direction. Although few of the largest historical seismic events in

  20. The Front of the Aar Massif: A Crustal-Scale Ramp Anticline?

    NASA Astrophysics Data System (ADS)

    Herwegh, Marco; Mock, Samuel; Wehrens, Philip; Baumberger, Roland; Berger, Alfons; Wangenheim, Cornelia; Glotzbach, Christoph; Kissling, Edi

    2015-04-01

    The front of the Aar Massif (Swiss Central Alps) is characterized by Paleozoic basement rocks exposed at altitudes of more than 4600m above sea level, followed by a steeply north dipping Mesozoic sedimentary cover and overlying Helvetic nappes. The sediments turn into subhorizontal orientations just few kilometers to the N, where the top of the basement is situated at depths of about 7000m below sea level. What is the origin of this vertical jump of about 12000m of the basement rocks over such short horizontal distances? Recent structural investigations at the Basement-Cover contact indicate a complex structural evolution involving reactivation of extensional faults and inversion of half-grabens during early compressional stages. In the internal parts of the Aar Massif a general steepening of the faults resulted with progressive compression. In the northern frontal part, however, a new spaced cleavage evolved, which is dipping with 20-30° to the SE. In places, the new cleavage in the basement rocks is intense and pervasive and correlates with a steepening of the basement-cover contact and its offsets of several tens to hundreds of meters. Hence strain is strongly partitioned in a large number of high strain zones, which cover a cumulative thickness of at least 2000m, eventually even much more considering subsurface continuation. The Mesozoic sediments affected by this large-scale deformation zone are either intensely ductile folded in the case of limestones or faulted and imbricated in the case of dolomites. These differences in deformation style result from the deformation conditions of about < 250-300°C, where calcite still deforms in a ductile manner, while dolomite and crystalline basement preferentially undergo brittle deformation in combination of dissolution-precipitation processes. In a large-scale point of view, we suggest that the high strain domain in the crystalline basement in fact represents a crustal-scale several kilometers wide shear zone, which

  1. Geothermobarometry of basaltic glasses from the Tamu Massif, Shatsky Rise oceanic plateau

    NASA Astrophysics Data System (ADS)

    Husen, Anika; Almeev, Renat R.; Holtz, François; Koepke, Jürgen; Sano, Takashi; Mengel, Kurt

    2013-10-01

    We present the results of a petrological study of core samples from Tamu Massif (Site U1347), recovered during the Shatsky Rise Integrated Ocean Drilling Program (IODP) Expedition 324. The basaltic glasses from Site U1347 are evolved tholeiitic basalts containing 5.2-6.8 wt% MgO, and are principally located within the compositional field of mid-ocean ridge basalts (MORBs) but they have systematically higher FeO, lower Al2O3, SiO2, and Na2O concentrations, and the CaO/Al2O3 ratios are among the highest known for MORBs. In this sense, glasses from Site U1347 more closely resemble basaltic magmas from the Ontong Java Plateau (OJP), although they still have lower SiO2 concentrations. In contrast to MORB and similar to OJP, our fractionation corrected values of Na2O and CaO/Al2O3 indicate more than 20% of partial melting of the mantle during the generation of the parental magmas of Tamu Massif. The water contents in the glasses, determined by midinfrared Fourier transform infrared (FTIR) spectroscopy, are MORB-like, and vary between 0.18 and 0.6 wt% H2O. The calculated pressure (P)-temperature (T) conditions at which the natural glasses represent cotectic olivine-plagioclase-clinopyroxene compositions range from 0.1 to 240 MPa and 1100 to 1150°C reflecting magma storage at shallow depth. The variation of the glass compositions and the modeled P-T conditions in correlation with the relative ages indicate that there were at least two different magmatic cycles characterized by variations in eruptive styles (massive flows or pillow lavas), chemical compositions, volatile contents, and preeruptive P-T conditions. Each magmatic cycle represents the progressive differentiation in course of polybaric crystallization after the injection of a more primitive magma batch. Magma crystallization and eruption episodes are followed by magmatic inactivity reflected in the core sequence by a sedimentary layer. Our data for Tamu Massif demonstrate that, similar to Ontong Java ocean

  2. Petrostructural evolution of the Beni Bousera peridotite massif (Rif belt, Morocco)

    NASA Astrophysics Data System (ADS)

    Frets, E. C.; Tommasi, A.; Garrido, C. J.; Vauchez, A. R.; Mainprice, D.; Amri, I.; Targuisti, K.

    2012-12-01

    Extension of continental lithosphere occurs in continental rifts, such as the East African, Baikal and Rio Grande rifts, and active convergent continental margins, such as in the Himalayas and the Alps. While the mechanisms of crustal thinning are increasingly understood, the processes governing the thinning of the lithospheric subcontinental mantle still remain barely constrained. Detailed structural and petrological mapping associated with a thorough microstructural study in the Beni Bousera orogenic peridotite (Rif Belt, N Morocco) allows constraining the tectono-metamorphic evolution produced by exhumation of the subcontinental lithospheric mantle in a lithospheric-scale shear zone. The Beni Bousera massif is composed by four tectono-metamorphic domains showing consistent kinematics, marked by a pervasive shallowly-dipping foliation bearing a NW-SE stretching lineation, which progressively rotates towards a N20-N30 trend in the NE, lowermost part of the massif. From top to bottom: garnet-spinel mylonites, Ariègite subfacies fine-grained porphyroclastic spinel peridotites, Ariègite-Seiland subfacies porphyroclastic- and Seiland subfacies coarse-porphyroclastic to coarse-granular spinel peridotites. Microstructures and crystal preferred orientations (CPO) in the four domains are consistent with deformation by dominant dislocation creep, but the continuous increase in average olivine grain size and decrease in the recrystallized volume fraction indicate decreasing work rates from top to bottom. The microstructures are consistent with the variation in synkinematic pressure and temperature conditions, which range from 900°C-2.0 GPa in grt-sp mylonites and 1150°C-1.8 GPa in the Seiland domain. The diffuse compositional layering as well as the microstructures and CPO in the Seiland domain suggest deformation in presence of melt. Gravitational instabilities due to local melt accumulation may account for the small areas bearing a vertical lineation in this domain

  3. Exploring the Notion That Subduction Erosion Has Removed or Submerged Costa Rica's Early Tertiary Arc Massifs

    NASA Astrophysics Data System (ADS)

    Scholl, D. W.

    2007-05-01

    Arc igneous rocks of Paleocene, Eocene, and Oligocene age are widely exposed in the southern, coastal region of Panama (Lissinna et al., EGU abstract, 2006). These rocks intrude or overlie mafic basement rock of the Caribbean Large Igneous Province (CLIP) of Late Cretaceous age that extends to the east to underlie the Caribbean Basin and form the Caribbean plate. Immediately west of Panama, in coastal Costa Rica, exposures of CLIP basement are not intruded or overlain by arc magmatic rocks of early Tertiary age. EXPLANATIONS: Potentially, the early Tertiary subduction zone that dipped beneath the Pacific margin of Panama did not extend to the west, thus no arc magmatism occurred where Costa Rica presently exists. Alternatively, the subduction zone bordering the Pacific edge of the CLIP extended below Costa Rica but former exposures of early Tertiary arc magmatic rocks piled there have been erosionally removed or buried beneath Miocene and younger arc massifs of interior mountain belts. EXPLORING A SUBDUCTION EROSION EXPLANATION Onshore and offshore evidence documents that subduction erosion thins and truncates the submerged rock framework of the Middle and South America forearc. The eroded (removed) material is transported toward and into the mantle within the subduction channel separating the upper plate of the forearc and lower plate of the subducting oceanic crust. The long-term (greater than 10 Myr) rate of truncation (i. e., migration of the trench toward a fixed, onshore reference) averages 2 to 3 km/Myr. Because of the subduction of the aseismic Cocos Ridge beneath Costa Rica, during at least the past 4 to 5 Myr the rate of truncation at this margin has been much higher. It is proposed that during the past 50 Myr subduction erosion has truncated the Costa Rica forearc by at least 100 km and either obliterated or deeply submerged arc massifs of early Tertiary age. Their exposed presence to the east in neighboring Panama reflects the circumstance that since

  4. Contrasting lithospheric mantle domains beneath the Massif Central (France) revealed by geochemistry of peridotite xenoliths

    NASA Astrophysics Data System (ADS)

    Lenoir, Xavier; Garrido, Carlos J.; Bodinier, Jean-Louis; Dautria, Jean-Marie

    2000-09-01

    We report major and trace element analyses for 82 coarse-grained peridotite xenoliths from 25 Cenozoic volcanic centres throughout the Massif Central (France). These data cover a region of about 150×150 km, allowing an investigation of large scale compositional variations in the subcontinental lithospheric mantle (SCLM). In agreement with textural variations, geochemical data define two contrasting lithospheric domains, situated north and south of latitude 45°30'. Peridotites of the northern domain show protogranular textures, characterised by clustered pyroxene-spinel distributions. They are rather refractory and depleted in MREE relative to HREE, but pervasively enriched in LREE and other highly incompatible elements. The samples show mantle-normalised patterns with negative anomalies of Nb, Ta, Zr and Hf, similar to enriched mantle xenoliths ascribed to carbonatitic metasomatism. In contrast, the peridotites of the southern domain are devoid of pyroxene-spinel clusters and are therefore referred to as coarse-granular. They are distinguished from the northern suite by more fertile compositions and relatively flat MREE-HREE patterns. In addition, only the harzburgites and a few lherzolites are enriched in LREE. Most southern domain lherzolites are depleted in these elements and the average composition of the southern suite is comparable to that of depleted MORB-source mantle (DMM). The main compositional differences between the two domains cannot be accounted for by a secular evolution of the Massif Central SCLM caused by Cenozoic plume upwelling. Instead, these differences record the existence of distinct lithospheric blocks assembled during the Variscan orogeny. To some degree, the northern and southern domains are reminiscent of cratonic and circumcratonic SCLM domains. Being relatively refractory and pervasively enriched in LREE, the northern domain displays similarities with cratonic SCLM. It is interpreted as a relatively ancient (pre

  5. FINAL REPORT. ACTINIDE-ALUMINATE SPECIATION IN ALKALINE RADIOACTIVE WASTE

    EPA Science Inventory

    Investigation of behavior of actinides in alkaline media containing Al(III) showed that no aluminate complexes of actinides in oxidation states (III-VII) were formed in alkaline solutions. At alkaline precipitation (pH 10-14) of actinides in presence of Al(III) formation of alumi...

  6. Sm-Nd dating of fluorite from the worldclass Montroc fluorite deposit, southern Massif Central, France

    USGS Publications Warehouse

    Munoz, M.; Premo, W.R.; Courjault-Rade, P.

    2005-01-01

    A three-point Sm-Nd isotope isochron on fluorite from the very large Montroc fluorite vein deposit (southern Massif Central, France) defines an age of 111??13 Ma. Initial ??Nd of -8.6 and initial 87Sr/86Sr of ???0.71245 suggest an upper crustal source of the hydrothermal system, in agreement with earlier work on fluid inclusions which indicated a basinal brine origin. The mid-Cretaceous age of ???111 Ma suggests the Albian/Aptian transition as the most likely period for large-scale fluid circulation during a regional extensional tectonic event, related to the opening of the North Atlantic ocean. ?? Springer-Verlag 2004.

  7. Tonalite sill emplacement at an oblique plate boundary: northeastern margin of the Bohemian Massif

    NASA Astrophysics Data System (ADS)

    Parry, Matthew; Sˇtípská, Pavla; Schulmann, Karel; Hrouda, Frantisˇek; Jezˇek, Josef; Kröner, Alfred

    1997-10-01

    A tonalitic sill has been examined at the Variscan transpressive boundary of the Lugian and Silesian plates at the NE margin of the Bohemian Massif. A structural, petrological and geochronological study reveals that it was emplaced syn-tectonically with major ductile shearing in lower crustal rocks. Magmatic and pre-rheological critical melt percentage (RCMP) fabrics are concordant with the hanging wall structures but discordant with those of the footwall. The AMS study shows the predominance of flattening strain at the margins and plane strain fabrics in the core. Numerical modelling of AMS fabrics is in good agreement with the hypothesis of magma flow and deformation in oblique transpression. A tectonic model was developed explaining emplacement and syn-tectonic deformation of progressively cooled tonalitic intrusion.

  8. Oxidation state of the lithospheric mantle beneath the Massif Central,France

    NASA Astrophysics Data System (ADS)

    Uenver-Thiele, L.; Woodland, A. B.; Downes, H.; Altherr, R.

    2012-04-01

    The Tertiary and Quaternary volcanism of the French Massif Central sampled the underlying subcontinental lithospheric mantle (SCLM) in the form of xenoliths over a wide geographic area of ~20.000km2. Such an extensive distribution of xenoliths provides an unique opportunity to investigate regional variations in mantle structure and composition. On the basis of textural and geochemical differences, Lenoir et al. (2000) and later Downes et al. (2003) identified two distinct domains in the SCLM lying north and south of latitude 45° 30' N, respectively. The northern domain is relatively refractory, but has experienced pervasive enrichment of LREE. The southern domain is generally more fertile, exhibiting depletion in LREE. A metasomatic overprint has developed to variable extents in many xenolith suites. The different histories of these two juxtaposed blocks of SCLM should also be reflected in their oxidation state, with local variations also to be expected due to metasomatic interactions. For example, if carbonate-melt metasomatism played a role in the LREE enrichment of the northern domain (Lenoir et al. 2000; Downes et al. 2003), then such mantle should be relatively oxidised. Since surprisingly little redox data are currently available, we are undertaking a study to determine the oxidation state of the SCLM beneath the Massif Central over the largest geographical area possible. All xenoliths investigated are spinel peridotites, mostly with protogranular textures (although some samples are porphyroclastic or equigranular). Most samples are nominally anhydrous although minor amphibole is present in some xenolith suites. Major element compositions of the individual minerals were determined by microprobe. Two-pyroxene temperatures (BKN) range from 750° to ~1200° C. Ferric iron contents of spinel were determined by Mössbauer spectroscopy and gave a range of Fe3+/ Fetot from 0.191 to 0.418, with a conservative uncertainty of ±0.02. These data were used to calculate

  9. Permafrost detection in the headwalls of receding glaciers at the Dachstein Massif, Northern Calcareous Alps, Austria

    NASA Astrophysics Data System (ADS)

    Rode, Matthias; Gitschthaler, Christoph; Schnepfleitner, Harald; Kellerer-Pirklbauer, Andreas; Sass, Oliver

    2014-05-01

    The Northern Calcareous Alps cover a large area of the Austrian Alps forming a boundary zone between the Alpine Foreland to the north and the crystalline Central Alps to the south. Generally, climate in this area is more maritime compared to the mountain ranges further south. Few small glaciers are to be found mostly on north-facing slopes. The Northern Calcareous Alps reach maximum elevations of about 3000 m asl. Some of highest summits are to be found are located in the Dachstein Massif reaching 2995 m asl (47° 28' 32″ N, 13° 36' 23″ E). Occurrence, thickness and thermal regime of permafrost at this mountain massif are widely unknown and knowledge is based on simulations only. In contrast, the glaciation changes at this mountain massif (e.g. Schladminger and Hallstätter glaciers) have been well documented for decades. Within the framework of the research project ROCKING ALPS - dealing with frost weathering and rockfall in alpine regions - knowledge of permafrost distribution in the headwalls surrounding the receding glaciers is substantial to understand rock decay. For this reason, several techniques have been applied in order to detect bedrock permafrost. During the winter of 2012 22 i-buttons (temperature sensors) were attached to rock walls with different orientations but at similar elevations (2600-2700 m asl). Most of these sites were later covered by an insulating winter snow cover therefore allowing the calculation of the base temperature of the winter snow cover (BTS). These BTS data have been used as a first indicator of permafrost presence. In selected rock walls of several mountains in the massif - Koppenkarstein (2863 m asl), Dirndln (2829 m asl) and Gjaidstein (2794 m asl) - additional 2D-geoelectric surveys (five ERT profiles with a length of 100 m and 2 m electrode spacing) were measured in summer 2013. The high resistivities (> 50.000 ohm.m) at about 1.5 m depth and deeper strongly suggest permafrost existence inside the bedrock at all

  10. Application of GIS technologies to monitor secondary radioactive contamination in the Delegen mountain massif

    NASA Astrophysics Data System (ADS)

    Alipbeki, O.; Kabzhanova, G.; Kurmanova, G.; Alipbekova, Ch.

    2016-06-01

    The territory of the Degelen mountain massif is located within territory of the former Semipalatinsk nuclear test site and it is an area of ecological disaster. Currently there is a process of secondary radioactive contamination that is caused by geodynamic processes activated at the Degelen array, violation of underground hydrological cycles and as a consequence, water seepage into the tunnels. One of the methods of monitoring of geodynamic processes is the modern technology of geographic information systems (GIS), methods of satellite radar interferometry and high accuracy satellite navigation system in conjunction with radioecological methods. This paper discusses on the creation of a GIS-project for the Degelen array, facilitated by quality geospatial analysis of the situation and simulation of the phenomena, in order to maximize an objective assessment of the radiation situation in this protected area.

  11. Mineral compositions of plutonic rocks from the Lewis Hills massif, Bay of Islands ophiolite

    NASA Technical Reports Server (NTRS)

    Smith, Susan E.; Elthon, Don

    1988-01-01

    Mineral compositions of residual and cumulate rocks from the Lewis Hills massif of the Bay of Islands ophiolite complex are reported and interpreted in the context of magnetic processes involved in the geochemical evolution of spatially associated diabase dikes. The mineral compositions reflect greater degrees of partial melting than most abyssal peridotites do and appear to represent the most depleted end of abyssal peridotite compositions. Subsolidus equilibration between Cr-Al spinal and olivine generally has occurred at temperatures of 700 to 900 C. The spinel variations agree with the overall fractionation of basaltic magmas producing spinels with progressively lower Cr numbers. The compositions of clinopyroxenes suggest that the fractionation of two different magma series produced the various cumulate rocks.

  12. Physical-Chemical Factors Affecting the Low Quality of Natural Water in the Khibiny Massif

    NASA Astrophysics Data System (ADS)

    Mazukhina, Svetlana; Masloboev, Vladimir; Chudnenko, Konstantin; Maksimova, Viktoriia; Belkina, Natalia

    2014-05-01

    One peculiarity of the Khibiny Massif is its spatial location. Rising over 1000 m above the surrounding hilly land and thus obstructing the passage of air masses, it promotes condensation and accumulation of surface and underground water. Annual precipitation here amounts to 600-700 mm in the valleys and up to 1600 mm on mountainous plateaus. Using this water for drinking and household purposes is problematic due to excess Al and F concentrations and high pH values. Now it is known that in its profile, the Massif is represented by three hydrogeological subzones: the upper (aerated), medium and lower ones. The upper subzone spreads throughout the Massif and is affected by the local drainage network and climatic conditions. The medium subzone is permanently saturated with underground water flowing horizontally to sites of discharge at the level of local river valleys and lakes. The fissure-vein water in the lower subzone is confined to tectonic fractures and faults in the so far underexplored, deeper parts of the Massif. Being abundant, this water ascends under high pressure. At places, water has been observed spurting from as deep as 700 m, and even 960 m. In the latter case, the temperature of ascending water was higher than 18 centigrade (Hydrogeology of the USSR, V. 27, 1971). This work was undertaken to reveal the nature of the low quality of water in the Khibiny by using physical-chemical modeling (software package Selector, Chudnenko, 2010). Processes of surface and underground water formation in the Khibiny were examined within a physical-chemical model (PCM) of the "water-rock-atmosphere-hydrogen" system. In a multi-vessel model used, each vessel represented a geochemical level of the process interpreted as spatiotemporal data - ξ (Karpov, 1981). The flow reactor consisted of 4 tanks. In the first tank, water of the Kuniok River (1000 L) interacted with atmosphere and an organic substance. The resulting solution proceeded to tanks 2-4 containing with

  13. Fluid flow and polymetallic sulfide mineralization in the Kettara shear zone (Jebilet Massif, Variscan Belt, Morocco)

    NASA Astrophysics Data System (ADS)

    N'diaye, I.; Essaifi, A.; Dubois, M.; Lacroix, B.; Goodenough, K. M.; Maacha, L.

    2016-07-01

    The Kettara shear zone is a regional wrench shear zone within the Jebilet massif of Western Morocco, part of the Variscan orogenic belt. This massif is characterized by bimodal magmatism, largely intrusive, and by a number of polymetallic massive sulfide deposits. A syntectonic mafic-ultramafic intrusion and an adjacent, deformed pyrrhotite-rich massive sulfide deposit are located within a 'compressional jog' of the shear zone. Hydrothermal alteration in both the intrusion and the wall rocks adjacent to the deposit is characterized by syntectonic replacement processes leading to formation of chlorite-schists and quartz ± calcite veins. Fluid inclusions in mineralized (pyrrhotite-bearing) quartz veins from the wall rocks adjacent to the deposit and in veins associated with chlorite-schists within the intrusion indicate a prevalence of H2O-CO2-CH4-N2 and H2O-salt fluid systems. In the mineralized veins the fluid shows reducing conditions, with gas dominated by CH4 and N2 and salinities around 7.5 wt% NaCl, whereas in the chlorite shear zones fluid is CO2 dominated and salinities are higher than 23 wt% NaCl. Hydrogen and oxygen isotopic compositions of chlorite and quartz are similar and demonstrate involvement of metamorphic water in both the deposit and the intrusion. The data are consistent with a regional metamorphic fluid flow through the Kettara shear zone. The migrating metamorphic fluids were reduced in the organic matter-rich host rocks leading to deposition of sulfides in the mineralized veins. There are two possible hypotheses for the origin of these mineralized veins: either they were formed during deformation and remobilization of a syn-sedimentary massive sulfide deposit, or they were formed synchronously with the sulfide deposit during development of the Kettara shear zone.

  14. Cancrinite from nepheline syenite (mariupolite) of the Oktiabrski massif, SE Ukraine, and its growth history

    NASA Astrophysics Data System (ADS)

    Dumańska-Słowik, Magdalena; Pieczka, Adam; Heflik, Wiesław; Sikorska, Magdalena

    2016-03-01

    Secondary cancrinite, (Na5.88K< 0.01)∑ 5.88(Ca0.62 Fe0.01Mn0.01Zn< 0.01 Mg< 0.01)∑ 0.64[Si6.44Al 5.56O24](CO3)0.67(OH)0.26(F< 0.01,Cl< 0.01)·2.04H2O), was found as accessory component of mariupolite (albite-aegirine nepheline syenite) from the Oktiabrski massif in the Donbass (SE Ukraine). It probably crystallized from a subsolidus reaction involving nepheline (and sodalite?) and calcite dissolved in the aqueous-carbonic fluid at the maximum temperature of 930 °C, decreasing to hydrothermal conditions. It is depleted in sodium, calcium and carbon, what results in the occurrence of vacant positions at both cationic and anionic sites. Ca-deficient cancrinite crystallized from the same hydrothermal Si-undersaturated fluids enriched in the ions such as Na+, Ca2 +, Cl-, F-, HCO3-, which formed calcite, sodalite, natrolite and fluorite. It has dark-red CL colours with patchy zoning, what indicates the variable/diverse fluid composition during its formation. In the CL spectrum of cancrinite only one broad emission band at 410 nm is observed, which can be attributed to O* center (the recombination of a free electron with an O- hole center). The formation of secondary CO3-rich species, i.e. cancrinite and calcite in mariupolite suggests that redox conditions in the Oktiabrski massif were oxidizing at the postmagmatic stage.

  15. Cancrinite from nepheline syenite (mariupolite) of the Oktiabrski massif, SE Ukraine, and its growth history.

    PubMed

    Dumańska-Słowik, Magdalena; Pieczka, Adam; Heflik, Wiesław; Sikorska, Magdalena

    2016-03-15

    Secondary cancrinite, (Na5.88K<0.01)∑5.88(Ca0.62 Fe0.01Mn0.01Zn<0.01 Mg<0.01)∑0.64[Si6.44Al 5.56O24](CO3)0.67(OH)0.26(F<0.01,Cl<0.01)·2.04H2O), was found as accessory component of mariupolite (albite-aegirine nepheline syenite) from the Oktiabrski massif in the Donbass (SE Ukraine). It probably crystallized from a subsolidus reaction involving nepheline (and sodalite?) and calcite dissolved in the aqueous-carbonic fluid at the maximum temperature of 930 °C, decreasing to hydrothermal conditions. It is depleted in sodium, calcium and carbon, what results in the occurrence of vacant positions at both cationic and anionic sites. Ca-deficient cancrinite crystallized from the same hydrothermal Si-undersaturated fluids enriched in the ions such as Na(+), Ca(2+), Cl(-), F(-), HCO3(-), which formed calcite, sodalite, natrolite and fluorite. It has dark-red CL colours with patchy zoning, what indicates the variable/diverse fluid composition during its formation. In the CL spectrum of cancrinite only one broad emission band at 410 nm is observed, which can be attributed to O* center (the recombination of a free electron with an O(-) hole center). The formation of secondary CO3-rich species, i.e. cancrinite and calcite in mariupolite suggests that redox conditions in the Oktiabrski massif were oxidizing at the postmagmatic stage. PMID:26773267

  16. The age of Kondyor massif dunites (Aldan Province, Russia): First U-Pb isotopic data

    NASA Astrophysics Data System (ADS)

    Malitch, K. N.; Efimov, A. A.; Badanina, I. Yu.

    2012-09-01

    The material and isotope-geochemical peculiarities of zircons from dunites of the Kondyor massif (Aldan Province, Southeast Siberian Craton) have been described for the first time. This massif is associated with an economic platinum placer deposit. On the basis of detailed study of the morphology, internal structure, and geochemical characteristics, zircons have been subdivided into two types. The first type is represented by crystals of oval and rounded shapes, characterized by a bimodal distribution of "ancient" (2477 ± 18 and 1885 ± 52 Ma) U-Pb (SHRIMP-II) ages. The second type of zircons forms idiomorphic crystals and aggregates of prismatic habitus, forming two "young" age clusters (176 ± 1.2 and 143 ± 2.0 Ma). The obtained results allow us to make a conclusion about the long evolution of platinum-bearing dunites. The first type of zircons formed by metamictic cores and homogeneous peripheral rims indicates the time of metamorphism at the Archean-Proterozoic boundary (˜2.5 Ga), implying an older age of porous zircon cores. Such zircons characterize the minimal age of the initial mantle substance or a close time when the platinum-bearing dunite was generated. Based on their formation time, the second type of zircons can be referred to the epoch of tectonic-magmatic activation of the Aldan Shield. The new geochronological data, along with the material identity of dunites from the Urals and the Aldan Province, argue for a common genetic origin of platinum-bearing dunites of the fold belts and ancient cratons.

  17. Cenozoic denudation of the Menderes Massif and its geodynamic framework: slab tear or not?

    NASA Astrophysics Data System (ADS)

    Gessner, Klaus; Gallardo, Luis; Markwitz, Vanessa; Ring, Uwe; Thomson, Stuart

    2014-05-01

    Despite having experienced similar rates of convergence during the Alpine Orogeny, the Hellenides and Anatolides display fundamental differences in crust and mantle structure across a region that broadly coincides with the Aegean coastline of the Anatolian peninsula. The Menderes Massif experienced early Miocene tectonic denudation and surface uplift in the footwall of a north-directed extensional detachment system, followed by late Miocene to recent fragmentation by E-W and NW-SE trending graben systems, resulting in one of Earth's largest metamorphic core complexes. Based on the interpretation of geological and geophysical data we propose that the tectonic denudation of the Menderes Massif was caused by late Oligocene/early Miocene lithosphere scale transtension along the boundary of the Adriatic and Anatolian lithospheric domains, when rollback of the Aegean slab affected the Aegean-Menderes section of the Tethyan Orogen. In addition to previously hypothesized crustal discontinuities, gravity data, earthquake locations and seismic velocity anomalies highlight a north-south oriented boundary in the upper mantle between a fast slab below the Aegean and a slow asthenospheric region below western Turkey. As an alternative to the common interpretation of this discontinuity representing the western edge of a slab tear, we propose that the change in lithospheric structure is the result of how different lithosphere domains responded to roll-back: relatively slow removal of lithospheric mantle below western Anatolia versus trench retreat in the rapidly extending Aegean Sea region. Our findings highlight the significance of lateral variations in subduction-collision systems for the formation of continental plateaux and metamorphic core complexes.

  18. Proterozoic massif anorthosites and related rocks in Labrador: the anorthosite-charnockite connection

    SciTech Connect

    Emslie, R.F.

    1985-01-01

    Massif anorthosites of Labrador are closely associated in space and time with voluminous, felsic, fayalite- and ferrous pyroxene-bearing igneous rocks. These include charnockites, monzonites, biotite-hornblende granites, and locally syenites. Igneous charnockites form major parts of some of the granitic complexes. In Mistastin batholith for example, charnockitic assemblages comprise about 35% of a total area of 6500 sq. km. Feldspar pairs and coexisting fayalite-opx-qtz in these rocks indicate P and T near 3.5 kb, 750/sup 0/C, assumed to represent near solidus equilibration. Diorites and monzonites intruded by charnockite have mesoperthites implying crystallization T>900/sup 0/C presumably recording earlier stages of crystallization. Oxide and silicate assemblages indicate redox conditions between FMQ and WM oxygen buffers and water pressures well below Ptotal. Younger biotite-hornblende granites and quartz syenites lack Ti-mt. but retain fayalite suggesting that magmatic crystallization was largely closed to water and oxygen. Initial Sr isotope ratios in charnockite-granite suites of central labrador support derivation of the magmas largely or entirely from crustal source rocks. Compositions of mafic silicates and plagioclase, associated Fe-Ti oxide concentrations, trace elements and Sr isotopes in massif anorthosites are in accord with the rocks being crystallization products of substantially fractionated, originally more mafic, mantle magmas. Close association of high temperature, water-poor, reduced crustal melts is consistent with a fusion process in which heat supply and oxygen buffering were controlled by fractional crystallization of a substantial body of mafic magma subjacent to continental crust.

  19. Homogeneous /sup 18/O enrichment of the Marcy Anorthosite Massif, Adirondack Mountains, New York

    SciTech Connect

    Morrison, J.; Valley, J.W.

    1985-01-01

    The Marcy Anorthosite Massif in the Adirondack Mountains, New York, is a composite intrusion that was metamorphosed to granulite facies at approx. 1.1 Ga. The massif is dominantly anorthosite but ranges from anorthosite (1-10% mafics) to oxide-rich pyroxenite layers (up to 98% mafics). In the St Regis Quad (SRQ) systematic variations in the percentage of mafics (POM) roughly parallel the foliation and increase toward the contacts (Davis, 1971). In 47 SRQ samples studied the POM varies from 2-25%; garnet ranges from 0-11%, pyroxene from <1-16% and oxides from <1-8%. Percent phenocrysts varies between 1-80. The Port Kent-Westport Unit (PKW) and an associated hybrid unit show significantly greater textural variability. The POM Varies from 1-50%; garnet ranges from 0-18%, pyroxene from 0-15%, oxides from 0-3% and phenocrysts vary from 0-80%. A total of 28 unaltered plagioclase phenocrysts have been analyzed for delta/sup 18/O: in 13 SRQ samples delta/sup 18/O = 9.0-9.8 (x=9.4. sigma=0.2) and in 15 samples from the PKW and hybrid units values of delta/sup 18/O=8.5-10.5 (x=9.5.sigma0.5). No correlations exist between the modal parameters and delta/sup 18/O. The results from SRQ demonstrate an extreme homogeneity suggesting for the first time a pristine magmatic character which is supported by the virtual absence of metasedimentary inclusions. This contrasts with PKW where inclusions are common and delta/sup 18/O values are more heterogeneous. Further analyses will evaluate the possibility of an anomalous source region as a cause of the /sup 18/O enrichment in the anorthosite.

  20. Diamonds Discovered in Five Peridotite Massifs Along the Yarlung-Zangbo Suture in South Tibet: Tectonic Implications

    NASA Astrophysics Data System (ADS)

    Xu, X.; Yang, J.; Ba, D.; Li, Y.; Zhao, L.; Robinson, P. T.

    2011-12-01

    Many ophiolitic peridotite massifs occur along the more than 1500-km-long Yarlung-Zangbo suture in south Tibet, which marks the boundary between the Indian and Eurasian plates after closure of Neo-Tethys at about 55 Ma. Some of the massifs are very large, e.g., the Xigaze massif (ca. 700 km2) in the middle segment, and the Purang (ca. 600 km2) and Dongbo (ca. 400 km2) massifs in the western segment of the suture. In-situ diamonds and moissanite, along with many unusual, highly reduced minerals, such as native Fe, Cr, Ni and metal alloys have been previously reported from chromitites and peridotites of the Luobusa ophiolitic massif in the eastern segment of the suture. Coesite pseudomorphing stishovite from the Luobusa chromitite suggests depths of formation >300 km. Here we present the first report of diamonds and other unusual minerals in four other peridotite bodies along the Yarlung-Zangbo suture, namely from east to west, the Xigaze, Dangqiong, Purang and Dongbo massifs. These massifs consist mainly of harzburgite, lherzolite and dunite, probably of MOR type, that were modified in a SSZ environment. Several tens of diamonds and some unusual minerals such as moissanite were recovered by standard mineral separation techniques from individual samples ranging from 300 to 600 kg in weight. The diamonds are yellowish-green in color, about 0.1-0.3 mm in size, and have octahedral and cone-like forms. These diamonds are similar to those found in the Luobusa massif, and commonly contain inclusions of Ni-Mn-Co alloys, a feature that distinguishes them from kimberlitic and metamorphic diamonds. Textural evidence and Ca-K-Cl fluid inclusions indicate that they grew from C-rich fluids. Fifty analyses of diamonds from the Yarlung-Zangbo suture yielded δ13CPDB values ranging from -18.3 % to -28.7%, with an average of -24.6%. There are no statistical differences in the isotopic composition among diamonds from the different localities or among those occurring in chromitite or

  1. Photolysis of alkaline-earth nitrates

    NASA Astrophysics Data System (ADS)

    Kriger, L. D.; Miklin, M. B.; Dyagileva, E. P.; Anan'ev, V. A.

    2013-02-01

    Peroxynitrite and nitrite ions are the diamagnetic products of photolysis (with light at a wavelength of 253.7 nm) of alkaline-earth nitrates; the paramagnetic products and hydrogen peroxide were not found. The structural water in alkaline-earth nitrate crystals did not affect the qualitative composition of the photodecomposition products. The quantum yield of nitrite ions was 0.0012, 0.0038, 0.0078, and 0.0091 quanta-1 and that of peroxynitrite ions was 0.0070, 0.0107, 0.0286, and 0.0407 quanta-1 for Sr(NO3)2, Ba(NO3)2, Ca(NO3)2 · 4H2O, and Mg(NO3)2 · 6H2O, respectively.

  2. Alkaline earth cation extraction from acid solution

    DOEpatents

    Dietz, Mark; Horwitz, E. Philip

    2003-01-01

    An extractant medium for extracting alkaline earth cations from an aqueous acidic sample solution is described as are a method and apparatus for using the same. The separation medium is free of diluent, free-flowing and particulate, and comprises a Crown ether that is a 4,4'(5')[C.sub.4 -C.sub.8 -alkylcyclohexano]18-Crown-6 dispersed on an inert substrate material.

  3. The alkaline earth intercalates of molybdenum disulfide

    NASA Technical Reports Server (NTRS)

    Somoano, R. B.; Hadek, V.; Rembaum, A.; Samson, S.; Woollam, J. A.

    1975-01-01

    Molybdenum disulfide has been intercalated with calcium and strontium by means of the liquid ammonia technique. Chemical, X-ray, and superconductivity data are presented. The X-ray data reveal a lowering of crystal symmetry and increase of complexity of the structure upon intercalation with the alkaline earth metals. The Ca and Sr intercalates start to superconduct at 4 and 5.6 K, respectively, and show considerable anisotropy regarding the critical magnetic field.

  4. Surfactant-enhanced alkaline flooding field project

    SciTech Connect

    French, T.R.

    1991-10-01

    The Tucker sand of Helper (KS) field is a candidate for surfactant-enhanced alkaline flooding. The geology of the Helper site is typical of many DOE Class I reservoirs. The Tucker sand of Helper field was deposited in a fluvial dominated deltaic environment. Helper oil can be mobilized with either chemical system 2 or chemical system 3, as described in this report. Oil fields in the Gulf Coast region are also good candidates for surfactant-enhanced alkaline flooding. The results from laboratory tests conducted in Berea sandstone cores with oil brine from Helper (KS) field are encouraging. The crude oil is viscous and non-acidic and, yet, was mobilized by the chemical formulations described in this report. Significant amounts of the oil were mobilized under simulated reservoir conditions. The results in Berea sandstone cores were encouraging and should be verified by tests with field core. Consumption of alkali, measured with field core, was very low. Surfactant loss appeared to be acceptable. Despite the good potential for mobilization of Helper oil, certain reservoir characteristics such as low permeability, compartmentalization, and shallow depth place constraints on applications of any chemical system in the Tucker sand. These constraints are typical of many DOE Class I reservoirs. Although Hepler field is not a perfect reservoir in which to apply surfactant- enhanced alkaline flooding, Hepler oil is particularly amenable to mobilization by surfactant-enhanced alkaline systems. A field test is recommended, dependent upon final evaluation of well logs and cores from the proposed pilot area. 14 refs., 21 figs., 10 tabs.

  5. Alkaline injection for enhanced oil recovery: a status report

    SciTech Connect

    Mayer, E.H.; Berg, R.L.; Carmichael, J.D.; Weinbrandt, R.M.

    1983-01-01

    In the past several years, there has been renewed interest in enhanced oil recovery (EOR) by alkaline injection. Alkaline solutions also are being used as preflushes in micellar/polymer projects. Several major field tests of alkaline flooding are planned, are in progress, or recently have been completed. Considerable basic research on alkaline injection has been published recently, and more is in progress. This paper summarizes known field tests and, where available, the amount of alkali injected and the performance results. Recent laboratory work, much sponsored by the U.S. DOE, and the findings are described. Alkaline flood field test plans for new projects are summarized.

  6. Alkaline flooding for enhanced oil recovery

    SciTech Connect

    Gittler, W.E.

    1983-09-01

    There are over 12 active projects of varying size using one of 3 major types of alkaline agents. These include sodium silicate, caustic soda, and soda ash. Among the largest pilots currently is the THUMS project in the Wilmington field, California. Plans called for the injection of a 4% weight concentration of sodium orthosilicate over a 60% PV. Through the first 3 yr, over 27 million bbl of chemicals have been injected. Gulf Oil is operating several alkaline floods, one of which is located off shore in the Quarantine Bay field, Louisiana. In this pilot, sodium hydroxide in a weight concentration of 5 to 12% is being injected. Belco Petroleum Corp. has reported that their pilot operating in the Isenhour Unit in Wyoming is using a .5% weight concentration of soda ash in conjunction with a polymer. Other uses for alkaline agents in chemical flooding include the use of silicate as a preflush or sacrificial agent in micellar/polymer and surfactant recovery systems. In addition, caustic has been tested in the surface-mixed caustic emulsion process while orthosilicate has been tested in a recovery method known as mobility-controlled caustic floods.

  7. Subcontinental rift initiation and ocean-continent transitional setting of the Dinarides and Vardar zone: Evidence from the Krivaja-Konjuh Massif, Bosnia and Herzegovina

    NASA Astrophysics Data System (ADS)

    Faul, Ulrich H.; Garapić, Gordana; Lugović, Boško

    2014-08-01

    The Dinaride and Vardar zone ophiolite belts extend from the south-eastern margins of the Alps to the Albanian and Greek ophiolites. Detailed sampling of the Krivaja-Konjuh massif, one of the largest massifs in the Dinaride belt, reveals fertile compositions and an extensive record of deformation at spinel peridotite facies conditions. High Na2O clinopyroxene and spinel-orthopyroxene symplectites after garnet indicate a relatively high pressure, subcontinental origin of the southern and western part of Krivaja, similar to orogenic massifs such as Lherz, Ronda and the Eastern Central Alpine peridotites. Clinopyroxene and spinel compositions from Konjuh show similarities with fertile abyssal peridotite. In the central parts of the massif the spinel lherzolites contain locally abundant patches of plagioclase, indicating impregnation by melt. The migrating melt was orthopyroxene undersaturated, locally converting the peridotites to massive olivine-rich troctolites. Massive gabbros and more evolved gabbro veins cross-cutting peridotites indicate continued melt production at depth. Overall we infer that the massif represents the onset of rifting and early stages of formation of a new ocean basin. In the south of Krivaja very localized chromitite occurrences indicate that much more depleted melts with supra-subduction affinity traversed the massif that have no genetic relationship with the peridotites. This indicates that volcanics with supra-subduction affinity at the margins of the Krivaja-Konjuh massif record separate processes during closure of the ocean basin. Comparison with published compositional data from other Balkan massifs shows that the range of compositions within the Krivaja-Konjuh massif is similar to the compositional range of the western massifs of the Dinarides. The compositions of the Balkan massifs show a west to east gradient, ranging from subcontinental on the western side of the Dinarides to depleted mid-ocean ridge/arc compositions in the Vardar

  8. Algorithm of Rock Burst Preparation Scenario Construction in Rock Massif under Explosion Influence using seismic Catalogue Data

    NASA Astrophysics Data System (ADS)

    Hachay, Olga; Khachay, Oleg; Klimko, Valeriy; Shipeev, Oleg

    2014-05-01

    A new algorithm of seismological information processing of detailed mines catalogue with use kinematic and dynamical characteristics of deformation waves, which propagate with different velocities in the rock massif, which is under heavy influence of single blasts and technological explosions is developed. It is estimated that the waves, which propagate with the velocities from 10 to 1 m/hour are primary carrier of the energy in the massif and promote its releasing. Events, which occur in the massive with these waves with releasing energy less than 104 joules promote to the creep rebuilding of the massif. Events, which occur in the massive with these waves with releasing energy more, than 105 joules, can be used as rock burst precursory and it is recommend taking into account by changing of explosions in the indicated part of the massif. The whole absence of such events indicates the growing of the stress massif state in the mine as a whole. The received joined information from the seismic catalogue is very significant for forecasting of dangerous events in the rock mines. That algorithm can be used also for analyzing seismic natural events preparation. Key words: massif response, slow deformation waves, seismic mine catalogue, analyze of observed data, algorithm of seismological information processing. 1.Hachay O. A. The reflection of synergetic Features in the Response of geological Medium on outer Force Actions. / O. A. Hachay, O. Yu. Khachay, V. K. Klimko, O. Yu. Shipeev // Advances in heterogeneous Material Mechanics - Shanghai, China, 2011. -P. 361-366. 2.Hachay O. A. Construction of a State Evolution dynamical Model of a Rock Massive, which is in a regime of energetic Pumping. / O. A. Hachay, A. Yu. Khachay, O. Yu. Khachay // Geophysical Research abstracts. -2011, -Vol. 13, - EGU2011 - 1528. 3.Khachay O.A. Dynamical model for evolution of Rock Massive State as a Response on a Changing of Stress-Deformed State. / O. A. Hachay, A. Yu. Khachay, O. Yu. Khachay

  9. The fate of added alkalinity in model scenarios of ocean alkalinization

    NASA Astrophysics Data System (ADS)

    Ferrer González, Miriam; Ilyina, Tatiana

    2014-05-01

    The deliberate large-scale manipulation of the Earth's climate (geo-engineering) has been proposed to mitigate climate change and ocean acidification. Whilst the mitigation potential of these technologies could sound promising, they may also pose many environmental risks. Our research aims at exploring the ocean-based carbon dioxide removal method of alkalinity enhancement. Its mitigation potential to reduce atmospheric CO2 and counteract the consequences of ocean acidification, risks and unintended consequences are studied. In order to tackle these questions, different scenarios are implemented in the state-of-the-art Earth system model of the Max Planck Institute for Meteorology. The model configuration is based on the 5th phase of the coupled model intercomparison project following a high CO2 future climate change scenario RCP8.5 (in which radiative forcing rises to 8.5 W/m² in 2100). Two different scenarios are performed where the alkalinity is artificially added globally uniformly in the upper ocean. In the first scenario, alkalinity is increased as a pulse by doubling natural values of the first 12 meters. In the second scenario we add alkalinity into the same ocean layer such that the atmospheric CO2 concentration is reduced from RCP8.5 to RCP4.5 levels (with the radiative forcing of 4.5 W/m² in 2100). We investigate the fate of the added alkalinity in these two scenarios and compare the differences in alkalinity budgets. In order to increase oceanic CO2 uptake from the atmosphere, enhanced alkalinity has to stay in the upper ocean. Once the alkalinity is added, it will become part of the biogeochemical cycles and it will be distributed with the ocean currents. Therefore, we are particularly interested in the residence time of the added alkalinity at the surface. Variations in CO2 partial pressure, seawater pH and saturation state of carbonate minerals produced in the implemented scenarios will be presented. Collateral changes in ocean biogeochemistry and

  10. New insights into the history and origin of the southern Maya block, SE Mexico: U-Pb-SHRIMP zircon geochronology from metamorphic rocks of the Chiapas massif

    USGS Publications Warehouse

    Weber, Bodo; Iriondo, Alexander; Premo, Wayne R.; Hecht, Lutz; Schaaf, Peter

    2007-01-01

    The histories of the pre-Mesozoic landmasses in southern México and their connections with Laurentia, Gondwana, and among themselves are crucial for the understanding of the Late Paleozoic assembly of Pangea. The Permian igneous and metamorphic rocks from the Chiapas massif as part of the southern Maya block, México, were dated by U–Pb zircon geochronology employing the SHRIMP (sensitive high resolution ion microprobe) facility at Stanford University. The Chiapas massif is composed of deformed granitoids and orthogneisses with inliers of metasedimentary rocks. SHRIMP data from an anatectic orthogneiss demonstrate that the Chiapas massif was part of a Permian (∼ 272 Ma) active continental margin established on the Pacific margin of Gondwana after the Ouachita orogeny. Latest Permian (252–254 Ma) medium- to high-grade metamorphism and deformation affected the entire Chiapas massif, resulting in anatexis and intrusion of syntectonic granitoids. This unique orogenic event is interpreted as the result of compression due to flat subduction and accretionary tectonics. SHRIMP data of zircon cores from a metapelite from the NE Chiapas massif yielded a single Grenvillian source for sediments. The majority of the zircon cores from a para-amphibolite from the SE part of the massif yielded either 1.0–1.2 or 1.4–1.5 Ga sources, indicating provenance from South American Sunsás and Rondonian-San Ignacio provinces.

  11. The age and petrogenesis of alkaline magmatism in the Ampasindava Peninsula and Nosy Be archipelago, northern Madagascar

    NASA Astrophysics Data System (ADS)

    Cucciniello, C.; Tucker, R. D.; Jourdan, F.; Melluso, L.; Morra, V.

    2016-04-01

    The Ampasindava alkaline province consists of a series of circular and elliptical intrusions, lava flows, dyke swarms and plugs of Cenozoic age emplaced into the Mesozoic-Cenozoic sedimentary rocks of the Antsiranana basin (NW Madagascar) and above the crystalline basement. The magmatism in the Ampasindava region is linked to a NW-SE trending extensional tectonic setting. New 40Ar/39Ar age determinations on feldspar separate of alkali granites and basaltic dykes yielded ages of 18.01 ± 0.36 Ma and 26 ± 7 Ma, respectively. Alkali basalts and basanites, nepheline syenites and phonolites, and silica saturated-to-oversaturated syenites, trachytes, granites and rhyolites are the main outcropping lithologies. These rocks have sodic affinity. The felsic rocks are dominant, and range from peraluminous to peralkaline. The mantle-normalized incompatible element patterns of the mafic lavas match those of Na-alkaline lavas in within-plate rift settings. The patterns are identical in shape and absolute concentrations to those of the Bobaomby (Cap d'Ambre) and Massif d'Ambre primitive volcanic rocks. These geochemical features are broadly compatible with variable degrees of partial melting of incompatible element-enriched mantle sources. The mineralogical and geochemical variations are consistent with fractional crystallization processes involving removal of olivine, feldspar, clinopyroxene, amphibole, Fe-Ti oxides and apatite. Removal of small amount of titanite explains the concave upward lanthanide pattern in the evolved nepheline syenites and phonolites, which are additionally rich in exotic silicates typical of agpaitic magmas (eudialyte, F-disilicates).

  12. Scorpions from the Mitaraka Massif in French Guiana: Description of one new genus and species (Scorpiones: Chactidae).

    PubMed

    Lourenço, Wilson R

    2016-01-01

    A new genus and species, Spinochactas mitaraka gen. n., sp. n. (Chactidae) are described from the Mitaraka Massif in French Guiana, a site located near the borders of French Guiana, Brazil, and Suriname. The description of the new genus and species brings further evidence of the biogeographic pattern of distribution presented by some elements of the family Chactidae endemic to the Tepuys or to the Inselberg formations of South America. PMID:26995397

  13. The western limits of the Seattle and Tacoma faults and their interaction with faults of the Olympic Massif, Washington (Invited)

    NASA Astrophysics Data System (ADS)

    Lamb, A.; Blakely, R. J.; Liberty, L. M.; Pratt, T. L.; Sherrod, B. L.

    2013-12-01

    Recently acquired high-resolution seismic-reflection and magnetic data show that the Seattle fault of Washington State extends 24-km west of its previously mapped extent and thus comprises a >100-km-long active fault zone. These same data reveal largely concealed faults and folds that kinematically link the Seattle fault with active faults in the Olympic Massif. Linkage between the Seattle fault and the north-northeast-striking Saddle Mountain fault in the Olympic Massif may explain the synchroneity of M7 earthquakes occurring on both these faults approximately 1,100 years ago. The western limits of the 20-km-long east-striking Tacoma fault, a backthrust in the hanging wall of the Seattle fault zone, forms the southern margin of the Seattle uplift in contact with the Tacoma basin to the south. A ~20-km-long potential-field lineament extends from the western limits of the Tacoma fault northward to the Seattle fault and may reflect a structure linking these active faults. A geologic model based on magnetic, gravity, and seismic data shows that this potential-field lineament is likely caused by a low-angle, west-verging thrust fault, that we refer to as the Dewatto fault. We suggest that the Dewatto fault was initiated during exhumation of the Olympic Massif but, because of changes in principal strain direction, today largely accommodates north-directed, strike-slip motion along the west margin of the Seattle uplift. Thus, the Dewatto and Saddle Mountain faults and the western parts of the Seattle and Tacoma faults kinematically interact to accommodate north-directed horizontal displacement of the Seattle uplift relative to the Olympic Massif.

  14. The Galicia-Ossa-Morena Zone: Proposal for a new zone of the Iberian Massif. Variscan implications

    NASA Astrophysics Data System (ADS)

    Arenas, Ricardo; Díez Fernández, Rubén; Rubio Pascual, Francisco J.; Sánchez Martínez, Sonia; Martín Parra, Luis Miguel; Matas, Jerónimo; González del Tánago, José; Jiménez-Díaz, Alberto; Fuenlabrada, Jose M.; Andonaegui, Pilar; Garcia-Casco, Antonio

    2016-06-01

    Correlation of a group of allochthonous terranes (referred to as basal, ophiolitic and upper units) exposed in the NW and SW of the Iberian Massif, is used to propose a new geotectonic zone in the southern branch of the Variscan Orogen: the Galicia-Ossa-Morena Zone. Recent advances in SW Iberia identify most of the former Ossa-Morena Zone as another allochthonous complex of the Iberian Massif, the Ossa-Morena Complex, equivalent to the Cabo Ortegal, Órdenes, Malpica-Tui, Bragança and Morais complexes described in NW Iberia. The new geotectonic zone and its counterparts along the rest of the Variscan Orogen constitute an Internal Variscan Zone with ophiolites and units affected by high-P metamorphism. The Galicia-Ossa-Morena Zone includes a Variscan suture and pieces of continental crust bearing the imprint of Ediacaran-Cambrian events related to the activity of peri-Gondwanan magmatic arcs (Cadomian orogenesis). In the Iberian Massif, the general structure of this geotectonic zone represents a duplication of the Gondwanan platform, the outboard sections being juxtaposed on top of domains located closer to the mainland before amalgamation. This interpretation offers an explanation that overcomes some issues regarding the differences between the stratigraphic and paleontological record of the central and southern sections of the Iberian Massif. Also, equivalent structural relationships between other major geotectonic domains of the rest of the Variscan Orogen are consistent with our interpretation and allow suspecting similar configurations along strike of the orogen. A number of issues may be put forward in this respect that potentially open new lines of thinking about the architecture of the Variscan Orogen.

  15. Phanerozoic polyorogenic deformation in southern Jiuling Massif, northern South China block: Constraints from structural analysis and geochronology

    NASA Astrophysics Data System (ADS)

    Chu, Yang; Lin, Wei

    2014-06-01

    The structure of the Jiuling Massif has been investigated in order to delineate the polyorogenic deformation and discuss its geodynamic evolution and orogenic mechanisms. Detailed structural analysis indicates that the D1 event is characterized by top-to-the NNW ductile shearing with pervasive foliation, and mineral and stretching lineation developed in the entire region. Compared with the D1 deformation, D2 structures are localized in ductile shear zones with subvertical foliation and subhorizontal E-W trending lineation, indicating a dextral ductile shearing. The D3 event, marked by folds and thrusts mainly in a brittle domain, modified the D1 structures by asymmetrical folds. The dominant D4 structures are gravitational folds and normal faults, corresponding to a later extension. Our new geochronological data suggest that the D1 event occurred between 465 and 380 Ma with D2 dextral shearing at the end of this Early Paleozoic orogen, and the D3 event has been constrained at 245-215 Ma. The final uplift of the Jiuling Massif by the D4 event can be correlated with the Late Mesozoic extension across the eastern South China block. Along with previous studies in the South China block, the structural pattern of the Jiuling Massif elucidates the influence of the Early Paleozoic and Early Mesozoic intracontinental belts triggered by repeated reactivation of the Jiangshan-Shaoxing Fault. Combined with deformation to the south, the Early Paleozoic belt shows a positive flower pattern, with opposing kinematics, rooted in the Jiangshan-Shaoxing Fault. During the Early Mesozoic, a general intracontinental belt was developed with uniform kinematics in both the Jiuling Massif and the Xuefengshan Belt, possibly resulted from the far-field effect of the Triassic NW-directed Paleo-Pacific subduction.

  16. The Tolbachik volcanic massif: A review of the petrology, volcanology and eruption history prior to the 2012-2013 eruption

    NASA Astrophysics Data System (ADS)

    Churikova, T. G.; Gordeychik, B. N.; Edwards, B. R.; Ponomareva, V. V.; Zelenin, E. A.

    2015-12-01

    The primary goal of this paper is to summarize all of the published data on the Tolbachik volcanic massif in order to provide a clear framework for the geochronologic, petrologic, geochemical and to a lesser extent the geophysical and tectonic characteristics of the Tolbachik system established prior to the 2012-2013 eruption. The Tolbachik massif forms the southwestern part of the voluminous Klyuchevskoy volcanic group in Kamchatka. The massif includes two large stratovolcanoes, Ostry ("Sharp") Tolbachik and Plosky ("Flat") Tolbachik, and a 70 km long zone of the basaltic monogenetic cones that form an arcuate rift-like structure running across the Plosky Tolbachik summit. The Tolbachik massif gained international attention after the 1975-1976 Great Tolbachik Fissure Eruption (GTFE), which was one of the largest eruptions of the 20th century and one of the six largest basaltic fissure eruptions in historical time. By the end of the GTFE, 2.2 km3 of volcanic products of variable basaltic compositions with MORB-like isotopic characteristics covered an area of > 1000 km2. During the following three decades more than 700 papers on various aspects of this eruption have been published both in national and international journals. Although the recent 2012-2013 eruption, which is the main topic of this volume, was not as long as the GTFE in duration or as large in area and volume of the erupted deposits, it brought to the surface a unique volcanic material never found before. In order to understand the data from new eruptions and make significant progress towards a better understanding of the Tolbachik magmatic system it is important to be able to put the new results into the historic context of previous research.

  17. The thermal, metamorphic and magmatic evolution of a rapidly exhuming terrane: the Nanga Parbat Massif, northern Pakistan

    NASA Astrophysics Data System (ADS)

    Whittington, A. G.

    The Nanga Parbat-Haramosh Massif (NPHM) is the most northerly outcrop of Indian Plate rocks in the Himalayan orogen, exposed by rapid recent exhumation through the structurally overlying Kohistan Island Arc in northern Pakistan. Exhumation has been achieved by erosion in the apparent absence of extensional tectonics. Metabasaltic dykes intruded into polymetamorphic basement rocks provide time markers that distinguish early from late fabrics that probably correlated with Precambrian and Himalayan deformation respectively. Nanga Parbat is anomalous within the Himalayan orogen for both the timing and nature of metamorphism and anatexis. A multidisciplinary approach allows the thermal history to be tightly constrained. Metamorphism is characterised by cordierite growth during near-isothermal decompression. Garnet inclusion assemblages record P-T conditions of 720 +/- 50 deg C and 7.5 +/- 1.5 kbar, while spinel-cordierite intergrowths unique to the massif interior formed at 710 +/- 60 deg C and 5.0 +/- 1.1 kbar. Lower grade assemblages are exposed towards the massif margins. Tourmaline leucogranite plutons and sheets are characterised by similar trace element geochemistry to Miocene High Himalayan granites, indicative of vapour-absent crustal melting as would result from rapid decompression, but were emplaced more than 10 million years later. More recently, fluid infiltration into conjugate shear zones accommodating vertical stretching in the core of the massif resulted in anatexis and the formation of restitic cordierite-bearing pods. 40Ar-39Ar studies indicate regional cooling below 400 deg C as recently as 1 Ma, and the distribution of excess 40Ar in basement samples is indicative of magmatic/metamorphic fluids at depths > 10 km. One-dimensional thermal modelling indicates that increasing cooling rates through time do not require increasing exhumation rates because advection of heat results in a steepened near-surface geotherm. These models predict both the style and

  18. Lower Pliensbachian caldera volcanism in high-obliquity rift systems in the western North Patagonian Massif, Argentina

    NASA Astrophysics Data System (ADS)

    Benedini, Leonardo; Gregori, Daniel; Strazzere, Leonardo; Falco, Juan I.; Dristas, Jorge A.

    2014-12-01

    In the Cerro Carro Quebrado and Cerro Catri Cura area, located at the border between the Neuquén Basin and the North Patagonian Massif, the Garamilla Formation is composed of four volcanic stages: 1) andesitic lava-flows related to the beginning of the volcanic system; 2) basal massive lithic breccias that represent the caldera collapse; 3) voluminous, coarse-crystal rich massive lava-like ignimbrites related to multiple, steady eruptions that represent the principal infill of the system; and, finally 4) domes, dykes, lava flows, and lava domes of rhyolitic composition indicative of a post-collapse stage. The analysis of the regional and local structures, as well as, the architectures of the volcanic facies, indicates the existence of a highly oblique rift, with its principal extensional strain in an NNE-SSW direction (˜N10°). The analyzed rocks are mainly high-potassium dacites and rhyolites with trace and RE elements contents of an intraplate signature. The age of these rocks (189 ± 0.76 Ma) agree well with other volcanic sequences of the western North Patagonian Massif, as well as, the Neuquén Basin, indicating that Pliensbachian magmatism was widespread in both regions. The age is also coincident with phase 1 of volcanism of the eastern North Patagonia Massif (188-178 Ma) represented by ignimbrites, domes, and pyroclastic rocks of the Marifil Complex, related to intraplate magmatism.

  19. Seismic imaging of the western Iberian crust using ambient noise: Boundaries and internal structure of the Iberian Massif

    NASA Astrophysics Data System (ADS)

    Silveira, Graça; Afonso Dias, Nuno; Villaseñor, Antonio

    2013-03-01

    We present new Rayleigh-wave dispersion maps of the western Iberian Peninsula for periods between 8 and 30 s, obtained from correlations of seismic ambient noise, following the recent increase in seismic broadband network density in Portugal and Spain. Group velocities have been computed for each station pair using the empirical Green's functions generated by cross-correlating one-day-length seismic ambient-noise records. The resulting high-path density allows us to obtain lateral variations of the group velocities as a function of period in cells of 0.5° × 0.5° with an unprecedented resolution. As a result we were able to address some of the unknowns regarding the lithospheric structure beneath SW Iberia. The dispersion maps allow the imaging of the major structural units, namely the Iberian Massif, and the Lusitanian and Algarve Meso-Cenozoic basins. The Cadiz Gulf/Gibraltar Strait area corresponds to a strong low-velocity anomaly, which can be followed to the largest period inverted, although slightly shifted to the east at longer periods. Within the Iberian Massif, second-order perturbations in the group velocities are consistent with the transitions between tectonic units composing the massif.

  20. Geology and Tectonic Evolution of the Kazdaǧ Massif (NW Anatolia)

    NASA Astrophysics Data System (ADS)

    Erdoğan, B.; Akay, E.; Hasözbek, A.; Satır, M.; Siebel, W.

    2009-04-01

    In the northwestern part of Anatolia along the Izmir-Ankara Suture Zone, the Kazdağ and Uludağ metamorphic massifs form an E-W trending belt between the Sakarya Continent in the north and the Menderes Massif in the south. Internal succession of these two massifs have been described as metamorphic complexes consisting of various kinds of micaschists, quartz mica schist, gneisses, amphibolites and marbles. In the Kazdağ metamorphics, metaophiolites have been described additionally (Okay et al., 1991; Yaltırak and Okay, 1994; Okay et al., 1996; Duru et al., 2004). These metamorphic complexes were considered to form the basement of the Sakarya Continent tectonically overlain by the Early Permian (Topuz et al., 2004) to Late Triassic (Okay and Monie, 1997; Okay et al., 2002) Karakaya Complex. This old basement and the Karakaya Complex were suggested to be unconformably overlain by Liassic and younger platform limestones and detritals (Altıner et al., 1991). In the literature, it has also been suggested that the Kazdağ Massif had experienced polyphase metamorphism, first during Carboniferous time, second during Early Triassic and third during Tertiary (Bingöl, 1971; Okay et al., 1996; Okay and Satır, 2000). In this study we mapped the Kazdağ Massif on 1/25000 scale, studied its internal stratigraphy and structures and performed some petrologic analyses and radiogenic age determinations. Stratigraphically in the lower part of the Kazdağ metamorphic sequence, there is a part of an oceanic crust represented by metaultramafic rocks and gabbroic metacumulates. Geochemistry of these banded metagabbros show a mid-oceanic affinity. This oceanic crust is overlain, along an unconformity, by a platform type marble succession. At the base of the marbles, there is a basal conglomerate, clasts of which derived from the underlying ultramafic sequence. Thick white marble sequence is overlain along a gradational boundary with a metadetrital succession consisting of quartz mica

  1. Cl-rich hydrous mafic mineral assemblages in the Highiș massif, Apuseni Mountains, Romania

    NASA Astrophysics Data System (ADS)

    Bonin, Bernard; Tatu, Mihai

    2016-01-01

    The Guadalupian (Mid-Permian) Highiș massif (Apuseni Mountains, Romania) displays a bimodal igneous suite of mafic (gabbro, diorite) and A-type felsic (alkali feldspar granite, albite granite, and hybrid granodiorite) rocks. Amphibole is widespread throughout the suite, and yields markedly high chlorine contents. Three groups are identified: Cl-rich potassic hastingsite (2.60-3.40 wt% Cl) within A-type felsic rocks and diorite, mildly Cl-rich pargasite to hornblende (0.80-1.90 wt% Cl) within gabbro, and low F-Cl hornblende within gabbro and hybrid granodiorite. Coexisting biotite is either Cl-rich within diorite, or F-Cl-poor to F-rich within A-type felsic rocks. Chlorine and fluorine are distributed in both mafic phases, according to the F-Fe and Cl-Mg avoidance rules. The low-Ti contents suggest subsolidus compositions. Cl-rich amphibole within diorite and A-type felsic rocks yields a restricted temperature range - from 575 °C down to 400 °C, whereas mildly Cl-rich amphibole within gabbro displays the highest range - from 675 to 360 °C. Temperatures recorded by Cl-rich biotite within diorite range from 590 to 410 °C. Biotite within A-type felsic rocks yields higher temperatures than amphibole: the highest values- from 640 to 540 °C - are recorded in low-F-Cl varieties, whereas the lowest values- from 535 to 500 °C - are displayed by F-rich varieties. All data point to halogen-rich hydrothermal fluids at upper greenschist facies conditions percolating through fractures and shear zones and pervasively permeating the whole Highiș massif, with F precipitating as interstitial fluorite and Cl incorporating into amphibole, during one, or possibly several, hydrothermal episodes that would have occurred during a ~ 150 My-long period of time extending from the Guadalupian (Mid-Permian) to the Albian (Mid-Cretaceous).

  2. CRE dating on the scarps of large landslides affecting the Belledonne massif ( French Alps)

    NASA Astrophysics Data System (ADS)

    Lebrouc, V.; Baillet, L.; Schwartz, S.; Jongmans, D.; Gamond, J. F.; Bourles, D.; Le Roux, O.; Carcaillet, J.; Braucher, R.

    2012-04-01

    The southwestern edge of the Belledonne Massif (French Alps) consists of micaschists unconformably covered with Mesozoic sediments and Quaternary deposits. The morphology corresponds to a glacial plateau (Mont Sec plateau) bordered by steep slopes (around 40°), where moraines and peat bog subsist. The massif is incised by the East-West trending Romanche valley that was shaped by several cycles of quaternary glaciations and deglaciations. Slopes are affected by several active or past large scale rock mass instabilities. Cosmic Ray Exposure (CRE) dating was applied on the head scarps of three large landslides, one of which being the active Séchilienne landslide whose headscarp was already dated by Leroux et al. [2009]. Dating results suggest a concomitant initiation of these instabilities at about 7 ± 2 10Be ka, thousands years after the total downwastage of the valley. A different kinematic behaviour was however observed on two contiguous landslides for which continuous exposure profiles were obtained. On the Séchilienne landslide, 23 samples were collected from internal and lateral scarps, as well as on polished bedrock surfaces, with the aim of dating the internal kinematics of the landslide. Preliminary dating results obtained on polished surfaces and near the top of the scarps show unexpected low 10Be concentrations, suggesting the existence of thin moraine or peat bog deposits masking the bedrock, which have been subsequently eroded. The minimum thickness of these deposits was estimated assuming a constant denudation rate over time. Exposure date profiles show that the studied lateral and internal scarps were initiated at the same period as the Sechilienne headscarp. An increase in the exposure rate was also observed between 2 and 1 ka, in agreement with that evidenced along the headscarp. Forty other samples have been collected in the landslide to corroborate these results. Reference Le Roux, O., S. Schwartz , J.-F. Gamond, D. Jongmans, D. Bourles, R

  3. Cl-rich hydrous mafic mineral assemblages in the Highiș massif, Apuseni Mountains, Romania

    NASA Astrophysics Data System (ADS)

    Bonin, Bernard; Tatu, Mihai

    2016-08-01

    The Guadalupian (Mid-Permian) Highiș massif (Apuseni Mountains, Romania) displays a bimodal igneous suite of mafic (gabbro, diorite) and A-type felsic (alkali feldspar granite, albite granite, and hybrid granodiorite) rocks. Amphibole is widespread throughout the suite, and yields markedly high chlorine contents. Three groups are identified: Cl-rich potassic hastingsite (2.60-3.40 wt% Cl) within A-type felsic rocks and diorite, mildly Cl-rich pargasite to hornblende (0.80-1.90 wt% Cl) within gabbro, and low F-Cl hornblende within gabbro and hybrid granodiorite. Coexisting biotite is either Cl-rich within diorite, or F-Cl-poor to F-rich within A-type felsic rocks. Chlorine and fluorine are distributed in both mafic phases, according to the F-Fe and Cl-Mg avoidance rules. The low-Ti contents suggest subsolidus compositions. Cl-rich amphibole within diorite and A-type felsic rocks yields a restricted temperature range - from 575 °C down to 400 °C, whereas mildly Cl-rich amphibole within gabbro displays the highest range - from 675 to 360 °C. Temperatures recorded by Cl-rich biotite within diorite range from 590 to 410 °C. Biotite within A-type felsic rocks yields higher temperatures than amphibole: the highest values- from 640 to 540 °C - are recorded in low-F-Cl varieties, whereas the lowest values- from 535 to 500 °C - are displayed by F-rich varieties. All data point to halogen-rich hydrothermal fluids at upper greenschist facies conditions percolating through fractures and shear zones and pervasively permeating the whole Highiș massif, with F precipitating as interstitial fluorite and Cl incorporating into amphibole, during one, or possibly several, hydrothermal episodes that would have occurred during a ~ 150 My-long period of time extending from the Guadalupian (Mid-Permian) to the Albian (Mid-Cretaceous).

  4. Methane Seepage at Hyperalkaline Springs in the Ronda Peridotite Massif (Spain)

    NASA Astrophysics Data System (ADS)

    Etiope, G.; Vadillo, I.; Whiticar, M. J.; Marques, J. M.; Carreira, P. M.; Tiago, I.; Benavente, J.; Jimenez, P.; Urresti, B.

    2014-12-01

    Methane-rich, hyperalkaline spring waters and bubbling pools have been sampled in the Ronda peridotite massif in southern Spain. Water chemistry (T: 17.1-21.5 ºC; pH: 10.7-11.7; DO: <2 mg/L; Ca-OH facies) is characteristic of present-day serpentinization. Dissolved CH4 concentrations range from 0.1 to 3.2 mg/L. CH4 stable C and H isotope ratios suggest a dominant abiotic origin in two natural spring sites (delta13C: -13 to -29 ‰ VPDB; delta2H: -309 to -333 ‰ VSMOW) and a mixed biotic-abiotic origin in springs with artificial water delivery systems (i.e., pipes or fountains; delta13C: -44 to -69 ‰; delta2H: -180 to -319 ‰). At the natural springs, gas is mainly released through bubbles close to the water outlet (CH4 flux ~1 kg/day by individual bubble trains), and subordinately by microseepage from the ground, even at distances of ~100 m from the bubble-spring site (flux of 10's, up to 97, mg CH4 m-2day-1). Gas seepage is strictly controlled by faults. Under-saturation of CH4 in water, bubbling and seepage location suggest that CH4 is not exclusively transported to the surface by hyperalkaline water, but it follows autonomous migration pathways along faults. Similar 'dry' seepage of abiotic gas was observed in the Philippines, New Zealand, Turkey and Italy. Like other land-based serpentinization systems, the Ronda peridotite massif is characterized by low heat flow (<40 mW/m2), with temperatures <60°C at depths of 1.5 km. At these low T and high pH conditions, CO32- is the only available carbon source dissolved in the water, and unlikely contributes to catalysed Fischer-Tropsch Type reactions. Methane production from CO2 hydrogenation in a gas phase system (unsaturated fractured rocks) cannot be excluded. The presence of ruthenium-enriched chromitites in the Ronda peridotites may support the hypothesis that CH4 is produced by CO2 hydrogenation catalyzed by Ru minerals, even at temperatures below 100°C, as demonstrated in recent laboratory experiments

  5. Lithospheric Structure Along the Wide-Angle Seismic Reflection Transect of the Central Iberian Massif

    NASA Astrophysics Data System (ADS)

    Ehsan, Siddique Akhtar; Carbonell, Ramon; Cembrowski, Marcel; Marti, David; Gil, Alba; Marzan, Ignacio; Ayarza, Puy; Martinez-Poyatos, David; Simancas, Jose Fernando; Azor, Antonio

    2014-05-01

    The Iberian Massif is the largest outcrop of the Late Paleozoic Variscan Orogen in western Europe. In May 2012, a spatially dense high resolution wide-angle seismic reflection profile ALCUDIA was acquired across the Central Iberian Massif. The ALCUDIA wide-angle profile investigates lithospheric structure of the Central Iberian Zone and a suture zone (the Central Unit). The experiment consisted in a main SW-NE line of receivers, c. 300 km long, and a supplementary transect, c. 35 km long, that sampled the crust beneath the Central Iberian System. The acoustic energy generated by 5 shots, c. 70 km apart, was recorded by over 900 TEXANS (single component, digital recording stations) from the IRIS-PASSCAL Instrument Center. Each shot consisted in 1 TM of explosives fired in a single 55-65 m deep borehole. Approximately, 100 stations were deployed across the Central Iberian System in an effort to map the topography of the crust mantle boundary beneath this mountain range. This design generated enough energy to be able to identify Pn and even mantle reflections. The preliminary analysis of the shot gathers reveals that the recorded events features relatively low frequencies (4-30 Hz). The processing of the shot gathers resulted into high amplitude reflective events within the upper crust and strong PmP phases. From the southwest to northeast, the interpreted PmP arrivals are located at c. 11 s and c. 12 s (normal incidence traveltime) respectively. The ALCUDIA wide-angle profile provided a detailed P-wave velocity structural model and complemented the previously acquired normal incidence deep seismic profile ALCUDIA. The velocity model obtained by forward modelling constraints the composition of the crust and upper mantle. The upper crust is located at c. 13 km and the Moho is in the 32-36 km range, equates to normal incidence reflection profile ALCUDIA. Existing knowledge indicates that the mid-lower crust along the southern part of the CIZ is characterized by

  6. Scattering of teleseismic waves in the lower crust Observations in the Massif Central, France

    NASA Astrophysics Data System (ADS)

    Ritter, Joachim R. R.; Martin Mai, P.; Stoll, Gerald; Fuchs, Karl

    1997-02-01

    High-frequency coda signals consistently recorded by a temporary seismic network of 29 short-period stations during a 6-month survey in the French Massif Central are concordant with independent evidence for a heterogeneous lower crust obtained from wide-angle and near-vertical reflection experiments in the same region. The teleseismic recordings of 22 events have been analysed in record sections rather than as single station seismograms. Following the low-frequency (LF; 0.5-1.5 Hz) first P-arrival a high-frequency (HF) coda (2-4 Hz dominant frequency) extends over several seconds duration. The HF signals become clearly visible after bandpass filtering, but can also be identified in the original seismograms. In event sections the HF coda forms a consistent pattern of reverberations which is characterized by the following properties: (1) the duration is typically longer on the radial (4-15 s) than on the vertical (3-11 s) component; (2) the beginning of the HF coda, referred to the picked LF first P-arrivals varies between 0-2.5 s, with a dominance around 1.5-2 s; (3) the amplitude of the HF coda is about 3%-10% of the primary LF P-phase amplitude; (4) the signals are incoherent between neighbouring stations and over the network; (5) the HF coda arrives dominantly around the plane of incidence of the teleseismic wave in the first 2 s to maximum 4 s; afterwards a widening of the particle motion to an elliptical shape is observed, indicating arrivals off the sagittal plane. The data parameters (1) to (5) point to the conclusion that the HF signals are generated by a scattering process. Wide-angle and CDP-reflection experiments in the same region measured a similar reverberating coda pattern and located the origin also in the lower crust. These observations and the data parameters of the HF coda suggest that the HF teleseismic waves are scattered at heterogeneities in the lower crust in the Massif Central. In this contribution we mainly concentrate on the presentation

  7. Paleoproterozoic sequences and magmatic complexes of the Losevo suture zone of the Voronezh crystalline massif: Geological position, material composition, geochemistry, and paleogeodynamics

    NASA Astrophysics Data System (ADS)

    Terentiev, R. A.

    2014-03-01

    In order to resolve the contradictions associated with uncertainty in the identification of the material composition, subdivision, and conditions of formation of the Paleoproterozoic intrusive, metavolcanogenic, and metasedimentary sequences of the Losevo suture zone of the Voronezh crystalline massif, this work presents geological, petrographic, petrochemical, and geochemical features of these sequences. The stratigraphic and magmatic scheme of the central part of the Losevo suture zone is clarified. In particular, the Paleoproterozoic Losevo Series is divided into two sequences: Strelitsa (marginal sea) and Podgornoe (island arc). A new hypabyssal Novo-Voronezh metagabbro-diabase complex, comagmatic to metatholeiites of the Podgornoe sequence, is distinguished. The isotope age of the Strelitsa sequence is assumed to be 2172 ± 17 Ma on the basis of the results of age dating of zircon cores from the Usman plagiogranites, intruding this sequence. The upper age boundary of the Strelitsa sequence corresponds to the age of premetamorphic gabbro of the Rozhdestvenskoe complex, comagmatic to metavolcanites (2120 ± 11-2158 ± 43 Ma). The age of the Usman plagiogranite complex is clarified. On the basis of geological-structural and petrographic-mineralogical analyses of metavolcanogenic rocks, lithological analysis of metasedimentary formations, and new geochemical data obtained from metavolcanites and metamorphosed deposits, the pattern of paleogeodynamic evolution of the Losevo suture zone in the first half of the Paleoproterozoic is proposed. The next stages are distinguished: (1) intrusion of tholeiites of transition T-MORB type in spreading zones and deposition of terrigenous strata in the marginal sea basins; (2) intrusion of Nb-depleted tholeiites and plagiorhyolites, the geochemical characteristics indicating their formation in the subduction setting; (3) intrusion of gabbroids of the Rozhdestvenskoe complex; (4) formation of an island arc synchronously with

  8. Alkaline chemistry of transuranium elements and technetium and the treatment of alkaline radioactive wastes

    SciTech Connect

    Delegard, C.H.; Peretrukhin, V.F.; Shilov, V.P.; Pikaev, A.K.

    1995-05-01

    Goal of this survey is to generalize the known data on fundamental physical-chemical properties of TRUs and Tc, methods for their isolation, and to provide recommendations that will be useful for partitioning them from alkaline high-level wastes.

  9. Isotope Sm-Nd age of the paleoproterozoic PGE-bearing Monchetundra massif trachytoid gabbronorites (Fennoscandian shield)

    NASA Astrophysics Data System (ADS)

    Kunakkuzin, Evgeniy; Bayanova, Tamara; Serov, Pavel; Borisenko, Elena

    2015-04-01

    Monchetundra massif is located in the central part of the Kola Peninsula (Russia) and it is the south-eastern part of the Main Ridge Intrusion. Monchetundra massif together with well-known layered mafic-ultramafic PGE-bearing intrusions in the Fennoscandian shield such as the Fedorovo-Pansky complex, the mt. Generalskaya, the Monchepluton is of interest as a target for the PGE prospecting (Mitrofanov et al. 2006; Nerovich et al., 2009; Grokhovskaya et al., 2003). According to some previously researchers (Nazimova, Rayan, 2008, Nerovich et al., 2009, Layered intrusions…p.1, 2004) rocks of the Monchetundra massif is subdivided into two to five syngenetic zones. Hence the last isotope-geochronological and isotope-geochemical data revealed that the massif includes at least four groups of mafic rocks distinguished by formation ages (Bayanova et al., 2010). The aim of this work is to present Sm-Nd dating results of trachytoid gabbronorites, which are the second mafic rocks group in the Monchetundra massif. The Sm-Nd investigations for these rocks were carried out for the first time. The second group of mafic rocks comprises of medium-grained and coarse-grained mesocratic gabbronorites of trachytoid texture, with they characterized by well-preserved primary magmatic minerals and gabbro-ophitic texture. The U-Pb ages on single zircon-baddeleyite for these rocks recently obtained (2505 ± 6 Ma, 2501 ± 8 Ma, 2504.4±2.7 Ma and 2507.5±7.7 Ma (Layered intrusions…p.1., 2004, Borisenko et al., 2013)). Two samples of trachytoid gabbronorites were selected to study these rocks by Sm-Nd isotopic method. Mineral isochrons plotted from plagioclase, ortho- and clinopyroxene and whole-rock minerals gave ages of 2496±27 (MSWD = 0.9; ɛNd = -1.6±0.5) and 2492±55 Ma (MSWD = 0.5; ɛNd = -1.7±0.5). The new Sm-Nd ages obtained are close to the U-Pb data on zircons and baddeleyites for this rocks group and consider as oridin of second mafic rocks group. All investigations are

  10. Internal structure of the Aar Massif: What can we learn in terms of exploration for deep geothermal energy?

    NASA Astrophysics Data System (ADS)

    Herwegh, Marco; Baumberger, Roland; Wehrens, Philip; Schubert, Raphael; Berger, Alfons; Maeder, Urs; Spillmann, Thomas

    2014-05-01

    The successful use of deep geothermal energy requires 3D flow paths, which allow an efficient heat exchange between the surrounding host rocks and the circulating fluids. Recent attempts to exploit this energy resource clearly demonstrate that the new technology is facing sever problems. Some major problems are related to the prediction of permeability, the 3D structure of the flow paths and the mechanical responses during elevated fluid pressures at depths of several kilometers. Although seemingly new in a technical perspective, nature is facing and solving similar problems since the beginning of the Alpine orogeny. Based on detailed studies in the Hasli Valley (Aar Massif) we can demonstrate that deformation and fluid flow are strongly localized along mechanical anisotropies (e.g. lithological variations, brittle and ductile faults). Some of them already evolved during Variscan and post-Variscan times. Interestingly, these inherited structures are reactivated over and over again during the Alpine orogeny. Their reactivation occurred at depths of ~13-15 km with elevated temperatures (400-475°C) and involved both ductile and brittle deformation processes. Brittle deformation in form of hydrofracking was always present due to the circulating fluids. It is this process, which was and still is responsible for seismic activity. With progressive uplift and exhumation of the Aar Massif, ductile deformation structures became replaced by brittle cataclasites and fault gouges during fault activity at shallower crustal levels. Existing hydrotest data from the Grimsel Test Site (Nagra's underground research laboratory) indicate that these brittle successors of the ductile shear zones are domains of enhanced recent fluid percolation. Note that although being exposed today, the continuation of these fault structures are still active at depth in both brittle and ductile deformation modes, a fact that can be inferred from recent uplift rates and the active seismicity. On the

  11. Structural Evolution in the Aar Massif (Central Alps): First attempts of linking the micron- to the kilometer-scale

    NASA Astrophysics Data System (ADS)

    Wehrens, P.; Baumberger, R.; Herwegh, M.

    2012-04-01

    The Aar massif belongs to the external massifs of the Alps and is mainly composed of granitoids and gneisses. Despite numerous detailed studies in the past decades, the overall exhumation history and the associated massif internal deformation (internal strain distribution and its evolution in time, kinematics etc.) are largely unknown at present. In this project, we aim to investigate the role of shear zones in the deformation history at a variety of scales. In this context it is important to understand their microstructural evolution, the involved deformation processes, kinematics and relative ages as well as the associated changes in rheology. A GIS-based remote-sensing structural map, verified by fieldwork, (see Baumberger et al., this volume) served as base for our investigations. Lithological differences between the units (Central Aare granite, ZAGr; Grimsel granodiorte, GrGr and gneisses) cause strain to localize along these contacts. Furthermore, the initial magmatic differentiation in the granitoids locally controls the Alpine deformational overprint because of differences in effective viscosity during solid-state deformation. This behavior is illustrated by the increase of foliation intensity and the number of shear zones per rock volume from ZAGr to GrGr. Preliminary results show that deformation at the N boundary of the Aar massif has to be distinguished from the central and the southern part. In the North steep NE-SW trending foliations and shear zones with subvertical lineations represent the major structures. The shear zones acted both as normal faults and as reverse faults, which mostly used pre-existing lithological boundaries between the different gneiss units. In a later stage, E-W trending shear zones and shear bands with moderate dipping angles cross cut the earlier structures. They always show a top to the North component and might be related to the late north directed movements of the Aar massif. Yet, no absolute age dating has been performed

  12. DNA DAMAGE QUANTITATION BY ALKALINE GEL ELECTROPHORESIS.

    SciTech Connect

    SUTHERLAND,B.M.; BENNETT,P.V.; SUTHERLAND, J.C.

    2004-03-24

    Physical and chemical agents in the environment, those used in clinical applications, or encountered during recreational exposures to sunlight, induce damages in DNA. Understanding the biological impact of these agents requires quantitation of the levels of such damages in laboratory test systems as well as in field or clinical samples. Alkaline gel electrophoresis provides a sensitive (down to {approx} a few lesions/5Mb), rapid method of direct quantitation of a wide variety of DNA damages in nanogram quantities of non-radioactive DNAs from laboratory, field, or clinical specimens, including higher plants and animals. This method stems from velocity sedimentation studies of DNA populations, and from the simple methods of agarose gel electrophoresis. Our laboratories have developed quantitative agarose gel methods, analytical descriptions of DNA migration during electrophoresis on agarose gels (1-6), and electronic imaging for accurate determinations of DNA mass (7-9). Although all these components improve sensitivity and throughput of large numbers of samples (7,8,10), a simple version using only standard molecular biology equipment allows routine analysis of DNA damages at moderate frequencies. We present here a description of the methods, as well as a brief description of the underlying principles, required for a simplified approach to quantitation of DNA damages by alkaline gel electrophoresis.

  13. Autonomous in situ measurements of seawater alkalinity.

    PubMed

    Spaulding, Reggie S; DeGrandpre, Michael D; Beck, James C; Hart, Robert D; Peterson, Brittany; De Carlo, Eric H; Drupp, Patrick S; Hammar, Terry R

    2014-08-19

    Total alkalinity (AT) is an important parameter for describing the marine inorganic carbon system and understanding the effects of atmospheric CO2 on the oceans. Measurements of AT are limited, however, because of the laborious process of collecting and analyzing samples. In this work we evaluate the performance of an autonomous instrument for high temporal resolution measurements of seawater AT. The Submersible Autonomous Moored Instrument for alkalinity (SAMI-alk) uses a novel tracer monitored titration method where a colorimetric pH indicator quantifies both pH and relative volumes of sample and titrant, circumventing the need for gravimetric or volumetric measurements. The SAMI-alk performance was validated in the laboratory and in situ during two field studies. Overall in situ accuracy was -2.2 ± 13.1 μmol kg(-1) (n = 86), on the basis of comparison to discrete samples. Precision on duplicate analyses of a carbonate standard was ±4.7 μmol kg(-1) (n = 22). This prototype instrument can measure in situ AT hourly for one month, limited by consumption of reagent and standard solutions. PMID:25051401

  14. Solubility of uranium in alkaline salt solutions

    SciTech Connect

    Hobbs, D.T.; Edwards, T.B.

    1994-03-29

    The solubility of uranium in alkaline salt solutions was investigated to screen for significant factors and interactions among the major salt components and temperature. The components included in the study were the sodium salts of hydroxide, nitrate, nitrite, aluminate, sulfate, and carbonate. General findings from the study included: (1) uranium solubilities are very low (1-20 mg/L) for all solution compositions at hydroxide concentrations from 0.1 to 17 molar (2) carbonate, sulfate, and aluminate are not effective complexants for uranium at high hydroxide concentration, (3) uranium solubility decreases with increasing temperature for most alkaline salt solutions, and (4) uranium solubility increases with changes in solution chemistry that reflect aging of high level waste (increase in nitrite and carbonate concentrations, decrease in nitrate and hydroxide concentrations). A predictive model for the concentration of uranium as a function of component concentrations and temperature was fitted to the data. All of the solution components and temperature were found to be significant. There is a significant lack of fit for the model, which suggests that the dependence on the uranium solubility over the wide range of solution compositions is non-linear and/or that there are other uncontrolled parameters which are important to the uranium solubility.

  15. Molecular modeling of human alkaline sphingomyelinase.

    PubMed

    Suresh, Panneer Selvam; Olubiyi, Olujide; Thirunavukkarasu, Chinnasamy; Strodel, Birgit; Kumar, Muthuvel Suresh

    2011-01-01

    Alkaline sphingomyelinase, which is expressed in the human intestine and hydrolyses sphingomyelin, is a component of the plasma and the lysosomal membranes. Hydrolase of sphingomyelin generates ceramide, sphingosine, and sphingosine 1-phosphate that have regulatory effects on vital cellular functions such as proliferation, differentiation, and apoptosis. The enzyme belongs to the Nucleotide Pyrophosphatase/Phosphodiesterase family and it differs in structural similarity with acidic and neutral sphingomyelinase. In the present study we modeled alkaline sphingomyelinase using homology modeling based on the structure of Nucleotide Pyrophosphatase/Phosphodiesterase from Xanthomonas axonopodis with which it shares 34% identity. Homology modeling was performed using Modeller9v7. We found that Cys78 and Cys394 form a disulphide bond. Further analysis shows that Ser76 may be important for the function of this enzyme, which is supported by the findings of Wu et al. (2005), that S76F abolishes the activity completely. We found that the residues bound to Zn(2+) are conserved and geometrically similar with the template. Molecular Dynamics simulations were carried out for the modeled protein to observe the effect of Zinc metal ions. It was observed that the metal ion has little effect with regard to the stability but induces increased fluctuations in the protein. These analyses showed that Zinc ions play an important role in stabilizing the secondary structure and in maintaining the compactness of the active site. PMID:21544170

  16. Bone alkaline phosphatase in rheumatic diseases.

    PubMed

    Beyeler, C; Banks, R E; Thompson, D; Forbes, M A; Cooper, E H; Bird, H

    1995-07-01

    A double monoclonal immunoradiometric assay specific for bone alkaline phosphatase (BAP) was used to determine whether the raised total alkaline phosphatase (TAP) often found in patients with active rheumatoid arthritis (RA) and ankylosing spondylitis (AS) is derived from bone or liver. Fifty-eight patients with RA were compared to 14 with AS and 14 with non-inflammatory rheumatic diseases (NI). None had clinical liver disease and only one had a slightly elevated aspartate transaminase activity. Elevated BAP concentrations were found in seven patients (5 RA, 1 AS, 1 NI), only two of whom also had abnormal TAP. Abnormal TAP activities were found in only three patients (all RA). BAP did not correlate with disease activity in RA or AS. In contrast, TAP correlated with disease activity (assessed by plasma viscosity) in RA (P < 0.002) and gamma-glutamyl transferase (GGT) also correlated with plasma viscosity in RA (P < 0.01). Both TAP and BAP were significantly correlated with GGT in RA (P < 0.001 and P < 0.02, respectively). These findings are discussed, together with possible reasons for the conflicting nature of some of the observations. PMID:7486797

  17. Advanced inorganic separators for alkaline batteries

    NASA Technical Reports Server (NTRS)

    Sheibley, D. W. (Inventor)

    1982-01-01

    A flexible, porous battery separator comprising a coating applied to a porous, flexible substrate is described. The coating comprises: (1) a thermoplastic rubber-based resin which is insoluble and unreactive in the alkaline electrolyte; (2) a polar organic plasticizer which is reactive with the alkaline electrolyte to produce a reaction product which contains a hydroxyl group and/or a carboxylic acid group; and (3) a mixture of polar particulate filler materials which are unreactive with the electrolyte, the mixture comprising at least one first filler material having a surface area of greater than 25 meters sq/gram, at least one second filler material having a surface area of 10 to 25 sq meters/gram, wherein the volume of the mixture of filler materials is less than 45% of the total volume of the fillers and the binder, the filler surface area per gram of binder is about 20 to 60 sq meters/gram, and the amount of plasticizer is sufficient to coat each filler particle. A method of forming the battery separator is also described.

  18. The Chineysky layered massif (Siberia, Russia) and Upper Zone of the Bushveld Complex: resemblance and difference features

    NASA Astrophysics Data System (ADS)

    Gongalskiy, B.; Krivolutskaya, N.

    2009-04-01

    Layered intrusions represent a small part of a large group of continental basic-ultrabasic complexes. They attract geologists' attention due to their unusual magmatic structures and associated PGE, Cr and V deposits. The outstanding example of this phenomenon is the Bushveld Complex in South Africa. The largest layered intrusion in Russia is the Chineysky massif (Transbaikalia, Siberia). It is characterized by excellent layering and accompanying titanomagnetite and sulfide mineralization. It hosts Russia's largest deposits of Fe-Ti-V ores which are also among the world's largest [1]. Origin of such huge metal concentrations in the crust is unsettled problem. Therefore the ore conditions' determination from different intrusions is very actually. We compared the structure, rock and parental magmas compositions for two plutons mentioned above. The Chineysky massif consists of gabbronorites and anorthozites and the petrography of the rocks resembles that of the Upper Zone of the Bushveld [3]. Vanadium ores from these two intrusions are very similar: they are represented by massive and disseminated varieties. However, the small size of Chineysky massiv gives an opportunity to observe the number of petrological processes in a frame of one area, as opposed to Bushveld, where this is impossible. The separateness of the bodies and the scarcity of geochemical data on their rocks precluded the development of a comprehensive model for the evolution of magmatism in this part of the Kodar- Udokan trough. So one of the tasks of our research was to study the spatial and genetic relations between the ultrabasite-basite intrusive bodies and their possible grouping within a single magmatic system, with the Chineysky massif being its part. The second tasks was to determine the phase characteristics of the parental magma of the massif . An important aspect of this study was the examination of the inner structure of the Chineysky massiv. The main features of the structure are following

  19. The corrosion resistance of thermoset composites in alkaline environments

    SciTech Connect

    Kelley, D.H.; Thompson, M.J.

    1998-12-31

    Corrosion engineers need guidelines for selecting thermoset resins for aggressive applications such as hot alkali and alkaline peroxide. The suitability of fiberglass-reinforced plastic (FRP) for alkaline service depends on factors such as the ester content of the resin, the unsaturated monomer composition, and the cure system. The purpose of the present paper is to show the effect of these factors on the alkaline corrosion resistance of FRP and provide corrosion engineers with the guidance needed for selecting the best epoxy vinyl ester resins for alkaline environments.

  20. Rechargeable Zn-MnO sub 2 alkaline batteries

    SciTech Connect

    Wruck, W.J.; Reichman, B.; Bullock, K.R.; Kao, W.H. )

    1991-12-01

    In this paper progress in the development of rechargeable alkaline zinc-manganese dioxide cells is described. The advantages and limitations of the system are evaluated. Laboratory tests run on commercial primary alkaline cells as well as model simulations of a bipolar MnO{sub 2} electrode show that the rechargeable alkaline battery may be able to compete with lead-acid, nickel-cadmium, and secondary lithium cells for low- to moderate-rate applications. However, because of this poor performance at high rates and low temperatures, the alkaline MnO{sub 2} battery is not suitable for present automotive starting applications.

  1. Time scales of regional circulation of saline fluids in continental aquifers (Armorican massif, Western France)

    NASA Astrophysics Data System (ADS)

    Armandine Les Landes, A.; Aquilina, L.; Davy, P.; Vergnaud, V.; le Carlier, C.

    2014-06-01

    In recent decades, saline fluids have been sampled worldwide at great depths in continental basements. Although some of them have been attributed to marine transgressions the mechanisms allowing their circulation is not understood. In this paper, we describe the horizontal and vertical distribution of moderately saline fluids (60 to 1400 mg L-1) sampled at depths ranging from 41 to 200 m in aquifers at the regional scale of the Armorican Massif (northwestern France). The horizontal and vertical distributions of high chloride concentrations are in good agreement with both the altitudinal and vertical limits and succession of the three major transgressions between the Mio-Pliocene and Pleistocene ages. The mean chloride concentration for each transgression area is exponentially related to the time spanned until present. It defines the potential laws of leaching of marine waters by fresh meteoric waters. The results of the Armorican aquifers provide the first observed constraints for the time scales of seawater circulation in the continental basement and the subsequent leaching by fresh meteoric waters. The general trend of increasing chloride concentration with depth and the time frame for the flushing process provide useful information to develop conceptual models of the paleo-functionning of Armorican aquifers.

  2. Timescales of regional circulation of saline fluids in continental crystalline rock aquifers (Armorican Massif, western France)

    NASA Astrophysics Data System (ADS)

    Armandine Les Landes, A.; Aquilina, L.; Davy, P.; Vergnaud-Ayraud, V.; Le Carlier, C.

    2015-03-01

    In recent decades, saline fluids have been sampled worldwide at great depths in continental basements. Although some of them have been attributed to marine transgressions, the mechanisms allowing their circulation are not understood. In this paper, we describe the horizontal and vertical distributions of moderately saline fluids (60 to 1400 mg L-1) sampled at depths ranging from 41 to 200 m in crystalline rock aquifers on the regional scale of the Armorican Massif (northwestern France). The horizontal and vertical distributions of high chloride concentrations are in good agreement with both the altitudinal and vertical limits and the succession of the three major transgressions between the Mio-Pliocene and Pleistocene ages. The mean chloride concentration for each transgression area is exponentially related to the time spanned until the present. It defines the potential laws of leaching (displacement) of marine waters by fresh meteoric waters. The results of the Armorican aquifers provide the first observed constraints for the timescales of seawater circulation in the continental crystalline basement and the subsequent leaching by fresh meteoric waters. The general trend of increasing chloride concentration with depth and the time frame for the flushing process provide useful information to develop conceptual models of the paleo-functioning of Armorican aquifers.

  3. Vorticity analysis in calcite tectonites: An example from the Attico-Cycladic massif (Attica, Greece)

    NASA Astrophysics Data System (ADS)

    Spanos, D.; Xypolias, P.; Koukouvelas, I.

    2015-11-01

    Although calcite tectonites are widespread in nature their use to quantify flow vorticity is limited. We use new (micro-)structural, petrofabric and vorticity data to analyse the kinematics of flow in outcrop-scale calcite mylonite zones. These zones are genetically related to a crustal-scale NE-directed ductile thrust (Basal Thrust) that emplaced the Blueschist over the Basal unit during the exhumation of the Attico-Cycladic Massif. Calcite microstructures reveal that the last stage of deformation occurred at temperatures 200-300 °C achieved by mild heating, which is possibly related with the reburial of the Basal Thrust's footwall. Vorticity analyses were based on the degree of asymmetry of calcite c-axis fabrics as well as on the assumption that the orientation of the long axes of calcite neoblasts within an oblique foliation delineates the direction of instantaneous stretching axis. Both methodological approaches provide consistent estimates with a simple shear component between 55% and 82% (Wn = 0.76-0.96). The use of the stress axis (σ1) orientation recorded by twin-c-axis-pairs to quantify vorticity generally gives significantly lower simple shear component. Comparison of our vorticity estimates with previous estimates inferred from quartz fabrics and rigid porphyroclasts reveals that exhumation-related deformation in the nappe pile was steady state.

  4. Raman mapping of coesite inclusions in garnet from the Kokchetav Massif (Northern Kazakhstan).

    PubMed

    Korsakov, Andrey V; Hutsebaut, Didier; Theunissen, Karel; Vandenabeele, Peter; Stepanov, Alexander S

    2007-12-15

    Coesite inclusions occur in a wide range of lithologies and coesite is therefore a powerful ultrahigh-pressure (UHP) indicator. The transformation of coesite to quartz is evidenced by three optically well identifiable characteristics (e.g. palisade textures, radial crack patterns, polycrystalline quartz pseudomorphs). Under overpressure monomineralic coesite (on an optical basis), lacking the above transformation characteristics may survive. Raman micro-spectroscopy was applied on monomineralic coesite inclusions in garnet porphyroblasts from diamond-bearing garnet-clinozoisite-biotite gneisses of the Barchi-Kol area (Kokchetav Massif, Northern Kazakhstan). These coesite inclusions are euhedral and display a characteristic anisotropic hallo. However, Raman maps and separate spectra of these inclusions display shifted bands for coesite and quartz. Microscopically undetectable, quartz shows on the Raman map as a thin shell around coesite inclusion. Shift of the main coesite band allows to estimate their overpressure: coesite inclusions record 0-2.4 GPa in garnet and zircon. The quartz shell remains under lower pressure 0-1.6 GPa. The possible application of coesite and quartz Raman geobarometers for UHP metamorphic rocks is discussed. PMID:17553735

  5. Raman imaging of fluid inclusions in garnet from UHPM rocks (Kokchetav massif, Northern Kazakhstan).

    PubMed

    Korsakov, Andrey V; Dieing, Thomas; Golovin, Aleksandr V; Toporski, Jan

    2011-10-01

    Confocal Raman imaging of fluid inclusions in garnet porphyroblasts from diamond-grade metamorphic calc-silicate rocks from the Kumdy-Kol microdiamond deposit (Kokchetav Massif, Northern Kazakhstan) reveals that these fluid inclusions consist of almost pure water with different step-daughter phases (e.g., calcite, mica and rare quartz). These fluid inclusions are characterized by negative crystal shape of the host-garnet and they exclusively occur within the core of garnet porphyroblasts. These observations are consistent with their primary origin, most likely at ultrahigh-pressure (UHP) metamorphic conditions. The euhedral newly formed garnet, different in color and composition, was found to be associated with these fluid inclusions. It is proposed that newly formed garnet and water fluid inclusions appear by reaction between the hydrous fluid and the garnet-host. These fluid inclusions provide an unequivocal record of almost pure H(2)O fluids, indicating water-saturated conditions within subducted continental crust during prograde stage and/or ultrahigh-P metamorphism. PMID:21377920

  6. AMS 14C Dates for Extinct Lemurs from Caves in the Ankarana Massif, Northern Madagascar

    NASA Astrophysics Data System (ADS)

    Simons, Elwyn L.; Burney, David A.; Chatrath, Prithijit S.; Godfrey, Laurie R.; Jungers, William L.; Rakotosamimanana, Berthe

    1995-03-01

    An extensive late Quaternary fauna, including many extinct giant lemurs, has been collected recently in a 110+-km system of caves in the Ankarana Massif of northern Madagascar. AMS 14C dates for the acid-insoluble (collagen/gelatin) fraction of bones of the giant lemur Megaladapis (26,150 ± 400 and 12,760 ± 70 yr B.P.) confirm its presence in the area during the late Pleistocene and provide the first Pleistocene 14 C ages from bones of the extinct megafauna of the island. The first date from bones of the recently described extinct Babakotia radofilai (4400 ± 60 yr B.P.) shows that it was present in northern Madagascar in mid-Holocene times. A comparatively recent age of 1020 ± 50 yr B.P. for the extinct Archaeolemur indicates survival of this genus for at least a millennium after the first direct evidence for humans in Madagascar. This suggests that the island's "extinction window" may have represented a longer time span than would have been expected under the Blitzkrieg model of late Quaternary extinctions. A mid-Holocene age (4560 ± 70 yr B.P.) for a bone sample of the small extant lemur Hapalemur simus indicates that the disappearance of this now-restricted species from the Ankarana occurred after this date. New data from the Ankarana and other sites on the island add to the consensus that major biotic changes occurred on Madagascar in the late Holocene.

  7. Using several monitoring techniques to measure the rock mass deformation in the Montserrat Massif

    NASA Astrophysics Data System (ADS)

    Janeras, M.; Jara, J. A.; López, F.; Marturià, J.; Royán, M. J.; Vilaplana, J. M.; Aguasca, A.; Fàbregas, X.; Cabranes, F.; Gili, J. A.

    2015-09-01

    Montserrat Mountain is located near Barcelona in Catalonia, at the north-east corner of Spain, and its massif is formed by conglomerate interleaved by siltstone/sandstone with steep slopes very prone to rock falls. The increasing visitor's number in the monastery area, reaching 2.4 million per year, has pointed out the risk derived from rock falls for this building area and also for the terrestrial accesses, both roads and rack railway. A risk mitigation plan is currently been applied for 2014-2016 that contains monitoring testing and implementation as a key point. The preliminary results of the pilot tests carried out during 2014 are presented, also profiting from previous sparse experiences and data, and combining 4 monitoring techniques under different conditions of continuity in space and time domains, which are: displacement monitoring with Ground-based Synthetic Aperture Radar and characterization at slope scale, with an extremely non uniform atmospheric phase screen because of the stepped topography and atmosphere stratification; Terrestrial Laser Scanner surveys quantifying frequency for unnoticed activity of small rock falls, and monitoring rock block displacements over 1cm; monitoring of rock joints with a wireless net of sensors; and tentative surveying for singular rocky needles with Total Station.

  8. Adjusting stream-sediment geochemical maps in the Austrian Bohemian Massif by analysis of variance

    USGS Publications Warehouse

    Davis, J.C.; Hausberger, G.; Schermann, O.; Bohling, G.

    1995-01-01

    The Austrian portion of the Bohemian Massif is a Precambrian terrane composed mostly of highly metamorphosed rocks intruded by a series of granitoids that are petrographically similar. Rocks are exposed poorly and the subtle variations in rock type are difficult to map in the field. A detailed geochemical survey of stream sediments in this region has been conducted and included as part of the Geochemischer Atlas der Republik O??sterreich, and the variations in stream sediment composition may help refine the geological interpretation. In an earlier study, multivariate analysis of variance (MANOVA) was applied to the stream-sediment data in order to minimize unwanted sampling variation and emphasize relationships between stream sediments and rock types in sample catchment areas. The estimated coefficients were used successfully to correct for the sampling effects throughout most of the region, but also introduced an overcorrection in some areas that seems to result from consistent but subtle differences in composition of specific rock types. By expanding the model to include an additional factor reflecting the presence of a major tectonic unit, the Rohrbach block, the overcorrection is removed. This iterative process simultaneously refines both the geochemical map by removing extraneous variation and the geological map by suggesting a more detailed classification of rock types. ?? 1995 International Association for Mathematical Geology.

  9. Analysis of the upper massif of the craniofacial with the radial method – practical use

    PubMed Central

    Lepich, Tomasz; Dąbek, Józefa; Stompel, Daniel; Gielecki, Jerzy S.

    2011-01-01

    Introduction The analysis of the upper massif of the craniofacial (UMC) is widely used in many fields of science. The aim of the study was to create a high resolution computer system based on a digital information record and on vector graphics, that could enable dimension measuring and evaluation of craniofacial shape using the radial method. Material and methods The study was carried out on 184 skulls, in a good state of preservation, from the early middle ages. The examined skulls were fixed into Molisson's craniostat in the author's own modification. They were directed in space towards the Frankfurt plane and photographed in frontal norm with a digital camera. The parameters describing the plane and dimensional structure of the UMC and orbits were obtained thanks to the computer analysis of the function recordings picturing the craniofacial structures and using software combining raster graphics with vector graphics. Results It was compared mean values of both orbits separately for male and female groups. In female skulls the comparison of the left and right side did not show statistically significant differences. In male group, higher values were observed for the right side. Only the circularity index presented higher values for the left side. Conclusions Computer graphics with the software used for analysing digital pictures of UMC and orbits increase the precision of measurements as well as the calculation possibilities. Recognition of the face in the post mortem examination is crucial for those working on identification in anthropology and criminology laboratories. PMID:22291834

  10. Geologic implications of seafloor character and carbonate lithification imaged on the domal core of Atlantis Massif

    NASA Astrophysics Data System (ADS)

    Greene, John A.; Tominaga, Masako; Blackman, Donna K.

    2015-11-01

    We document the seafloor character on Atlantis Massif, an ocean core complex located at 30°N on the Mid-Atlantic Ridge, with an emphasis on the distribution of carbonate features. Seafloor imagery, near-bottom backscatter, and bathymetry were analyzed on the Central Dome and the Western Shoulder of the exposed footwall to the detachment, and on the Eastern Block, a hanging wall to the fault. We merged Argo II still images to produce photo-mosaics and evaluated these together with video imagery, acoustic reflectivity, and basic rock composition. The seafloor was classified as unconsolidated sediment, lithified carbonate crust, consolidated carbonate cap, exposed basement, or rubble, and the spatial distribution of each type was assessed. Unconsolidated sediment, exposed basement, and rubble were documented in all three regions studied. Lithified carbonate crust was also present on the Western Shoulder and eastern Central Dome. Consolidated carbonate cap was found on the Eastern Block. The formation of the carbonate rock is interpreted to reflect precipitation and/or sediment cementation via fluids derived from serpentinization. Both processes occur at the nearby Lost City Hydrothermal Field. The newly documented locations of seafloor carbonate lithification therefore mark pathways of past, possibly recent, fluid flux from subsurface water-rock reaction zones and represent an additional constituent of the carbon cycling hosted by oceanic lithosphere.

  11. Spatial variability in channel and slope morphology within the Ardennes Massif, and its link with tectonics

    NASA Astrophysics Data System (ADS)

    Sougnez, N.; Vanacker, V.

    2010-09-01

    Geomorphic processes that produce and transport sediment, and incise river valleys are complex; and often difficult to quantify over longer timescales of 103 to 105 years. Morphometric indices that describe the topography of hill slopes, valleys and river channels have commonly been used to compare morphological characteristics between catchments and to relate them to hydrological and erosion processes. This work focuses on a wide range of slope and river channel morphometric indices to study their behavior and strength in regions affected by low to moderate tectonic activity. We selected 10 catchments of about 150 to 250 km2 across the Ardennes Massif that cover various tectonic domains with uplift rates ranging from about 0.06 to 0.20 mm year-1 since mid-Pleistocene times. The morphometric analysis indicates that the slope and channel morphology of third-order catchments is not yet in topographic steady-state, and exhibits clear convexities in slope and river profiles. Our data indicate that the fluvial system is the main driver of topographic evolution and that the spatial pattern of uplift rates is reflected in the distribution of channel steepness and convexity. The spatial variation that we observe in slope and channel morphology between the 10 third-order catchments suggests that the response of the fluvial system was strongly diachronous, and that a transient signal of adjustment is migrating from the Meuse valley towards the Ardennian headwaters.

  12. Nature of radioactive contamination of components of ecosystems of streamflows from tunnels of Degelen massif.

    PubMed

    Panitskiy, A V; Lukashenko, S N

    2015-06-01

    The paper provides data on environmental contamination due to radionuclides' migration with water. As a result of investigations there was obtained data on character of contamination of soil cover, surface water and underflow from tunnels of Degelen massif. Character of radionuclides' spatial distribution in environment was also shown. Mobility ranges of radionuclides' vertical and horizontal movements have been established in soils both across and along the stream flow. There was also shown a possibility to forecast radionuclides' concentration in soil by specific activity of these radionuclides in water. Different concentrations of radionuclides in associated components of the ecosystem (surface waters - ground waters - soils) have shown disequilibrium of their condition in this system. Generalization of investigation results for tunnel water streams' with water inflows, chosen as investigation objects in this work, allows to forecast radionuclides' behavior in meadow soils and other ecosystems of water streams from tunnels of Degelen test site. Based on analysis of curves, describing radionuclides' behavior in horizontal direction, we can forecast, that at this stage (137)Cs and (239+240)Pu would not be distributed more than 1.5 km from the access to the daylight surface, (90)Sr - not more than 2 km. PMID:25791901

  13. Boiling fluids in a region of rapid uplift, Nanga Parbat Massif, Pakistan

    NASA Astrophysics Data System (ADS)

    Craw, D.; Koons, P. O.; Winslow, D.; Chamberlain, C. P.; Zeitler, P.

    1994-12-01

    The Nanga Parbat massif of northern Pakistan is currently undergoing rapid uplift (approx. 5-10 mm/a), resulting in near-surface elevated temperatures. Numerous quartz veins cut geologically young structures (less than 2 Ma), attesting to widespread young fluid flow. Fluid inclusions in quartz veins are predominantly low density water vapor (down to 0.05 mg/cu m), with some low density carbon dioxide vapor, and the fluid is predominantly meteoric in origin. Fluid inclusions provide evidence for boiling near to the critical points for water and for 5 wt% NaCl solution (up to 410 C). Head-driven meteoric water was convecting in fracture permeability under hydrostatic pressures which followed the boiling point-depth curve and near-boiling springs emanate from the surface. Hydrostatic pressures persisted to depths of about 6 km below the topographic surface, or near to sea level, where the brittle-ductile transition is inferred to lie. Numerical modeling of conductive heat flow in an area of high relief during rapid uplift indicates that the shape of the near-surface conductive geotherm is significantly influenced by topographic relief. Reasonable approximations for topgraphy at Nanga Parbat produce a conductive geotherm which implies high, near-surface geothermal gradients (greater than 100 C/km, and the isotherms describe a giant pillar of heat. Above about 4 km, fluid temperature is greater than conductive rock temperature in permeable zones which carry convecting boiling meteoric fluid.

  14. Three-dimensional shape and emplacement of the Cardenchosa deformed pluton (Variscan Orogen, southwestern Iberian Massif)

    NASA Astrophysics Data System (ADS)

    Simancas, J. Fernando; Galindo-Zaldívar, Jesús; Azor, Antonio

    2000-04-01

    The Cardenchosa pluton is a Lower Carboniferous Variscan granite located in the southwestern Iberian Massif. It intruded along the contact between the Sierra Albarrana and Azuaga tectonic units. To the northwest the pluton connects with the left-lateral Azuaga fault. The pluton appears in the footwall of the low-angle normal Casa del Café fault, which crops out to the west of the granite. Gravimetric modelling shows the pluton to have a flat bottom at a depth of 2 km. Strain analysis of post-emplacement deformation of the pluton indicates that: (a) the deformation of the pluton accommodates the displacement of the Azuaga fault; and (b) the pluton prior to the solid state deformation was a lens-shaped laccolith of approximately 10 km diameter and 2 km thickness. The Cardenchosa pluton was a single pulse of magma trapped in a rheological discontinuity of the upper crust (the contact between the Sierra Albarrana and Azuaga units). The magma would ascend through dikes since no root has been detected. The tectonic scenario during the intrusion was one of regional extension.

  15. Effect of alkaline addition on anaerobic sludge digestion with combined pretreatment of alkaline and high pressure homogenization.

    PubMed

    Fang, Wei; Zhang, Panyue; Zhang, Guangming; Jin, Shuguang; Li, Dongyi; Zhang, Meixia; Xu, Xiangzhe

    2014-09-01

    To improve anaerobic digestion efficiency, combination pretreatment of alkaline and high pressure homogenization was applied to pretreat sewage sludge. Effect of alkaline dosage on anaerobic sludge digestion was investigated in detail. SCOD of sludge supernatant significantly increased with the alkaline dosage increase after the combined pretreatment because of sludge disintegration. Organics were significantly degraded after the anaerobic digestion, and the maximal SCOD, TCOD and VS removal was 73.5%, 61.3% and 43.5%, respectively. Cumulative biogas production, methane content in biogas and biogas production rate obviously increased with the alkaline dosage increase. Considering both the biogas production and alkaline dosage, the optimal alkaline dosage was selected as 0.04 mol/L. Relationships between biogas production and sludge disintegration showed that the accumulative biogas was mainly enhanced by the sludge disintegration. The methane yield linearly increased with the DDCOD increase as Methane yield (ml/gVS)=4.66 DDCOD-9.69. PMID:24703958

  16. Understanding the Tectonic Deformation of Turkish Blocks since Mesozoic; A Paleomagnetic study on the Nigde-Kirsehir Massif and the Taurides

    NASA Astrophysics Data System (ADS)

    Mualla, Cinku; Mumtaz, Hisarli; Ulker, Beyza; Kaya, Nurcan; Oksum, Erdinc; Yilmaz, Yucel; Orbay, Naci

    2015-04-01

    It is reported that the Nigde-Kirsehir massif which constitutes the main fragment of Anatolia is rifted from the Taurides-Anatolides in Mesozoic and that the Intra-Tauride ocean exist between these blocks. Another group of researchers believed that the Intra Tauride ocean did not exist. They assumed that the Nigde-Kirsehir massif existed as a promotory of the Taurides. In this sense, both the Nigde-Kirsehir massif and the Taurides experienced several deformation phases due to the consumption of the oceanic strand (s) and the amalgamation of the Anatolian blocks after collision in the end of the paleotectonic time, whereas in the neotectonic time the traces of the westwards excursion of Anatolia was effective. Previous paleomagnetic studies showed that the Nigde-Kirsehir massif rotated 90° anticlockwise during Jurassic to Eocene time and other studies showed that the collision between the Nigde-Kirsehir massif and the Pontides resulted by deformation which was accomodated by regional faults. In the south of the Nigde-Kirsehir massif, it was proposed that all the rocks in Carboniferous to Eosen were remagnetized due to nap emplacement in Eocene. Because of several alternative interpretations about the tectonic deformation of the Nigde-Kirsehir massif in relation between the Taurides and the Pontides, we report new paleomagnetic results from Late Jurassic to Miocene rocks in the Nigde-Kirsehir massif and its surrounding. A total of 138 different sites were sampled from Jurassic to Miocene rocks in the south of the Nigde-Kirsehir massif around Ki ri kkale, Tuzgölü, Uluki şla and Kayseri, whereas in the Central Taurides Late Jurassic- Lower Cretaceous platform type carbonates and ophiolitic rocks from Mersin and Pozanti were collected. Paleomagnetic results evaluated together with previous paleomagnetic data indicate that all the studied rocks carry a magnetization before folding according to positive incremental fold tests. It has been shown that in the SE/E (SE

  17. Lithologic Distribution and Geologic History of the Apollo 17 Site: The Record in Soils and Small Rock Particles from the Highland Massifs

    NASA Technical Reports Server (NTRS)

    Jolliff, Bradley L.; Rockow, Kaylynn M.; Korotev, Randy L.; Haskin, Larry A.

    1996-01-01

    Through analysis by instrumental neutron activation (INAA) of 789 individual lithic fragments from the 2 mm-4 mm grain-size fractions of five Apollo 17 soil samples (72443, 72503, 73243, 76283, and 76503) and petrographic examination of a subset, we have determined the diversity and proportions of rock types recorded within soils from the highland massifs. The distribution of rock types at the site, as recorded by lithic fragments in the soils, is an alternative to the distribution inferred from the limited number of large rock samples. The compositions and proportions of 2 mm-4 mm fragments provide a bridge between compositions of less than 1 mm fines and types and proportions of rocks observed in large collected breccias and their clasts. The 2 mm-4 mm fraction of soil from South Massif, represented by an unbiased set of lithic fragments from station-2 samples 72443 and 72503, consists of 71% noritic impact-melt breccia, 7% Incompatible-Trace-Element-(ITE)-poor highland rock types (mainly granulitic breccias), 19% agglutinates and regolith breccias, 1% high-Ti mare basalt, and 2% others (very-low-Ti (VLT) basalt, monzogabbro breccia, and metal). In contrast, the 2 mm - 4 mm fraction of a soil from the North Massif, represented by an unbiased set of lithic fragments from station-6 sample 76503, has a greater proportion of ITE-poor highland rock types and mare-basalt fragments: it consists of 29% ITE-poor highland rock types (mainly granulitic breccias and troctolitic anorthosite), 25% impact-melt breccia, 13% high-Ti mare basalt, 31 % agglutinates and regolith breccias, 1% orange glass and related breccia, and 1% others. Based on a comparison of mass- weighted mean compositions of the lithic fragments with compositions of soil fines from all Apollo 17 highland stations, differences between the station-2 and station-6 samples are representative of differences between available samples from the two massifs. From the distribution of different rock types and their

  18. Sr, Nd, Hf and Pb isotope systematics of basaltic samples from IODP Site U1349A, Ori Massif of the Shatsky Rise Oceanic Plateau, Northwest Pacific

    NASA Astrophysics Data System (ADS)

    Romanova, I.; Murphy, D. T.; Geldmacher, J.; Heydolph, K.

    2011-12-01

    Shatsky Rise is located on the northwest Pacific plate, and has an elongated structure from southeast to northwest. It represents a large oceanic plateau (up to 500 km wide) that was formed between 140-150 Ma in an active spreading ridge at relatively high emplacement rates (1.2-4.6 km3/y), similar to those of some flood basalt provinces [1]. Whether the Shatsky Rise formed by the impact of a mantle plume head or by shallow mantle processes at a rapidly extending triple junction is a matter of ongoing debate. Geochemical research will provide vital information on mantle sources and melting conditions contributing to LIP magmatism [1]. The Ori Massif is one of the three elevated massifs within the Shatsky Rise, comprising a volume of 0.7 × 106 km3. It is situated in the middle of the plateau with the largest edifice Tamu Massif to the southeast and the smaller Shirshov Massif to the northwest. Within plume theory Ori Massif formed at an intermediate to early stage of a plume volcanism. In shallow mantle theory it formed from a shallow lithospheric source during oceanic spreading at a triple junction [1]. During IODP Expedition 324 two sites were drilled on Ori Massif, one of which, U1349A, targeted the summit. The Hole U1349A penetrated 250.4m beneath the seafloor, and includes 165.1m of sediments and 85.3m of igneous basement. The uppermost volcanic flows (~55m) are highly vesicular, stongly altered to reddish brown clays and contain abundant pseudomorphs after olivine. These flows are underlain by highly altered volcaniclastic breccia (>40m) [1]. Here we present Sr, Nd, Hf and Pb isotope characterisation of the U1349A basaltic basement samples. Our results on the Ori Massif will be combined with isotope data from the Tamu Massif and Shirshov Massif. Thus, some preliminary conclusions about the source of mantle material that formed the Shatsky Rise oceanic plateau and its variation in space and time can be made. [1] Expedition 324 Scientists (2010) Expedition

  19. Dolomite Dissolution in Alkaline Cementious Media

    NASA Astrophysics Data System (ADS)

    Mittermayr, Florian; Klammer, Dietmar; Köhler, Stephan; Dietzel, Martin

    2010-05-01

    Chemical alteration of concrete has gained much attention over the past years as many cases of deterioration due to sulphate attack, thaumasite formation (TSA) or alkali silica reactions (ASR) have been reported in various constructions (Schmidt et al, 2009). Much less is known about the so called alkali carbonate reaction (ACR). It is believed that dolomite aggregates can react with the alkalis from the cement, dissolve and form calcite and brucite (Katayama, 2004). Due to very low solubility of dolomite in alkaline solutions this reaction seems doubtful. In this study we are trying to gain new insides about the conditions that can lead to the dissolution of dolomite in concrete. Therefore we investigated concrete samples from Austrian tunnels that show partially dissolved dolomite aggregates. Petrological analysis such as microprobe, SEM and Raman spectroscopy as well as a hydrochemical analysis of interstitial solutions and ground water and modelling with PhreeqC (Parkhurst and Appelo, 1999) are carried out. In addition a series of batch experiments is set up. Modelling approaches by PhreeqC show a thermodynamically possibility in the alkaline range when additional Ca2+ in solution causes dolomite to become more and more undersaturated as calcite gets supersaturated. Interacting ground water is enriched in Ca2+and saturated with respect to gypsum as marine evaporites are found in situ rocks. Furthermore it is more likely that Portlandite (Ca(OH)2) plays a more important role than Na and K in the cement. Portlandite acts as an additional Ca2+ source and is much more abundant than the alkalies. Some interstitial solutions are dominated mainly by Na+ and SO42- and reach concentrations up to 30 g/l TDS. It is believed that solutions can even reach thenardite saturation as efflorescences are found on the tunnel walls. In consequence dolomite solubility increases with increasing ionic strength. pH > 11 further accelerate the process of dedolomitization by the removal

  20. Continental crust subducted deeply into lithospheric mantle: the driving force of Early Carboniferous magmatism in the Variscan collisional orogen (Bohemian Massif)

    NASA Astrophysics Data System (ADS)

    Janoušek, Vojtěch; Schulmann, Karel; Lexa, Ondrej; Holub, František; Franěk, Jan; Vrána, Stanislav

    2014-05-01

    The vigorous Late Devonian-Early Carboniferous plutonic activity in the core of the Bohemian Massif was marked by a transition from normal-K calc-alkaline, arc-related (~375-355 Ma), through high-K calc-alkaline (~346 Ma) to (ultra-)potassic (343-335 Ma) suites, the latter associated with mainly felsic HP granulites enclosing Grt/Spl mantle peridotite bodies. The changing chemistry, especially an increase in K2O/Na2O and 87Sr/86Sri with decrease in 143Nd/144Ndi in the basic end-members, cannot be reconciled by contamination during ascent. Instead it has to reflect the character of the mantle sources, changing over time. The tectonic model invokes an oceanic subduction passing to subduction of the attenuated Saxothuringian crust under the rifted Gondwana margin (Teplá-Barrandian and Moldanubian domains). The deep burial of this mostly refractory felsic metaigneous material is evidenced by the presence of coesite/diamond (Massonne 2001; Kotková et al. 2011) in the detached UHP slices exhumed through the subduction channel and thrusted over the Saxothuringian basement, and by the abundance of felsic HP granulites (> 2.3 GPa), some bearing evidence for small-scale HP melt separation, in the orogen's core (Vrána et al. 2013). The subduction channel was most likely formed by 'dirty' serpentinites contaminated by the melts/fluids derived from the underlying continental-crust slab (Zheng 2012). Upon the passage through the orogenic mantle, the continental crust-slab derived material not only contaminated the adjacent mantle forming small bodies/veins of pyroxenites (Becker 1996), glimmerites (Becker et al. 1999) or even phlogopite- and apatite-bearing peridotites (Naemura et al. 2009) but the felsic HP-HT granulites also sampled the individual peridotite types at various levels. Eventually the subducted felsic material would form an (U)HP continental wedge under the forearc/arc region, to be later redistributed under the Moldanubian crust by channel flow and crustal

  1. Alkaline pulping of some eucalypts from Sudan.

    PubMed

    Khristova, P; Kordsachia, O; Patt, R; Dafaalla, S

    2006-03-01

    Four eucalypts (Eucalyptus camaldulensis, Eucalyptus microtheca, Eucalyptus tereticornis and Eucalyptus citriodora) grown in Sudan were examined for their suitability for pulping and papermaking with different alkaline methods. Their physical, morphological and chemical characteristics are reported. The pulping trials with E. citriodora and E. tereticornis were carried out using the kraft-AQ, soda-AQ, modified AS/AQ (ASA), ASAM and kraft methods. For the other two species, only the ASAM and the kraft process were applied. ASAM pulping gave the best results in terms of yield, degree of delignification, mechanical and optical pulp properties. The best pulps, obtained in kraft and ASAM cooking of E. citriodora, were bleached to 88% ISO brightness in a totally chlorine free bleaching sequence (OQ1O/PQ2P). The bleached pulps, especially the ASAM pulp, showed good papermaking properties and would be suitable for manufacture of writing and printing grades of paper. PMID:15935655

  2. Alkaline oxide conversion coatings for aluminum alloys

    SciTech Connect

    Buchheit, R.G.

    1996-02-01

    Three related conversion coating methods are described that are based on film formation which occurs when aluminum alloys are exposed to alkaline Li salt solutions. Representative examples of the processing methods, resulting coating structure, composition and morphology are presented. The corrosion resistance of these coatings to aerated 0.5 M NaCl solution has been evaluated as a function of total processing time using electrochemical impedance spectroscopy (EIS). This evaluation shows that excellent corrosion resistance can be uniformly achieved using no more than 20 minutes of process time for 6061-T6. Using current methods a minimum of 80 minutes of process time is required to get marginally acceptable corrosion resistance for 2024-T3. Longer processing times are required to achieve uniformly good corrosion resistance.

  3. Alkaline dechlorination of chlorinated volatile organic compounds

    SciTech Connect

    Gu, B.; Siegrist, R.L.

    1996-06-01

    The vast majority of contaminated sites in the United States and abroad are contaminated with chlorinated volatile organic compounds (VOCs) such as trichloroethylene (TCE), trichloroethane (TCA), and chloroform. These VOCs are mobile and persistent in the subsurface and present serious health risks at trace concentrations. The goal of this project was to develop a new chemical treatment system that can rapidly and effectively degrade chlorinated VOCs. The system is based on our preliminary findings that strong alkalis such as sodium hydroxide (NaOH) can absorb and degrade TCE. The main objectives of this study were to determine the reaction rates between chlorinated VOCs, particularly TCE, and strong alkalis, to elucidate the reaction mechanisms and by-products, to optimize the chemical reactions under various experimental conditions, and to develop a laboratory bench- scale alkaline destruction column that can be used to destroy vapor- phase TCE.

  4. The Alkaline Dissolution Rate of Calcite.

    PubMed

    Colombani, Jean

    2016-07-01

    Due to the widespread presence of calcium carbonate on Earth, several geochemical systems, among which is the global CO2 cycle, are controlled to a large extent by the dissolution and precipitation of this mineral. For this reason, the dissolution of calcite has been thoroughly investigated for decades. Despite this intense activity, a consensual value of the dissolution rate of calcite has not been found yet. We show here that the inconsistency between the reported values stems mainly from the variability of the chemical and hydrodynamic conditions of measurement. The spreading of the values, when compared in identical conditions, is much less than expected and is interpreted in terms of sample surface topography. This analysis leads us to propose benchmark values of the alkaline dissolution rate of calcite compatible with all the published values, and a method to use them in various chemical and hydrodynamic contexts. PMID:27282839

  5. Properties of cathode materials in alkaline cells

    NASA Astrophysics Data System (ADS)

    Salkind, A. J.; McBreen, J.; Freeman, R.; Parkhurst, W. A.

    1984-04-01

    Conventional and new cathode materials in primary and secondary alkaline cells were investigated for stability, structure, electrochemical reversibility and efficiency. Included were various forms of AgO for reserve type silver zinc batteries, a new material - AgNiO2 and several nickel electrodes for nickel cadmium and nickel hydrogen cells for aerospace applications. A comparative study was made of the stability of electroformed and chemically prepared AgO. Stability was correlated with impurities. After the first discharge AgNiO2 can be recharged to the monovalent level. The discharge product is predominantly silver. Plastic bonded nickel electrodes display a second plateau on discharge. Additions of Co(OH)2 largely eliminate this.

  6. Polyvinyl alcohol membranes as alkaline battery separators

    NASA Technical Reports Server (NTRS)

    Sheibley, D. W.; Gonzalez-Sanabria, O.; Manzo, M. A.

    1982-01-01

    Polyvinly alcohol (PVA) cross-linked with aldehyde reagents yields membranes that demonstrate properties that make them suitable for use as alkaline battery separators. Film properties can be controlled by the choice of cross-linker, cross-link density and the method of cross-linking. Three methods of cross-linking and their effects on film properties are discussed. Film properties can also be modified by using a copolymer of vinyl alcohol and acrylic acid as the base for the separator and cross-linking it similarly to the PVA. Fillers can be incorporated into the films to further modify film properties. Results of separator screening tests and cell tests for several variations of PBA films are discussed.

  7. Oxygen electrodes for rechargeable alkaline fuel cells

    NASA Technical Reports Server (NTRS)

    Swette, Larry; Giner, Jose

    1987-01-01

    Electrocatalysts and supports for the positive electrode of moderate temperature single unit rechargeable alkaline fuel cells were investigated and developed. The electrocatalysts are defined as the material with a higher activity for the oxygen electrode reaction than the support. Advanced development will require that the materials be prepared in high surface area forms, and may also entail integration of various candidate materials. Eight candidate support materials and seven electrocatalysts were investigated. Of the 8 support, 3 materials meet the preliminary requirements in terms of electrical conductivity and stability. Emphasis is now on preparing in high surface area form and testing under more severe corrosion stress conditions. Of the 7 electrocatalysts prepared and evaluated, at least 5 materials remain as potential candidates. The major emphasis remains on preparation, physical characterization and electrochemical performance testing.

  8. Development of an alkaline fuel cell subsystem

    NASA Technical Reports Server (NTRS)

    1987-01-01

    A two task program was initiated to develop advanced fuel cell components which could be assembled into an alkaline power section for the Space Station Prototype (SSP) fuel cell subsystem. The first task was to establish a preliminary SSP power section design to be representative of the 200 cell Space Station power section. The second task was to conduct tooling and fabrication trials and fabrication of selected cell stack components. A lightweight, reliable cell stack design suitable for the SSP regenerative fuel cell power plant was completed. The design meets NASA's preliminary requirements for future multikilowatt Space Station missions. Cell stack component fabrication and tooling trials demonstrated cell components of the SSP stack design of the 1.0 sq ft area can be manufactured using techniques and methods previously evaluated and developed.

  9. The Nickel(111)/Alkaline Electrolyte Interface

    NASA Technical Reports Server (NTRS)

    Wang, Kuilong; Chottiner, G. S.; Scherson, D. A.; Reid, Margaret A.

    1991-01-01

    The electrochemical properties of Ni (111) prepared and characterized in ultra high vacuum, UHV, by surface analytical techniques have been examined in alkaline media by cyclic voltammetry using an UHV-electrochemical cell transfer system designed and built in this laboratory. Prior to the transfer, the Ni(111) surfaces were exposed to saturation coverages of CO in UHV in an attempt to protect the surface from possible contamination with other gases during the transfer. Temperature Programmed Desorption, TPD, of CO-dosed Ni (111) surfaces displaying sharp c(4x2), LEED patterns, subsequently exposed to water-saturated Ar at atmospheric pressure in an auxiliary UHV compatible chamber and finally transferred back to the main UHV chamber, yielded CO2 and water as the only detectable products. This indicates that the CO-dosed surfaces react with water and/or bicarbonate and hydroxide as the most likely products. Based on the integration of the TPD peaks, the combined amounts of H2O and CO2 were found to be on the order of a single monolayer. The reacted c(4x2)CO/Ni(111) layer seems to protect the surface from undergoing spontaneous oxidation in strongly alkaline solutions. This was evidenced by the fact that the open circuit potential observed immediately after contact with deaerated 0.1 M KOH was about 0.38 V vs. DHE, drifting slightly towards more negative values prior to initiating the voltametric scans. The average ratio of the integrated charge obtained in the first positive linear scan in the range of 0.35 to 1.5 V vs. DHE (initiated at the open circuit potential) and the first (and subsequent) linear negative scans in the same solution yielded for various independent runs a value of 3.5 +/- 0.3. Coulometric analysis of the cyclic voltammetry curves indicate that the electrochemically formed oxyhydroxide layer involves a charge equivalent to 3.2 +/- 0.4 layers of Ni metal.

  10. Alkaline cleaner replacement for printed wiring board fabrication

    SciTech Connect

    Goldammer, S.E.; Pemberton, S.E.; Tucker, D.R.

    1997-04-01

    A replacement alkaline cleaning chemistry was qualified for the copper cleaning process used to support printed wiring board fabrication. The copper cleaning process was used to prepare copper surfaces for enhancing the adhesion of dry film photopolymers (photoresists and solder masks) and acrylic adhesives. The alkaline chemistry was used to remove organic contaminates such as fingerprints.

  11. TOTAL ALKALINITY OF SURFACE WATERS OF THE US

    EPA Science Inventory

    This map provides a synoptic illustration of the national patterns of surface water alkalinity in the conterminous United States. Alkalinity is the most readily available measure of the acid-neutralizing capacity of surface waters and provides a reasonable estimate o...

  12. Removal of plutonium and americium from alkaline waste solutions

    DOEpatents

    Schulz, Wallace W.

    1979-01-01

    High salt content, alkaline waste solutions containing plutonium and americium are contacted with a sodium titanate compound to effect removal of the plutonium and americium from the alkaline waste solution onto the sodium titanate and provide an effluent having a radiation level of less than 10 nCi per gram alpha emitters.

  13. The Chemistry of Paper Preservation Part 4. Alkaline Paper.

    ERIC Educational Resources Information Center

    Carter, Henry A.

    1997-01-01

    Discusses the problem of the inherent instability of paper due to the presence of acids that catalyze the hydrolytic degradation of cellulose. Focuses on the chemistry involved in the sizing of both acid and alkaline papers and the types of fillers used. Discusses advantages and problems of alkaline papermaking. Contains 48 references. (JRH)

  14. ANNUAL REPORT. ACTINIDE-ALUMINATE SPECIATION IN ALKALINE RADIOACTIVE WASTE

    EPA Science Inventory

    Highly alkaline radioactive waste tanks contain a number of transuranic species, in particular U, Np, Pu, and Am-the exact forms of which are currently unknown. Knowledge of actinide speciation under highly alkaline conditions is essential towards understanding and predicting the...

  15. Les dykes basiques du massif ancien de l'Ourika (Atlas de Marrakech, Maroc): géochimie et significationThe basic dykes of the Ourika old massif (High Atlas of Marrakech): Geochemistry and significance

    NASA Astrophysics Data System (ADS)

    Barakat, Ahmed; Marignac, Christian; Bouabdelli, Mohamed

    The Precambrian massif of Ourika is crosscut by two systems of basic dykes, striking N40°E and N90-120°E. Using incompatible trace elements, the two systems form two distinct chemical groups, displaying a continental tholeiitic affinity. The composition variations between the two defined groups can be due to heterogeneities of mantle sources and to contamination, during the magma ascent, by the continental crust. The emplacement of these basic dykes, before the late-PIII formations, can be related to the Neoproterozoic distension generalised to the Anti-Atlas chain. To cite this article: A. Barakat et al., C. R. Geoscience 334 (2002) 827-833.

  16. Salt- and alkaline-tolerance are linked in Acacia.

    PubMed

    Bui, Elisabeth N; Thornhill, Andrew; Miller, Joseph T

    2014-07-01

    Saline or alkaline soils present a strong stress on plants that together may be even more deleterious than alone. Australia's soils are old and contain large, sometimes overlapping, areas of high salt and alkalinity. Acacia and other Australian plant lineages have evolved in this stressful soil environment and present an opportunity to understand the evolution of salt and alkalinity tolerance. We investigate this evolution by predicting the average soil salinity and pH for 503 Acacia species and mapping the response onto a maximum-likelihood phylogeny. We find that salinity and alkalinity tolerance have evolved repeatedly and often together over 25 Ma of the Acacia radiation in Australia. Geographically restricted species are often tolerant of extreme conditions. Distantly related species are sympatric in the most extreme soil environments, suggesting lack of niche saturation. There is strong evidence that many Acacia have distributions affected by salinity and alkalinity and that preference is lineage specific. PMID:25079493

  17. Rockfall hazard assessment by means of the magnitude-frequency curves in the Montserrat Massif (central Catalonia, Spain): first insights

    NASA Astrophysics Data System (ADS)

    Janeras, Marc; Domènech, Guillem; Pons, Judit; Prat, Elisabet; Buxó, Pere

    2016-04-01

    Montserrat Massif is located about 50 km North-West of Barcelona (Catalonia, North-Eastern Spain). The rock massif is constituted by an intercalation of conglomerate and fine layers of siltstones due to the Montserrat fan-delta sedimentation within the Eocene age. The current relief is consequence of the several depositional episodes and the later tectonic uplift, leading to stepped slopes up to 250 m high, and a total height difference close to 1000 m. Montserrat Mountain has been a pilgrimage place since the settlement of the monastery, around the year 1025, and a spot of touristic interest, mostly within the last 150 years, when the first rack railway was inaugurated to reach the sanctuary. The amount of 2.4 M visitors in 2014 reveals the potential risk derived from rockfalls. To assess and mitigate this risk, a plan funded by the Catalan government is currently under development. Three rockfall mechanisms and magnitude ranges have been identified (Janeras et al. 2011): 1) physicochemical weathering causing the detachment of pebbles and aggregates (0.0001 - 0.1 m3); 2) thermic-induced tensions responsible for the generation of slabs and plates (0.1 - 10 m3); and 3) intersection of structural joints within the rock mass resulting in blocks of 10 - 10,000 m3. In order to quantify the rockfall hazard, a magnitude-frequency analysis has been performed starting from an event-based inventory gathered from field surveillance and historical research. A methodology has been applied to take the maximum profit of only 30 registers with information on volume and date. The massif has been split into several domains with sampling homogeneity. For each one, there have been defined several periods of time during which, all the rockfall events of a given volume have been recorded. Thus, the magnitude-frequency relationship, for each domain, has been calculated. Results show that the curves are well fitted by a power law with exponents ranging from -0.59 to -0.68 for magnitudes

  18. Geometry and thermal structure of the Menderes Massif Core Complex (Western Turkey), implications for thermal evolution of Hellenic subduction zone

    NASA Astrophysics Data System (ADS)

    Roche, Vincent; Jolivet, Laurent; Guillou-Frottier, Laurent; Tuduri, Johann; Bouchot, Vincent; Beccaletto, Laurent; Lahfid, Abdeltif

    2016-04-01

    The eastern Mediterranean region is one of the most promising geothermal areas, with more than 250 geothermal fields discovered in Turkey (Parlaktuna, 2013), in a region of active tectonics and volcanism. Although the potential of these deep geothermal resources has not been systematically investigated yet, the geothermal activity of the western Turkey area is the most recent signature of the high heat flow (120-140 mW/m²; Aydin, 2005, from Teczan, 1995). Based on Turkish data, 2084 MWt are being utilized for direct applications and most of the energy originates from the Menderes Massif (Baba et al., 2015). This large-scale thermal anomaly at the surface is correlated to a long wavelength east-west increase of surface heat flow that could reflect the thermal state of Aegean subduction zone at depth. In order to better understand and characterize the possible connections between large-scale mantle dynamics and surface processes in space and time, we study the structure and thermal evolution of the Menderes Massif. Both the acceleration of the Aegean extension in the Middle Miocene and the recent escape of Anatolia have been proposed to result from several slab tearing events, the first one being located below western Turkey and the Eastern Aegean Sea. These events have triggered the formation of metamorphic complexes with contrasted exhumation P-T paths. While the extension in the Aegean domain is well-characterized with high-temperature domes in the center and east, the succession of several metamorphic events in the Menderes Massif and their significance in terms of geodynamics is still debated. Hence, the exhumation history is key to understanding the temporal and spatial distribution of the thermal signature of the Hellenic slab and its tearing/detachment. The Menderes Massif displays a large variety of metamorphic facies, from the Barrovian type metamorphism in the Eocene (the Main Menderes Metamorphism) to the coeval (?) HP-LT metamorphism on the southernmost

  19. The Kokchetav Massif, Kazakhstan: "Type locality" of diamond-bearing UHP metamorphic rocks

    NASA Astrophysics Data System (ADS)

    Schertl, H.-P.; Sobolev, N. V.

    2013-02-01

    After the discovery of metamorphic coesite in crustal rocks from the Western Alps (Italy) and the Western gneiss region (Norway) in the mid 1980s of the last century, metamorphic diamond was observed only a few years later "in situ" in the Kokchetav Massif (Kazakhstan). Findings of such coesite- and diamond-bearing ultrahigh pressure metamorphic (UHP) rocks with protoliths formed or embedded in crustal levels and subsequently experienced PT-conditions within or even higher than the coesite stability field have dramatically changed our geodynamic view of orogenetic processes. These occurrences provide evidence that crustal rocks were subducted into mantle depths and exhumed to the surface. Recent studies even suggest continental subduction to depths exceeding 300 km. These rocks have been extensively studied and many new and important observations have been made. Thus far, more than 350 papers have been published on various aspects of Kokchetav UHP rocks. The Kokchetav Massif of northern Kazakhstan is part of one of the largest suture zones in Central Asia and contains slices of HP and UHP metamorphic rocks. Classical UHP rocks mainly occur in the Kumdy Kol, Barchi Kol and Kulet areas, and include a large variety of lithologies such as calcsilicate rocks, eclogite, gneisses, schists, marbles of various compositions, garnet-pyroxene-quartz rocks, and garnet peridotite. Most of them contain microdiamonds; some of which reach a grain size of 200 μm. Most diamond grains show cuboid shapes but in rare cases, diamonds within clinozoisite gneiss from Barchi Kol occur as octahhedral form. Microdiamonds contain highly potassic fluid inclusions, as well as solid inclusions like carbonates, silicates and metal sulfides, which favour the idea of diamond formation from a C-O-H bearing fluid. Nitrogen isotope data and negative δ13C values of Kokchetav diamonds indicate a metasedimentary origin. PT-estimates of Kokchetav UHP rocks yield peak metamorphic conditions of at least 43

  20. Serpentinite Carbonation in the Pollino Massif (southern Italy) for CO2 Sequestration

    NASA Astrophysics Data System (ADS)

    Carmela Dichicco, Maria; Mongelli, Giovanni; Paternoster, Michele; Rizzo, Giovanna

    2015-04-01

    Anthropogenic gas emissions are projected to change future climates with potentially nontrivial impacts (Keller et al., 2008 and references therein) and the impacts of the increased CO2 concentration are, among others, the greenhouse effect, the acidification of the surface of the ocean and the fertilization of ecosystems (e.g. Huijgen and Comans, 2003). Geologic Sequestration into subsurface rock formations for long-term storage is part of a process frequently referred to as "carbon capture and storage" or CCS. A major strategy for the in situ geological sequestration of CO2 involves the reaction of CO2 with Mg-silicates, especially in the form of serpentinites, which are rocks: i) relatively abundant and widely distributed in the Earth's crust, and ii) thermodynamically convenient for the formation of Mg-carbonates (e.g., Brown et al., 2011). In nature, carbonate minerals can form during serpentinization or during hydrothermal carbonation and weathering of serpentinites whereas industrial mineral carbonation processes are commonly represented by the reaction of olivine or serpentine with CO2 to form magnesite + quartz ± H2O (Power et al., 2013). Mineral carbonation occurs naturally in the subsurface as a result of fluid-rock interactions within serpentinite, which occur during serpentinization and carbonate alteration. In situ carbonation aims to promote these reactions by injecting CO2 into porous, subsurface geological formations, such as serpentinite-hosted aquifers. In the northern sector of the Pollino Massif (southern Italy) extensively occur serpentinites (Sansone et. al., 2012) and serpentinite-hosted aquifers (Margiotta et al., 2012); both serpentinites and serpentinite-hosted aquifers are the subject of a comprehensive project devoted to their possible use for in situ geological sequestration of CO2. The serpentinites derived from a lherzolitic and subordinately harzburgitic mantle, and are within tectonic slices in association with metadolerite dykes

  1. Distribution patterns, properties and ages of Pleistocene periglacial slope deposits in the eastern Rhenish Massif

    NASA Astrophysics Data System (ADS)

    Sauer, Daniela; Scholten, Thomas; Felix-Henningsen, Peter; Kadereit, Annette

    2010-05-01

    Pleistocene periglacial slope deposits (PPSD) cover almost continuously the low mountain areas of Germany. They are interpreted as the result of frost weathering, gelisolifluction, cryoturbation, meltwater outwash processes and loess incorporation. Four types of PPSD are distinguished in the German classification system: A Basal Layer consists entirely of debris of the underlying rock, which it usually directly overlies. It occurs in almost every relief position, and several Basal Layers may have formed on top of each other. An Intermediate Layer contains varying proportions of loess. It is only found in relief positions favourable for loess accumulation and preservation. Its position within a vertical sequence of PPSD is usually on top of a Basal Layer. An Upper Layer consists of a mixture of rock debris and loess, and contains generally a lower amount of loess than a possibly underlying Intermediate Layer. It has a remarkably steady thickness of around 50 cm, as confirmed in many studies. The Top Layer is mostly restricted to the surroundings of outcrops of particularly resistant rock in higher regions and mainly consists of rock debris. PPSD were investigated in the eastern Westerwald area, at the eastern edge of the Rhenish Massif, Germany. Parent rock, exposition, position and shape of slope were expected to be factors influencing the occurrence, thickness and properties of the different types of PPSD. Therefore, profiles were excavated on the main rock types in the area, which are shale, quartzite and diabase. On each rock type, profiles were studied along catenas in NW, SW, SE and NE exposition, each catena including a profile in upper, middle and footslope position. In upper slope positions on shale an Upper Layer covers directly the rock, independent of exposition. In downslope direction, still above the mid slope profiles, a Basal Layer appears between the Upper Layer and the rock. In upper slope positions on quartzite, a Basal Layer is already present

  2. Dirty or Tidy ? Contrasting peraluminous granites in a collapsing Orogen: Examples from the French Massif Central

    NASA Astrophysics Data System (ADS)

    Villaros, Arnaud; Pichavant, Michel; Moyen, Jean-François; Cuney, Michel; Deveaud, Sarah; Gloaguen, Eric; Melleton, Jérémie

    2013-04-01

    Post collisional collapse commonly enhances crustal melting. Such melting typically produces peraluminous granitic magmas. In the French Massif Central, a mid-crustal segment of the western Variscan belt, two large granitic bodies were produced during the collapse of the Variscan Belt. The St Sylvestre Leucogranitic Complex (SSyL) in the western part of the Massif Central and the Velay Migmatitic Complex (VMC) in the Eastern part. Although these two complexes are formed in similar geodynamic context they present meaningful petrological and geochemical differences. The VMC (~305 Ma) is clearly intrusive in migmatitic terranes. The migmatitic host recorded two successive melting events M3 (720 °C and 5kb) dated between 335 and 315 Ma and M4 (850°C and 4 kb) dated at 305 Ma. The compositions of the VMC are strictly H2O-undersaturated and ranges from leucogranitic to granodioritic. Three main successive granite types have been distinguished (1) A heterogeneous banded biotite granite, (2) A main biotite-cordierite granite, where cordierite can be prismatic, as cockade or pseudomorphic (3) a late magmatic with large K-feldspar phenocryst and prismatic cordierite. The compositions of the VMC granites are quite similar to typical Australian S-type granites in the sense that they also show a positive correlation between ferromagnesian abundance and aluminosity. The SSyL (~320 Ma) is intrusive in upper greenschist facies to upper amphibolite migmatitic metasediment and orthogneiss (~3kb). The compositional variety observed in the SSyL suggests a continuous trend from a moderately mafic, peraluminous magma (cd- and sill- granite) to a H2O saturated granite ("two-mica" granite) facies and finally to an extremely felsic, H2O-saturated magma. Three granitic units have been recognized in the SSyL: (1) the western "Brame Unit" composed of the less evolved cd- and sill- granite facies (2) the central "St Sylvestre Unit", composed mainly by U-rich two-mica granite, intruded by two

  3. Spatiotemporal waves caused by gravitational instability of an arbitrary stratified elasto-viscous rock massif

    NASA Astrophysics Data System (ADS)

    Ryzhak, Eugeny; Mukhamediev, Shamil; Sinyukhina, Svetlana

    2015-04-01

    The cause of the spatially-temporal wave-like out-of-plane distortions of originally horizontal layers of the earth's crust is still one of the most important and debated problems in solid earth physics. Are these distortions originated due to action of the high horizontal compressions applied to a massif or, contrary, they are the result of spontaneous deformation of the massif under gravity without action of another pronounced external agents? The second possibility is called the gravity instability. Understanding of the geodynamic evolution of the region is crucially dependent on what the answer will be chosen from the above alternative. Lord Rayleigh (1883) was the first who solved the problem of gravity instability for the system of 2 infinite layers of ideal incompressible fluids and showed that the system is gravitationally unstable when the upper fluid is denser than the lower one (i.e. the density inversion exists). Since then numerous attempts have been made to generalise the properties of constituents. 1961 till now were the years of unsuccessful attempts to take into account the elastic properties of fluids. We used the principally new approach to the stability analysis of a system which is a bounded 3D multi-layered fluid domain possessing cross-sections of arbitrary shape and prescribed boundary conditions at all parts of the boundary. It is assumed that the fluid is arbitrary stratified according to both density ρ and nonlinear elastic properties. By using a static energy criterion for stability/instability alongside with the reference ("Lagrangian") description of a continuum we succeeded in solving the problem completely, namely, we obtained the necessary and sufficient condition for stability (violation of which is the necessary and sufficient condition for instability). It was found that the system under study is unstable if and only if 1) density inversion exists at least at one interface between the fluids and/or 2) there exists a depth range

  4. Phosphatidylinositol anchor of HeLa cell alkaline phosphatase

    SciTech Connect

    Jemmerson, R.; Low, M.G.

    1987-09-08

    Alkaline phosphatase from cancer cells, HeLa TCRC-1, was biosynthetically labeled with either /sup 3/H-fatty acids or (/sup 3/H)ethanolamine as analyzed by sodium dodecyl sulfate-polyacrylamide gel electrophoresis and fluorography of immunoprecipitated material. Phosphatidylinositol-specific phospholipase C (PI-PLC) released a substantial proportion of the /sup 3/H-fatty acid label from immunoaffinity-purified alkaline phosphatase but had no effect on the radioactivity of (/sup 3/H)ethanolamine-labeled material. PI-PLC also liberated catalytically active alkaline phosphatase from viable cells, and this could be selectively blocked by monoclonal antibodies to alkaline phosphatase. However, the alkaline phosphatase released from /sup 3/H-fatty acid labeled cells by PI-PLC was not radioactive. By contrast, treatment with bromelain removed both the /sup 3/H-fatty acid and the (/sup 3/H)ethanolamine label from purified alkaline phosphatase. Subtilisin was also able to remove the (/sup 3/H)ethanolamine label from the purified alkaline phosphatase. The /sup 3/H radioactivity in alkaline phosphatase purified from (/sup 3/H)ethanolamine-labeled cells comigrated with authentic (/sup 3/H)ethanolamine by anion-exchange chromatography after acid hydrolysis. The data suggest that the /sup 3/H-fatty acid and (/sup 3/H)ethanolamine are covalently attached to the carboxyl-terminal segment since bromelain and subtilisin both release alkaline phosphatase from the membrane by cleavage at that end of the polypeptide chain. The data are consistent with findings for other proteins recently shown to be anchored in the membrane through a glycosylphosphatidylinositol structure and indicate that a similar structure contributes to the membrane anchoring of alkaline phosphatase.

  5. U-Pb dating and composition of inclusions in zircon from ophiolitic gabbro of the Klyuchevsk massif (Middle Urals): Results and geological interpretation

    NASA Astrophysics Data System (ADS)

    Smirnov, V. N.; Ivanov, K. S.; Koroteev, V. A.; Erokhin, Yu. V.; Khiller, V. V.

    2016-06-01

    The U-Pb (SHRIMP) dating of zircon from the layered complex of ophiolitic gabbro in the Klyuchevsk massif yielded an age of 456 ± 6 Ma corresponding within the limits of error to zircon dates obtained for other petrographic varieties from this massif. The investigation of the composition of silicate inclusions in dated zircon grains revealed that they are represented by typical metamorphic minerals: albite, zoisite, and secondary amphiboles. The data indicate that zircon was crystallized during metamorphic transformations of gabbroids and its U-Pb age (Late Ordovician-Silurian) is characteristic of all rocks in the ophiolite association of the Klyuchevsk massif indicating the age of metamorphism, not their formation time.

  6. Alpine thermal events in the central Serbo-Macedonian Massif (southeastern Serbia)

    NASA Astrophysics Data System (ADS)

    Antić, Milorad D.; Kounov, Alexandre; Trivić, Branislav; Wetzel, Andreas; Peytcheva, Irena; von Quadt, Albrecht

    2016-07-01

    The Serbo-Macedonian Massif (SMM) represents a crystalline belt situated between the two diverging branches of the Eastern Mediterranean Alpine orogenic system, the northeast-vergent Carpatho-Balkanides and the southwest-vergent Dinarides and the Hellenides. We have applied fission-track analysis on apatites and zircons, coupled with structural field observations in order to reveal the low-temperature evolution of the SMM. Additionally, the age and geochemistry of the Palaeogene igneous rocks (i.e. Surdulica granodiorite and dacitic volcanic rocks) were determined by the LA-ICPMS U-Pb geochronology of zircons and geochemical analysis of main and trace elements in whole-rock samples. Three major cooling stages have been distinguished from the late Early Cretaceous to the Oligocene. The first stage represents rapid cooling through the partial annealing zones of zircon and apatite (300-60 °C) during the late Early to early Late Cretaceous (ca. 110-ca. 90 Ma). It is related to a post-orogenic extension following the regional nappe-stacking event in the Early Cretaceous. Middle to late Eocene (ca. 48-ca. 39 Ma) cooling is related to the formation of the Crnook-Osogovo-Lisets extensional dome and its exhumation along low-angle normal faults. The third event is related to regional cooling following the late Eocene magmatic pulse. During this pulse, the areas surrounding the Surdulica granodiorite (36 ± 1 Ma) and the slightly younger volcanic bodies (ca. 35 Ma) have reached temperatures higher than the apatite closure temperature (120 °C) but lower than ca. 250 °C. The geochemistry of the igneous samples reveals late- to post-orogenic tectonic setting during magma generation.

  7. Rates of high altitude rock wall erosion: four years of laserscanning in the Mont Blanc massif

    NASA Astrophysics Data System (ADS)

    Ravanel, L.; Deline, P.; Jaillet, S.

    2009-04-01

    Many rockfalls detach from steep high-Alpine rock walls, and were especially frequent during the hot summer of 2003 in the Alps. It is hypothesized that an observed increase of high mountain rock wall instability is related to permafrost changes. Nevertheless, because of a lack of systematic observations, magnitude and frequency of high mountain rock-slope instabilities remain poorly known up to now. As a part of the French-Italian PERMAdataROC project (2005-2008) and the EU-funded transalpine PermaNET project (2008-2011), we use the Terrestrial Laserscanning method for remote monitoring of geomorphological activity from the ground, focusing on seven steep high-Alpine rock walls (elevation: 3000-4500 m a.s.l.) affected by permafrost in the Mont-Blanc massif. Here we present the methodology to get high-resolution digital elevation models (DEM) of rock walls surveyed annually by laserscanning and to make diachronic comparisons of those DEM. This work has been carried out using a ground-based LiDAR Optech ILRIS-3D, working up to 800 m in the best conditions of surface reflectivity. We present the key results of this first quantification of high altitude rock wall instability, based on the first four years of measurement at Les Drus, Aiguille du Midi, Grand Flambeau, Aiguille d'Entrèves, Tour Ronde, Aiguille Blanche de Peuterey and Piliers de Freiney - Grand Pilier d'Angle. The main instabilities affected the West Face of Les Drus (546 m3 of rock detached between October 2005 and October 2006), the Tour Ronde East Face (536 m3 between 2005 and 2006, and 266 m3 between 2007 and 2008) and the close Freshfield ridge (448 m3 between 2006 and 2007). The high resolution of the DEM also allows performing remote geomechanical characterization of the rock faces. First results about survey of fractures will be also present.

  8. UHP kyanite eclogite associated with garnet peridotite and diamond-bearing granulite, northern Bohemian Massif

    NASA Astrophysics Data System (ADS)

    Kotková, Jana; Janák, Marian

    2015-06-01

    Kyanite eclogites enclosed in garnet peridotites may provide important information on P-T evolution of orogenic peridotites in deep subduction and collision zones. Kyanite eclogite interlayered with garnet peridotite occurs in the borehole T-7, in the Saxothuringian basement of the northern part of the Bohemian Massif. This orogenic peridotite of mantle origin is associated with felsic granulites, which contain diamond as a consequence of deep subduction of the continental crust. Here, we report on the metamorphic evolution of kyanite eclogite, which shows a well-preserved peak-pressure mineral assemblage of garnet, omphacite, kyanite and phengite. Conventional geothermobarometry, average PT method and thermodynamic modelling constrain the metamorphic conditions of this assemblage up to 3.5-4.5 GPa at 900-1050 °C. Two compositional types of garnet, i.e., Mg-rich and Ca-rich, have been recognised. Thermodynamic modelling shows that the composition of Ca-rich garnet with XCa (0.35-0.37) in the core corresponds to stability of garnet at 3.5-4.5 GPa. Amphibole and zoisite are preserved as inclusions in garnet cores, and they are stable below 2.5 GPa, indicating that garnet grew at the expense of these phases at increasing P-T conditions during the prograde evolution of the rock. A post-peak metamorphism decompression and cooling are recorded by decrease of Ca-Eskola end-member in omphacite, drop in XMg and XGrs at garnet rim and a very restricted formation of pargasitic amphibole in the matrix. The absence of symplectites after omphacite in the investigated eclogite may be due to a very low content of quartz and possibly also fluid in the rock. Our study suggests that kyanite-bearing eclogite underwent UHP metamorphism as a consequence of subduction, together with interlayered garnet peridotite. Both rocks were incorporated into the subducted continental crust (diamond-bearing granulites) during the Variscan orogeny.

  9. Table-mountain geology and surficial geochemistry: Chimantá Massif, Venezuelan Guayana shield

    NASA Astrophysics Data System (ADS)

    Briceño, H.; Schubert, C.; Paolini, J.

    The Chimantá Massif consists of eleven table-mountains (up to more than 2600 m in elevation), which are remnants of the Auyán-tepui planation surface (with a possible Cretaceous initial age) cut into siliceous sandstones of the Matauí Formation, the highest unit of the Precambrian Roraima Group. The sandstones are gently folded and several fracture systems control weathering and erosion. The Matauí Formation was intruded by Precambrian diabase dikes and sills. This relationship invalidates previous suggestions that the Roraima Group contained an unconformity separating Lower Precambrian from upper Mesozoic units. Ombrotrophic peat-bogs are conspicuous features on the summits of the table-mountains. Peat formation probably began in the early Holocene, initiated by algae and lichens, accumulation of humidity and detritus, plant colonization of weathered rock surfaces, a low rate of organic decomposition, and high rainfall. The geochemistry of Ca, K, Fe, Si, Cl, I, and Br is discussed. The nutrient cycle consists of sunlight, which contributes to photosynthetic processes, and rainwater, which partly provides the nutrients, dissolves the bedrock, and transports the nutrients from the bedrock and eventually out of the system as river or stream water. The natural waters (rain-, river and stream, peat, and plant waters) are acid (pH range 3.5-4.7) and act on the sandstone, dissolving the siliceous cement and liberating the sand grains. This is the primary weathering mechanism and produces the karst-like topography of the table-mountain summits. Through geologic time (probably up to about 70 million years), this weathering has produced the spectacular table-mountain and savanna landscape of the Gran Sabana.

  10. Alpine thermal events in the central Serbo-Macedonian Massif (southeastern Serbia)

    NASA Astrophysics Data System (ADS)

    Antić, Milorad D.; Kounov, Alexandre; Trivić, Branislav; Wetzel, Andreas; Peytcheva, Irena; von Quadt, Albrecht

    2015-11-01

    The Serbo-Macedonian Massif (SMM) represents a crystalline belt situated between the two diverging branches of the Eastern Mediterranean Alpine orogenic system, the northeast-vergent Carpatho-Balkanides and the southwest-vergent Dinarides and the Hellenides. We have applied fission-track analysis on apatites and zircons, coupled with structural field observations in order to reveal the low-temperature evolution of the SMM. Additionally, the age and geochemistry of the Palaeogene igneous rocks (i.e. Surdulica granodiorite and dacitic volcanic rocks) were determined by the LA-ICPMS U-Pb geochronology of zircons and geochemical analysis of main and trace elements in whole-rock samples. Three major cooling stages have been distinguished from the late Early Cretaceous to the Oligocene. The first stage represents rapid cooling through the partial annealing zones of zircon and apatite (300-60 °C) during the late Early to early Late Cretaceous (ca. 110-ca. 90 Ma). It is related to a post-orogenic extension following the regional nappe-stacking event in the Early Cretaceous. Middle to late Eocene (ca. 48-ca. 39 Ma) cooling is related to the formation of the Crnook-Osogovo-Lisets extensional dome and its exhumation along low-angle normal faults. The third event is related to regional cooling following the late Eocene magmatic pulse. During this pulse, the areas surrounding the Surdulica granodiorite (36 ± 1 Ma) and the slightly younger volcanic bodies (ca. 35 Ma) have reached temperatures higher than the apatite closure temperature (120 °C) but lower than ca. 250 °C. The geochemistry of the igneous samples reveals late- to post-orogenic tectonic setting during magma generation.

  11. Conventional U-Pb dating versus SHRIMP of the Santa Barbara Granite Massif, Rondonia, Brazil

    USGS Publications Warehouse

    Sparrenberger, I.; Bettencourt, Jorge S.; Tosdal, R.M.; Wooden, J.L.

    2002-01-01

    The Santa Ba??rbara Granite Massif is part of the Younger Granites of Rondo??nia (998 - 974 Ma) and is included in the Rondo??nia Tin Province (SW Amazonian Craton). It comprises three highly fractionated metaluminous to peraluminous within-plate A-type granite units emplaced in older medium-grade metamorphic rocks. Sn-mineralization is closely associated with the late-stage unit. U-Pb monazite conventional dating of the early-stage Serra do Cicero facies and late-stage Serra Azul facies yielded ages of 993 ?? 5 Ma and 989 ?? 13 Ma, respectively. Conventional multigrain U-Pb isotope analyses of zircon demonstrate isotopic disturbance (discordance) and the preservation of inherited older zircons of several different ages and thus yield little about the ages of Sn-granite magmatism. SHRIMP U-Pb ages for the Santa Ba??rbara facies association yielded a 207Pb/206Pb weighted-mean age of 978 ?? 13 Ma. The textural complexity of the zircon crystals of the Santa Ba??rbara facies association, the variable concentrations of U, Th and Pb, as well as the mixed inheritance of zircon populations are major obstacles to using conventional multigrain U-Pb isotopic analyses. Sm-Nd model ages and ??Nd (T) values reveal anomalous isotopic data, attesting to the complex isotopic behaviour within these highly fractionated granites. Thus, SHRIMP U-Pb zircon and conventional U-Pb monazite dating methods are the most appropriate to constrain the crystallization age of the Sn-bearing granite systems in the Rondo??nia Tin Province.

  12. The structural evolution of dunite and chromite ore from the Kharcheruz Massif, the Polar Urals

    NASA Astrophysics Data System (ADS)

    Chernyshov, A. I.; Yurichev, A. N.

    2016-03-01

    The Kharcheruz block of the Syumkeu ultramafic massif is a southern fragment of the Khadata ophiolitic belt, which closes the ophiolites of the Polar Urals in the north. The block, striking in the latitudinal direction, is sheetlike in shape and primarily composed of dunite with nearly latitudinal zones of chromite mineralization. The dunites are subject to ductile deformation various in intensity, and this variability is displayed in their heterogeneous structure and texture. The following microstructural types are distinguished by the variety and intensity of their deformation: protogranular → mesogranular → porphyroclastic → porphyrolath → mosaic. The petrostructural patterns of olivines pertaining to the above types reflect conditions of ductile deformation. Protogranular dunite is formed as a product of pyroxene decomposition in mantle harzburgite accompanied by annealing recrystallization at a temperature above 1000°C. Mesogranular dunite is formed as a product of high-temperature plastic flow by means of translation sliding in olivine and diffuse creep at a temperature dropping from 1000 to 650°C and at a low rate (<10-6 s-1). Cr-spinel segregates into linear zones of disseminated chromite mineralization within zones of bedding-plane plastic flow. Porphyroclastic and mosaic dunites are formed under conditions of intense deformation at a temperature of 500-750°C and at a significant rate (>10-6 s-1). Dunite is deformed by means of syntectonic recrystallization and subordinate translation gliding. Linear zones of disseminated mineralization undergo destruction thereby, with the formation of lenticular chromitite bodies from which ductile olivine is squeezed out with the formation of densely impregnated and massive ores.

  13. Microstructural evolution of the Yugu peridotites in the Gyeonggi Massif, Korea

    NASA Astrophysics Data System (ADS)

    Park, M.; Jung, H.

    2015-12-01

    The Yugu peridotite is the largest and freshest ultramafic body in the Gyeonggi Massif, Korean Peninsula, which potentially has a tectonic affinity to the eastward extension of the Qinling-Dabie-Sulu collision belt in China. In spite of its tectonic and rheological importance, only few mineralogical and petrological studies have been reported from Yugu peridotite. In order to understand the microstructural evolution of the Yugu peridotites, we conducted a detailed analysis of the microstructures and petro-fabrics. The majority of Yugu peridotite body is significantly serpentinized, and it consists predominantly of spinel harzburgite together with minor lherzolite, dunite, and clinopyroxenite. We collected peridotites from mainly two areas (northwestern and southwestern parts) of the Yugu ultramafic body, and all samples are spinel harzburgites consisting of olivine, orthopyroxene, clinopyroxene, spinel, and amphibole. These samples have similar mineralogy except for the varied amount of clinopyroxene and amphibole. These mineral contents are generally increasing from proto-mylonite peridotites to mylonite peridotites. Based on microstructural characteristics of highly deformed peridotites (especially grain-size of olivine), we classified the samples into four textural types, which are proto-mylonite, proto-mylonite to mylonite transition, mylonite, and ultra-mylonite. Depending on the texture of specimen, it is found that the lattice-preferred orientation (LPO) of olivine varies from A-type (proto-mylonite) via D-type like (mylonite) to E-type (ultra-mylonite). The fabric strength of olivine (M-index and J-index) systematically decreases with decreasing grain-size of olivine from proto-mylonite via mylonite to ultra-mylonite. The cause of fabric evolution in the Yugu peridotites will be discussed.

  14. The rare earth element potential of kaolin deposits in the Bohemian Massif (Czech Republic, Austria)

    NASA Astrophysics Data System (ADS)

    Höhn, S.; Frimmel, H. E.; Pašava, J.

    2014-12-01

    Four kaolin deposits in the Bohemian Massif were studied in order to assess the potential for the recovery of rare earth elements (REE) as by-products from the residue after extraction and refining of the raw kaolin. The behaviour of REE + Y during kaolinitization was found to be largely a function of pre-alteration mineralogy. In the examples studied, i.e. granite-derived deposits of Kriechbaum (Austria) and Božičany, and arkose-derived deposits of Kaznějov and Podbořany (all Czech Republic), the REE + Y are predominantly hosted by monazite which has remained unaffected by kaolinitization. The overall REE + Y content of the variably kaolinitized rocks is strongly dependent on their genesis. While ion adsorption plays only a minor role in the concentration of REE + Y in the studied kaolinitized rocks, the processing and refining of the raw kaolin leads to residues that are enriched in REE + Y by a factor of up to 40. The use of a magnetic separator and a hydrocyclone in the processing of the raw material can yield REE + Y contents of as much as 0.77 wt%. Although this value compares well with the REE + Y concentration in some potentially economic REE + Y projects elsewhere, the overall tonnage of the (REE + Y)-enriched residue is by far not sufficient to consider economic extraction of REE + Y as by-product. Our results are most probably applicable also to other kaolin deposits derived from the weathering of Hercynian basement granites elsewhere (e.g. in Saxonia and Bavaria, Germany). Overall, the potential for REE + Y production as by-product from kaolin mining has to be regarded as minimal.

  15. Episodic exhumation and relief growth in the Mont Blanc massif, Western Alps from numerical modelling of thermochronology data

    NASA Astrophysics Data System (ADS)

    Glotzbach, C.; van der Beek, P. A.; Spiegel, C.

    2011-04-01

    The Pliocene-Quaternary exhumational and topographic evolution of the European Alps and its potential climatic and tectonic controls remain a subject of controversy. Here, we apply inverse numerical thermal-kinematic modelling to a spatially dense thermochronological dataset (apatite fission-track and (U-Th)/He) of both tunnel and surface samples across the Mont Blanc massif in the Western Alps, complemented by new zircon fission-track data, in order to better quantify its Neogene exhumation and relief history. Age-elevation relationships and modelling results show that an episodic exhumation scenario best fits the data. Initiation of exhumation in the Mont Blanc massif at 22 ± 2 Ma with a rate of 0.8 ± 0.15 km/Myr is probably related to NW-directed thrusting during nappe emplacement. Exhumation rates decrease at 6 ± 2 Ma to values of 0.15 ± 0.65 km/Myr, which we interpret to be the result of a general decrease in convergence rates and/or extensive exposure of less erodible crystalline basement rocks from below more easily erodible Mesozoic sediments. Finally, local exhumation rates increase up to 2.0 ± 0.6 km/Myr at 1.7 ± 0.8 Ma. Modelling shows that this recent increase in local exhumation can be explained by valley incision and the associated increase in relief at 0.9 ± 0.8 Ma, leading to erosional unloading, isostatic rebound and additional rock uplift and exhumation. Given the lack of tectonic activity as evidenced by constant thermochronological ages along the tunnel transect, we suggest that the final increase in exhumation and relief in the Mont Blanc massif is the result of climate change, with the initiation of mid-Pleistocene glaciations leading to rapid valley incision and related local exhumation.

  16. 10Be exposure dating of onset and timing of Neoglacial glacier advances in the Ecrins massif, French Alps

    NASA Astrophysics Data System (ADS)

    Le Roy, Melaine; Deline, Philip; Carcaillet, Julien

    2013-04-01

    Alpine glaciers are known to be highly sensitive to change in temperature and precipitation on decadal to centennial time scales. For two decades, numerous studies on Holocene climate revealed a period marked by abrupt cold reversals (e.g. 8.2 ka event) with increasing frequency and magnitude after the Holocene Climatic Optimum, during the so-called Neoglacial period (roughly the last 4 ka). State-of-the-art studies indicate that largest alpine glaciers failed to exceed their Little Ice Age (LIA) extent during these LIA Type-Events, unlike certain smaller glaciers. In the French Alps, very few investigations were conducted to date on Holocene glacier variability. Almost all studies focused on the most glacierized area: the Mont Blanc massif, where suitable organic remains to apply radiocarbon dating and dendrochronology are available. Other glacierized massifs are poorly studied, without any Holocene/Neoglacial glacier chronology up to now. Here, we present the results of a study focusing on six glacier forefields distributed in the Ecrins massif. Detailed geomorphological mapping and in-situ produced 10Be dating were carried on multi-crested so-called "LIA composite moraines". The targeted ridges are located in distal position with respect to late LIA drift in order to identify Holocene cold pulses that have led to (or slightly exceeded) LIA-like glacier extent. The 35 10Be ages obtained revealed that the onset of Neoglacial occurred at ~4.2 ka, and that at least two other advances were recorded at ~3.3 ka and ~0.85 ka. One site has yielded a nearly complete Neoglacial record as four discrete events have been dated. These results highlight the potential of lateral moraine ridge stratigraphy which could yield accurate record when sufficiently preserved, but also the different preservation of landforms along the glacier margin which could censor the record.

  17. Perceptions of social and environmental changes in a Mediterranean forest during the last 100 years: the Gavarres Massif.

    PubMed

    Rodríguez-Carreras, Roser; Ubeda, Xavier; Outeiro, Luís; Asperó, Francesc

    2014-06-01

    During the last century the landscape of the mid-Mediterranean mountains has undergone major transformations. The precipitous decline in the economic viability of forest products has engendered ever-thickening forests and agricultural lands have reverted to forest land cover. The related exodus of existing inhabitants since 1960 has led to new styles of occupancy: residential and touristic land uses have emerged while the primary and secondary sectors have largely disappeared. The object of the present study is to review how these transformations have developed in a specific area of north-eastern of Catalonia, known as the Gavarres Massif. The study applies a qualitative approach, based on interviews with stakeholders including active members of the local community and others who utilize or visit the area, all of whom are representatives of different social groups with a wide range of interests and points of view with regard to the massif. The information collected from the perspectives and opinions of the participants is coupled with objective data about the area. The result of this investigation is a rich variety of perceptions on landscape and social transformation and its current functional dynamics. Analyzing the information obtained allows us to understand the fact that the disappearance of the rural world is directly related to the collapse of an entire economic system that relied on the environment. In this study, two divergent points of view arise, one which supports recovering past landscapes and another which favours managing changes, conserving the existing landscape. Proposals for the current and future territorial management of Les Gavarres are presented. The diversity of opinions which emerges with regard to managing necessary changes in the massif emphasizes the importance of increased social dialogue. PMID:24060242

  18. Geological and geochemical reconnaissance in the central Santander Massif, Departments of Santander and Norte de Santander, Colombia

    USGS Publications Warehouse

    Evans, James George

    1976-01-01

    The central Santander Massif is composed of Precambrian Bucaramanga Gneiss and pre-Devonian Silgara Formation intruded by Mesozoic quartz diorite, quartz monzonite, and alaskite and Cretaceous or younger porphyry. Triassic (Bocas Formation), Jurassic (Jordan and Giron Formations).and Cretaceous (Tambor, Rosa Blanca, Paja, Tablazo, Simiti, La Luna, and Umir Formations) sedimentary rocks overlie the metamorphic rocks and are younger than most of the intrusions. A geological and geochemical reconnaissance of part of the central Santander Massif included the Vetas and California gold districts. At Vetas the gold is generally in brecciated aphanitic quartz and phyllonite. Dark-gray material in the ore may be graphite. The ore veins follow steep west-northwest- and north-northeast-striking fracture zones. No new gold deposits were found. Additional geochemical studies should concentrate on western Loma Pozo del Rey and on improvement of the gold extraction process. At California the gold is in pyritiferous quartz veins and quartz breccia. Ore containing black sooty material (graphite?) is highly radioactive. Some of the mineralization is post-Lower Cretaceous. Soil samples indicate that gold deposits lie under the thick blanket of soil on the ridges above the zone of mining. Three principal gold targets are outlined by gold and associated minerals in pan concentrates. The close relation of gold and copper anomalies suggests that copper may be useful as a pathfinder for gold elsewhere in the region. Based on occurrences of gold or high concentrations of pyrite or chalcopyrite in pan concentrates and on analytical data, eight potential gold targets are outlined in the central massif. Reconnaissance of the surrounding region is warranted.

  19. Pan-African magmatism in the Menderes Massif: geochronological data from leucocratic tourmaline orthogneisses in western Turkey

    NASA Astrophysics Data System (ADS)

    Koralay, O. E.; Candan, O.; Chen, F.; Akal, C.; Oberhänsli, R.; Satır, M.; Dora, O. Ö.

    2012-11-01

    The Menderes Massif, exposed in western Anatolia, is a metamorphic complex cropping out in the Alpine orogenic belt. The metamorphic rock succession of the Massif is made up of a Precambrian basement and overlying Paleozoic-early Tertiary cover series. The Pan-African basement is composed of late Proterozoic metasedimentary rocks consisting of partially migmatized paragneisses and conformably overlying medium- to high-grade mica schists, intruded by orthogneisses and metagabbros. Along the southern flank of the southern submassif, we recognized well-preserved primary contact relationship between biotite and leucocratic tourmaline orthogneisses and country rocks as the orthogneisses represent numerous large plutons, stocks and vein rocks intruded into a basement of garnet mica schists. Based on the radiometric data, the primary deposition age of the precursors of the country rocks, garnet mica schist, can be constrained between 600 and 550 Ma (latest Neoproterozoic). The North Africa-Arabian-Nubian Shield in the Mozambique Belt can be suggested as the possible provenance of these metaclastics. The intrusion ages of the leucocratic tourmaline orthogneisses and biotite orthogneisses were dated at 550-540 Ma (latest Neoproterozoic-earliest Cambrian) by zircon U/Pb and Pb/Pb geochronology. These granitoids represent the products of the widespread Pan-African acidic magmatic activity, which can be attributed to the closure of the Mozambique Ocean during the final collision of East and West Gondwana. Detrital zircon ages at about 550 Ma in the Paleozoic muscovite-quartz schists show that these Pan-African granitoids in the basement form the source rocks of the cover series of the Menderes Massif.

  20. New structural field data on the timing and kinematics of deformation and exhumation of the Mont Blanc massif

    NASA Astrophysics Data System (ADS)

    Egli, Daniel; Mancktelow, Neil

    2010-05-01

    The Mont Blanc massif is one of the external crystalline massifs, which represent the basement of the former European continental margin and therefore belong to the Helvetic domain. It mainly consists of polymetamorphic Late Proterozoic to Early Paleozoic gneisses intruded by the Variscan Mont Blanc granite (Von Raumer et al. 1993). The timing and kinematics of deformation and exhumation of the Mont Blanc massif is a controversial topic and various models have been proposed. Low-temperature thermochronology studies provide an extensive data set for estimating exhumation rates in Neogene times (e.g. Seward & Mancktelow 1994; Leloup et al. 2005; Glotzbach et al. 2008), but detailed structural studies to critically asses and constrain the proposed kinematic models are largely lacking. Glotzbach et al. (2008) show that the exhumation is episodic, with rates changing from relatively fast (~2.5 km/Ma before 6 Ma) to a slow phase (<0.5 km/Ma between 6 and 3.5 Ma), in turn followed by acceleration to ~1 km/Ma after 3 Ma. Our study presents new structural data from the south-eastern side of the Mont Blanc massif and the adjacent sediments and addresses the tectonic evolution and late stage exhumation history of the massif. The goal is to assess the importance of tectonics versus climate for controlling exhumation, as well as to establish the overall geometry of uplift (2D pop-up, 3D dextral transpressive model, large scale backfolding). A major back-thrust was proposed by previous authors ("Mont Blanc back-thrust", e.g. Leloup et al. 2005, Rolland et al. 2007), characterized as a relatively steeply north-west dipping thrust bringing the Mont Blanc basement back over the tectonostratigraphically higher Helvetic and Ultrahelvetic metasediments. 40Ar¬-39Ar dating of white micas interpreted to have grown during movement on the Mont Blanc back-thrust indicates an initiation of movement around 16 Ma (Rolland et al. 2007). Leloup et al. (2005) suggest a reactivation of this

  1. Acoustic method for defining the stress state of a rock massif based on solution of the seismic inverse problem

    NASA Astrophysics Data System (ADS)

    Nazarov, L. A.; Nazarova, L. A.; Romenskii, E. I.; Tcheverda, V. A.; Epov, M. I.

    2016-02-01

    A method for estimating the stress-strain state of a rock massif in the vicinity of underground facilities is substantiated. This method is based on solution of the boundary inverse problem of defining the components of an external stress field from the acoustic sounding data. The acoustic sounding data used are the arrival times of diving head longitudinal waves, recorded in a long mine shaft. Numerical experiments have revealed the optimal arrangement of the recording network and the limited relative error in the input data, which, taken together, provide for solvability of the inverse problem.

  2. The migmatite-gneiss complex of the Chuya-Kendyktas sialic massif (Southern Kazakhstan): Structure and age

    NASA Astrophysics Data System (ADS)

    Tretyakov, A. A.; Degtyarev, K. E.; Kovach, V. P.; Kotov, A. B.; Salnikova, E. B.; Pilitsyna, A. V.; Yakovleva, S. Z.

    2016-03-01

    A migmatite-gneiss complex made up of paraand orthogneisses and crystalline schists with bodies of ultrametagenic tonalites is distinguished in the basement of the northwestern part of the Chuya-Kendyktas Massif. ID-TIMS dating of accessory zircon from orthogneisses and ultrametagenic tonalites in combination with LA-ICP-MS analyses of detrital zircons from garnet-biotite paragneisses showed that the migmatite-gneiss complex was formed after protoliths with an age within 800-770 Ma and completed its evolution in the first half of the Neoproterozoic.

  3. Quantification of low elevation relief vertical movements from global sea level curves and scattered marine deposits (Armorican Massif, France)

    NASA Astrophysics Data System (ADS)

    Bessin, Paul; Guillocheau, François; Robin, Cécile; Bauer, Hugues; Schroëtter, Jean-Michel

    2016-04-01

    Amplitudes of vertical movements, amount of burial or of denudation are often too low or too old to be quantified from thermochronological or cosmogenic isotopes methods. This is the case for the vertical movements experienced by European Variscan basements of low relief during Cenozoic times. Some of these basements bear scattered thin Cenozoic marine sediments. Thus, we proposed to quantify Cenozoic vertical movements from i) current elevation of well dated marine sediments scattered on these basements, corrected from their bathymetry of deposition provided by their sedimentary facies and ii) elevation of global sea level at time of sediment deposition from a new compilation of available curves. This compilation highlights that i) curve which takes into account ocean basin volume change are consistent for the ca. 100 to 40 Ma "greenhouse" period whereas ii) curves based on coreholes backstripping methods better reflect global sea level changes since ca. 40 Ma. For their respective time intervals, both are in accordance with curves which together take into account ocean water volume and ocean basin volume changes. We quantify Cenozoic vertical movements of the Armorican Massif showcase. This massif is French Variscan basement of low relief (elevation < 420 m), two times buried then exhumed during Jurassic to Paleocene times, which bears numerous Cenozoic remnants of marine sediments of four periods: Bartonian, Rupelian, Langhian-Serravalian and Piacezian-Gelasian. We evidence a tree-step history of Cenozoic vertical movements and deformation: i) 38-34 Ma: a phase of near stability of the massif related to no to low deformation period for the Western Europe; ii) 30-16 Ma: a phase of low subsidence which coeval to a long wavelength subsidence of Western Europe which is proposed to be mantle-driven (dynamic topography); iii) 3.5-0 Ma: an overall bulging phase of the massif related to Apulia-Eurasia convergences due to Africa-Apulia and Iberia plates convergence which

  4. Thermal history and extensional exhumation of a high-temperature crystalline complex (Hırkadağ Massif, Central Anatolia)

    NASA Astrophysics Data System (ADS)

    Lefebvre, Côme; Kalijn Peters, M.; Wehrens, Philip C.; Brouwer, Fraukje M.; van Roermund, Herman L. M.

    2015-12-01

    The Central Anatolian Crystalline Complex (CACC) is a large continental domain exposed in central Turkey that was affected by high temperature metamorphism during the Late Cretaceous. As a result of this event, Paleozoic sediments became metamorphosed, initially under Barrovian conditions, then overprinted locally by high temperature-low pressure metamorphism, and intruded by widespread batholiths. In this study we focus on the crystalline Hırkadağ Massif located in the central part of the CACC, where we applied an integrated approach involving metamorphic, structural and geochronological analysis in order to elucidate its tectonic history from burial to exhumation. Our metamorphic study reveals that conditions of metamorphism reached ~ 7-8 kbar/700 °C and were relatively homogeneous at the scale of the Hırkadağ Massif. Coeval with the regional metamorphism, the rocks were intensely deformed as reflected by isoclinal folding, the development of a pervasive foliation and top-to-the-SE shearing. This was followed by decompression to pressures of ~ 3-4 kbar at 800 °C, which may be linked to the emplacement of local granodioritic intrusions at ~ 77 Ma. Subsequent cooling of the Hırkadağ high-grade metamorphic and intrusive rocks is indicated by 40Ar/39Ar cooling ages of 68.8 ± 0.9 Ma (biotite) and 67.0 ± 1.2 Ma (potassium feldspar). Evidence for tectonic exhumation has been identified within the marbles at the NE margin of the Hırkadağ Massif, in the form of discrete protomylonitic and mylonitic shear bands showing a consistent N40-60 top-to-NE sense of shear. Further east, the contact between brecciated mylonitic marbles and non-metamorphic conglomerates preserves the typical structural features of an upper-crustal detachment fault. Restoration of the Hırkadağ Massif and the CACC to their late Cretaceous configuration suggests that the LP-HT metamorphism, magmatism and extensional structures evolved as a result of the development and exhumation of a ~ N

  5. Research the dynamical characteristics of slow deformation waves as a rock massif response to explosions during its outworking

    NASA Astrophysics Data System (ADS)

    Hachay, Olga; Khachay, Oleg; Shipeev, Oleg

    2015-04-01

    As a result of long-term natural geomechanics and geophysical observation data on mines of complex ore rocks, generalization of the non-linear reaction of rock massif to heavy dynamic influences have been established. In addition, pendulum type waves have been observed and the sources of them have been located inside geoblocks of different hierarchic levels (Oparin et al., 2010). At the same time, these waves propagate with wide low (compared with seismic waves) velocity values (Kurlenja et al., 1993; Oparin et al., 2006). Research into the massif state with the use of the dynamic systems theory approach (Naimark et al., 2009; Chulichkov, 2003; Hachay et al., 2010) has been developed to ascertain the criteria of dissipative regimes changing for real rock massifs, which are under heavy man-caused influence. To realize such research we used the data from the seismic record of the Tashtagol mine for the two-year period from June 2006 up to June 2008. We used the space-time coordinates for all dynamic massif event responses, which occurred during that period inside the mine space and for the explosions - values fixed by seismic station energy (Hachay et al., 2010). The phase diagrams of the massif state for the northern and southern parts of the mine space were plotted in coordinates Ev(t) and d(Ev(t))/dt, t - time - in parts of 24 hours, Ev - the dissipated massive seismic energy - in joules. Hachay et al., (2010) analysed the morphology of seismic response phase trajectories on the explosion influences during different serial intervals in the southern part of the mine. In that period, according to data for different explosions in the mine, the majority of the total energy had been injected into the southern part of the mine. Moreover, at the end of 2007, just in the southern part, the strongest rock burst during the whole history of the working mine happened. We developed a new processing method of seismological information in real, which we can use directly in the

  6. Batteries: from alkaline to zinc-air.

    PubMed

    Dondelinger, Robert M

    2004-01-01

    There is no perfect disposable battery--one that will sit on the shelf for 20 years, then continually provide unlimited current, at a completely constant voltage until exhausted, without producing heat. There is no perfect rechargeable battery--one with all of the above characteristics and will also withstand an infinite overcharge while providing an equally infinite cycle life. There are only compromises. Every battery selection is a compromise between the ideally required characteristics, the advantages, and the limitations of each battery type. General selection of a battery type to power a medical device is largely outside the purview of the biomed. Initially, these are engineering decisions made at the time of medical equipment design and are intended to be followed in perpetuity. However, since newer cell types evolve and the manufacturer's literature is fixed at the time of printing, some intelligent substitutions may be made as long as the biomed understands the characteristics of both the recommended cell and the replacement cell. For example, when the manufacturer recommends alkaline, it is usually because of the almost constant voltage it produces under the devices' design load. Over time, other battery types may be developed that will meet the intent of the manufacturer, at a lower cost, providing longer operational life, at a lower environmental cost, or with a combination of these advantages. In the Obstetrical Doppler cited at the beginning of this article, the user had put in carbon-zinc cells, and the biomed had unknowingly replaced them with carbonzinc cells. If the alkaline cells recommended by the manufacturer had been used, there would have been the proper output voltage at the battery terminals when the [table: see text] cells were at their half-life. Instead, the device refused to operate since the battery voltage was below presumed design voltage. While battery-type substitutions may be easily and relatively successfully made in disposable

  7. Microbial thiocyanate utilization under highly alkaline conditions.

    PubMed

    Sorokin, D Y; Tourova, T P; Lysenko, A M; Kuenen, J G

    2001-02-01

    Three kinds of alkaliphilic bacteria able to utilize thiocyanate (CNS-) at pH 10 were found in highly alkaline soda lake sediments and soda soils. The first group included obligate heterotrophs that utilized thiocyanate as a nitrogen source while growing at pH 10 with acetate as carbon and energy sources. Most of the heterotrophic strains were able to oxidize sulfide and thiosulfate to tetrathionate. The second group included obligately autotrophic sulfur-oxidizing alkaliphiles which utilized thiocyanate nitrogen during growth with thiosulfate as the energy source. Genetic analysis demonstrated that both the heterotrophic and autotrophic alkaliphiles that utilized thiocyanate as a nitrogen source were related to the previously described sulfur-oxidizing alkaliphiles belonging to the gamma subdivision of the division Proteobacteria (the Halomonas group for the heterotrophs and the genus Thioalkalivibrio for autotrophs). The third group included obligately autotrophic sulfur-oxidizing alkaliphilic bacteria able to utilize thiocyanate as a sole source of energy. These bacteria could be enriched on mineral medium with thiocyanate at pH 10. Growth with thiocyanate was usually much slower than growth with thiosulfate, although the biomass yield on thiocyanate was higher. Of the four strains isolated, the three vibrio-shaped strains were genetically closely related to the previously described sulfur-oxidizing alkaliphiles belonging to the genus Thioalkalivibrio. The rod-shaped isolate differed from the other isolates by its ability to accumulate large amounts of elemental sulfur inside its cells and by its ability to oxidize carbon disulfide. Despite its low DNA homology with and substantial phenotypic differences from the vibrio-shaped strains, this isolate also belonged to the genus Thioalkalivibrio according to a phylogenetic analysis. The heterotrophic and autotrophic alkaliphiles that grew with thiocyanate as an N source possessed a relatively high level of cyanase

  8. Microbial Thiocyanate Utilization under Highly Alkaline Conditions

    PubMed Central

    Sorokin, Dimitry Y.; Tourova, Tatyana P.; Lysenko, Anatoly M.; Kuenen, J. Gijs

    2001-01-01

    Three kinds of alkaliphilic bacteria able to utilize thiocyanate (CNS−) at pH 10 were found in highly alkaline soda lake sediments and soda soils. The first group included obligate heterotrophs that utilized thiocyanate as a nitrogen source while growing at pH 10 with acetate as carbon and energy sources. Most of the heterotrophic strains were able to oxidize sulfide and thiosulfate to tetrathionate. The second group included obligately autotrophic sulfur-oxidizing alkaliphiles which utilized thiocyanate nitrogen during growth with thiosulfate as the energy source. Genetic analysis demonstrated that both the heterotrophic and autotrophic alkaliphiles that utilized thiocyanate as a nitrogen source were related to the previously described sulfur-oxidizing alkaliphiles belonging to the gamma subdivision of the division Proteobacteria (the Halomonas group for the heterotrophs and the genus Thioalkalivibrio for autotrophs). The third group included obligately autotrophic sulfur-oxidizing alkaliphilic bacteria able to utilize thiocyanate as a sole source of energy. These bacteria could be enriched on mineral medium with thiocyanate at pH 10. Growth with thiocyanate was usually much slower than growth with thiosulfate, although the biomass yield on thiocyanate was higher. Of the four strains isolated, the three vibrio-shaped strains were genetically closely related to the previously described sulfur-oxidizing alkaliphiles belonging to the genus Thioalkalivibrio. The rod-shaped isolate differed from the other isolates by its ability to accumulate large amounts of elemental sulfur inside its cells and by its ability to oxidize carbon disulfide. Despite its low DNA homology with and substantial phenotypic differences from the vibrio-shaped strains, this isolate also belonged to the genus Thioalkalivibrio according to a phylogenetic analysis. The heterotrophic and autotrophic alkaliphiles that grew with thiocyanate as an N source possessed a relatively high level of cyanase

  9. Net alkalinity and net acidity 2: Practical considerations

    USGS Publications Warehouse

    Kirby, C.S.; Cravotta, C.A., III

    2005-01-01

    The pH, alkalinity, and acidity of mine drainage and associated waters can be misinterpreted because of the chemical instability of samples and possible misunderstandings of standard analytical method results. Synthetic and field samples of mine drainage having various initial pH values and concentrations of dissolved metals and alkalinity were titrated by several methods, and the results were compared to alkalinity and acidity calculated based on dissolved solutes. The pH, alkalinity, and acidity were compared between fresh, unoxidized and aged, oxidized samples. Data for Pennsylvania coal mine drainage indicates that the pH of fresh samples was predominantly acidic (pH 2.5-4) or near neutral (pH 6-7); ??? 25% of the samples had pH values between 5 and 6. Following oxidation, no samples had pH values between 5 and 6. The Standard Method Alkalinity titration is constrained to yield values >0. Most calculated and measured alkalinities for samples with positive alkalinities were in close agreement. However, for low-pH samples, the calculated alkalinity can be negative due to negative contributions by dissolved metals that may oxidize and hydrolyze. The Standard Method hot peroxide treatment titration for acidity determination (Hot Acidity) accurately indicates the potential for pH to decrease to acidic values after complete degassing of CO2 and oxidation of Fe and Mn, and it indicates either the excess alkalinity or that required for neutralization of the sample. The Hot Acidity directly measures net acidity (= -net alkalinity). Samples that had near-neutral pH after oxidation had negative Hot Acidity; samples that had pH < 6.3 after oxidation had positive Hot Acidity. Samples with similar pH values before oxidation had dissimilar Hot Acidities due to variations in their alkalinities and dissolved Fe, Mn, and Al concentrations. Hot Acidity was approximately equal to net acidity calculated based on initial pH and dissolved concentrations of Fe, Mn, and Al minus the

  10. Francisella DnaK Inhibits Tissue-nonspecific Alkaline Phosphatase*

    PubMed Central

    Arulanandam, Bernard P.; Chetty, Senthilnath Lakshmana; Yu, Jieh-Juen; Leonard, Sean; Klose, Karl; Seshu, Janakiram; Cap, Andrew; Valdes, James J.; Chambers, James P.

    2012-01-01

    Following pulmonary infection with Francisella tularensis, we observed an unexpected but significant reduction of alkaline phosphatase, an enzyme normally up-regulated following inflammation. However, no reduction was observed in mice infected with a closely related Gram-negative pneumonic organism (Klebsiella pneumoniae) suggesting the inhibition may be Francisella-specific. In similar fashion to in vivo observations, addition of Francisella lysate to exogenous alkaline phosphatase (tissue-nonspecific isozyme) was inhibitory. Partial purification and subsequent proteomic analysis indicated the inhibitory factor to be the heat shock protein DnaK. Incubation with increasing amounts of anti-DnaK antibody reduced the inhibitory effect in a dose-dependent manner. Furthermore, DnaK contains an adenosine triphosphate binding domain at its N terminus, and addition of adenosine triphosphate enhances dissociation of DnaK with its target protein, e.g. alkaline phosphatase. Addition of adenosine triphosphate resulted in decreased DnaK co-immunoprecipitated with alkaline phosphatase as well as reduction of Francisella-mediated alkaline phosphatase inhibition further supporting the binding of Francisella DnaK to alkaline phosphatase. Release of DnaK via secretion and/or bacterial cell lysis into the extracellular milieu and inhibition of plasma alkaline phosphatase could promote an orchestrated, inflammatory response advantageous to Francisella. PMID:22923614

  11. Solubility of pllutonium in alkaline salt solutions

    SciTech Connect

    Hobbs, D.T.; Edwards, T.B.

    1993-02-26

    Plutonium solubility data from several studies have been evaluated. For each data set, a predictive model has been developed where appropriate. In addition, a statistical model and corresponding prediction intervals for plutonium solubility as a quadratic function of the hydroxide concentration have been developed. Because of the wide range of solution compositions, the solubility of plutonium can vary by as much as three orders of magnitude for any given hydroxide concentration and still remain within the prediction interval. Any nuclear safety assessments that depend on the maximum amount of plutonium dissolved in alkaline salt solutions should use concentrations at least as great as the upper prediction limits developed in this study. To increase the confidence in the prediction model, it is recommended that additional solubility tests be conducted at low hydroxide concentrations and with all of the other solution components involved. To validate the model for application to actual waste solutions, it is recommended that the plutonium solubilities in actual waste solutions be determined and compared to the values predicted by the quadratic model.

  12. Process for treating alkaline wastes for vitrification

    DOEpatents

    Hsu, Chia-lin W.

    1994-01-01

    According to its major aspects and broadly stated, the present invention is a process for treating alkaline waste materials, including high level radioactive wastes, for vitrification. The process involves adjusting the pH of the wastes with nitric acid, adding formic acid (or a process stream containing formic acid) to reduce mercury compounds to elemental mercury and MnO{sub 2} to the Mn(II) ion, and mixing with class formers to produce a melter feed. The process minimizes production of hydrogen due to noble metal-catalyzed formic acid decomposition during, treatment, while producing a redox-balanced feed for effective melter operation and a quality glass product. An important feature of the present invention is the use of different acidifying and reducing, agents to treat the wastes. The nitric acid acidifies the wastes to improve yield stress and supplies acid for various reactions; then the formic acid reduces mercury compounds to elemental mercury and MnO{sub 2}) to the Mn(II) ion. When the pH of the waste is lower, reduction of mercury compounds and MnO{sub 2}) is faster and less formic acid is needed, and the production of hydrogen caused by catalytically-active noble metals is decreased.

  13. Hydrocarbon potential of an alkaline lake basin

    SciTech Connect

    Chen Jian Yu; Wang Gijun ); Ma Wanyi )

    1991-03-01

    The Biyan basin is an oil-rich intermountain basin in the central part of China. It is a half graben with a marginal normal fault in the south and a slope in the north. The thickest Eogene reaches 7 km in the center of the depression. This basin became a typical alkaline lake with specific sedimentary sequences composed of oil shale, trona, dolomite, and dark mudstone during Early Tertiary because of dry climate and peripheral source areas rich in Na-containing minerals. The source rock is characterized by abundant organic matter with a mean TOC of 2.5% and kerogen of good quality with H/C 1.4-1.7, and IH up to 800 mg/g. The study of biomarkers reveals a low Pr/Ph ratio and an abundant gammacerane and {minus}carotane, thus indicating an environment of high salinity and reduction. All geochemical data demonstrate multiple provinces of primary organic matter, of which halophilous prokaryotic organisms are likely contributors. Crude oil in the Biyan oil field contains high wax and low sulfur. The low-mature oil is discovered in dolomite beds. The high hydrocarbon potential of this basin is due to particularly favorable conditions for preservation and transformation of organic matter and high subsidence rates.

  14. Response of Desulfovibrio vulgaris to Alkaline Stress

    SciTech Connect

    Stolyar, S.; He, Q.; He, Z.; Yang, Z.; Borglin, S.E.; Joyner, D.; Huang, K.; Alm, E.; Hazen, T.C.; Zhou, J.; Wall, J.D.; Arkin, A.P.; Stahl, D.A.

    2007-11-30

    The response of exponentially growing Desulfovibrio vulgarisHildenborough to pH 10 stress was studied using oligonucleotidemicroarrays and a study set of mutants with genes suggested by microarraydata to be involved in the alkaline stress response deleted. The datashowed that the response of D. vulgaris to increased pH is generallysimilar to that of Escherichia coli but is apparently controlled byunique regulatory circuits since the alternative sigma factors (sigma Sand sigma E) contributing to this stress response in E. coli appear to beabsent in D. vulgaris. Genes previously reported to be up-regulated in E.coli were up-regulated in D. vulgaris; these genes included three ATPasegenes and a tryptophan synthase gene. Transcription of chaperone andprotease genes (encoding ATP-dependent Clp and La proteases and DnaK) wasalso elevated in D. vulgaris. As in E. coli, genes involved in flagellumsynthesis were down-regulated. The transcriptional data also identifiedregulators, distinct from sigma S and sigma E, that are likely part of aD. vulgaris Hildenborough-specific stress response system.Characterization of a study set of mutants with genes implicated inalkaline stress response deleted confirmed that there was protectiveinvolvement of the sodium/proton antiporter NhaC-2, tryptophanase A, andtwo putative regulators/histidine kinases (DVU0331 andDVU2580).

  15. Engineering challenges of ocean alkalinity enhancement

    NASA Astrophysics Data System (ADS)

    Kruger, T.; Renforth, P.

    2012-04-01

    The addition of calcium oxide (CaO) to the ocean as a means of enhancing the capacity of the ocean as a carbon sink was first proposed by Haroon Kheshgi in 1995. Calcium oxide is created by heating high purity limestone in a kiln to temperatures of approximately 1000°C. Addition of this material to the ocean draws carbon dioxide out of the atmosphere (approximately 1 tonne of CaO could sequester 1.3 tonnes of CO2). Abiotic carbonate precipitation is inhibited in the surface ocean. This is a carbon and energy expensive process, where approximately 0.8 tonnes of CO2 are produced at a point source for every tonne sequestered. The feasibility of ocean alkalinity enhancement requires capture and storage of the point source of CO2. We present details of a feasibility study of the engineering challenges of Kheshgi's method focusing on the potential scalability and costs of the proposed process. To draw down a PgC per year would require the extraction and processing of ~6Pg of limestone per year, which is similar in scale to the current coal industry. Costs are estimated at ~USD30-40 per tonne of CO2 sequestered through the process, which is favourable to comparative processes. Kheshgi, H. (1995) Energy 20 (9) 915-922

  16. Process for treating alkaline wastes for vitrification

    DOEpatents

    Hsu, Chia-lin W.

    1995-01-01

    A process for treating alkaline wastes for vitrification. The process involves acidifying the wastes with an oxidizing agent such as nitric acid, then adding formic acid as a reducing agent, and then mixing with glass formers to produce a melter feed. The nitric acid contributes nitrates that act as an oxidant to balance the redox of the melter feed, prevent reduction of certain species to produce conducting metals, and lower the pH of the wastes to a suitable level for melter operation. The formic acid reduces mercury compounds to elemental mercury for removal by steam stripping, and MnO.sub.2 to the Mn(II) ion to prevent foaming of the glass melt. The optimum amounts of nitric acid and formic acid are determined in relation to the composition of the wastes, including the concentrations of mercury (II) and MnO.sub.2, noble metal compounds, nitrates, formates and so forth. The process minimizes the amount of hydrogen generated during treatment, while producing a redox-balanced feed for effective melter operation and a quality glass product.

  17. Process for treating alkaline wastes for vitrification

    DOEpatents

    Hsu, C.L.W.

    1995-07-25

    A process is described for treating alkaline wastes for vitrification. The process involves acidifying the wastes with an oxidizing agent such as nitric acid, then adding formic acid as a reducing agent, and then mixing with glass formers to produce a melter feed. The nitric acid contributes nitrates that act as an oxidant to balance the redox of the melter feed, prevent reduction of certain species to produce conducting metals, and lower the pH of the wastes to a suitable level for melter operation. The formic acid reduces mercury compounds to elemental mercury for removal by steam stripping, and MnO{sub 2} to the Mn(II) ion to prevent foaming of the glass melt. The optimum amounts of nitric acid and formic acid are determined in relation to the composition of the wastes, including the concentrations of mercury (II) and MnO{sub 2}, noble metal compounds, nitrates, formates and so forth. The process minimizes the amount of hydrogen generated during treatment, while producing a redox-balanced feed for effective melter operation and a quality glass product. 4 figs.

  18. Production of alkaline protease from Cellulosimicrobium cellulans

    PubMed Central

    Ferracini-Santos, Luciana; Sato, Hélia H

    2009-01-01

    Cellulosimicrobium cellulans is one of the microorganisms that produces a wide variety of yeast cell wall-degrading enzymes, β-1,3-glucanase, protease and chitinase. Dried cells of Saccharomyces cerevisiae were used as carbon and nitrogen source for cell growth and protease production. The medium components KH2PO4, KOH and dried yeast cells showed a significant effect (p<0.05) on the factorial fractional design. A second design was prepared using two factors: pH and percentage of dried yeast cells. The results showed that the culture medium for the maximum production of protease was 0.2 g/l of MgSO4.7H2O, 2.0 g/l of (NH4)2SO4 and 8% of dried yeast cells in 0.15M phosphate buffer at pH 8.0. The maximum alkaline protease production was 7.0 ± 0.27 U/ml over the center point. Crude protease showed best activity at 50ºC and pH 7.0-8.0, and was stable at 50ºC. PMID:24031317

  19. Geochronology, geochemistry, and deformation history of Late Jurassic-Early Cretaceous intrusive rocks in the Erguna Massif, NE China: Constraints on the late Mesozoic tectonic evolution of the Mongol-Okhotsk orogenic belt

    NASA Astrophysics Data System (ADS)

    Tang, Jie; Xu, Wen-Liang; Wang, Feng; Zhao, Shuo; Li, Yu

    2015-09-01

    This paper presents new zircon and sphene U-Pb ages, biotite and hornblende 40Ar/39Ar ages, Hf isotopic data, and geochemical data for five Mesozoic plutons in the Erguna Massif of NE China. These data are used to constrain the late Mesozoic tectonic evolution of the Mongol-Okhotsk orogenic belt. This new dating, when combined with previously published ages, indicates that the Late Jurassic-Early Cretaceous (J3-K1) intrusive rocks can be subdivided into three stages that represent periods of magmatism during the Late Jurassic (~ 155 Ma), early Early Cretaceous (~ 137 Ma), and late Early Cretaceous (~ 123 Ma). In addition, the rocks have undergone later deformation recorded by peak ages of ~ 137 and ~ 123 Ma. The Late Jurassic and early Early Cretaceous intrusive rocks in the study area are dominantly syenogranites and are either A-type granites or are classified as alkaline series, suggesting that they formed in an extensional environment. The late Early Cretaceous intrusive rocks in this area are generally monzogranitic and were emplaced as dikes in an extensional environment, along with coeval bimodal volcanics. These data, combined with the presence of regional unconformities in the northern part of Hebei Province and western part of Liaoning Province, and the spatial distribution of coeval volcanic rocks in NE China, suggest the Late Jurassic and early Early Cretaceous magmatisms and the early Early Cretaceous deformation in this area occurred in an extensional environment related to the delamination of a thickened part of the crust after closure of the Mongol-Okhotsk Ocean. In comparison, the late Early Cretaceous deformation and magmatism occurred in an extensional environment related to either delamination of the previously thickened crust related to the Mongol-Okhotsk tectonic regime or the subduction of the Paleo-Pacific Plate, or the combined influence of these two tectonic regimes.

  20. Method of increasing the sulfation capacity of alkaline earth sorbents

    DOEpatents

    Shearer, John A.; Turner, Clarence B.; Johnson, Irving

    1982-01-01

    A system and method for increasing the sulfation capacity of alkaline earth carbonates to scrub sulfur dioxide produced during the fluidized bed combustion of coal in which partially sulfated alkaline earth carbonates are hydrated in a fluidized bed to crack the sulfate coating and convert the alkaline earth oxide to the hydroxide. Subsequent dehydration of the sulfate-hydroxide to a sulfate-oxide particle produces particles having larger pore size, increased porosity, decreased grain size and additional sulfation capacity. A continuous process is disclosed.

  1. Polyvinyl alcohol battery separator containing inert filler. [alkaline batteries

    NASA Technical Reports Server (NTRS)

    Sheibley, D. W.; Hsu, L. C.; Manzo, M. A. (Inventor)

    1981-01-01

    A cross-linked polyvinyl alcohol battery separator is disclosed. A particulate filler, inert to alkaline electrolyte of an alkaline battery, is incorporated in the separator in an amount of 1-20% by weight, based on the weight of the polyvinyl alcohol, and is dispersed throughout the product. Incorporation of the filler enhances performance and increases cycle life of alkaline batteries when compared with batteries containing a similar separator not containing filler. Suitable fillers include titanates, silicates, zirconates, aluminates, wood floor, lignin, and titania. Particle size is not greater than about 50 microns.

  2. Method of increasing the sulfation capacity of alkaline earth sorbents

    DOEpatents

    Shearer, J.A.; Turner, C.B.; Johnson, I.

    1980-03-13

    A system and method for increasing the sulfation capacity of alkaline earth carbonates to scrub sulfur dioxide produced during the fluidized bed combustion of coal in which partially sulfated alkaline earth carbonates are hydrated in a fluidized bed to crack the sulfate coating and convert the alkaline earth oxide to the hydroxide. Subsequent dehydration of the sulfate-hydroxide to a sulfate-oxide particle produces particles having larger pore size, increased porosity, decreased grain size and additional sulfation capacity. A continuous process is disclosed.

  3. Velocity structure near IODP Hole U1309D, Atlantis Massif, from waveform inversion of streamer data and borehole measurements

    NASA Astrophysics Data System (ADS)

    Harding, Alistair J.; Arnulf, Adrien F.; Blackman, Donna K.

    2016-06-01

    Seismic full waveform inversion (FWI) is a promising method for determining the detailed velocity structure of the igneous oceanic crust, especially for locations such as the Mid-Atlantic Ridge with significant lateral heterogeneity and seafloor topography. We examine the accuracy of FWI by inverting, after downward continuation to datum just above the seafloor, a multichannel seismic (MCS) profile from Atlantis Massif oceanic core complex at 30°N that passes close to Integrated Ocean Drilling Program (IODP) Hole U1309D and comparing the results against borehole measurements and existing on-bottom refraction data. The comparisons include the results of IODP Expedition 340T, which extended the sonic logging and vertical seismic profiling to the bottom of the borehole at 1400 m below seafloor. Compared to travel time tomography, the refinement in velocity and velocity gradient produced by FWI significantly improves the overall match to the borehole measurements, and allows the multilevel pattern of deformation and alteration of the detachment footwall seen in Hole U1309D to be extrapolated across the Central Dome. Prestack depth migration of the profile using the FWI velocities reveals the top and edges of the high-velocity, gabbroic core of the massif. It also indicates that the comparatively uniform gabbroic rocks drilled at Hole U1309D extend to ˜2.5 km below seafloor but overlie an extended, ˜2 km thick, mantle transition zone.

  4. Late Ordovician (post-Sardic) rifting branches in the North Gondwanan Montagne Noire and Mouthoumet massifs of southern France

    NASA Astrophysics Data System (ADS)

    Javier Álvaro, J.; Colmenar, Jorge; Monceret, Eric; Pouclet, André; Vizcaïno, Daniel

    2016-06-01

    Upper Ordovician-Lower Devonian rocks of the Cabrières klippes (southern Montagne Noire) and the Mouthoumet massif in southern France rest paraconformably or with angular discordance on Cambrian-Lower Ordovician strata. Neither Middle-Ordovician volcanism nor associated metamorphism is recorded, and the subsequent Middle-Ordovician stratigraphic gap is related to the Sardic phase. Upper Ordovician sedimentation started in the rifting branches of Cabrières and Mouthoumet with deposition of basaltic lava flows and lahar deposits (Roque de Bandies and Villerouge formations) of continental tholeiite signature (CT), indicative of continental fracturing. The infill of both rifting branches followed with the onset of (1) Katian (Ka1-Ka2) conglomerates and sandstones (Glauzy and Gascagne formations), which have yielded a new brachiopod assemblage representative of the Svobodaina havliceki Community; (2) Katian (Ka2-Ka4) limestones, marlstones, and shales with carbonate nodules, reflecting development of bryozoan-echinoderm meadows with elements of the Nicolella Community (Gabian and Montjoi formations); and (3) the Hirnantian Marmairane Formation in the Mouthoumet massif that has yielded a rich and diverse fossil association representative of the pandemic Hirnantia Fauna. The sealing of the subaerial palaeorelief generated during the Sardic phase is related to Silurian and Early Devonian transgressions leading to onlapping patterns and the record of high-angle discordances.

  5. Occurrence of an unknown Atlantic eruption in the Chaîne des Puys volcanic field (Massif Central, France)

    NASA Astrophysics Data System (ADS)

    Jouannic, G.; Walter-Simonnet, A. V.; Bossuet, G.; Cubizolle, H.; Boivin, P.; Devidal, J. L.; Oberlin, C.

    2014-08-01

    A volcanic ash layer, called MF1, was recently identified in Holocene sediments from the Gourgon and Molhiac peat bogs (Monts du Forez, French Massif Central). This ash layer consists of colorless shards with a heterogeneous trachytic to rhyolitic composition. The trace elements analyzed by Laser Ablation Inductively Coupled Plasma Mass Spectrometry (LA-ICP-MS) attest to a local origin. Radiocarbon dating of peat samples taken within and below the ash layer indicates the best age at 6339 ± 61 cal yr BP, i.e. an age contemporaneous with the volcanic activity of Montchal, Montcineyre and Pavin volcanoes from the Chaîne des Puys volcanic field. These volcanoes are characterized by basaltic and trachytic products, thus the rhyolitic composition of MF1 tephra suggests that it is likely originated from an unknown eruption. These results again confirm the interest of studying the distal volcanic ash fallouts in order to establish or specify records of past eruptions of volcanic fields. Identification of this new tephra layer also provides an additional tephrochronological marker for Eastern French Massif Central.

  6. Ssismic Methodologies Applied To The Characterization Of Fractured Rock Massifs: Case Studies

    NASA Astrophysics Data System (ADS)

    Marti, D.; Carbonell, R.; Flecha, I.; Palomeras, I.; Font-Capo, J.; Vazquez-Sune, E.; Perez-Estaun, A.

    2007-05-01

    The detailed characterization of fractured media in the shallow subsurface is becoming important. The detailed knowledge of the fracture network is mandatory in any hydrogeological model to constrain the potential pathways for water circulation. The geophysical methodolgies can provide a detailed image of the fractured rock and also the 3D distribution of physical properties. Two case studies are discussed in this work. The characterization of fractures in a waste disposal site and, the design and construction of a subway tunnel. In the first case, a multiseismic experiment was carried out in an old abandoned uranium mine. 2D and 3D seismic experiments including VSP, surface seismic reflection and travel time seismic tomography provided a 3D image of the internal structure of a granitic massif for hydrogeological studies of the preferred paths for the migration of contaminants. The tectonic stability of the site was also addressed by means of seismic measurements. The joint interpretation of all the available data enabled the interpretation of the low velocity anomalies in the 3D seismic tomography image as the fragile fractures and the alteration associated to them. A 3D image of the geometry of the heterogeneous weathered surface layer was also obtained. This surface is controlled by the complex network of faults and dykes observed in the area. The second case study involves 2D and 3D seismic experiments to aid the horizontal drilling of tunnels for a new subway line in Barcelona (Spain). Seismic data acquisition in a densely populated city is very difficult. The street layout determines the geometry of the acquisition experiments. The instrumentation can not always be located on the surface projection of the tunnel trace, therefore, pseudo 3D acquisition is required, deploying the instrumentation were it is possible. Furthermore, the shallow subsurface features extremely heterogeneous "weathered" layer of variable thickness (building fundations, sewage system

  7. Anatomy of an extensional shear zone in the mantle, Lanzo massif, Italy

    NASA Astrophysics Data System (ADS)

    Kaczmarek, Mary-Alix; Tommasi, AndréA.

    2011-08-01

    Analysis of the microstructures in the km-scale mantle shear zone that separates the northern and the central parts of the Lanzo peridotite massif provides evidence of an evolution in time and space of deformation processes accommodating shearing in the shallow mantle within an extensional setting. This shear zone displays an asymmetric distribution of deformation facies. From south to north, gradual reorientation of the foliation of coarse porphyroclastic plagioclase-bearing peridotites is followed by development of protomylonites, mylonites, and mm-scale ultramylonite bands. A sharp grain size gradient marks the northern boundary. Early deformation under near-solidus conditions in the south is recorded by preservation of weakly deformed interstitial plagioclase and almost random clinopyroxene and plagioclase crystal orientations. Feedback between deformation and melt transport probably led to melt focusing and strain weakening in the shear zone. Overprint of melt-rock reaction microstructures by solid-state deformation and decrease in recrystallized grain size in the protomylonites and mylonites indicate continued deformation under decreasing temperature. Less enriched peridotite compositions and absence of ultramafic dykes or widespread melt-impregnation microstructures north of the shear zone and clinopyroxene and amphibole enrichment in the mylonites and ultramylonites suggest that the shear zone acted as both a thermal barrier and a high-permeability channel for late crystallizing fluids. These observations, together with chemical data indicating faster cooling of central Lanzo relative to the northern body, corroborate that this shear zone is a mantle detachment fault. All deformation facies have crystal preferred orientations consistent with deformation by dislocation creep with dominant activation of the (010)[100] and (100)[001] systems in olivine and orthopyroxene, respectively. Dynamic recrystallization produces dispersion of olivine CPO but not a

  8. Microfracturing and fluid mixing in granites: W (Sn) ore deposition at Vaulry (NW French Massif Central)

    NASA Astrophysics Data System (ADS)

    Vallance, Jean; Cathelineau, Michel; Marignac, Christian; Boiron, Marie-Christine; Fourcade, Serge; Martineau, François; Fabre, Cécile

    2001-07-01

    The Vaulry W-(Sn) mineralisation, located at the eastern boundary of the Blond rare metal leucogranite, is contained in a set of subvertical quartz veins, locally with muscovite and minor quartz selvages. The sequence of deposition was: (1) milky quartz, predominantly as fracture filling, generally affected by subsequent ductile deformation; (2) hyaline quartz-wolframite-cassiterite; (3) minor sulphides. Other sets of quartz veinlets, although generally barren are observed in the Blond massif. Fluid migration at the microscopic scale within the granite and in the vicinity of quartz fractures was constrained by studying the geometry of fluid-inclusion planes and fluid-inclusion chemistry in and outside the mineralised area. Three major sets of subvertical fluid-inclusion planes are recognised: a N050°-060°E set, mostly developed in the veins and in the immediate vicinity, a N110°-130°E set, regionally developed in the granite and a N140-160°E set of local extent. As a whole, the density of FIP decreases from the mineralised zones toward the barren part of the pluton, except for the N140°-160°E set. These are locally abundant around quartz veinlets with similar orientations that form a broad "N-S" band near the Blond locality. Mineralising fluids observed as primary inclusions in cassiterite and in undeformed hyaline quartz are mostly aqueous, with moderate salinity and a minor volatile component, at variance with many other W-(Sn) deposits in the Variscan belt. Ore deposition occurred around 315°C, at an estimated depth of 5.5 km, under hydrostatic to slightly suprahydrostatic pressures. It resulted from fluid mixing, in the central part of a large hydrothermal system, between two end-members: (i) a hot (425-430°C) moderately saline fluid, that contained a diluted volatile component and, although Na-dominated, minor amounts of Li and Ca. The estimated δ18O indicates that this fluid was completely equilibrated with the tectono-magmatic pile (pseudo

  9. Devonian-Ordovician Magmatism in Chiapas Massif, Southern Maya Block, Mexico

    NASA Astrophysics Data System (ADS)

    Pompa-Mera, V.; Schaaf, P.; Weber, B.; Solis-Pichardo, G.; Hernandez-Trevino, T.; Ortega-Gutierrez, F.

    2008-12-01

    The Chiapas Massif (CM) is located in SE Mexico and extends over an area of more than 20,000 Km2 parallel to the Pacific coast between the Isthmus of Tehuantepec and the Guatemalan border. It constitutes the largest batholitic complex in Mexico and belongs to the Maya Block. The CM is predominantly formed by igneous, metaigneous and metasedimentary rocks. In the central CM several magmatic and metamorphic events have been identified in igneous rocks between Late Permian and Triassic times (220-240 Ma), together with a Jurassic tectonothermal event. Recent geochronological studies have been focused on granitic rocks from the central-southeastern CM and from this area, single grain zircon ages were also obtained from metasedimentary rocks. The results suggest that the basement rocks of the eastern CM and the Maya Block underwent several tectonothermal events since Ordovician and Devonian times. In this work, we present new data of magmatic and metamorphic rocks from the easternmost part of CM which confirms this hypothesis. Additionally, we present a semi-detailed geological map of this area showing some field relationship between the different units. We identified a new basal sequence significantly older than the Santa Rosa Formation, which has been considered up to now as forming the major underlying sequence of the CM, as well as the occurrence of several magmatic events in the Maya Block and in rocks from surrounding areas. The petrological, geochemical and geochronological features of these rocks show continuous crust recycling, the occurrence of within-plate magmatism in some parts with inherited Greenvillian and Archaean zircon grains as well as the occurrence of arc magmatism previous to accretion, deformation and terrane separation of the crustal blocks. Our new geochronological results obtained from the south easternmost part of the CM include a Rb-Sr biotite-muscovite age of 392+/-9 Ma and an Ar-Ar muscovite age of 406+/- 4 Ma from a tectonized granitic

  10. Seismicity without a fault ? Structural evidence from pseudotachylites in the UHP Dora Maira Massif

    NASA Astrophysics Data System (ADS)

    Zechmeister, M.; Ferre, E. C.; Geissman, J. W.; Cosca, M.; Caby, R.; Frima, C.; Ward, C.

    2004-12-01

    The Dora Maira massif, in the Italian Alps, is a world famous example of ultra-high pressure (UHP) metamorphism of crustal rocks with peak pressure of ca 3 GPa (depth ≈ 100 km) at about 35 My. Exhumation began shortly after the peak of metamorphism. The UHP rocks had equilibrated at a temperature of 250° C around 30 My. Pseudotachylite veins (1 to 20 mm thick) formed parallel to the syn-exhumation mylonitic foliation and were dated at 20.1 ± 0.5 Ma by Ar/Ar method. The geochronologic data suggests that the pseudotachylite veins formed at depths shallower than ≈ 10 km. These veins are found mainly in gently dipping medium grained phengite/coesite bearing orthogneiss. The generation veins are parallel to the foliation, constant in thickness and up to several tens of meters in length. Injection veins are less common and generally only a few cm in length. Structural mapping of UHP mylonitic gneisses and surrounding rocks reveals the dominance of high ductile strain, a puzzling lack of localized cataclastic deformation and the absence of fault associated with the pseudotachylite veins. The pseudotachylite veins are concentrated along a 50 m wide, foliation-parallel corridor. Conversely, the two major faults along which the UHP rocks were exhumed are > 500 m away from the pseudotachylite-bearing rocks and do not contain pseudotachylite veins. The formation of these pseudotachylite veins is clearly related to exhumation history of UHP rocks. The formation of pseudotachylite results from frictional melting as shown by microstructural criteria including corroded quartz grains and spherulitic microstructures. The localized heat source required for melting the UHP orthogneisses along narrow bands is attributed to frictional heat produced along the foliation plane. Fault-related pseudotachylite studies and friction experiments have shown that seismic strain rates (in the order of s-1) are required to maintain heat along the fault plane. At slower strain rates, heat would

  11. Inherited fossil anisotropic fabric in mantle lithosphere domains of the Bohemian Massif

    NASA Astrophysics Data System (ADS)

    Babuska, Vladislav; Plomerova, Jaroslava; Vecsey, Ludek

    2013-04-01

    Research of deep structure of the Bohemian Massif (BM) and other European regions exploits teleseismic data from dense temporary arrays of seismic stations. To study building elements of the BM we model 3D anisotropy and infer fabric of the mantle lithosphere by inverting jointly P-wave travel-time deviations and shear-wave splitting parameters from recordings of portable and permanent stations operating in the region for more than 20 years. Changes in orientation of the large-scale anisotropy, caused mainly by systematic preferred orientation of olivine, identify boundaries of domains of mantle lithosphere. Individual domains are characterized by a consistent large-scale orientation of anisotropy approximated by hexagonal symmetry with generally inclined symmetry axes (inclined foliation and/or lineation). We map five domains (microplates), each of them bearing a consistent fossil olivine fabric formed before their Variscan assembly. The domains are separated by tectonic boundaries (sutures) identified in the mantle lithosphere. The mantle domains correspond to major crustal units, but crustal and mantle boundaries are often shifted. The fabric of the northern and north-eastern BM is approximated best by peridotite aggregates with the (a,c) foliations dipping to the NNW and NE, respectively, whereas a model with the westerly dipping a lineation fits best the fabric of the south-eastern domain. The Saxothuringian fabric, NW of the Eger Rift, extends to the east across the Elbe Fault Zone (EFZ) and continues along this zone to the southeast beneath the Cretaceous Basin. The southeastward continuation of the Elbe Fault Zone seems to be related to the boundary between two different fabrics of the northern and southern parts of the Brunovistulian domain underlying the Moravo-Silesian zone. The anisotropy shows an underthrusting of the Brunovistulian micro-plate beneath the eastern rim of the BM and indicates that its northern and southern parts might represent

  12. Apatite-hosted melt inclusions in Damiao massif anorthosite complex, North China

    NASA Astrophysics Data System (ADS)

    Wang, M.; Veksler, I. V.; Zhang, Z.

    2014-12-01

    Models for the nelsonite formation are currently highly contentious, with liquid immiscibility and fractional crystallization as frequently proposed formation mechanisms. The nelsonites in the Damiao massif anorthosite complex in the North China Craton and experimental evidence are revisited for the existence of silica-free CaO-FeO-Fe2O3-TiO2-P2O5 immiscible nelsonitic liquids. Our results of differential scanning calorimetry (DSC) demonstrate that nelsonite with the composition of one-third apatite and two-thirds Fe-Ti oxides by weight completely melts well above 1450 ºC, which is in good agreement with numerous experimental studies of the CaO-P2O5-FexO system in connection to metallurgy. Thus, the composition cannot be molten at temperatures relevant for crystallization of the Damiao magma. A review of experimental studies of liquid immiscibility and analyses of natural immiscible glasses show that all the liquids on the Fe- and P-rich side of the miscibility gap have at least 20 wt. % of aluminosilicate components. Main results of this study come from the analyses of apatite-hosted melt inclusions in Damiao nelsonite. The inclusions range from ~3 to 200 μm in diameter. They are ubiquitous and meet all the morphological criteria of primary melt inclusions crystallised into assemblages of daughter minerals. Almost all of them contain vermiculite and chlorite, and some contain biotite, amphibole, phlogopite and Fe-Ti oxides. Out of dozens analysed inclusions, only three have high contents of SiO2 (62.1-73.8 wt. %) and low contents of FeO (0.25-2.35 wt. %). Bulk compositions of other inclusions show large variations in SiO2 (20.79-50.16 wt. %) and FeOt (13.44-32.78 wt. %). With a few exceptions, the inclusions are very low in CaO (0.04-1.51 wt. %, and high in Al2O3 (10-21.17 wt. %). Despite the high Fe content, the compositions differ from those of the typical immiscible Fe-rich melts. It appears that the cumulus apatite crystallised from Fe-rich, hydrated

  13. Mapping seismic anisotropy of the lithospheric mantle beneath the northern and eastern Bohemian Massif (central Europe)

    NASA Astrophysics Data System (ADS)

    Plomerová, Jaroslava; Vecsey, Luděk; Babuška, Vladislav

    2012-09-01

    We evaluate 3D body-wave anisotropic parameters—shear-wave splitting (fast S polarizations and delay times of the split slow shear waves) and directional terms of relative P-wave residuals from data of passive seismic experiment BOHEMA II (2004-2005). Data from 34 temporary stations increased substantial density of observations in the Bohemain Massif (BM) and allowed us to scan in detail the upper mantle structure of its northern and eastern parts. For the first time, we delimit domains of the mantle lithosphere in this part of the BM and infer 3D self-consistent models of their fabrics by a joint inversion of the body-wave anisotropic parameters. Fabrics of the northern and north-eastern parts of the BM are approximated best by peridotite aggregates with the (a,c) foliations dipping approximately to the N and NE, respectively, whereas a model with the westerly dipping a lineation fits best the fabric of the south-eastern domain. The Saxothuringian fabric, NW of the Eger Rift, extends to the east across the Elbe Fault Zone and continues along this zone to the southeast beneath the Cretaceous Basin. The south-eastward continuation of the Elbe Fault Zone seems to be related to the boundary between two different fabrics of the northern and southern Brunovistulian domains below the Moravo-Silesian zone. This study shows an underthrusting of the Brunovistulian micro-plate beneath the eastern rim of the BM and indicates that its northern and southern fragments might have originally belonged to Baltica and to Gondwana, respectively. According to a zone of distinctly decreased anisotropic signals, the Brunovistulian micro-plate extends at least about 100 km westward beneath the Moldanubian. With these new findings we update the domain-like mantle structure of the BM and compare the results with inferences from the upper mantle velocity tomography and depth changes of the lithosphere-asthenosphere boundary retrieved in a detailed model from relative residuals and from the

  14. Decorative marbles from the Krkonoše-Jizera Terrane (Bohemian Massif, Czech Republic): provenance criteria

    NASA Astrophysics Data System (ADS)

    Šťastná, Aneta; Přikryl, Richard

    2009-03-01

    Marbles from western part of the Krkonoše-Jizera Terrane (northern part of the Bohemian Massif) have been studied to obtain mineropetrographic and chemical reference data for provenance studies. Samples from six different quarries were analysed by mineralogical-petrographic and geochemical methods (optical microscopy, X-ray diffraction, stable isotope ratio analysis, cathodoluminescence, bulk magnetic susceptibility). Petrographic characteristics permit a distinction between fine-grained to medium-grained marbles from the Jizera Mts (amphibolite metamorphic facies) and fine-grained marbles from the Ještěd Mts (low-grade greenschist facies). The samples studied are mainly calcitic, with the exception of those from Raspenava in which dolomite is abundant in two types. The mineralogical composition of the insoluble residues is clinochlore ± serpentine ± tremolite ± diopside ± pyrite + magnetite in case of the locality Raspenava and clinochlore + muscovite ± quartz ± pyrite ± rutile ± haematite in case of the localities from the Ještěd Mts. δ13C and δ18O variations in primary and secondary carbonate phases allow to distinguish genetically different carbonate veins and permit quarry separation in one case (Raspenava, Jizera Mts). The δ13C and δ18O values of the groundmass range from -1 to +3‰ and from -8 to -20‰ (PDB), respectively. The δ13C and δ18O values of secondary carbonate veins decrease to -3‰ and reach more negative values up to -26‰ in case of δ18O. The fabric of cathodomicrofacies allows the distinction between calcite and dolomite, except three localities (Pilínkov, Horní Hanychov, Jitrava—rose type) with majority of quenchers (high content of iron in carbonate). The genetically different calcite is characterised by a pale and dark orange luminescence distribution. Serpentine, tremolite, forsterite, opaque minerals and quartz have no luminescence and very dull luminescence, respectively. The majority of studied marbles

  15. Generation and evolution processes of Paleoproterozoic massive-type Sancheong anorthosite complex, Yeongnam massif, Korea

    NASA Astrophysics Data System (ADS)

    Kang, Ji-Hoon; Lee, Deok-Seon

    2016-04-01

    The Paleoproterozoic (˜1.87-1.79 Ga) Sancheong anorthosite complex in the Jirisan province of the Yeongnam massif, Korea, consists of massive-type and foliation-type Sancheong anorthosite (SA), Fe-Ti ore body (FTO), and mafic granulite (MG). We report their characteristics and interrelation on foliations, occurrences, lithofacies, composition minerals, suggesting the generation and evolution processes of the Sancheong anorthosite complex with the origin of their foliations. The main characteristics and interrelation are as follows: multilayer structures of FTO, straight-, anastomosing-, uneven-types FTO and MG veins derived from blocking associate with size reduction of SA, gradual or irregular boundaries of SA blocks, FTO and MG showing bulbous lobate margins and comb structures between SA blocks, flow foliations and linear arrangements of FTO and MG, discontinuous shear zone of SA, orientation of FTO and MG foliations parallel to the boundaries of SA blocks, predominance of FTO and MG foliations toward the boundaries of SA blocks, flow folding structures of FTO and MG foliation, lithfacies change of MG into FTO by the injection of MG into SA, and very similar assemblage of mafic minerals and chemical composition of ilmenite and almost equal occurrence and foliation features between FTO and MG. Such evidences indicate that the SA, FTO, MG foliations are magmatic foliations which were formed in a not fully congealed state of SA from the results of the fracturing of partly congealed SA, the injection and flow of FTO and MG melts into the fractured SA, the dynamic intercompaction between them. It also implies that the SA, FTO, MG were not formed from the intrusion and differentiation of magmas which were different from each other in genesis and age but from the multiple fractionation and polybaric crystallization of the coeval and cogenetic magma. Our new model suggests that the Sancheong anorthosite complex was generated and evolved as following sequence: the

  16. Processes affecting the oceanic distributions of dissolved calcium and alkalinity

    SciTech Connect

    Shiller, A.M.; Gieskes, J.M.

    1980-05-20

    Recent studies of the CO/sub 2/ system have suggested that chemical processes in addition to the dissolution and precipitation of calcium carbonate affect the oceanic calcium and alkalinity distributions. Calcium and alkalinity data from the North Pacific have been examined both by using the simple physical-chemical model of previous workers and by a study involving the broader oceanographic context of these data. The simple model is shown to be an inadequate basis for these studies. Although a proton flux associated with organic decomposition may affect the alkalinity, previously reported deviations of calcium-alkalinity correlations from expected trends appear to be related to boundary processes that have been neglected rather than to this proton flux. The distribution of calcium in the surface waters of the Pacific Ocean is examined.

  17. Alkaline flood prediction studies, Ranger VII pilot, Wilmington Field, California

    SciTech Connect

    Mayer, E.H.; Breit, V.S.

    1982-01-01

    The paper discusses: (1) The design of a simulator to model alkaline displacement mechanisms and the current state-of-the-art understanding of in-situ caustic consumption. (2) Assimilation of laboratory core flood and rock consumption data. Use of this data in 1-D and 2-D limited area simulations, and a 3-D model of the entire pilot project. (3) Simulation studies of alkaline flood behavior in a small 2-D area of the field for various concentrations, slug sizes, long term consumption functions and two relative permeability adjustment mechanisms. (4) Scale up of 2-D simulation results, and their use in a 271 acre 1.097 x 10/sup 6/m/sup 2/), 7 layered 3-D model of the pilot. (5) Comparison of 3-D simulator results with initial field alkaline flood performance. (6) Recommended additional application of the simulator methods developed in this pilot and in other alkaline floods. 10 refs.

  18. ESTIMATION OF PHOSPHATE ESTER HYDROLYSIS RATE CONSTANTS. I. ALKALINE HYDROLYSIS

    EPA Science Inventory

    SPARC (SPARC Performs Automated Reasoning in Chemistry) chemical reactivity models were extended to allow the calculation of alkaline hydrolysis rate constants of phosphate esters in water. The rate is calculated from the energy difference between the initial and transition state...

  19. ESTIMATION OF PHOSPHATE ESTER HYDROLYSIS RATE CONSTANTS - ALKALINE HYDROLYSIS

    EPA Science Inventory

    SPARC (SPARC Performs Automated Reasoning in Chemistry) chemical reactivity models were extended to allow the calculation of alkaline hydrolysis rate constants of phosphate esters in water. The rate is calculated from the energy difference between the initial and transition state...

  20. Kinetics of the Fading of Phenolphthalein in Alkaline Solution.

    ERIC Educational Resources Information Center

    Nicholson, Lois

    1989-01-01

    Described is an experiment which illustrates pseudo-first-order kinetics in the fading of a common indicator in an alkaline solution. Included are background information, details of materials used, laboratory procedures, and sample results. (CW)

  1. Oxygen electrodes for rechargeable alkaline fuel cells

    NASA Technical Reports Server (NTRS)

    Swette, L.; Kackley, N.

    1989-01-01

    Electrocatalysts and supports for the positive electrode of moderate temperature single-unit rechargeable alkaline fuel cells are being investigated and developed. Candidate support materials were drawn from transition metal carbides, borides, nitrides and oxides which have high conductivity (greater than 1 ohm/cm). Candidate catalyst materials were selected largely from metal oxides of the form ABO sub x (where A = Pb, Cd, Mn, Ti, Zr, La, Sr, Na, and B = Pt, Pd, Ir, Ru, Ni (Co) which were investigated and/or developed for one function only, O2 reduction or O2 evolution. The electrical conductivity requirement for catalysts may be lower, especially if integrated with a higher conductivity support. All candidate materials of acceptable conductivity are subjected to corrosion testing. Materials that survive chemical testing are examined for electrochemical corrosion activity. For more stringent corrosion testing, and for further evaluation of electrocatalysts (which generally show significant O2 evolution at at 1.4 V), samples are held at 1.6 V or 0.6 V for about 100 hours. The surviving materials are then physically and chemically analyzed for signs of degradation. To evaluate the bifunctional oxygen activity of candidate catalysts, Teflon-bonded electrodes are fabricated and tested in a floating electrode configuration. Many of the experimental materials being studied have required development of a customized electrode fabrication procedure. In advanced development, the goal is to reduce the polarization to about 300 to 350 mV. Approximately six support materials and five catalyst materials were identified to date for further development. The test results will be described.

  2. The Martian ocean: First acid, then alkaline

    NASA Technical Reports Server (NTRS)

    Schaefer, M. W.

    1992-01-01

    In Mars' distant past, carbon dioxide and water may have been plentiful. Values of total outgassed CO2 from several to about 10 bar are consistent with present knowledge, and this amount of CO2 implies an amount of water outgassed equal to an equivalent depth of 500 to 1000 m. It is quite reasonable, therefore, to envision an early Mars in which there was a body or bodies of liquid water, perhaps in the northern plains, and a dense carbon dioxide atmosphere. Under such conditions, the pH of the water will be low, due to the dissolution of carbon dioxide in the water to form carbonic acid. This acidic water is capable of weathering the available rock quite intensely, particularly because this rock is likely to be heavily fractured (from meteorite bombardment) or even consist of fine particles (such as pyroclastic deposits). As time goes on, however, the carbon dioxide atmosphere will rapidly pass through the ocean to form carbonate deposits. As the density of the atmosphere decreases, so will the flux of carbonic acid into the ocean. Without this input of carbonic acid, the effect of the dissolved weathering products will be to increase the pH of the water. The ocean will then become alkaline. To study this process, I have developed a geochemical cycle model for the atmosphere-hydrosphere-regolith system of Mars. The treatment of geochemical cycles as complex kinetic chemical reactions has been undertaken for terrestrial systems in recent years with much success. This method is capable of elegantly handling the interactions between the simultaneous chemical reactions needed to understand such a system.

  3. Net alkalinity and net acidity 1: Theoretical considerations

    USGS Publications Warehouse

    Kirby, C.S.; Cravotta, C.A., III

    2005-01-01

    Net acidity and net alkalinity are widely used, poorly defined, and commonly misunderstood parameters for the characterization of mine drainage. The authors explain theoretical expressions of 3 types of alkalinity (caustic, phenolphthalein, and total) and acidity (mineral, CO2, and total). Except for rarely-invoked negative alkalinity, theoretically defined total alkalinity is closely analogous to measured alkalinity and presents few practical interpretation problems. Theoretically defined "CO 2-acidity" is closely related to most standard titration methods with an endpoint pH of 8.3 used for determining acidity in mine drainage, but it is unfortunately named because CO2 is intentionally driven off during titration of mine-drainage samples. Using the proton condition/mass- action approach and employing graphs to illustrate speciation with changes in pH, the authors explore the concept of principal components and how to assign acidity contributions to aqueous species commonly present in mine drainage. Acidity is defined in mine drainage based on aqueous speciation at the sample pH and on the capacity of these species to undergo hydrolysis to pH 8.3. Application of this definition shows that the computed acidity in mg L -1 as CaCO3 (based on pH and analytical concentrations of dissolved FeII, FeIII, Mn, and Al in mg L -1):aciditycalculated=50{1000(10-pH)+[2(FeII)+3(FeIII)]/56+2(Mn)/ 55+3(Al)/27}underestimates contributions from HSO4- and H+, but overestimates the acidity due to Fe3+ and Al3+. However, these errors tend to approximately cancel each other. It is demonstrated that "net alkalinity" is a valid mathematical construction based on theoretical definitions of alkalinity and acidity. Further, it is shown that, for most mine-drainage solutions, a useful net alkalinity value can be derived from: (1) alkalinity and acidity values based on aqueous speciation, (2) measured alkalinity minus calculated acidity, or (3) taking the negative of the value obtained in a

  4. Solvent processible, high-performance partially fluorinated copoly(arylene ether) alkaline ionomers for alkaline electrodes

    NASA Astrophysics Data System (ADS)

    Zhou, Junfeng; Ünlü, Murat; Anestis-Richard, Irene; Kim, Hyea; Kohl, Paul A.

    2011-10-01

    A solvent processable, low water uptake, partially fluorinated copoly(arylene ether) functionalized with pendant quaternary ammonium groups (QAPAE) was synthesized and uses as the ionomer in alkaline electrodes on fuel cells. The quaternized polymers containing fluorinated biphenyl groups were synthesized via chloromethylation of copoly(arylene ether) followed by amination with trimethylamine. The resulting ionomers were very soluble in polar, aprotic solvents. Highly aminated ionomers had conductivities approaching 10 mS cm-1 at room temperature. Compared to previous ionomers based on quaternized poly(arylene ether sulfone) (QAPSF) with similar ion exchange capacity (IEC), the water uptake of QAPAE was significantly less due to the hydrophobic octafluoro-biphenyl groups in the backbone. The performance of the fuel cell electrodes made with the QAPAE ionomers was evaluated as the cathode on a hybrid AEM/PEM fuel cell. The QAPAE alkaline ionomer electrode with IEC = 1.22 meq g-1 had superior performance to the electrodes prepared with QAPSF, IEC = 1.21 meq g-1 at 25 and 60 °C in a H2/O2 fuel cell. The peak power densities at 60 °C were 315 mW cm-2 for QAPAE electrodes and 215 mW cm-2 for QAPSF electrodes.

  5. Determination of Granite Rock Massif Weathering and Cracking of Surface Layers in the Oldest Parts of Medieval Mine Depending on Used Mining Method

    NASA Astrophysics Data System (ADS)

    Lednická, Markéta; Kaláb, Zdeněk

    2016-06-01

    The paper presents the use of selected non-destructive testing methods for the purpose of specifying information on weathering and cracking of surface layers of granite rock massif in the medieval Jeroným Mine (the Czech Republic). This mine has been declared the National Heritage Site of the Czech Republic and its opening as a mining museum to the public is gradually prepared. Geological and geomechanical evaluation documents the possibility to find all kinds of weathering grades of rock massif in this mine. Two non-destructive methods have been tested, namely the measurement of ultrasonic pulse velocity and the measurement of Schmidt hammer rebound value. Field measurements were performed in two selected galleries to verify the application of such methods in specific conditions of underground spaces. Used mining method is one of the parameters later influencing cracking of rock massif. In selected galleries, two different mining methods were used which means that a part of a gallery profile was mined out by hand tools in the Middle Ages and another part of the profile was later mined out by blasting. Measurements in these galleries have enabled to analyse the influence of used mining methods on cracking of rock massif in the impaired zone, and, consequently, on ongoing weathering processes in those zones.

  6. Overexpression of Human Bone Alkaline Phosphatase in Pichia Pastoris

    NASA Technical Reports Server (NTRS)

    Karr, Laurel; Malone, Christine, C.; Rose, M. Franklin (Technical Monitor)

    2000-01-01

    The Pichiapastoris expression system was utilized to produce functionally active human bone alkaline phosphatase in gram quantities. Bone alkaline phosphatase is a key enzyme in bone formation and biomineralization, yet important questions about its structural chemistry and interactions with other cellular enzymes in mineralizing tissues remain unanswered. A soluble form of human bone alkaline phosphatase was constructed by deletion of the 25 amino acid hydrophobic C-terminal region of the encoding cDNA and inserted into the X-33 Pichiapastoris strain. An overexpression system was developed in shake flasks and converted to large-scale fermentation. Alkaline phosphatase was secreted into the medium to a level of 32mgAL when cultured in shake flasks. Enzyme activity was 12U/mg measured by a spectrophotometric assay. Fermentation yielded 880mgAL with enzymatic activity of 968U/mg. Gel electrophoresis analysis indicates that greater than 50% of the total protein in the fermentation is alkaline phosphatase. A purification scheme has been developed using ammonium sulfate precipitation followed by hydrophobic interaction chromatography. We are currently screening crystallization conditions of the purified recombinant protein for subsequent X-ray diffraction analyses. Structural data should provide additional information on the role of alkaline phosphatase in normal bone mineralization and in certain bone mineralization anomalies.

  7. A fungal pathogen secretes plant alkalinizing peptides to increase infection.

    PubMed

    Masachis, Sara; Segorbe, David; Turrà, David; Leon-Ruiz, Mercedes; Fürst, Ursula; El Ghalid, Mennat; Leonard, Guy; López-Berges, Manuel S; Richards, Thomas A; Felix, Georg; Di Pietro, Antonio

    2016-01-01

    Plant infections caused by fungi are often associated with an increase in the pH of the surrounding host tissue(1). Extracellular alkalinization is thought to contribute to fungal pathogenesis, but the underlying mechanisms are poorly understood. Here, we show that the root-infecting fungus Fusarium oxysporum uses a functional homologue of the plant regulatory peptide RALF (rapid alkalinization factor)(2,3) to induce alkalinization and cause disease in plants. An upshift in extracellular pH promotes infectious growth of Fusarium by stimulating phosphorylation of a conserved mitogen-activated protein kinase essential for pathogenicity(4,5). Fungal mutants lacking a functional Fusarium (F)-RALF peptide failed to induce host alkalinization and showed markedly reduced virulence in tomato plants, while eliciting a strong host immune response. Arabidopsis plants lacking the receptor-like kinase FERONIA, which mediates the RALF-triggered alkalinization response(6), displayed enhanced resistance against Fusarium. RALF homologues are found across a number of phylogenetically distant groups of fungi, many of which infect plants. We propose that fungal pathogens use functional homologues of alkalinizing peptides found in their host plants to increase their infectious potential and suppress host immunity. PMID:27572834

  8. Cation exchange properties of zeolites in hyper alkaline aqueous media.

    PubMed

    Van Tendeloo, Leen; de Blochouse, Benny; Dom, Dirk; Vancluysen, Jacqueline; Snellings, Ruben; Martens, Johan A; Kirschhock, Christine E A; Maes, André; Breynaert, Eric

    2015-02-01

    Construction of multibarrier concrete based waste disposal sites and management of alkaline mine drainage water requires cation exchangers combining excellent sorption properties with a high stability and predictable performance in hyper alkaline media. Though highly selective organic cation exchange resins have been developed for most pollutants, they can serve as a growth medium for bacterial proliferation, impairing their long-term stability and introducing unpredictable parameters into the evolution of the system. Zeolites represent a family of inorganic cation exchangers, which naturally occur in hyper alkaline conditions and cannot serve as an electron donor or carbon source for microbial proliferation. Despite their successful application as industrial cation exchangers under near neutral conditions, their performance in hyper alkaline, saline water remains highly undocumented. Using Cs(+) as a benchmark element, this study aims to assess the long-term cation exchange performance of zeolites in concrete derived aqueous solutions. Comparison of their exchange properties in alkaline media with data obtained in near neutral solutions demonstrated that the cation exchange selectivity remains unaffected by the increased hydroxyl concentration; the cation exchange capacity did however show an unexpected increase in hyper alkaline media. PMID:25569300

  9. Earthquake location, active faulting, and P-wave velocity structure near a metamorphic massif in the eastern syntaxis of the Tibetan Plateau

    NASA Astrophysics Data System (ADS)

    Brown, L. E.; Meltzer, A.

    2011-12-01

    Within the core of the eastern syntaxis of the Himalaya, the Namche Barwa - Gyala Peri massif is a site of rapid exhumation where high grade metamorphic rocks from the mid to lower crust are exposed at the surface. Some of the world's highest relief is observed in this massif. The two peaks, standing over 7000m tall, are only 20km apart and are separated by a major river, the Tsangpo, at an elevation of 2500m. This impressive relief is maintained because these mountains constitute an actively forming, localized, antiformal structure, which is rapidly uplifting, while the Tsangpo downcuts through the structure. This tectonic situation is interesting because there appear to be feedbacks between topography and tectonics. As part of an effort to understand the dynamics associated with this localized structure, a temporary seismic network was used to record earthquakes near the massif. In this study approximately 2000 local earthquakes are used to define a 3-D velocity model and the locations of active faulting. The majority of events are part of an impressive spatial cluster which occurred during a series of earthquake swarms. This NW trending cluster has a vertical dip, extending to 15km in depth, and closely correlates to a topographic ridge immediately to the north of Namche Barwa. The Tsangpo takes a sharp turn when it reaches this ridge, flowing parallel to the base of the ridge, and the river then makes a dramatic 180° turn around the ridge. Given that the river's erosional power is thought to be responsible for localizing deformation into this area, it is significant that the Tsangpo's course through this area might be fault controlled. A second cluster of events is located to the west of Gyala Peri and trends to the north. Comparing this cluster to a geologic map shows that the events fall on a mapped thrust fault. This fault extends to the south of the massif, where there were no recorded events. This portion of the fault is interpreted to be locked. The

  10. A multidisciplinary study on the emplacement mechanism of the Qingyang-Jiuhua Massif in Southeast China and its tectonic bearings. Part I: Structural geology, AMS and paleomagnetism

    NASA Astrophysics Data System (ADS)

    Wei, W.; Chen, Y.; Faure, M.; Shi, Y. H.; Martelet, G.; Hou, Q. L.; Lin, W.; Le Breton, N.; Wang, Q. C.

    2014-06-01

    During the Cretaceous, the South China Block (SCB) experienced a widely distributed extensional event including numerous plutons emplacement and basin opening. Investigations on the tectonic regime coeval with pluton emplacement, and emplacement mechanism of the pluton remain relatively rare in the SCB. In order to address these questions, a multidisciplinary approach, including field structural and petrographic observations, anisotropy magnetic susceptibility (AMS) and paleomagnetic analyses, was carried out on the Qingyang-Jiuhua granitic massif which intrudes into the Lower Yangtze fold belt in the northeastern part of the SCB. The Qingyang-Jiuhua massif is composed of the granodioritic Qingyang and monzogranitic Jiuhua plutons dated by zircon U-Pb method at ca. 142 Ma, and ca. 131 Ma, respectively. Our structural observations show that the intrusion of the Qingyang-Jiuhua massif does not modify the fold strike. A weak ductile deformation of the country rocks and granitoid can be only observed in the boundary zone with limited contact metamorphism. In the contact aureole of the massif, the foliation follows the pluton contour, and the mineral lineation is rare. When present, it exhibits a down-dip attitude. Field and microstructural observations indicate isotropic magmatic textures in most parts of the massif. The AMS analysis of 93 sites reveals weak values for the anisotropy degree (PJ < 1.2) and oblate magnetic fabric dominance (T > 0) for most of the measured samples. Two principal foliation patterns are identified: horizontal foliations in the center of the plutons, and vertical foliations on the boundaries. Magnetic lineation strike is largely scattered, and weakly inclined at the scale of the entire massif. The paleomagnetic investigations indicate that (a) the younger Jiuhua pluton did not produce a remagnetization in the older Qingyang pluton, (b) no relative movement can be observed between these two plutons, (c) the entire massif did not experience

  11. New data for paleoprotherozoic PGE-bearing anorthosite of Kandalaksha massif (Baltic shield): U-Pb and Sm-Nd ages

    NASA Astrophysics Data System (ADS)

    Steshenko, Ekaterina; Bayanova, Tamara; Serov, Pavel

    2015-04-01

    The aims of this researches were to study the isotope U-Pb age of zircon and rutile and Sm-Nd (rock forming and sulphide minerals) on Kandalaksha anorthosite massif due to study of polimetamorphic history. In marginal zone firstly have been obtained the presence of sulphide mineralization with PGE (Chashchin, Petrov , 2013). Kandalaksha massif is located in the N-E part of Baltic shield and consists of three parts. Marginal zone (mesocratic metanorite) lies at the base of the massif. Main zone is composed of leucocratic metagabbro. The upper zone is alteration of mataanorthosite and leucocratic metagabbro. All rocks were subjected to granulate polymetamorphism. Two fractions of single grains from anorthosite of the massif gave precise U-Pb age, which is equal to 2450± 3 Ma. Leucocratic gabbro-norite were dated by U-Pb method, with age up to 2230 ± 10 Ma. This age reflects the time of granulite metamorphism according to data of (Mitrofanov, Nirovich, 2003). Two fractions of rutile have been analyzed by U-Pb method and reflect age of 1700 ± 10 Ma. It is known that the closure temperature of U-Pb system rutile is 400-450 ° C (Mezger et.al., 1989), thus cooling processes of massif rocks to these temperatures was about 1.7 Ga. These data reflect one of the stages of metamorphic alteration of the massif. Three stages of metamorphism are distinguished by Sm-Nd method. Isotope Sm-Nd dating on Cpx-WR line gives the age of 2311 Ma which suggested of high pressure granulite metamorphism. Moreover Cpx-Pl line reflect the age 1908 Ma of low pressure granulite metamorphism. Also two-points (Grt-Rt) Sm-Nd isochrone yield the age 1687 Ma of the last metamorphic alterations in Kandalaksha anorthosite massif. Model Sm-Nd age of the leucocratic gabbro-norite is 2796 Ma with positive ɛNd (+0.32). It means that the source of gabbro-norite was mantle reservoir. All investigations are devoted to memory of academician PAS F. MItrofanov which was a leader of scientific school for

  12. 21 CFR 862.1050 - Alkaline phosphatase or isoenzymes test system.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 8 2011-04-01 2011-04-01 false Alkaline phosphatase or isoenzymes test system... Test Systems § 862.1050 Alkaline phosphatase or isoenzymes test system. (a) Identification. An alkaline phosphatase or isoenzymes test system is a device intended to measure alkaline phosphatase or its...

  13. 21 CFR 862.1050 - Alkaline phosphatase or isoenzymes test system.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Alkaline phosphatase or isoenzymes test system... Test Systems § 862.1050 Alkaline phosphatase or isoenzymes test system. (a) Identification. An alkaline phosphatase or isoenzymes test system is a device intended to measure alkaline phosphatase or its...

  14. 40 CFR 420.110 - Applicability; description of the alkaline cleaning subcategory.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... alkaline cleaning subcategory. 420.110 Section 420.110 Protection of Environment ENVIRONMENTAL PROTECTION... Alkaline Cleaning Subcategory § 420.110 Applicability; description of the alkaline cleaning subcategory... alkaline cleaning baths to remove mineral and animal fats or oils from the steel, and those...

  15. Acidic minespoil reclamation with alkaline biosolids

    SciTech Connect

    Drill, C.; Lindsay, B.J.; Logan, T.L.

    1998-12-31

    The effectiveness of an alkaline stabilized biosolids product, N-Viro Soil (NVS), was studied at a wild animal preserve in Cumberland, OH. The preserve occupies land that was strip mined for high-sulfur coal. While most of the land has been conventionally reclaimed, several highly acidic hot spots remain. Two of these hot spots were studied through concurrent field, greenhouse, and laboratory projects. In April 1995, NVS was applied at rates ranging from 0--960 mt/ha (wet wt.) to plots at the two sites. The plots were seeded using a standard reclamation mix and soil samples were analyzed for chemical characteristics before and after application and also in 1996 and 1997. Soil pH increased from 3.5 to about 11 in the amended plots and soil EC values increased from 21.0 mmho/cm to a maximum of 6.0 mmho/cm in the amended plots immediately after application. Soil Cu and Zn concentrations also increased in the NVS amended plots, but this did not affect plant germination or growth. By the summer of 1996, soil pH values had decreased to 7.3--8.7 and EC values decreased to 0.34--1.36 mmho/cm to the amended plots. Soil samples were collected in September 1995 for physical analyses. N-Viro Soil improved the moisture retention and water conductivity properties of the spoil. The plots were monitored for growth during the summer of 1995 and plant biomass and soil samples were taken in 1996 and 1997 for trace element and nutrient analysis. NVS did not significantly increase trace element concentrations in the biomass. The addition of NVS to acid mine spoil improves the chemical and physical properties of the spoil material thus aiding vegetative establishment and growth. NVS improves the chemical nature of the spoil by increasing pH and providing micro and macronutrients and improves the physical properties of the spoil with the addition of organic matter.

  16. Age and mineralogy of supergene uranium minerals — Tools to unravel geomorphological and palaeohydrological processes in granitic terrains (Bohemian Massif, SE Germany)

    NASA Astrophysics Data System (ADS)

    Dill, H. G.; Gerdes, A.; Weber, B.

    2010-04-01

    Uranyl phosphates (torbernite, autunite, uranocircite, saleeite) and hydrated uranyl silicates (normal and beta-uranophane) found in various erosion levels and structures in the Late Variscan granites at the western edge of the Bohemian Massif, Germany, were the target of mineralogical investigations and age dating, using conventional and more advanced techniques such as Laser-Ablation-Inductive-Coupled-Plasma Mass Spectrometry (LA-ICP-MS). Supergene U minerals have an edge over other rock-forming minerals for such studies, because of their inherent ‘clock’ and their swift response to chemical and physical environmental changes on different scales. Uraniferous phoscretes and silcretes, can be used to characterize the alkalinity/acidity of meteoric/per descensum fluids and to constrain the redox conditions during geomorphic processes. This study aims to decipher the geomorphological and palaeohydrological regime that granitic rocks of the Central European Variscides (Moldanubian and Saxothuringian zones) went through during the Neogene and Quaternary in the foreland of the rising Alpine mobile fold belt. The study provides an amendment to the current sub-division of the regolith by introducing the term “hydraulith”, made up of percolation and infiltration zones, for the supergene alteration zone in granitic terrains. It undercuts the regolith at the brink of the phreatic to vadose hydrological zones. Based upon the present geomorphological and mineralogical studies a four-stage model is proposed for the evolution of the landscape in a granitic terrain which might also be applicable to other regions of the European Variscides, considering the hydrological facies changes along with paleocurrent and paleoslope in the basement and the development of the fluvial drainage system in the foreland. Stage I (U mineralization in the infiltration zone) is a mirror image of the relic granitic landscape with high-altitude divides and alluvial-fluvial terraces. Its

  17. Lower crust exhumation and ongoing continental convergence in the Variscan Maures-Tanneron Massif, France, geological synthesis and numerical models

    NASA Astrophysics Data System (ADS)

    Gerbault, Muriel; Schneider, Julie; Corsini, Michel; Reverso-Peila, Alexandre

    2015-04-01

    The Maures-Tanneron Massif together with Corsica and Sardinia compose the present day southeastern part of the Variscan belt. Pressure-temperature-time patterns were compiled to adress how rocks once forming a thick orogenic crust were exhumed, from burial conditions of ca. 10 kb and ca. 800°C. A continuous evolution from subduction to collision, from ca. 420 Ma to 290 Ma has recently been proposed by Schneider et al., 2014, ending with orthogonal Permean rifting. Here we complement this study by exploring the thermo-mechanical conditions prevailing during the massive exhumation of this orogenic crust. Based on field observations and petrological analysis indicative of the acceleration of partial melting during ongoing convergence, our numerical models test a scenario in which pre-thickened units located at 40-60 km depth, would have molten due to internal heating and burrial, and were progressively exhumed by gravitationally-driven instabilities to the surface, within ~15-25 Myrs. Assuming temperature dependent elasto-visco-plastic behavior, we have tested rheological layering including mafic or felsic units, far-field convergence and surface processes, as well as temperature-dependent melting conditions and density and viscosity evolution. In order to reproduce asymmetrical exhumation over the given time-scales and over an extent area of more than 50 km synchroneous with the development of compressional folds in the upper crust, a best fit was obtained for an applied far-field convergence of 0.5 cm/yr, equivalent to present day Alpine convergence rates, and a bulk crustal viscosity of at least 102° Pa.s. Crustal heat source had to contribute significantly, whereas a too shallow mantle heat source triggers exceedingly warm and fast exhumation. We propose that the evolution from transpressional to tensile conditions perpendicular to the orogenic axis (north-south Permean rifting versus East-West vergence of the orogenic structures), occurred progressively as

  18. Record of metal workshops in peat deposits: history and environmental impact on the Mont Lozère Massif, France.

    PubMed

    Baron, S; Lavoie, M; Ploquin, A; Carignan, J; Pulido, M; De Beaulieu, J L

    2005-07-15

    This study aims to document the history of the metallurgical activities on the Mont Lozère massif in the Cévennes Mountains in Southern France. Many medieval sites of metallurgical wastes (slags) have been reported on the massif. These sites are thought to represent ancient lead workshops. The impact of past metallurgical activity on the environment was studied using geochemical and palynological techniques on a core collected in the Narses Mortes peatland near medieval smelting area. Two main periods of smelting activities during the last 2200 years were revealed bythe lead concentration and isotopic composition along the core profile: the first period corresponds to the Gallic period (approximately ca. 300 B.C. to ca. 20 A.D.) and the second one to the Medieval period (approximately ca. 1000-1300 A.D.). Forest disturbances are associated with lead anomalies for the two metallurgical activities described. The impact of the first metallurgy was moderate during the Gallic period, during which beech and birch were the tree species most affected. The second period corresponds to the observed slag present in the field. Along with agropastoral activities, the medieval smelting activities led to the definitive disappearance of all tree species on the summit zones of Mont Lozère. The abundance of ore resources and the earlier presence of wood on the massif justify the presence of workshops at this place. The relationship between mines and ores has been documented for the Medieval period. There is no archaeological proof concerning the Gallic activity. Nevertheless, 2500-2100 years ago, the borders of the Gallic Tribe territory, named the Gabales, were the same as the present-day borders of the Lozère department. Julius Caesar reported the existence of this tribe in 58 B.C. in "De Bello Gallico", and in Strabon (Book IV, 2.2) the "Gabales silver" and a "treasure of Gabales" are mentioned, but to this day, they have not been found. PMID:16082940

  19. Extinction vulnerability of tropical montane endemism from warming and upslope displacement: a preliminary appraisal for the highest massif in Madagascar

    PubMed Central

    RAXWORTHY, CHRISTOPHER J; PEARSON, RICHARD G; RABIBISOA, NIRHY; RAKOTONDRAZAFY, ANDRY M; RAMANAMANJATO, JEAN-BAPTISTE; RASELIMANANA, ACHILLE P; WU, SHENGHAI; NUSSBAUM, RONALD A; STONE, DÁITHÍ A

    2008-01-01

    One of the predicted biological responses to climate warming is the upslope displacement of species distributions. In the tropics, because montane assemblages frequently include local endemics that are distributed close to summits, these species may be especially vulnerable to experiencing complete habitat loss from warming. However, there is currently a dearth of information available for tropical regions. Here, we present a preliminary appraisal of this extinction threat using the herpetological assemblage of the Tsaratanana Massif in northern Madagascar (the island's highest massif), which is rich with montane endemism. We present meteorological evidence (individual and combined regional weather station data and reanalysis forecast data) for recent warming in Madagascar, and show that this trend is consistent with recent climate model simulations. Using standard moist adiabatic lapse rates, these observed meteorological warming trends in northern Madagascar predict upslope species displacement of 17–74 m per decade between 1993 and 2003. Over this same period, we also report preliminary data supporting a trend for upslope distribution movements, based on two surveys we completed at Tsaratanana. For 30 species, representing five families of reptiles and amphibians, we found overall mean shifts in elevational midpoint of 19–51 m upslope (mean lower elevation limit 29–114 m; mean upper elevation limit −8 to 53 m). We also found upslope trends in mean and median elevational observations in seven and six of nine species analysed. Phenological differences between these surveys do not appear to be substantial, but these upslope shifts are consistent with the predictions based on meteorological warming. An elevational range displacement analysis projects complete habitat loss for three species below the 2 °C ‘dangerous’ warming threshold. One of these species is not contracting its distribution, but the other two were not resampled in 2003. A preliminary

  20. Mantle refertilization by melts of crustal-derived garnet pyroxenite: Evidence from the Ronda peridotite massif, southern Spain

    NASA Astrophysics Data System (ADS)

    Marchesi, Claudio; Garrido, Carlos J.; Bosch, Delphine; Bodinier, Jean-Louis; Gervilla, Fernando; Hidas, Károly

    2013-01-01

    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 lherzolite. These secondary lherzolites differ from common spinel lherzolite 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 lherzolite 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

  1. Alkalinity Enrichment Enhances Net Calcification of a Coral Reef Flat

    NASA Astrophysics Data System (ADS)

    Albright, R.; Caldeira, K.

    2015-12-01

    Ocean acidification is projected to shift reefs from a state of net accretion to one of net dissolution sometime this century. While retrospective studies show large-scale changes in coral calcification over the last several decades, it is not possible to unequivocally link these results to ocean acidification due to confounding factors of temperature and other environmental parameters. Here, we quantified the calcification response of a coral reef flat to alkalinity enrichment to test whether reef calcification increases when ocean chemistry is restored to near pre-industrial conditions. We used sodium hydroxide (NaOH) to increase the total alkalinity of seawater flowing over a reef flat, with the aim of increasing carbonate ion concentrations [CO32-] and the aragonite saturation state (Ωarag) to values that would have been attained under pre-industrial atmospheric pCO2 levels. We developed a dual tracer regression method to estimate alkalinity uptake (i.e., calcification) in response to alkalinity enrichment. This approach uses the change in ratios between a non-conservative tracer (alkalinity) and a conservative tracer (a non-reactive dye, Rhodamine WT) to assess the fraction of added alkalinity that is taken up by the reef as a result of an induced increase in calcification rate. Using this method, we estimate that an average of 17.3% ± 2.3% of the added alkalinity was taken up by the reef community. In providing results from the first seawater chemistry manipulation experiment performed on a natural coral reef community (without artificial confinement), we demonstrate that, upon increase of [CO32-] and Ωarag to near pre-industrial values, reef calcification increases. Thus, we conclude that, the impacts of ocean acidification are already being felt by coral reefs. This work is the culmination of years of work in the Caldeira lab at the Carnegie Institution for Science, involving many people including Jack Silverman, Kenny Schneider, and Jana Maclaren.

  2. The Mirdita Eastern Ophiolite, Albania: petrological evidence for MORB Mantle in the Tropoje peridotite massif?

    NASA Astrophysics Data System (ADS)

    Ntaflos, Theodoros; Onuzi, Kujtim; Hauzenberger, Christoph; Rice, A. Hugh N.; Proßegger, Peter; Mekshiqi, Nazir; Kaza, Gjon

    2016-04-01

    The Mirdita ophiolites in northern Albania are divided into the Western Mirdita Ophiolite (WMO), with MORB geochemical affinities, and the Eastern Mirdita Ophiolite (EMO), for which suprasubduction geochemical affinities have been reported. Ultramafic massifs in the WMO are often plagioclase bearing lherzolites/harzburgites whereas those in the EMO are strongly depleted spinel harzburgites. The Tropoje ultramafic-mafic complex, which forms the northernmost part of the EMO, consists of spinel harzburgites, wherlites, orthopyroxenites and gabbros. The spinel harzburgites, which experienced variable degrees of serpentinization, are coarse- to medium-grained. One of the most striking features of the Tropoje ultramafic rocks is an outcrop of exceptionally fresh coarse- to medium-grained spinel harzburgites. While occasionally the peridotites exhibit a weak foliation, the prevalent texture is protogranular. Olivine is mainly coarse-grained (up to 6 mm size), typically showing kink-bands that frequently contain submicron-sized spinel exsolution lamellae. Both orthopyroxene and clinopyroxene, with grain size up to 3 mm and 1.5 mm, respectively, carry very thin exsolution lamellae of the other pyroxene. Spinel, up to 1 mm in size, is interstitial between boundaries of the associated silicates. The mineral compositions of the spinel harzburgites indicate that they are strongly depleted in basaltic components. The rock-forming minerals (olivine, orthopyroxene and clinopyroxene) are all highly magnesian and chemically homogenous. The magnesium numbers (Mg#=100xMg/[Mg+Fe]) for olivine and orthopyroxene are fairly homogeneous and vary within the narrow range of 90.9-91.6 and 91.5-91.7, respectively. The clinopyroxene is exceptionally highly magnesian, with Mg# ranging between 93.6 and 95.4. In both orthopyroxene and clinopyroxene, the Al2O3 contents range from 0.95 to 1.75 and from 0.62 to 2.27 wt%, respectively. Spinel shows a considerable variation in Al2O3 and Cr2O3. The

  3. Seismic tomography of the upper mantle beneath the Bohemian Massif (central Europe)

    NASA Astrophysics Data System (ADS)

    Karousova, H.; Plomerova, J.; Vecsey, L.; Munzarova, H.

    2012-04-01

    We present a comprehensive test for teleseismic tomography of the upper mantle beneath the southern part of the Bohemian Massif (BM) based on data of passive experiments BOHEMA III and the northern part of the ALPASS (Mitterbauer et al., Tectonophysics 2011) as well as preliminary results. A new semi-automatic picker was applied for measuring P-wave arrival times from correlated extremes of waveforms recorded at 58 temporary seismic stations and 55 permanent observatories during 2005-2006. To calculate P-velocity perturbations, we selected 173 events from epicentral distances between 25° and 90°, and with magnitude higher than 4.5. Before the travel-time inversion itself, we analysed carefully relative P-wave residuals and cleaned the dataset of the travel-times from outliers and instabilities in timing for further processing. To eliminate leakage of crustal effects into the upper mantle velocity images, we corrected the observed travel-times for crustal structure according to 3D models of the BM and Eastern Alps crust (Karousova et al., Studia Geophys. Geod. 2012; Behm et al., GJI 2007). In order to optimize model parameterization, initial velocities and damping factors we perform different synthetic tests. Checkerboard and synthetic tests with artificial heterogeneities and shifted parameterization are calculated to explore sensitivity and resolution in individual nodes. Models with indistinctive velocity perturbations in the resolved parts tend to be more sensitive to ray geometry in the upper mantle and consequently could accentuate even insignificant heterogeneities. We show series of velocity perturbation images in three parts of the BM retrieved in three successive passive seismic experiments BOHEMA I-III. No distinct 'tube-like' low velocity heterogeneity, which could be interpreted as a small plume beneath the Eger Rift is imaged in tomography in western BM from the BOHEMA I data. Relatively small velocity perturbations exist in the upper mantle beneath

  4. Soil thermal regime and geomorphogenesis at Fuentes Carrionas massif (Cantabrian Range, NW Iberian Peninsula).

    NASA Astrophysics Data System (ADS)

    Pellitero, Ramon; Serrano Cañadas, Enrique

    2015-04-01

    Fuentes Carrionas is a massif within the Cantabrian Range, in NW Iberian Peninsula. Its altitude ranges between 1400 and 2500 meters and its climate is an oceanic/Mediterranean transition one, with cold temperatures and heavy snowfall in the winter/early spring season, and a warm and dry summer season. Due to its outstanding altitude and lithological variety in the Cantabrian Range context, Fuentes Carrionas holds some periglacial activity (gelifluction, frost shattering) which is absent elsewhere in NW Iberian Peninsula. This work is relates the soil thermal regime across the mountain gradient to landforms formation. 14 thermometers (11 i-button, protected in a plastic can, and three UTL data loggers) were buried at a shallow depth (10 cm.) between autumn 2009 and summer 2012. 12 thermometers were placed between 1900 and 2400 m.a.s.l. at 250 meters altitude interval at the four main aspects. Two additional thermometers were place in the Curavacas N face for permafrost identification. Thermometers were calibrated to yield a measurement every 6 hours starting from 8 AM during one year's time. Data was collected annually in the summer season. Some additional soil temperature data was obtained from an external project in the same area for the 2007-2009 interval. In this case thermometers were "Hobbo" model, and they were also buried to a shallow depth. Results show a permafrost free mountain range. Annual average soil temperatures range between 1 and 8 degrees Celsius. Snow pack appears as a decisive factor in winter temperatures, as the zero curtain effect can be tracked in many cases. Snow cover patterns show a distinctive behavior between S and N aspects, with a 3 months snow cover on the southern faces and between 6 and 9 at the northern analogues. This cover has a relevant impact on geomorphological processes. There is a clear relation between spring snow melt and solifluction or channelized erosion. Also, snow cover prevents the occurrence of freeze/thaw cycles

  5. Carbonates in mantle xenoliths from French Massif Central: inference for carbonatite-related metasomatism.

    NASA Astrophysics Data System (ADS)

    Wagner, Christiane; Deloule, Etienne

    2016-04-01

    Mantle xenoliths from the sub-continental lithospheric mantle (SCLM) frequently display evidence of metasomatism by melts or fluids of variable composition, e.g. alkali-basaltic, alkali-carbonate or carbonate melts. Carbonate-bearing mantle xenoliths are particularly interesting as highly mobile carbonate melts are likely prominent metasomatic agents of the mantle. This study presents detailed petrographic descriptions and major and trace element compositions of minerals in protogranular spinel lherzolites from the Mont Coupet occurrence (Devès province, French Massif Central), with focus on the carbonate phases to discuss their possible link to carbonatite melt. Two representative samples are described here. MC9 shows no evidence for infiltration of the host basanitic magma. Carbonates occur (1) as large (100 μm - 200 μm) anhedral crystals in interstitial pockets at triple point of primary olivine grains, (2) in a few cross-cutting veins (up to 200 μm width), (3) along grain boundaries and (4) in composite carbonate-silicate pockets from well-developed reaction zones, in which carbonates fill globular vesicles. The reaction zone contains secondary subhedral to euhedral phases: Al- and Ti-rich clinopyroxene, Ca-rich olivine, Cr-rich spinel and quenched plagioclase and relict sieved-textured primary spinel. MC2 shows carbonate-bearing thin (< 50 μm width) interconnected veinlets and only a few poorly-developed reaction zones around primary spinel. Large carbonate crystals (1), as in sample MC9, occur associated with (2) fibrous carbonate with a well-formed meniscus at the boundary between the two carbonate types. In some reaction zones the carbonate patches (3) show well-developed concentric carbonate structures, similar to those observed in the globular vesicles from the host basanite. In sample MC9, the carbonate is an alkali-free Mg-poor calcite (XCa = 0.95 - 0.98; with 0.5 - 1.8 wt. % MgO) whatever the occurrence. In sample MC2, carbonates are Mg

  6. Significance of Diamond-free Heterogeneous UHP Dolomitic Marble From the Kokchetav Massif

    NASA Astrophysics Data System (ADS)

    Aoki, K.; Ogasawara, Y.

    2003-12-01

    Local heterogeneity of fluid conditions during UHP metamorphism has been well demonstrated in a cm-scaled continuous sample of UHP marble (sample no. Y665) from the Kumdy-kol in the Kokchetav Massif. This banded carbonate rock sample consists of three zones; zone-A: dolomitic marble with abundant Ti-clinohumite, zone-B: dolomite marble, zone-C: dolomitic marble without forsterite and Ti-clinohumite. All three zones lack diamond. Zone-A consists of Ti-clinohumite, forsterite, diopside, Mg-calcite, dolomite, symplectite, and is characterized by the presence of Ti-clinohumite and by Ti-clinohumite-aragonite tie-line at the peak metamorphic condition. Diopside lacks lamella. Garnet is completely retrograded to symplectite (Di + Spl + Mg-Cal). Large-grained Ti-clinohumite shows clear compositional zoning of TiO2 between core (1.5-1.8 wt.%) and rim (2.2-3.4 wt.%). Some Ti-clinohumite grains contain very thin needles with preferred orientations. Zone-B consists mainly of dolomite, diopside, phlogopite, symplectite (Di + Spl + Mg-Cal) with minor amount of Mg-calcite, and is characterized by the stability of dolomite-diopside tie-line and by lack of Ti-clinohumite and forsterite. No lamella was observed in diopside. Garnet is rarely preserved. Zone-C consists mainly of Mg-calcite, dolomite, diopside, garnet and phlogopite and is characterized by phlogopite lamellae in diopside that indicate high pressure conditions. Phlogopite lamellae in diopside were confirmed by the laser Raman spectroscopy (Raman bands: 681.3 cm-1 and 357.9 cm-1 ) and by microprobe analysis. Lack of Ti-clinohumite and forsterite also characterizes this zone. Garnet has been well preserved from the retrograde reaction. High MgCO3 calcite (originally aragonite + dolomite) with large-grained exsolved dolomite lamellae occurs. All three zones have different bulk compositions each other; however, the tie-line relations cannot be explained by their bulk compositions. In zones C and B, diopside-dolomite tie

  7. Stability relations of Ti-bearing assemblages in UHP marbles from the Kokchetav Massif

    NASA Astrophysics Data System (ADS)

    Kikuchi, M.; Ogasawara, Y.

    2003-12-01

    Stability relations of Ti-bearing phases (rutile, titanite, Ti-clinohumite) in UHP marbles from the Kokchetav Massif, northern Kazakhstan were well analyzed by the phase relations in the model system CaO-MgO-SiO2-TiO2-CO2-H2O. Three types of UHP marbles have been described in the Kumdy-kol area: diamond-bearing dolomite marble (type-A), diamond-free Ti-clinohumite-bearing dolomitic marble (type-B), and diamond-free calcite marble (type-C) (Ogasawara et al., 2000; 2002), and they contain a distinct Ti-bearing phase, rutile, Ti-clinohumite, and titanite, respectively. The characteristics of these three marbles are as in the followings. Type-A: Dominant carbonate is dolomite. Abundant microdiamonds are included in garnet and diopside. Diopside-dolomite tie-line was stable. Diopside contains K-bearing silicate lamellar. The peak assemblage was dolomite + diopside + aragonite + garnet + rutile + diamond. Type-B: High MgCO3-calcite (originally aragonite + dolomite) is distinct. No diamond occurs. Diopside lacks lamellar texture. The peak assemblage was aragonite + dolomite + garnet + Ti-clinohumite or forsterite. Type-C: Only carbonate phase is calcite (originally aragonite). No diamond occurs. Titanite contains coesite exsolution lamellae and indicated supersilicic compositions stable at UHP conditions (P > 6GPa). Diopside contains phengite and K-feldspar lamellae. The peak assemblage was aragonite + diopside + K-feldspar + garnet + titanite. The solid-solid reaction, CaTiSiO5 (titanite) + CaMg(CO3)2 (dolomite) = CaCO3 (aragonite) + CaMgSi2O6 (diopside) + TiO2 (rutile), controlled the stability of Ti-bearing phases in calcite marble and dolomite marble. At UHP conditions, aragonite + diopside + rutile assemblage is stable compared with titanite + dolomite, and divides the compositional space into dolomite-free and dolomite-bearing tetrahedrons in the model system CaO-MgO-SiO2-TiO2. The presence of titanite in calcite marble indicates that the P-T condition was located

  8. Molecular and biochemical characterization of a new alkaline active multidomain xylanase from alkaline wastewater sludge.

    PubMed

    Zhao, Yanyu; Meng, Kun; Luo, Huiying; Huang, Huoqing; Yuan, Tiezheng; Yang, Peilong; Yao, Bin

    2013-02-01

    A xylanase gene, xyn-b39, coding for a multidomain glycoside hydrolase (GH) family 10 protein was cloned from the genomic DNA of the alkaline wastewater sludge of a paper mill. Its deduced amino acid sequence of 1,481 residues included two carbohydrate-binding modules (CBM) of family CBM_4_9, one catalytic domain of GH 10, one family 9 CBM and three S-layer homology (SLH) domains. xyn-b39 was expressed heterologously in Escherichia coli, and the recombinant enzyme was purified and characterized. Xyn-b39 exhibited maximum activity at pH 7.0 and 60 °C, and remained highly active under alkaline conditions (more than 80 % activity at pH 9.0 and 40 % activity at pH 10.0). The enzyme was thermostable at 55 °C, retaining more than 90 % of the initial activity after 2 h pre-incubation. Xyn-b39 had wide substrate specificity and hydrolyzed soluble substrates (birchwood xylan, beechwood xylan, oat spelt xylan, wheat arabinoxylan) and insoluble substrates (oat spelt xylan and wheat arabinoxylan). Hydrolysis product analysis indicated that Xyn-b39 was an endo-type xylanase. The K (m) and V (max) values of Xyn-b39 for birchwood xylan were 1.01 mg/mL and 73.53 U/min/mg, respectively. At the charge of 10 U/g reed pulp for 1 h, Xyn-b39 significantly reduced the Kappa number (P < 0.05) with low consumption of chlorine dioxide alone. PMID:23117673

  9. L-tectonites and deep mantle wedge deformations in the Limo ultramafic massif (Cabo Ortegal Complex, NW Spain)

    NASA Astrophysics Data System (ADS)

    Puelles, Pablo; Ábalos, Benito; Gil Ibarguchi, José Ignacio; Mendia, Miren; José Santos Zalguegui, Francisco

    2010-05-01

    The Cabo Ortegal Complex is one of the Allochthonous Complexes of northwest Iberia. The complexes are variable subducted continental and oceanic lithosphere fragments obducted onto the Gondwana edge during the Variscan orogeny. They comprise a Lower Allochthon, a sandwiched ophiolitic complex, and an Upper Allochthon made of rock units metamorphosed under high-pressure conditions and amalgamated in an oblique subduction/collision orogenic channel. The structurally uppermost high-pressure sheet consists of arc-root lithospheric mantle peridotites that rest on high-pressure granulite facies rocks, eclogites and gneisses with eclogite boudins. The ultramafic rocks outcrop in three major massifs (Limo, Herbeira and Uzal from N to S) and in a number of much smaller klippen structures. They are serpentinized amphibole-bearing harzburgite, chromian spinel- and PGE-bearing dunite, and garnet-bearing massive pyroxenite. The Limo ultramafic massif has been considered so far as a fairly massive harzburgitic massif without a clear internal arrangement or fabric. However, new field data and microstructural observations show that harzburgites are L-tectonites and that this fabric is recognizable at various scales (from aerial photos to the outcrop and microscopic scales). The structures described form a hm-thick ultramafic tectonite stack which resembles the structural relationships already known in the easternmost sector of the neighbour Herbeira massif. Subhorizontal mineral and stretching lineations are defined by spinel and orthopyroxene and trend N010°-030°E. Extremely elongated sheath-like folds bear axes parallel to the lineation and show axial ratios >15, tubular and isoclinal structures in XZ sections and eye- and anvil-structures in structural sections perpendicular to the lineation. Sigmoidal shapes of peridotite foliation trajectories in XZ sections indicate a top-to-the-NNE tectonic displacement of hanging wall blocks (according to present-day geographic

  10. First findings of monocrystalline aragonite inclusions in garnet from diamond-grade UHPM rocks (Kokchetav Massif, Northern Kazakhstan).

    PubMed

    Korsakov, Andrey V; Vandenabeele, Peter; Perraki, Maria; Moens, Luc

    2011-10-01

    The presence of aragonite inclusions in garnet from diamond-grade metamorphic rocks from the Kokchetav Massif, Northern Kazakhstan was identified for the first time by means of Raman analyses and mapping. Aragonite appears within the inclusions up to 50 μm in size as a single crystal. These inclusions have rounded shape. The grain boundary between the host-garnet is smooth. No cracks occur around the aragonite inclusions. No significant shift in the main aragonite Raman band was measured. These observations indicate that residual pressure within the inclusion is minor. These findings imply either non-UHPM origin of the host garnet or significant plastic deformation of host minerals during retrograde stage. These features should be taken into account for recovery peak metamorphic conditions and modeling of exhumation processes of UHPM complexes. PMID:21247793

  11. The promotion of geotourism in protected areas: a proposal of itinerary through the Matese Massif (Campania and Molise regions, Italy).

    NASA Astrophysics Data System (ADS)

    Rosskopf, Carmen Maria; Filocamo, Francesca; Amato, Vincenzo; Cesarano, Massimo

    2016-04-01

    The Matese Massif is a ca. 1000 km2 wide and NW-SE elongated carbonate relief, located in the inner sector of the Southern Apennine chain. It has a tabular setting with steep structural slopes bordering the central high mountain sector including its major peaks and is crossed from approximately west to east by the border between Campania and Molise regions. The Matese Mountains represent a key area for the comprehension of the geological and tectonic evolution of the Southern Apennines since Mesozoic times. Its long-term geomorphological evolution has been controlled by Quaternary tectonics and climate variations that have allowed the temporary or permanent establishment of various environments and morphodynamics. Deposits and landforms originated by glacial, periglacial, karst and fluvial processes, along with a rich assemblage of tectonic-structural features and landforms of complex origin have given origin to a geological heritage of exceptional value. The geosites actually censured within the Campanian sector of Matese are reported in the Geosites Map of Campania, available at the website of Campania Region and partly included in the Italian Geosites Inventory of ISPRA. The geosites of the Molise sector have been recently assessed within the geosite inventory carried out by Molise University. They are reported in the Geosites Map of Molise, available at the website of Molise Region, and partly included in the ISPRA's National Inventory of Geosites. The Matese area is largely included in protected areas: the Campania portion falls within the Matese Regional Park, established in 2002, while most of the Molise sector falls in the extensive ZPS/SIC IT72222287. To better protect and exploit the unique natural and geological heritage of the Matese Massif, numerous initiatives aimed at the establishment of the National Park of Matese have continued for several years and very recent attempts to promote the Matese Geopark have been made, but unfortunately without any

  12. The Cenozoic history of the Armorican Massif: New insights from the deep CDB1 borehole (Rennes Basin, France)

    NASA Astrophysics Data System (ADS)

    Bauer, Hugues; Bessin, Paul; Saint-Marc, Pierre; Châteauneuf, Jean-Jacques; Bourdillon, Chantal; Wyns, Robert; Guillocheau, François

    2016-05-01

    Borehole CDB1 (675.05 m) crosses the deepest Cenozoic sedimentary basin of the Armorican Massif, the Rennes Basin, to reach the underlying basement at a depth of 404.92 m, made up of the Late Neoproterozoic to Early Cambrian Brioverian Group, weathered down to 520 m depth. The basin's Cenozoic deposits are divided into seven formations, ranging from Early-Middle Bartonian to Late Pliocene in age. Coastal sediments at the very base, along with a thick Priabonian lacustrine episode, imply a major revision of the regional palaeogeography, whilst a very steady and low-energy lacustrine-palustrine environment throughout the Priabonian and Early Rupelian argue for an aggradational system associated with uniform subsidence. Palynological assemblages attest to environmental and climatic changes through the Eocene and Early Oligocene, in accordance with regional and global trends (Eocene-Oligocene Transition).

  13. Cross-border radon index map 1:100 000 Lausitz - Jizera - Karkonosze - Region (northern part of the Bohemian Massif).

    PubMed

    Barnet, Ivan; Pacherová, Petra; Preusse, Werner; Stec, Bartosz

    2010-10-01

    The first cross-border map describing the radon (Rn) risk from bedrock was assembled in the northern part of the Bohemian Massif at a scale 1:100 000. The map covers the area of Lausitz (Germany), Karkonosze (Czech Republic and Poland) and Jizera (Czech Republic). The map is based on 818 measurements of soil gas Rn in rock types of Precambrian to Mesozoic age with variable geology. Geographic information system (GIS) processing enabled a good coincidence of soil gas Rn concentrations between data from all three countries in lithologically adjacent rock types as well as the direct correlation to georeferenced indoor Rn values, which was tested using the Czech indoor Rn data. The method of data processing can contribute to assembling the European Geogenic Radon Map. PMID:20022148

  14. Strain partitioning in the Belledonne and Pelvoux massifs. Some clues to understand the Variscan tectono-thermal evolution.

    NASA Astrophysics Data System (ADS)

    Fréville, Kévin; Trap, Pierre; Faure, Michel; Melleton, Jeremie; Blein, Olivier

    2016-04-01

    This contribution presents new structural, petrological, geochemical and geochronological data obtained in the Variscan basement of the Alpine Belledonne and Pelvoux External Crystalline massifs. The Belledonne-Pelvoux area is a stack of four litho-tectonic units. The uppermost unit is the early Ordovician Chamrousse ophiolite. It overthrusts a volcanic-sedimentary unit (VSU) made of an alternation of volcanoclastic rocks, plagiogranites and metapelites. The VSU crops out in the eastern Belledonne and western Pelvoux massifs. It is unconformably overlain by a Visean sandstone-conglomerate series with felsic lava (keratophyres). The lowermost litho-tectonic unit is made of felsic and mafic migmatites and granitoids that form the major part of the Pelvoux massif. The western boundary of this tectonic pile is the "synclinal median" strike-slip fault, on the western side of which crops out the Belledonne micaschist unit made of Cambro-ordovician turbiditic series. The structural analysis revealed four main tectono-thermal events: Dx, D1, D2, and D3. Dx is only recorded in relictual metamorphic assemblage in Ky-Grt-Ab bearing micaschist from the VSU holding an obduction metamorphic gradient (3kbar, 370°C up to 7kbar, 430°C). The age of the Dx event remains unknown. The D1 event, characterized by westward low-angle dipping foliation (S1) and a NE-SW striking stretching lineation (L1), is responsible for the crustal thickening resulting of the Eastward emplacement of the Chamrousse ophiolite upon the VSU. D1 is coeval with a barrovian metamorphism with P-T conditions of 6kbar, 600°C recorded in metapelites, and partial melting developed at the base of the VSU. Monazite LA-ICP-MS U-Pb dating revealed that D1 crustal thickening occurred at 337±7 Ma. D2 is a sinistral transpressional deformation responsible for the folding of S1 and L1, and the development of a NE-SW trending pervasive sub-vertical foliation S2. In the lower structural domain, i.e. the partially molten

  15. High grade metamorphism in the Bundelkhand massif and its implications on Mesoarchean crustal evolution in central India

    NASA Astrophysics Data System (ADS)

    Singh, S. P.; Dwivedi, S. B.

    2015-02-01

    The Bundelkhand Gneissic Complex (BnGC) in the central part of the Bundelkhand massif preserves a supracrustal unit which includes pelitic (garnet-cordierite-sillimanite gneiss, garnet-sillimanite gneiss, biotite gneiss and garnet-biotite gneiss) and mafic (hornblende-biotite gneiss and garnetiferous amphibolite) rocks. Granulite facies metamorphism of the complex initiated with breaking down of biotite to produce garnet and cordierite in the pelitic gneisses. Geothermobarometric calculations indicate metamorphic conditions of 720°C/6.2 kbar, followed by a retrograde (687°C/4.9 kbar) to very late retrograde stages of metamorphism (579°C/4.4 kbar) which is supported by the formation of late cordierite around garnet. The P-T conditions and textural relations of the garnet-cordierite-bearing gneiss suggest a retrograde cooling path of metamorphism.

  16. Platinum potential of mafic-ultramafic massifs in the western part of the Dambuka ore district (Upper Amur Region, Russia)

    NASA Astrophysics Data System (ADS)

    Melnikov, A. V.; Stepanov, V. A.; Moiseenko, V. G.

    2016-02-01

    New data on the Pt potential of mafic-ultramafic massifs of the Khani-Maya, Uldegit, and Dzhalta complexes in the western part of the Dambuka ore district are discussed. The Khani-Maya Complex is represented by metamorphosed gabbro, gabbronorites, gabbro anorthosites, subordinate pyroxenites, hornblendites, and peridotites. The Uldegit Complex is composed of pyroxenites, hornblendites, gabbro, gabbronorites, norites, troctolites, peridotites, dunites, actinolite-tremolites, serpentinites, anthophyllites, and tremolite-plagioclase rocks. The Dzhalta Complex is formed of peridotites, gabbro, eclogitized gabbro, hornblendites, cortlandites, and pyroxenites. All these complexes differ from each other by the concentrations of Ni, Cu, Co, Au, and platinoids depending on the composition of the constituting rocks and the presence of sulfide minerals.

  17. A preliminary spatial-temporal study of some soil characteristics in the calcareous massif of Sicó, Portugal.

    PubMed

    Torres, Maria Odete; Neves, Maria Manuela

    2016-01-01

    The mountainous massif of Sicó, in the centre of Portugal, is an extensive area composed of calcareous Jurassic formations. Hillside calcareous soils, with high pH, present chemical restrictions to support plant growth and are subjected to important erosion processes leading to their degradation if not protected by vegetation. In a first year of study some soil physicochemical characteristics have been measured in some geo-referenced locations of a larger design experiment and an exploratory spatial analysis has been performed. The objective of this study was to present some suggestions in order to give sustainable phosphorus fertiliser recommendations aiming to establish pastures in these soils and thus support traditional livestock activity. Ten years apart, those soil characteristics have been measured again in the same locations and comparisions have been made. The objective was to understand the variability of the soil properties under study in order to better adequate the fertiliser soil management regarding the area restoration. PMID:27087036

  18. Ionic conductivity of alkaline (Li 2O, Na 2O) and alkaline-earth (BaO) borates in crystallization (vitrification) region

    NASA Astrophysics Data System (ADS)

    Solntsev, V. P.; Davydov, A. V.

    2011-11-01

    In this paper we report the existence of abnormal behavior of electric properties of alkaline (Li 2O,Na 2O) and alkaline-earth (BaO) borate in the melt—a crystal (glass) transition region. Results of measurement of conductivity in the mentioned interval evidence the existence of a strong variation of electric properties depending on the concentration of alkaline and alkaline-earth ions. The reasons of such behavior are discussed.

  19. Unravelling the effects of melt depletion and secondary infiltration on mantle Re-Os isotopes beneath the French Massif Central

    NASA Astrophysics Data System (ADS)

    Harvey, J.; Gannoun, A.; Burton, K. W.; Schiano, P.; Rogers, N. W.; Alard, O.

    2010-01-01

    Spinel lherzolite xenoliths from Mont Briançon, French Massif Central, retain evidence for multiple episodes of melt depletion and melt/fluid infiltration (metasomatism). Evidence for primary melt depletion is still preserved in the co-variation of bulk-rock major elements (MgO 38.7-46.1 wt.%; CaO 0.9-3.6 wt.%), and many samples yield unradiogenic bulk-rock Os isotope ratios ( 187Os/ 188Os = 0.11541-0.12626). However, many individual xenoliths contain interstitial glasses and melt inclusions that are not in equilibrium with the major primary minerals. Incompatible trace element mass balance calculations demonstrate that metasomatic components comprise a significant proportion of the bulk-rock budget for these elements in some rocks, ranging to as much as 25% of Nd and 40% of Sr Critically, for Re-Os geochronology, melt/fluid infiltration is accompanied by the mobilisation of sulfide. Consequently, bulk-rock isotope measurements, whether using lithophile (e.g. Rb-Sr, Sm-Nd) or siderophile (Re-Os) based isotope systems, may only yield a perturbed and/or homogenised average of these multiple events. Osmium mass balance calculations demonstrate that bulk-rock Os in peridotite is dominated by contributions from two populations of sulfide grain: (i) interstitial, metasomatic sulfide with low [Os] and radiogenic 187Os/ 188Os, and (ii) primary sulfides with high [Os] and unradiogenic 187Os/ 188Os, which have been preserved within host silicate grains and shielded from interaction with transient melts and fluid. The latter can account for >97% of bulk-rock Os and preserve geochronological information of the melt from which they originally precipitated as an immiscible liquid. The Re-depletion model ages of individual primary sulfide grains preserve evidence for melt depletion beneath the Massif Central from at least 1.8 Gyr ago despite the more recent metasomatic event(s).

  20. Endolithic microbial communities in carbonate precipitates from serpentinite-hosted hyperalkaline springs of the Voltri Massif (Ligurian Alps, Northern Italy).

    PubMed

    Quéméneur, Marianne; Palvadeau, Alexandra; Postec, Anne; Monnin, Christophe; Chavagnac, Valérie; Ollivier, Bernard; Erauso, Gaël

    2015-09-01

    The Voltri Massif is an ophiolitic complex located in the Ligurian Alps close to the city of Genova (Northern Italy) where several springs discharge high pH (up to 11.7), low salinity waters produced by the active serpentinization of the ultramafic basement. Mixing of these hyperalkaline waters with the river waters along with the uptake of atmospheric carbon dioxide forms brownish carbonate precipitates covering the bedrock at the springs. Diverse archaeal and bacterial communities were detected in these carbonate precipitates using 454 pyrosequencing analyses of 16S ribosomal RNA (rRNA) genes. Archaeal communities were dominated by members of potential methane-producing and/or methane-oxidizing Methanobacteriales and Methanosarcinales (Euryarchaeota) together with ammonia-oxidizing Nitrososphaerales (Thaumarchaeota) similar to those found in other serpentinization-driven submarine and terrestrial ecosystems. Bacterial communities consisted of members of the Proteobacteria, Actinobacteria, Planctomycetes, Bacteroidetes, Chloroflexi, and Verrucomicrobia phyla, altogether accounting for 92.2% of total retrieved bacterial 16S rRNA gene sequences. Amongst Bacteria, potential chemolithotrophy was mainly associated with Alpha- and Betaproteobacteria classes, including nitrogen-fixing, methane-oxidizing or hydrogen-oxidizing representatives of the genera Azospirillum, Methylosinus, and Hydrogenophaga/'Serpentinomonas', respectively. Besides, potential chemoorganotrophy was attributed mainly to representatives of Actinobacteria and Planctomycetales phyla. The reported 16S rRNA gene data strongly suggested that hydrogen, methane, and nitrogen-based chemolithotrophy can sustain growth of the microbial communities inhabiting the carbonate precipitates in the hyperalkaline springs of the Voltri Massif, similarly to what was previously observed in other serpentinite-hosted ecosystems. PMID:25874424

  1. Magmatic/metasomatic amphibole in the mantle: evidence from the Balmuccia lherzolite massif, Ivrea zone, western Italian Alps

    SciTech Connect

    Shervais, J.W.

    1985-01-01

    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 lherzolite 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 lherzolite, 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 lherzolite 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.

  2. Multistage evolution of UHT granulites from the southernmost part of the Gföhl Nappe, Bohemian Massif, Lower Austria

    NASA Astrophysics Data System (ADS)

    Schantl, Philip; Hauzenberger, Christoph; Linner, Manfred

    2016-04-01

    A detailed petrological investigation has been undertaken in leucocratic kyanite-garnet bearing and mesocratic orthopyroxene bearing granulites from the Dunkelsteiner Wald, Pöchlarn-Wieselburg and Zöbing granulite bodies from the Moldanubian Zone in the Bohemian Massif (Austria). A combination of textural observations, conventional geothermobarometry, phase equilibrium modelling as well as major and trace element analyses in garnet enables us to confirm a multistage Variscan metamorphic history. Chemically homogenous garnet cores with near constant grossular-rich plateaus are considered to reflect garnet growth during an early HP/UHP metamorphic evolution. Crystallographically oriented rutile exsolutions restricted to those grossular-rich garnet cores point to a subsequent isothermal decompression of the HP/UHP rocks. Overgrowing garnet rims show a pronounced zonation and are interpreted as the result of dehydration melting reactions during an isobaric heating phase which could have taken place near the base of an overthickened continental crust, where the previously deeply subducted rocks were exhumed to. For this HP granulite facies event maximum PT conditions of ~1050 °C and 1.6 GPa have been estimated from leucocratic granulites comprising the peak mineral assemblage quartz, ternary feldspar, garnet, kyanite and rutile. The pronounced zoning of garnet rims indicates that the HP granulite facies event must have been short lived since diffusion in this temperature region is usually sufficient fast to homogenize a zoning pattern in garnet. A retrogressive metamorphic stage is documented in these rocks by the replacement of kyanite to sillimanite and the growth of biotite. This retrograde event took place within the granulite facies but at significantly lower pressures and temperatures with ~0.8 GPa and ~760 °C. This final stage of re-equilibration is thought to be linked with a second exhumation phase into middle crustal levels accompanied by intensive

  3. Statistical adaptation of ALADIN RCM outputs over the French alpine massifs - application to future climate and snow cover

    NASA Astrophysics Data System (ADS)

    Rousselot, M.; Durand, Y.; Giraud, G.; Mérindol, L.; Dombrowski-Etchevers, I.; Déqué, M.

    2012-01-01

    In this study, snowpack scenarios are modelled across the French Alps using dynamically downscaled variables from the ALADIN Regional Climate Model (RCM) for the control period (1961-1990) and three emission scenarios (SRES B1, A1B and A2) by the mid- and late of the 21st century (2021-2050 and 2071-2100). These variables are statistically adapted to the different elevations, aspects and slopes of the alpine massifs. For this purpose, we use a simple analogue criterion with ERA40 series as well as an existing detailed climatology of the French Alps (Durand et al., 2009a) that provides complete meteorological fields from the SAFRAN analysis model. The resulting scenarios of precipitation, temperature, wind, cloudiness, longwave and shortwave radiation, and humidity are used to run the physical snow model CROCUS and simulate snowpack evolution over the massifs studied. The seasonal and regional characteristics of the simulated climate and snow cover changes are explored, as is the influence of the scenarios on these changes. Preliminary results suggest that the Snow Water Equivalent (SWE) of the snowpack will decrease dramatically in the next century, especially in the Southern and Extreme Southern part of the Alps. This decrease seems to result primarily from a general warming throughout the year, and possibly a deficit of precipitation in the autumn. The magnitude of the snow cover decline follows a marked altitudinal gradient, with the highest altitudes being less exposed to climate change. Scenario A2, with its high concentrations of greenhouse gases, results in a SWE reduction roughly twice as large as in the low-emission scenario B1 by the end of the century. This study needs to be completed using simulations from other RCMs, since a multi-model approach is essential for uncertainty analysis.

  4. Middle Proterozoic emplacement and deformation of metanorthosite and related rocks in the northeastern Marcy massif, Adirondack Mountains, New York

    SciTech Connect

    Fakundiny, R.H. ); Muller, P.D. . Dept. of Earth Sciences)

    1993-03-01

    Geologic mapping in the Elizabethtown and Mount Marcy 15 foot quadrangles in the northeastern Adirondack Mountains has shown that Middle Proterozoic anorthosite suite rocks of the Marcy massif were intruded in at least two temporally distinguishable episodes separated by a period of localized ductile shearing. Strain was concentrated in a 100 m to > 1 km thick zone consisting mainly of metamorphosed gabbroic anorthosite, ferrodiorite, and ferrosyenite gneiss with subordinate granite gneiss, calc-silicate gneiss, amphibolite, and marble. This zone of flat to steeply-dipping layered gneisses, designated the Elizabethtown ductile deformation zone (EDDZ) for exposures along Rt 9 south of Elizabethtown, appears to extend from Lake Champlain on the east to at least Lake Placid on the west. Its upper boundary is most clearly evident where it occurs in olivine metagabbro bodies of Jay and Iron Mountain. Massive metagabbro is sheared and recrystallized into amphibolite gneiss. The lower boundary of the zone is more difficult to map, but commonly lies within contaminated metamorphosed gabbroic anorthosite and ferrodiorite gneiss that characterize the margins of the massif in the area. Rocks of the EDDZ display pervasive mesoscopic S and LS fabrics, but exhibit totally recrystallized microtextures. Kinematic indicators such as winged porphyroclasts and S-C fabrics are sporadically developed and provide a regionally ambiguous sense of shear. The authors favor a regional extension origin for the fabrics. Mineral assemblages defining the EDDZ fabrics are consistent with granulite facies conditions during shear-zone development and suggest a lower crustal position. Mapping suggests that the younger anorthosite intrusions were mainly domical and generated a chaotic contact zone typified by block structure and dikes of ferrodiorite, ferromonzonite, and ferrosyenite.

  5. Physico-chemical conditions of crystallization of the Guli ulrabasic massif (North Part of the Siberian Platform): evidence from melt inclusions

    NASA Astrophysics Data System (ADS)

    Simonov, Vladimir; Vasiliev, Yuri; Kotlyarov, Alexey; Stupakov, Sergey

    2014-05-01

    Conditions of formation of the Guli ultrabasic massif (Maimecha Kotui Province in the North Part of the Siberian Platform) attract attention of numerous researchers. For the solution of genetic problems of various rocks from this ultramafic complex the data on melt inclusions in minerals has been earlier used (Sokolov et al., 1999; Rass, Plechov, 2000; Sokolov, 2003; Panina, 2006). At the same time, formation of dunites, occupying the main volume of the Guli massif, remain almost not considered by means of thermobarogeochemical methods and the role of magmatic processes in this case is not ascertained. As a result of melt inclusions study in the Cr-spinel the new data on physical and chemical parameters of dunite crystallization in the Guli ulrabasic massif was obtained. On the ratio (Na2O + K2O) - SiO2 the majority of analyses of glasses and calculated compositions of inclusions settle down in the field of subalkaline series. On the diagram MgO - SiO2 bulk chemical compositions of inclusions (with the magnesium content of 19-28 wt. %) correspond to picrites and picrite-basalts. They are in close association with the data on inclusions in the Cr-spinel from dunites of Konder (Siberian Platform) and Nizhnii Tagil (Ural Mountains) platinum-bearing ultrabasic massifs and also are situated near to the field of inclusions in the olivine phenocrysts from meimechites (Maimecha Kotui Province in the North Part of the Siberian Platform). Similarity of melt inclusions in the Cr-spinel from the dunite of the Guli massif and in the olivine from meimechites is established on the variety of petrochemical components - Al2O3, CaO, Na2O, K2O. The calculated compositions of inclusions from dunites coincide mostly with the data on inclusions from meimechites, while glasses of inclusions from Cr-spinel contain less titan and magnesium. As a whole for the melts of the Maimecha Kotui Province (that form both dunites of the Guli massif and meimechites) much higher contents of TiO2 (from

  6. Field measurement of alkalinity and pH

    USGS Publications Warehouse

    Barnes, Ivan

    1964-01-01

    The behavior of electrometric pH equipment under field conditions departs from the behavior predicted from Nernst's law. The response is a linear function of pH, and hence measured pH values may be corrected to true pH if the instrument is calibrated with two reference solutions for each measurement. Alkalinity titrations may also be made in terms of true pH. Standard methods, such as colorimetric titrations, were rejected as unreliable or too cumbersome for rapid field use. The true pH of the end point of the alkalinity titration as a function of temperature, ionic strength, and total alkalinity has been calculated. Total alkalinity in potable waters is the most important factor influencing the end point pH, which varies from 5.38 (0 ? C, 5 ppm (parts per million) HC0a-) to 4.32 (300 ppm HC0a-,35 ? C), for the ranges of variables considered. With proper precautions, the pH may be determined to =i:0.02 pH and the alkalinity to =i:0.6 ppm HCO3- for many naturally occurring bodies of fresh water.

  7. Reductive dechlorination of carbon tetrachloride using buffered alkaline ascorbic acid.

    PubMed

    Lin, Ya-Ting; Liang, Chenju

    2015-10-01

    Alkaline ascorbic acid (AA) was recently discovered as a novel in-situ chemical reduction (ISCR) reagent for remediating chlorinated solvents in the subsurface. For this ISCR process, the maintenance of an alkaline pH is essential. This study investigated the possibility of the reduction of carbon tetrachloride (CT) using alkaline AA solution buffered by phosphate and by NaOH. The results indicated that CT was reduced by AA, and chloroform (CF) was a major byproduct at a phosphate buffered pH of 12. However, CT was completely reduced by AA in 2M NaOH without CF formation. In the presence of iron/soil minerals, iron could be reduced by AA and Fe(2+) tends to precipitate on the mineral surface to accelerate CT degradation. A simultaneous transfer of hydrogenolysis and dichloroelimination would occur under phosphate buffered pH 12. This implies that a high alkaline environment is a crucial factor for maintaining the dominant pathway of two electron transfer from dianionic AA to dehydroascorbic acid, and to undergo dichloroelimination of CT. Moreover, threonic acid and oxalic acid were identified to be the major AA decomposition products in alkaline solutions. PMID:25912910

  8. Characterization of Human Bone Alkaline Phosphatase in Pichia Pastoris

    NASA Technical Reports Server (NTRS)

    Malone, Christine C.; Ciszak, Eva; Karr, Laurel J.

    1999-01-01

    A soluble form of human bone alkaline phosphatase has been expressed in a recombinant strain of the methylotrophic yeast Pichia pastoris. We constructed a plasmid containing cDNA encoding for human bone alkaline phosphatase, with the hydrophobic carboxyl terminal portion deleted. Alkaline phosphatase was secreted into the medium to a level of 32mg/L when cultured in shake flasks, and enzyme activity was 12U/mg, as measured by a spectrophotometric assay. By conversion to a fermentation system, a yield of 880mg/L has been achieved with an enzyme activity of 968U/mg. By gel electrophoresis analysis, it appears that greater than 50% of the total protein in the fermentation media is alkaline phosphatase. Although purification procedures are not yet completely optimized, they are expected to include filtration, ion exchange and affinity chromatography. Our presentation will focus on the purification and crystallization results up to the time of the conference. Structural data should provide additional information on the role of alkaline phosphatase in normal bone mineralization and in certain bone mineralization anomalies.

  9. Investigating mechanisms of alkalinization for reducing primary breast tumor invasion.

    PubMed

    Robey, Ian F; Nesbit, Lance A

    2013-01-01

    The extracellular pH (pHe) of many solid tumors is acidic as a result of glycolytic metabolism and poor perfusion. Acidity promotes invasion and enhances metastatic potential. Tumor acidity can be buffered by systemic administration of an alkaline agent such as sodium bicarbonate. Tumor-bearing mice maintained on sodium bicarbonate drinking water exhibit fewer metastases and survive longer than untreated controls. We predict this effect is due to inhibition of tumor invasion. Reducing tumor invasion should result in fewer circulating tumor cells (CTCs). We report that bicarbonate-treated MDA-MB-231 tumor-bearing mice exhibited significantly lower numbers of CTCs than untreated mice (P < 0.01). Tumor pHe buffering may reduce optimal conditions for enzymes involved in tumor invasion such as cathepsins and matrix metalloproteases (MMPs). To address this, we tested the effect of transient alkalinization on cathepsin and MMP activity using enzyme activatable fluorescence agents in mice bearing MDA-MB-231 mammary xenografts. Transient alkalinization significantly reduced the fluorescent signal of protease-specific activatable agents in vivo (P ≤ 0.003). Alkalinization, however, did not affect expression of carbonic anhydrase IX (CAIX). The findings suggest a possible mechanism in a live model system for breast cancer where systemic alkalinization slows the rate of invasion. PMID:23936808

  10. Solar ponds in alkaline lake and oil well regions

    SciTech Connect

    Lodhi, M.A.K.

    1996-05-01

    Solar ponds are probably the simplest technology available for useful conversion of solar energy. The basic technology is proven. Solar ponds have been shown to be technically feasible and economically viable for many applications particularly for thermal use. The electrical conversion and use of solar energy via solar ponds is still questionable in general for economic viability. By putting the untapped sources together in the South Plains region it looks promising economically both for thermal and electrical conversions and applications. There are a number of alkaline lake basins randomly scattered in the South Plains region of the USA. In that area there are thousands of crude oil producing wells which produce brine in abundance. Selection of suitable alkaline lake basins as a solar pond site and as depository sites of brine from oil wells and using of this brine and salty water from alkaline lakes makes the solar pond economically viable for both thermal and electrical demands in the area.

  11. Alkaline hydrogen peroxide pretreatment of softwood: hemicellulose degradation pathways.

    PubMed

    Alvarez-Vasco, Carlos; Zhang, Xiao

    2013-12-01

    This study investigated softwood hemicelluloses degradation pathways during alkaline hydrogen peroxide (AHP) pretreatment of Douglas fir. It was found that glucomannan is much more susceptible to alkaline pretreatment than xylan. Organic acids, including lactic, succinic, glycolic and formic acid are the predominant products from glucomannan degradation. At low treatment temperature (90°C), a small amount of formic acid is produced from glucomannan, whereas glucomannan degradation to lactic acid and succinic acid becomes the main reactions at 140°C and 180°C. The addition of H2O2 during alkaline pretreatment of D. fir led to a significant removal of lignin, which subsequently facilitated glucomannan solubilization. However, H2O2 has little direct effect on the glucomannan degradation reaction. The main degradation pathways involved in glucomannan conversion to organics acids are elucidated. The results from this study demonstrate the potential to optimize pretreatment conditions to maximize the value of biomass hemicellulose. PMID:24185034

  12. Extraction of the transplutonium elements from alkaline solutions

    SciTech Connect

    Karalova, Z.K.; Bukina, T.I.; Myasoedov, B.F.

    1986-03-01

    This paper investigates the extraction of transplutonium elements (TPE) and other elements using aliquat-336 and alkylpyrocatechol from strongly alkaline solutions in the presence of complexforming substances. It was shown by the methods of NMR and IR spectroscopy that elements can be extracted from alkaline solutions both in the form of coordination-saturated internal complex compounds and in the form of ionic associates, the anionic portion of which consists either of hydroxo-complexes of the cooresponding metals or their compounds with the complex-forming substance. Together with the TPE and REE the authors also studied the extraction of Fe(III), Ru(III), Zr(IV), Pu(IV), Pa(V), Nb(V), U(VI), Cs(I), and Th(IV) from alkaline solutions.

  13. Anaerobic digestion of tomato processing waste: Effect of alkaline pretreatment.

    PubMed

    Calabrò, Paolo S; Greco, Rosa; Evangelou, Alexandros; Komilis, Dimitrios

    2015-11-01

    The objective of the work was to assess the effect of mild alkaline pretreatment on the anaerobic biodegradability of tomato processing waste (TPW). Experiments were carried out in duplicate BMP bottles using a pretreatment contact time of 4 and 24 h and a 1% and 5% NaOH dosage. The cumulative methane production during a 30 d period was recorded and modelled. The alkaline pretreatment did not significantly affect methane production in any of the treatments in comparison to the control. The average methane production for all runs was 320 NmL/gVS. Based on first order kinetic modelling, the alkaline pretreatment was found to slow down the rate of methanogenesis, mainly in the two reactors with the highest NaOH dosage. The biodegradability of the substrates ranged from 0.75 to 0.82 and from 0.66 to 0.72 based on two different approaches. PMID:26292773

  14. Actinide-Aluminate Speciation in Alkaline Radioactive Waste

    SciTech Connect

    Dr. David L. Clark; Dr. Alexander M. Fedosseev

    2001-12-21

    Investigation of behavior of actinides in alkaline media containing AL(III) showed that no aluminate complexes of actinides in oxidation states (IIII-VIII) were formed in alkaline solutions. At alkaline precipitation IPH (10-14) of actinides in presence of AL(III) formation of aluminate compounds is not observed. However, in precipitates contained actinides (IIV)<(VI), and to a lesser degree actinides (III), some interference of components takes place that is reflected in change of solid phase properties in comparison with pure components or their mechanical mixture. The interference decreases with rise of precipitation PH and at PH 14 is exhibited very feebly. In the case of NP(VII) the individual compound with AL(III) is obtained, however it is not aluminate of neptunium(VII), but neptunate of aluminium(III) similar to neptunates of other metals obtained earlier.

  15. Alkaline direct alcohol fuel cells using an anion exchange membrane

    NASA Astrophysics Data System (ADS)

    Matsuoka, Koji; Iriyama, Yasutoshi; Abe, Takeshi; Matsuoka, Masao; Ogumi, Zempachi

    Alkaline direct alcohol fuel cells using an OH-form anion exchange membrane and polyhydric alcohols were studied. A high open circuit voltage of ca. 800 mV was obtained for a cell using Pt-Ru/C (anode) and Pt/C (cathode) at 323 K, which was about 100-200 mV higher than that for a DMFC using Nafion ®. The maximum power densities were in the order of ethylene glycol > glycerol > methanol > erythritol > xylitol. Silver catalysts were used as a cathode catalyst to fabricate alkaline fuel cells, since silver catalyst is almost inactive in the oxidation of polyhydric alcohols. Alkaline direct ethylene glycol fuel cells using silver as a cathode catalyst gave excellent performance because higher concentrations of fuel could be supplied to the anode.

  16. Magmatic evolution in the N-Gondwana margin related to the opening of the Rheic Ocean—evidence from the Upper Parautochthon of the Galicia-Trás-os-Montes Zone and from the Central Iberian Zone (NW Iberian Massif)

    NASA Astrophysics Data System (ADS)

    Dias da Silva, Ícaro; Díez Fernández, Rubén; Díez-Montes, Alejandro; González Clavijo, Emilio; Foster, David A.

    2016-06-01

    LA-MC-ICP-MS U-Pb zircon ages and whole-rock geochemical data obtained from volcanic rocks erupted in the northern margin of Gondwana provide new insights on the polyphase magmatic evolution of the NW Iberian domain during the establishment of passive margin conditions in Lower Paleozoic times. The U-Pb data show crystallization ages of ca. 455 Ma for two calc-alkaline rhyolites sampled in the Upper Parautochthon of the eastern Galicia—Trás-os-Montes Zone (GTMZ) and for an intraplate basalt intruded into Middle Ordovician slates of the autochthonous series of the Central Iberian Zone (CIZ). Together with previous data, the ages obtained reveal a periodic magmatic activity across the northern Gondwana margin during the Lower Paleozoic, which is comparable to that observed in NE Iberia and in other massifs of the Mediterranean realm. Both geochronological and geochemical data reinforce paleontological and stratigraphic evidences for paleogeographic proximity between these domains and contribute to the recognition of extensional-related magmatism along the northern margin of Central Gondwana associated with the opening of the Rheic Ocean.

  17. Magmatic evolution in the N-Gondwana margin related to the opening of the Rheic Ocean—evidence from the Upper Parautochthon of the Galicia-Trás-os-Montes Zone and from the Central Iberian Zone (NW Iberian Massif)

    NASA Astrophysics Data System (ADS)

    Dias da Silva, Ícaro; Díez Fernández, Rubén; Díez-Montes, Alejandro; González Clavijo, Emilio; Foster, David A.

    2015-08-01

    LA-MC-ICP-MS U-Pb zircon ages and whole-rock geochemical data obtained from volcanic rocks erupted in the northern margin of Gondwana provide new insights on the polyphase magmatic evolution of the NW Iberian domain during the establishment of passive margin conditions in Lower Paleozoic times. The U-Pb data show crystallization ages of ca. 455 Ma for two calc-alkaline rhyolites sampled in the Upper Parautochthon of the eastern Galicia—Trás-os-Montes Zone (GTMZ) and for an intraplate basalt intruded into Middle Ordovician slates of the autochthonous series of the Central Iberian Zone (CIZ). Together with previous data, the ages obtained reveal a periodic magmatic activity across the northern Gondwana margin during the Lower Paleozoic, which is comparable to that observed in NE Iberia and in other massifs of the Mediterranean realm. Both geochronological and geochemical data reinforce paleontological and stratigraphic evidences for paleogeographic proximity between these domains and contribute to the recognition of extensional-related magmatism along the northern margin of Central Gondwana associated with the opening of the Rheic Ocean.

  18. Alkalinity production in intertidal sands intensified by lugworm bioirrigation

    PubMed Central

    Rao, Alexandra M.F.; Malkin, Sairah Y.; Montserrat, Francesc; Meysman, Filip J.R.

    2014-01-01

    Porewater profiles and sediment-water fluxes of oxygen, nutrients, pH, calcium, alkalinity, and sulfide were measured in intertidal sandflat sediments from the Oosterschelde mesotidal lagoon (The Netherlands). The influence of bioturbation and bioirrigation by the deep-burrowing polychaete Arenicola marina on the rates and sources of benthic alkalinity generation was examined by comparing measurements in intact and defaunated sediment cores before and after the addition of A. marina in summer and fall 2011. Higher organic matter remineralization rates, shallower O2 penetration, and greater sediment-water solute fluxes were observed in summer, consistent with higher sediment community metabolic rates at a higher temperature. Lugworm activity stimulated porewater exchange (5.1 × in summer, 1.9 × in fall), organic matter remineralization (6.2 × in summer, 1.9 × in fall), aerobic respiration (2.4 × in summer, 2.1 × in fall), alkalinity release (4.7 × in summer, 4.0 × in fall), nutrient regeneration, and iron cycling. The effects of lugworm activity on net sediment-water fluxes were similar but more pronounced in summer than in fall. Alkalinity release in fall was entirely driven by metabolic carbonate dissolution, while this process explained between 22 and 69% of total alkalinity production in summer, indicating the importance of other processes in this season. By enhancing organic matter remineralization and the reoxidation of reduced metabolites by the sediment microbial community, lugworm activity stimulated the production of dissolved inorganic carbon and metabolic acidity, which in turn enhanced metabolic CaCO3 dissolution efficiency. In summer, evidence of microbial long distance electron transport (LDET) was observed in defaunated sediment. Thus, alkalinity production by net carbonate dissolution was likely supplemented by anaerobic respiration and LDET in summer. PMID:25431515

  19. Alkalinity production in intertidal sands intensified by lugworm bioirrigation.

    PubMed

    Rao, Alexandra M F; Malkin, Sairah Y; Montserrat, Francesc; Meysman, Filip J R

    2014-07-01

    Porewater profiles and sediment-water fluxes of oxygen, nutrients, pH, calcium, alkalinity, and sulfide were measured in intertidal sandflat sediments from the Oosterschelde mesotidal lagoon (The Netherlands). The influence of bioturbation and bioirrigation by the deep-burrowing polychaete Arenicola marina on the rates and sources of benthic alkalinity generation was examined by comparing measurements in intact and defaunated sediment cores before and after the addition of A. marina in summer and fall 2011. Higher organic matter remineralization rates, shallower O2 penetration, and greater sediment-water solute fluxes were observed in summer, consistent with higher sediment community metabolic rates at a higher temperature. Lugworm activity stimulated porewater exchange (5.1 × in summer, 1.9 × in fall), organic matter remineralization (6.2 × in summer, 1.9 × in fall), aerobic respiration (2.4 × in summer, 2.1 × in fall), alkalinity release (4.7 × in summer, 4.0 × in fall), nutrient regeneration, and iron cycling. The effects of lugworm activity on net sediment-water fluxes were similar but more pronounced in summer than in fall. Alkalinity release in fall was entirely driven by metabolic carbonate dissolution, while this process explained between 22 and 69% of total alkalinity production in summer, indicating the importance of other processes in this season. By enhancing organic matter remineralization and the reoxidation of reduced metabolites by the sediment microbial community, lugworm activity stimulated the production of dissolved inorganic carbon and metabolic acidity, which in turn enhanced metabolic CaCO3 dissolution efficiency. In summer, evidence of microbial long distance electron transport (LDET) was observed in defaunated sediment. Thus, alkalinity production by net carbonate dissolution was likely supplemented by anaerobic respiration and LDET in summer. PMID:25431515

  20. Alkalinity production in intertidal sands intensified by lugworm bioirrigation

    NASA Astrophysics Data System (ADS)

    Rao, Alexandra M. F.; Malkin, Sairah Y.; Montserrat, Francesc; Meysman, Filip J. R.

    2014-07-01

    Porewater profiles and sediment-water fluxes of oxygen, nutrients, pH, calcium, alkalinity, and sulfide were measured in intertidal sandflat sediments from the Oosterschelde mesotidal lagoon (The Netherlands). The influence of bioturbation and bioirrigation by the deep-burrowing polychaete Arenicola marina on the rates and sources of benthic alkalinity generation was examined by comparing measurements in intact and defaunated sediment cores before and after the addition of A. marina in summer and fall 2011. Higher organic matter remineralization rates, shallower O2 penetration, and greater sediment-water solute fluxes were observed in summer, consistent with higher sediment community metabolic rates at a higher temperature. Lugworm activity stimulated porewater exchange (5.1 × in summer, 1.9 × in fall), organic matter remineralization (6.2 × in summer, 1.9 × in fall), aerobic respiration (2.4 × in summer, 2.1 × in fall), alkalinity release (4.7 × in summer, 4.0 × in fall), nutrient regeneration, and iron cycling. The effects of lugworm activity on net sediment-water fluxes were similar but more pronounced in summer than in fall. Alkalinity release in fall was entirely driven by metabolic carbonate dissolution, while this process explained between 22 and 69% of total alkalinity production in summer, indicating the importance of other processes in this season. By enhancing organic matter remineralization and the reoxidation of reduced metabolites by the sediment microbial community, lugworm activity stimulated the production of dissolved inorganic carbon and metabolic acidity, which in turn enhanced metabolic CaCO3 dissolution efficiency. In summer, evidence of microbial long distance electron transport (LDET) was observed in defaunated sediment. Thus, alkalinity production by net carbonate dissolution was likely supplemented by anaerobic respiration and LDET in summer.

  1. Alkaline solution absorption of carbon dioxide method and apparatus

    DOEpatents

    Hobbs, D.T.

    1991-01-01

    Disclosed is a method for measuring the concentration of hydroxides (or pH) in alkaline solutions, using the tendency of hydroxides to adsorb CO{sub 2}. The method comprises passing CO{sub 2} over the surface of an alkaline solution in a remote tank before and after measurements of the CO{sub 2} concentration. Comparison of the measurements yields the adsorption fraction from which the hydroxide concentration can be calculated using a correlation of hydroxide or pH to adsorption fraction. A schematic is given of a process system according to a preferred embodiment of the invention. 2 figs.

  2. The mechanism of radiolysis of alkaline-earth nitrates

    NASA Astrophysics Data System (ADS)

    Anan'ev, V.; Kriger, L.; Miklin, M.

    2015-04-01

    The formation of peroxynitrite and nitrite in crystalline alkaline-earth nitrates under γ-irradiation at 310 K by optical reflectance spectroscopy has been studied. The radiolysis of Sr(NO3)2 and Ba(NO3)2 results in nitrite and peroxynitrite, Mg(NO3)2·6H2O and Ca(NO3)2·4H2O - nitrite. The mechanism for nitrite and peroxynitrite formation under γ-irradiation of crystalline alkaline-earth nitrates has been discussed.

  3. Surfactant-enhanced low-pH alkaline flooding

    SciTech Connect

    Peru, D.A. and Co., Columbia, MD . Research Div.); Lorenz, P.B. )

    1990-08-01

    This paper reports sodium bicarbonate investigated as a potential alkaline agent in surfactant-enhanced alkaline flooding because it has very little tendency to dissolve silicate minerals. In experiments performed with Wilmington, CA, crude oil and three types of surfactants, the bicarbonate/surfactant combination caused a marked lowering of interfacial tension (IFT). Bicarbonate protected the surfactant against divalent cations and reduced adsorption of surfactant and polymer on various minerals. Coreflood test confirm that sodium bicarbonate plus surfactant can be an effective alternative to the high-pH flooding process.

  4. Advanced technology for extended endurance alkaline fuel cells

    NASA Technical Reports Server (NTRS)

    Sheibley, D. W.; Martin, R. A.

    1987-01-01

    Advanced components have been developed for alkaline fuel cells with a view to the satisfaction of NASA Space Station design requirements for extended endurance. The components include a platinum-on-carbon catalyst anode, a potassium titanate-bonded electrolyte matrix, a lightweight graphite electrolyte reservoir plate, a gold-plated nickel-perforated foil electrode substrate, a polyphenylene sulfide cell edge frame material, and a nonmagnesium cooler concept. When incorporated into the alkaline fuel cell unit, these components are expected to yield regenerative operation in a low earth orbit Space Station with a design life greater than 5 years.

  5. Alkalinity distribution in the western North Atlantic Ocean margins

    NASA Astrophysics Data System (ADS)

    Cai, Wei-Jun; Hu, Xinping; Huang, Wei-Jen; Jiang, Li-Qing; Wang, Yongchen; Peng, Tsung-Hung; Zhang, Xin

    2010-08-01

    Total alkalinity (TA) distribution and its relationship with salinity (S) along the western North Atlantic Ocean (wNAO) margins from the Labrador Sea to tropical areas are examined in this study. Based on the observed TA-S patterns, the mixing processes that control alkalinity distribution in these areas can be categorized into a spectrum of patterns that are bracketed by two extreme mixing types, i.e., alongshore current-dominated and river-dominated. Alongshore current-dominated mixing processes exhibit a segmented mixing line with a shared mid-salinity end-member. In such cases (i.e., Labrador Sea, Gulf of Maine, etc.), the y-intercept of the high salinity segment of the mixing line is generally higher than the local river alkalinity values, and it reflects the mixing history of the alongshore current. In contrast, in river-dominated mixing (Amazon River, Caribbean Sea, etc.), good linear relationships between alkalinity and salinity are generally observed, and the zero salinity intercepts of the TA-S regressions roughly match those of the regional river alkalinity values. TA-S mixing lines can be complicated by rapid changes in the river end-member value and by another river nearby with a different TA value (e.g., Mississippi-Atchafalaya/Gulf of Mexico). In the wNAO margins, regression intercepts and river end-members have a clear latitudinal distribution pattern, increasing from a low of ˜300 μmol kg-1 in the Amazon River plume to a high value between ˜500-1100 μmol kg-1 in the middle and high latitude margins. The highest value of ˜2400 μmol kg-1 is observed in the Mississippi River influenced areas. In addition to mixing control, biological processes such as calcification and benthic alkalinity production may also affect ocean margin alkalinity distribution. Therefore, deriving inorganic carbon system information in coastal oceans using alkalinity-salinity relationships, in particular, those of generic nature, may lead to significant errors.

  6. The fluid phase evolution during the formation of carbonatite of the Guli massif: Evidence from the isotope (C, N, Ar) data

    NASA Astrophysics Data System (ADS)

    Buikin, A. I.; Verchovsky, A. B.; Kogarko, L. N.; Grinenko, V. A.; Kuznetsova, O. V.

    2016-02-01

    The first data on variations of the isotope composition and element ratios of carbon, nitrogen, and argon in carbonatites of different generations and ultrabasic rocks of the Guli massif obtained by the method of step crushing are reported. It is shown that early carbonatite differs significantly from the later ones by the concentration of highly volatile components, as well as by the isotope compositions of carbon (CO2), argon, and hydrogen (H2O). The data obtained allow us to conclude that the mantle component predominated in the fluid at the early stages of formation of rocks of the Guli massif, whereas the late stages of carbonatite formation were characterized by an additional fluid source, which introduced atmospheric argon, and most likely a high portion of carbon dioxide with isotopically heavy carbon.

  7. Reply to Comment on "The Late Devonian Variscan suture of the Iberian Massif: A correlation of high-pressure belts in NW and SW Iberia"

    NASA Astrophysics Data System (ADS)

    Fernández, Rubén Díez; Arenas, Ricardo

    2016-02-01

    The existence of a large allochthonous nappe pile emplaced onto the hinterland of the Iberian Massif and covering most of the basement of NW and SW Iberia proposed by Díez Fernández and Arenas has been called into question on the basis of structural, geophysical, and regional data from SW Iberia. The discussion provided here is based on a revision of the fundamentals of the Variscan geology of NW Iberia and on a more detailed presentation of the geology of SW Iberia. Our counterarguments reveal the reasoning of Simancas et al. against the verisimilitude of the large allochthonous pile as inconclusive, incomplete, or erroneous in some cases. Therefore, we maintain that our structural correlation and its implications remain fully valid for the case of the Iberian Massif.

  8. Use of Digital Elevation Models to understand map landforms and history of the magmatism Khibiny Massif (Kola Peninsula, Russia)

    NASA Astrophysics Data System (ADS)

    Chesalova, Elena; Asavin, Alex

    2016-04-01

    This work presents an improved geomorphological methodology that uses 3D model of relief, remotely-sensed data, geological, geophysical maps and tools of Geographical Information Systems. On the basis of maps of 1: 50,000 and 1: 200,000 the Digital Elevation model (DEM) of Khibiny massif was developed. We used software ARC / INFO v10.2 ESRI. A DEM was used for analyzing landform by extracting the slope gradient, curvature, valley pro?les, slope, aspect and so on. The results were gradually re?ned from the interpretation of satellite imagery and geological map Geomorphological analysis will allow us to determine spatial regularities in inner massive construction. We try to found areas where gas emissions (CH4/H2) enrich, according to morphometry, geology, tectonic and other environments. The main regional blocks were de?ned by different morphological evidences: impression zone, similar to subsidence caldera; uplift zone, domed area (located in the highest part of massif and zone of intersection of main faults) and others. It says that there are the few stages in the development of the Khibiny massif. There is no common concept of the consequence of intrudes magmatic phases now. And we hope that our geomorphical analysis take a new evidences about this problems. Locations of the blocks' borders (tectonic zones) were recognized by lineament analysis of valleys and tectonic faults presented in relief. Erosion system is represented by valleys of 4 ranks. It inherits the zone of tectonic disturbances 3 groups of faults were recognized: 1) Global lineament system cross whole peninsula - existing before Khibiny massif intrusion; 2) Faults associated with the formation of the intrusive phases sequence and magma differentiation and with later collision history during magma cooling; 3) Crack system related to neotectonic process. We believed that if different magmatic phases intrude in similar tectonic environment, the common spatial system of faults will be formed. Really we

  9. The Armorican Massif (Western France) - A buried relief two times exhumed in response to Iberia-Eurasia movements (Early Cretaceous, base of Cenozoic)

    NASA Astrophysics Data System (ADS)

    Bessin, Paul; Guillocheau, François; Robin, Cécile; Bauer, Hugues; Schroëtter, Jean-Michel

    2014-05-01

    The Armorican Massif is an outcropping Variscan basement located in Western France. The age of its exhumation is debated, as most of the outcropping European basements: Is this relief a remnant of the planation of the Variscan Belt or a buried and then exhumed relief at time of the North-Atlantic (Biscay Bay) opening during Early Cretaceous or/and during the Africa-Eurasia convergence? We performed a geomorphological study (based on DEM analysis and field controls) of the different landforms of the Armorican Massif. The dating of those relief forms is based on their geometrical relationships with the weatherings and dated preserved sediments. Our results allow to propose a model of evolution of the Armorican Massif and of its relief for the Mesozoic to Cenozoic period and underscore four main points: (1) The Armorican relief preserved old landforms - planation surfaces (mainly pediments and pediplains) - of Triassic (?) to Early Cretaceous age buried by Jurassic and Upper Cretaceous (chalk) carbonate platforms. (2) Those paleo-landforms were exhumed at two periods (i) Early Cretaceous in response to the opening of the Biscay Bay and (ii) Upermost Cretaceous-Paleocene at time of the Iberia-Eurasia increasing of convergence. (3) A major planation surface - called the Armorican Surface - result from the Early Cretaceous physical and chemical (laterite) erosion when the Armorican Massif was the North rift shoulder of the Biscay Bay. This planation surface is later deformed (buckling?) and eroded during Uppermost Cretaceous and Paleocene. (4) During Paleogene times, a last generation of pediments is shaped and then flooded by the Mid-Miocene eustatic sea-level rise. (5) The Armorican relief and landforms is later incised by rivers, (i) during Upper Miocene to Pliocene and (ii) at the Early to Middle Pleistocene transition with the incision of the present-day valleys in both response to uplift (Apulia-Eurasia convergence) and climate (precipitation) change.

  10. Stable isotope and Ar/Ar evidence of prolonged multiscale fluid flow during exhumation of orogenic crust: Example from the Mont Blanc and Aar Massifs (NW Alps)

    NASA Astrophysics Data System (ADS)

    Rossi, M.; Rolland, Y.

    2014-09-01

    The spatial and temporal scales and the geometry of fluid pathways in a collisional orogen are investigated using stable isotope analysis (O, C, and H) and 40Ar/39Ar dating of vein minerals formed at circa 11-16 Ma in the Mont Blanc and the Aar External Crystalline Massifs. In both massifs 40Ar/39Ar dating of veins adularia provides evidence for progressive crystallization from 16 to 9 Ma, and mainly at 11-12 Ma following veins opening during shear zone activity. The fluid flow duration thus ranges from 4 to 5 Ma in the two massifs. The δ18O values of vein quartz and calcite are similar to those of undeformed crystalline and sedimentary host rocks, suggesting rock buffering, while carbon isotope ratios of vein calcites fall into three compositional groups. A-type veins have δ13C values that are buffered by the Helvetic metasediments, which suggests that these veins formed in a closed system from a locally derived CO2-rich fluid. The fluid in equilibrium with C-type veins has depleted δ13C values similar to mantle-CO2, while the intermediate δ13C values of B-type veins suggest mixing between the A-type and C-type fluids. These results are in agreement with crustal- to lithosphere-scale upward vertical fluid flow along vertical shear zones related to the strike-slip system bounding the Adriatic block since 16-20 Ma, connecting a deep-seated fluid to some downward flow in the sedimentary cover of External Crystalline Massifs.

  11. Alkalinity and hardness: Critical but elusive concepts in aquaculture

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Total alkalinity and total hardness are familiar variables to those involved in aquatic animal production. Aquaculturists – both scientists and practitioners alike – tend to have some understanding of the two variables and of methods for adjusting their concentrations. The chemistry and the biolog...

  12. Qualitative aspects of the degradation of mitomycins in alkaline solution.

    PubMed

    Beijnen, J H; den Hartigh, J; Underberg, W J

    1985-01-01

    The major degradation product in alkaline solution of mitomycin A, mitomycin C and porfiromycin is the corresponding 7-hydroxymitosane. The isolation and the physico-chemical and analytical properties of these compounds and their derivatized analogues are discussed. Data are presented on the degradation of mitomycin C at extremely high pH values. PMID:16867711

  13. Ocean alkalinity and the Cretaceous/Tertiary boundary

    NASA Technical Reports Server (NTRS)

    Caldeira, K. G.; Rampino, Michael R.

    1988-01-01

    A biogeochemical cycle model resolving ocean carbon and alkalinity content is applied to the Maestrichtian and Danian. The model computes oceanic concentrations and distributions of Ca(2+), Mg(2+), and Sigma-CO2. From these values an atmospheric pCO2 value is calculated, which is used to estimate rates of terrestrial weathering of calcite, dolomite, and calcium and magnesium silicates. Metamorphism of carbonate rocks and the subsequent outgassing of CO2 to the atmosphere are parameterized in terms of carbonate rock reservoir sizes, total land area, and a measure of overall tectonic activity, the sea-floor generation rate. The ocean carbon reservoir computed by the model is used with Deep Sea Drilling Project (DSDP) C-13 data to estimate organic detrital fluxes under a variety of ocean mixing rate assumptions. Using Redfield ratios, the biogenic detrital flux estimate is used to partition the ocean carbon and alkalinity reservoirs between the mixed layer and deep ocean. The calcite flux estimate and carbonate ion concentrations are used to determine the rate of biologically mediated CaCO3 titration. Oceanic productivity was severely limited for approximately 500 kyr following the K/T boundary resulting in significant increases in total ocean alkalinity. As productivity returned to the ocean, excess carbon and alkalinity was removed from the ocean as CaCO3. Model runs indicate that this resulted in a transient imbalance in the other direction. Ocean chemistry returned to near-equilibrium by about 64 mybp.

  14. Alkalinity Analysis. Training Module 5.220.2.77.

    ERIC Educational Resources Information Center

    Bonte, John L.; Davidson, Arnold C.

    This document is an instructional module package prepared in objective form for use by an instructor familiar with the acid-base titrimetric procedure for determining the hydroxide, carbonate and bicarbonate alkalinity of a water sample. Included are objectives, an instructor guide, student handouts and transparency masters. A video tape is also…

  15. Alkaline extraction of phenolic compounds from intact sorghum kernels

    Technology Transfer Automated Retrieval System (TEKTRAN)

    An aqueous sodium hydroxide solution was employed to extract phenolic compounds from whole grain sorghum without decortication or grinding as determined by Oxygen Radical Absorbance Capacity (ORAC). The alkaline extract ORAC values were more stable over 32 days compared to neutralized and freeze dri...

  16. Enzymatic method of determining lead using alkaline phosphatase

    SciTech Connect

    Shekhovtsova, T.N.; Kucheryaeva, V.V.; Dolmanova, I.F.

    1986-03-20

    The purpose of this work was to determine the possibility of using alkaline phosphatase to determine trace amounts of ions of a number of metals - Mg, Ba, Ca, Sr, Cd, Pb - for which there are virtually no sensitive and simple methods of determination.

  17. Alkaline flood prediction studies, Ranger VII pilot, Wilmington Field, California

    SciTech Connect

    Mayer, E.H.; Breit, V.S.

    1986-01-01

    This paper discusses the design of a simulator to model alkaline displacement mechanisms, along with the current understanding of in-situ caustic consumption. Assimilation of laboratory coreflood and rock consumption data, and their use in one- and two-dimensional (1D and 2D) limited area simulations and in three-dimensional (3D) models of the entire pilot project are given. This paper also reports simulation studies of alkaline flood behavior in a small 2D area of a field for various concentrations, slug sizes, long-term consumption functions, and two relative-permeability adjustment mechanisms. The scale-up of 2D simulation results and their use in a 271-acre (1096.7-ha), seven-layered, 3D model of the pilot are also discussed and 3D simulator results are compared with initial field alkaline flood performance. Finally, recommended additional applications of the simulator methods developed in this pilot and in other alkaline floods are discussed.

  18. Transcriptome analysis of Enterococcus faecalis in response to alkaline stress

    PubMed Central

    Ran, Shujun; Liu, Bin; Jiang, Wei; Sun, Zhe; Liang, Jingping

    2015-01-01

    Enterococcus faecalis is the most commonly isolated species from endodontic failure root canals; its persistence in treated root canals has been attributed to its ability to resist high pH stress. The goal of this study was to characterize the E. faecalis transcriptome and to identify candidate genes for response and resistance to alkaline stress using Illumina HiSeq 2000 sequencing. We found that E. faecalis could survive and form biofilms in a pH 10 environment and that alkaline stress had a great impact on the transcription of many genes in the E. faecalis genome. The transcriptome sequencing results revealed that 613 genes were differentially expressed (DEGs) for E. faecalis grown in pH 10 medium; 211 genes were found to be differentially up-regulated and 402 genes differentially down-regulated. Many of the down-regulated genes found are involved in cell energy production and metabolism and carbohydrate and amino acid metabolism, and the up-regulated genes are mostly related to nucleotide transport and metabolism. The results presented here reveal that cultivation of E. faecalis in alkaline stress has a profound impact on its transcriptome. The observed regulation of genes and pathways revealed that E. faecalis reduced its carbohydrate and amino acid metabolism and increased nucleotide synthesis to adapt and grow in alkaline stress. A number of the regulated genes may be useful candidates for the development of new therapeutic approaches for the treatment of E. faecalis infections. PMID:26300863

  19. Thermochemical alkaline degradation of polysaccharide materials: Product characterization and identification

    SciTech Connect

    Krochta, J.M.; Hudson, J.S.; Tillin, S.J.; Spala, K.

    1985-01-01

    Degradation of cellulosics or starch in alkaline solution produces mostly organic acids which are monocarboxylic in nature. Seven of the organic acids have been identified as formic, acetic, glycolic, lactic, 2-hydroxybutyric, 2-hydroxyisobutyric and 2-hydroxyvaleric acids. In total, their yields amount to 41-46% of starting material weight.

  20. Organic siliconate additive for alkaline zinc electrochemical cells

    SciTech Connect

    Dopp, R.B.

    1986-10-14

    This patent describes an alkaline electrochemical comprising an air cathode sub-assembly, with a means for supplying air to the cathode sub-assembly, a zinc anode an organic siliconate in contact with the anode, an electrolyte in contact with the zinc anode and a non-metallic separator between the cathode and the anode.

  1. Field screening of cowpea cultivars for alkaline soil tolerance

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Cowpea or Southernpea [Vigna unguiculata (L.) Walp.] is an important legume crop used as a feed for livestock, as a green vegetable and for consumption of its dry beans which provide 22-25% protein. The crop is very sensitive to alkaline soil conditions. When grown at soil pH of 7.5 or higher, cowp...

  2. Yield performance of cowpea genotypes grown in alkaline soils

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Cowpea or Southernpea [Vigna unguiculata (L.) Walp.] is an important legume crop used as a feed for livestock, as a green vegetable and for consumption of its dry beans which provide 22-25% protein. The crop is very sensitive to alkaline soil conditions. When grown at soil pH of 7.5 or higher, cowp...

  3. Process of treating cellulosic membrane and alkaline with membrane separator

    NASA Technical Reports Server (NTRS)

    Hoyt, H. E.; Pfluger, H. L. (Inventor)

    1970-01-01

    The improvement of water-soluble cellulose ether membranes for use as separators in concentrated alkaline battery cells is discussed. The process of contacting membranes with an aqueous alkali solution of concentration less than that of the alkali solution to be used in the battery but above that at which the membrane is soluble is described.

  4. Oxygen electrodes for rechargeable alkaline fuel cells. II

    NASA Technical Reports Server (NTRS)

    Swette, L.; Kackley, N.

    1990-01-01

    The primary objective of this program is the investigation and development of electrocatalysts and supports for the positive electrode of moderate temperature, single-unit, rechargeable alkaline fuel cells. Approximately six support materials and five catalyst materials have been identified to date for further development.

  5. Oxygen electrodes for rechargeable alkaline fuel cells, 3

    NASA Technical Reports Server (NTRS)

    Swette, L.; Kackley, N.; Mccatty, S. A.

    1991-01-01

    The investigation and development of electrocatalysts and supports for the positive electrode of moderate temperature single unit rechargeable alkaline fuel cells is described. Focus is on chemical and electrochemical stability and O2 reduction/evolution activity of the electrode in question.

  6. Oxygen electrodes for rechargeable alkaline fuel cells-II

    NASA Technical Reports Server (NTRS)

    Swette, L.; Kackley, N.

    1989-01-01

    The primary objective of this program is the investigation and development of electrocatalysts and supports for the positive electrode of moderate temperature single-unit rechargeable alkaline fuel cells. Approximately six support materials and five catalyst materials have been identified to date for further development.

  7. Release of bound procyanidins from cranberry pomace by alkaline hydrolysis

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Procyanidins in plant products are present as extractable or unextractable/bound forms. We optimized alkaline hydrolysis conditions to liberate bound procyanidins from dried cranberry pomace. Five mL of sodium hydroxide (2, 4, or 6N) was added to 0.5 g of cranberry pomace in screw top glass tubes,...

  8. Genesis and significance of the silico-aluminous nodules in the Ordovician of the Montagne Noire and the Massif Armoricain (France)

    NASA Astrophysics Data System (ADS)

    Becq-Giraudon, Jean-François; Bouillé, Suzanne; Chauvel, Jean-Jacques

    1992-04-01

    Siliceous nodules of the Arenigian of the Montagne Noire (southern France) and the Massif Armoricain (western France) are made up of quartz, illite and chlorite with secondary apatite and, less frequently, dolomite. Diffractometrical and geochemical data indicate that the chlorite is a chamosite (trioctahedral 2:1 chlorite), whose development may be accompanied by that of apatite and diminution of illite. Three types of nodules are defined: Type 1, siliceous nodules, with more than 85% of SiO 2, very frequent in the Montagne Noire; Type II, nodules made of a micaceous siltstone with chlorite matrix, abundant in the Massif Armoricain but present also in the Montagne Noire; Type III, chloritic nodules with a finely globular structure, especially developed in the Massif armoricain but observed in the Montagne Noire as well. The nodules are always poorer in illite than their host sediments and often show traces of the initial sediments. Their formation occurs after the deposition and prior to the development of foliation. The frequent presence of undistorted fossil remains suggests an early formation linked to the physico-chemical modifications occurring in an unconsolidated sediment around a decaying organism. The post-depositional mineralogical evolution should have started with an illite/dolomite assemblage and end up with a chamosite-dominant one, under cold climatic conditions. The simultaneous presence of the three types of nodules in the same formation, or even in the same beds, shows that this mineralogical differentiation is not strictly related to the diagenetic and metamorphic transformation of this material.

  9. The systematics and paleobiogeographic significance of Sub-Boreal and Boreal ammonites (Aulacostephanidae and Cardioceratidae) from the Upper Jurassic of the Bohemian Massif

    NASA Astrophysics Data System (ADS)

    Hrbek, Jan

    2014-10-01

    Upper Jurassic marine deposits are either rarely preserved due to erosion or buried under younger sediments in the Bohemian Massif. However, fossil assemblages from a few successions exposed in northern Bohemia and Saxony and preserved in museum collections document the regional composition of macro-invertebrate assemblages and thus provide unique insights into broad-scale distribution and migration pathways of ammonites during the Late Jurassic. In this paper, we focus on the systematic revision of ammonites from the Upper Oxfordian and Lower Kimmeridgian deposits of northern Bohemia and Saxony. The ammonites belong to two families (Aulacostephanidae and Cardioceratidae) of high paleobiogeographic and stratigraphic significance. Six genera belong to the family Aulacostephanidae (Prorasenia, Rasenia, Eurasenia, Rasenioides, Aulacostephanus, Aulacostephanoides) and one genus belongs to the family Cardioceratidae (Amoeboceras). They show that the Upper Jurassic deposits of the northern Bohemian Massif belong to the Upper Oxfordian and Lower Kimmeridgian and pa