Yakob, J. L.; Feineman, M. D.; Penniston-Dorland, S. C.; Eggler, D. H.
Measured 7Li/6Li of mineral separates from mantle xenoliths from diverse localities show unexpectedly large differences between olivines and pyroxenes, often with lighter Li found in the pyroxenes (Jeffcoate et al., 2007; Rudnick and Ionov, 2007; Ionov and Seitz, 2008). Although changes in isotopic fractionation with temperature could explain the differences, a kinetic isotope effect is as likely. Because 6Li diffuses faster than 7Li, bulk lithium exchange between two phases could result in dynamic isotopic fractionation, with the receiving phase becoming lighter and the donating phase becoming heavier. Thus if Li becomes more compatible in cpx upon cooling, that is, if DLiol/cpx is temperature-dependent, the diffusive exchange of Li will generate temporary 6Li enrichment in cpx and depletion in olivine. Experiments were conducted using a piston cylinder apparatus at 1100°C and 1.4 GPa (1-5 days) to determine DLiol/cpx. San Carlos olivine and Dekalb diopside were finely ground for starting materials. A mixture of olivine (52 wt%), diopside (34 wt%), albite (7 wt%), and quartz (7 wt%) powders (0.0145 g) was loaded into a Pt capsule inside of a Ni crucible. Milli-Q water with 100 ppm Li and 500 ppm Ba (obtained through dilution of stock solutions) was added (0.1100 g) to serve as the lithium source. Lithium concentrations in olivine and diopside from experiments held for 1, 3, and 5 days were determined by laser ablation ICP-MS. Partition coefficients DLiol/cpx from runs at 3 and 5 days are, within error, the same, 1.9 (0.3). These fall in the lower portion of the range, D = 2-7, of limited previous measurements (Brenan et al., 1998b, Blundy and Dalton, 2000; Caciagli-Warman 2010). Partitioning experiments at 700 and 900°C are ongoing. References Blundy, J. and Dalton, J. (2000) Experimental comparison of trace element partitioning between clinopyroxene and melt in carbonate and silicate systems, and implications for mantle metasomatism. Contrib. Mineral. Petrol
Carlson, R. W.; Ionov, D. A.
high elevation of the Hangay uplift.  Ionov, D.A., Contrib. Mineral. Petrol. 154, p455, 2007.  Ionov and Hofmann, EPSL 261, p620, 2007.
Krause, J.; Brügmann, G. E.; Pushkarev, E. V.
The partitioning of trace elements between rock forming minerals in igneous rocks is largely controlled by physical and chemical parameters e.g. temperature, pressure and chemical composition of the minerals and the coexisting melt. In the present study partition coefficients for REE between hornblende, orthopyroxene, feldspars, apatite and clinopyroxene in a suite of co-genetic alkaline and tholeiitic mafic rocks from the Ural Mountains (Russia) were calculated. The results give insights to the influence of the chemical composition of the parental melt on the partitioning behaviour of the REE. Nepheline-bearing, alkaline melanogabbros (tilaites) are assumed to represent the most fractionated products of the melt that formed the ultramafic cumulates in zoned mafic-ultramafic complexes in the Ural Mountains. Co-genetic with the latter is a suite of olivine gabbros, gabbronorites and hornblende gabbros formed from a tholeiitic parental melt. Negative anomalies for the HFSE along with low Nb and Ta contents and a positive Sr anomaly indicate a subduction related origin of all parental melts. The nepheline gabbros consist predominantly of coarse-grained clinopyroxene phenocrysts in a matrix of fine grained clinopyroxene, olivine, plagioclase, K-feldspar and nepheline with accessory apatite. The tholeiitic gabbros have equigranular to porphyric textures with phenocrysts of olivine, pyroxene and hornblende in a plagioclase rich matrix with olivine hornblende, pyroxene and accessory apatite. Element concentrations of adjacent matrix grains and rims of phenochrysts were measured with LA-ICPMS. The distribution of REE between hornblende and clinopyroxene in the tholeiitic rocks is similar for most of the elements (DHblCpx(La-Tm) = 2.7-2.8, decreasing to 2.6 and 2.4 for Yb and Lu, respectively). These values are about two times higher than published data (e.g. Ionov et al. 1997). Partition coefficients for orthopyroxene/clinopyroxene systematically decrease from the HREE
Prikhodko, V.; Ashchepkov, I.; Ntaflos, T.; Barkar, A.; Vysotsky, S.; Esin, S.; Kutolin, V.; Prussevich, A.
-Koppy rivers and Mount Kurgan) show that in lava plateau stage Cpx in spinel facies have LREE Zr, Hf, Nb, Ta depleted patterns common for subduction related mantle melts. The Pliocene post erosion lava xenoliths's CPX reveal humped REE patterns, small depletions in Zr deeper in Ta corresponding to minor garnet in source. Clinopyroxenes from Amph- bearing websteritis are closer in TRE to to melts burn in garnet- bearing lherzolites (HFSE enriched U, Th spidergrams indication carbonatite metasomatism. Cpx in Podgelbanochny xenoliths (Ionov, 1995) reveal LREE - Th, U, Nb, Ta enriched content probably related to carbonatitic metasomatism or melts formed after decomposition of Amph - Phl measomaic association. The small Zr and Pb minima suppose sulfide and minor rutile precipitation. The host plume of Pliocene basalts are close to derived from primitive mantle source deviating in Sr (peak) small fluctuations in Zr- Hf. Reconstructed with KD parental liquids for websterites from MountKurgan are close to erupted lavas in La/Ybn . Melts parental for Cr- Di in the xenoliths from Podgelbanochny are more enriched. The sequence of xenolths show the sequent enrichment of the mantle columns beneath basaltic plateaus with the melts of subduction related to plume source. RBRF grant 11-05-00060.
Ashchepkov, I. V.; Vladykin, N. V.; Kuligin, S. S.; Smelov, A. P.; Ntaflos, T.; Kostrovitsky, S. I.; Lelyukh, M. I.; Rotman, A. Ya.; Afanasiev, V. P.; Tychkov, N. S.; Malygina, E. V.; Ovchinnikov, Yu. I.; Palessky, S. V.; Nikolaeva, I. V.; Khmelnikova, O. S.; Nigmatulina, E. N.
The kimberlite fields cross several (7) tectonic terranes compiling Siberian craton. According tectonic data (Rosen et al., 2006 ) they are locating within the Paleoproterozoic Accretion Zone which have ~1.8 ma age corresponds to the peak of the Re/Os dates (Ionov et al , 2011; Malkovets et al., 2011) and dating in other isotopic systems (Rosen et al., 2006). The lithospheric mantle beneath seven different tectonic terrains in Siberia is characterized by TRE geochemistry and major elements of peridotitic clinopyroxenes. The mantle in Magan terrain contains more fertile peridotite in the South (Mir pipe) then in North (Alakite) which are metasomatized by subduction-related (LILE Sr-enriched) melts producing Phl and Cpx about 500-800 Ma ago. Daldyn terrain is essentially harburgitic in the west (abyssal peridotite ) but in the east is more differentiated to fertile and depleted varieties and more oxidized in Upper Muna (East Daldyn terrain). The Markha terrain (Nakyn) contains depleted but partly refertilized harzburgites, subducted pelitic material and abundant eclogites. Circum-Anabar mantle is ultradepleted in the lower part but in the upper regions it has been fertilized by fluid-rich melts very enriched in incompatible elements. The SCLM in Magan terrane near Mir pipe contains in upper part fertile and hydrous metasomatic peridotites and eclogite lens in middle part (40 kbas). More depleted lens starts from 50 kbar beneath Mir pipe. But SCLM of Internationalnaya pipe show large amount of eclogites and hybrid peridotite material at the same depth. In SCLM beneath Nakyn the more continuous thick peridotite sections contain abundant various eclogites and Garnet bearing Fe- rich micaceous rocks (metapellites in protolith) (Spetcius et al., 2004 ). The general granulite-gneiss siliceous character of terrane coincides with the rather fertile mantle type. In the Markha terrane the SCLM is essentially metasomatic and contains essentially depleted lenses near Aykhal and
Antoine, Bénard; Luc-Serge, Doucet; Sabine, Palle; Dmitri A., Ionov
. 0.4 along Z axis) 2PEF enables analysis of 3D textural relations of tiny individual MSS globules (˜10 μm) in their various habitus. Statistical microgeometric descriptions can be derived from volumetric image data. These results may permit refinement of models concerning (re-) crystallisation kinetics and miscibility conditions of sulphur species in various media likely to act in different mantle environments: silicate melt, fluid-rich silicate melt, silicate-rich fluid. Furthermore, this study provides 3D images with improved resolution of several components (silicate phases, sulfides, silicate glass) over the full thickness (>100 μm) of rock slices which cannot be done with classical methods. Besides 3D imaging of ‘hidden' phases in mantle rocks, it opens up new possibilities for other domains in geosciences like crystallography or petrophysics.  Bénard & Ionov (2010) GRA, this volume  Abramoff, M.D., Magelhaes, P.J. & Ram, S.J. (2004) Image processing with ImageJ. Biophoton. Int., 11, 36-42
Ashchepkov, Igor; Karmanov, Nikolai; Kanakin, Sergei; Ntaflos, Theodoros
Pleistocene Bartoy volcanoes 1.5-0.8 Ma (Ashchepkov et al., 2003) represent variable set of hydrous cumulates and megacrysts and peridotite mantle xenoliths from spinel facies (Ashchepkov, 1991; Ionov, Kramm, 1992). Hydrous peridotites give series of the temperature groups: 1) deformed Fe - lherzolites (1200-1100o) , 2) Phl porhyroclastiμ (1100-1020o), 3) Amph -Phl (1020-940o), 4) Dry protogranular (1020-940o), 5)Amph equigranular (940-880o) and 6) dry and fine grained (880-820o). and Fe-rich poikilitic (700-600o) (Ashchepkov, 1991). T according (Nimis, Taylor, 2000) The sequence of the megacrysts crystallized on the wall of basaltic feeder in pre - eruption stage is starting from HT dark green websterites (1300-1200o), black Cpx- Gar varieties (1250-1200o) evolved to Phl -CPx (1200-1130o) and Cpx - Kaers (1130-1020o) - Cpx low in TiO2., Ilm and San (<1000o) like in Vitim (Ashchepkov et la., 2011). The differentiation trends looks branched but the question if they. Differentiation ain relatively large magma bodies p produced Ga- Cpx (+Amph-Phl- Ilm +-San) and then Cpx-Gar -Pl cumulates in( ~8-12 kbar) interval. In the ToC-Fe# diagram the Intermediate trend between lherzolites and megacrysts sub parallel to lherzolitic is correspondent to the fractionation of the hydrous alkali basalt melts in vein network created from the highly H2O bearing basaltic derivates formed in intermediate magma chambers. The interaction of the peridotites with the pulsing rising and evolving basaltic system produced the wall rock metasomatism and separate groups of peridotites in different levels of mantle column. PT calculations show two PT path and probably melt intrusion events. Trace elements in glass from crystalline basalts show Zr, Pb dips and Ta, Nb, Sr enrichment for the black megacrystalline Cpx , Gar series. They show link with evolved basalts by HFSE, Ba enrichment but Cpx from kaersutite and further Gar - Cpx cumulates show depressions in Ta, Nb, Zr, and Pb moderate
Pearson, D. G.; Canil, D.; Shirey, S. B.
, Sierra Leone ( Deines and Haggerty, 2000)91.6 (B): Non-cratonic xenoliths erupted by alkalic and potassic mafic magmas sensu latoa BI: Cr-diopside lherzolite groupVery widespread and common in a variety of tectonic settings, off-craton. Dominantly spinel-facies (Al or Cr-spinel) lherzolites but can be garnet-facies and garnet-spinel facies (e.g., Vitim). Coarse grained, commonly little deformed, sometimes show preferred orientation. Include harzburgites, orthopyroxenites, clinopyroxenites, websterites, and wehrlites. Pargasite and phlogopite may also be common. Both low TiO2 and high TiO2 amphiboles can occur at the same locality. Accessory apatite, can be common locally (e.g., Bullenmerri, Victoria). Interstitial silicate glass can be present. Garnet and spinel facies significantly more olivine-rich and orthopyroxene poor than peridotites from cratons such as Kaapvaal and Siberia. Bulk rocks less depleted in Ca, Al, Fe, and lower in Mg than cratonic peridotites. Minerals generally higher Mg# and Cr# and lower Na and Ti than those of the Al-Augite group. Can be subdivided into type IA (LREE depleted clinopyroxene) and type IB (LREE enriched clinopyroxene).Victoria, SE Australia (Frey and Green, 1974); Vitim ( Ionov et al., 1993a); San Carlos and other W. USA localities ( Frey and Prinz, 1978; Wilshire and Shervais, 1975); Eifel ( Stosch and Seck, 1980); Hawaii ( Jackson and Wright, 1970); Scotland ( Menzies and Halliday, 1988)Garnet facies: Thumb, Navajo field ( Ehrenberg, 1982a, b); Pali-Aike, Patagonia ( Stern et al., 1989); Vitim, S. Siberia ( Ionov, 1993a, b)>0.85, Avg. ˜90 BII: Al-augite wehrlite-pyroxenite groupWidespread and common. Frequently clinopyroxene-rich rocks but widely variable: wehrlites, clinopyroxenites, dunites, websterites, lherzolites, lherzites, gabbros. Al-spinel is the typical aluminous phase but may contain plagioclase. Kaersutite common along with apatite, Fe-Ti oxides, and phlogopite. Some igneous and metamorphic textures. Composite