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• W2015604853 endingPage "59" @default.
• W2015604853 startingPage "47" @default.
• W2015604853 abstract "Samples from Archean high-grade metamorphic terranes in China and granulite-facies xenoliths from Australia (Chudleigh and McBride suites) and China (Hannuoba suite) have been analyzed to assess the Li concentrations and isotopic compositions of the middle and lower continental crust, respectively. Thirty composite samples from metamorphic terranes, including tonalite–trondjhemite–granodiorite (TTG) gneisses, amphibolites and felsic to mafic granulites, show a large variation in Li concentrations (5–33 ppm) but a relatively narrow range in δ7Li values, from + 1.7 to + 7.5 with a mean of + 4.0 ± 1.4 (1σ). These results suggest that the middle continental crust is relatively homogenous in Li isotopic composition and indistinguishable from the upper mantle. This may be a primary feature or may reflect homogenization of Li isotopes during exhumation of the metamorphic terranes. In contrast, Li isotopic compositions of granulite xenoliths from the lower crust vary significantly, with δ7Li ranging from − 17.9 to + 15.7. δ7Li of minerals also shows a very large spread from − 17.6 to + 16.7 for plagioclases and − 14.6 to + 12.7 for pyroxenes. Large Li isotopic variations exist between plagioclase and pyroxene, with pyroxenes (13 out of 14) isotopically equal to or lighter than coexisting plagioclases. Lithium concentrations of granulite xenoliths also vary widely (0.5 to 21 ppm) and are, on average, lower than those of terranes (5 ± 4 vs. 13 ± 6 ppm respectively, 1σ), consistent with a higher proportion of mafic lithologies and a higher metamorphic grade for the xenoliths. Pyroxene separates from granulite xenoliths have equal or significantly greater Li than coexisting plagioclase. These large Li isotopic variations between minerals and in whole-rock granulite xenoliths mostly reflect diffusion-driven kinetic isotopic fractionation during the interactions of xenoliths with host magma. Only those xenoliths that reach inter-mineral isotopic equilibria are likely to preserve the initial Li isotopic signatures of the lower crust. Eight such equilibrated samples have δ7Li from − 14 to + 14.3, with a concentration weighted average of + 2.5, which is our best estimate of the average δ7Li of the lower continental crust. The substantial isotopic heterogeneity of the lower crust may reflect the combined effects of isotopic fractionation during granulite-facies metamorphism, diffusion-driven isotopic fractionation during igneous intrusion and variable protolith compositions. Consistent with previous B elemental and O isotopic studies, the Li isotopic heterogeneity in the lower crust indicates that pervasive fluid migration and equilibration have not occurred. Using all data for granulite xenoliths, the Li concentration of the lower crust is estimated to be ∼ 8 ppm. Together with previous estimates of Li concentration in the upper and middle crust, the average Li concentration of the bulk continental crust is estimated to be 18 ppm, which is similar to previous estimates. The average Li isotopic composition of the continental crust is estimated to be + 1.2, which is isotopically lighter than upper mantle and may reflect the loss of isotopically heavy Li from the continents during weathering and metamorphic dehydration." @default.
• W2015604853 created "2016-06-24" @default.
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• W2015604853 date "2008-09-01" @default.
• W2015604853 modified "2023-10-17" @default.
• W2015604853 title "Lithium isotopic composition and concentration of the deep continental crust" @default.
• W2015604853 cites W1555238106 @default.
• W2015604853 cites W1570943294 @default.
• W2015604853 cites W1609442959 @default.
• W2015604853 cites W1645311784 @default.
• W2015604853 cites W1654280627 @default.
• W2015604853 cites W1965260509 @default.
• W2015604853 cites W1965612690 @default.
• W2015604853 cites W1971831894 @default.
• W2015604853 cites W1972943156 @default.
• W2015604853 cites W1973012528 @default.
• W2015604853 cites W1974774627 @default.
• W2015604853 cites W1975951422 @default.
• W2015604853 cites W1977431633 @default.
• W2015604853 cites W1982286853 @default.
• W2015604853 cites W1988032601 @default.
• W2015604853 cites W1990130984 @default.
• W2015604853 cites W1990749591 @default.
• W2015604853 cites W1990832360 @default.
• W2015604853 cites W1990912283 @default.
• W2015604853 cites W1991442438 @default.
• W2015604853 cites W1994267827 @default.
• W2015604853 cites W1996028505 @default.
• W2015604853 cites W1998139239 @default.
• W2015604853 cites W2002673413 @default.
• W2015604853 cites W2002847449 @default.
• W2015604853 cites W2004137187 @default.
• W2015604853 cites W2004629980 @default.
• W2015604853 cites W2005456362 @default.
• W2015604853 cites W2010309572 @default.
• W2015604853 cites W2014224653 @default.
• W2015604853 cites W2017722262 @default.
• W2015604853 cites W2017929561 @default.
• W2015604853 cites W2019751060 @default.
• W2015604853 cites W2022977865 @default.
• W2015604853 cites W2025794983 @default.
• W2015604853 cites W2025841258 @default.
• W2015604853 cites W2026356562 @default.
• W2015604853 cites W2028243759 @default.
• W2015604853 cites W2035562754 @default.
• W2015604853 cites W2036418534 @default.
• W2015604853 cites W2036920064 @default.
• W2015604853 cites W2038890283 @default.
• W2015604853 cites W2041186833 @default.
• W2015604853 cites W2042302826 @default.
• W2015604853 cites W2042472200 @default.
• W2015604853 cites W2043003723 @default.
• W2015604853 cites W2044861519 @default.
• W2015604853 cites W2047121008 @default.
• W2015604853 cites W2050088334 @default.
• W2015604853 cites W2050574042 @default.
• W2015604853 cites W2054787894 @default.
• W2015604853 cites W2057683220 @default.
• W2015604853 cites W2058977872 @default.
• W2015604853 cites W2060407598 @default.
• W2015604853 cites W2064798552 @default.
• W2015604853 cites W2066856460 @default.
• W2015604853 cites W2067428307 @default.
• W2015604853 cites W2072836657 @default.
• W2015604853 cites W2077822785 @default.
• W2015604853 cites W2083554094 @default.
• W2015604853 cites W2091946953 @default.
• W2015604853 cites W2092830972 @default.
• W2015604853 cites W2095976142 @default.
• W2015604853 cites W2097502986 @default.
• W2015604853 cites W2100732374 @default.
• W2015604853 cites W2101882551 @default.
• W2015604853 cites W2107688672 @default.
• W2015604853 cites W2107692552 @default.
• W2015604853 cites W2127706723 @default.
• W2015604853 cites W2127888210 @default.
• W2015604853 cites W2133539256 @default.
• W2015604853 cites W2135251040 @default.
• W2015604853 cites W2135991059 @default.
• W2015604853 cites W2136863770 @default.
• W2015604853 cites W2142319922 @default.
• W2015604853 cites W2146063546 @default.
• W2015604853 cites W2158909637 @default.
• W2015604853 cites W2168661179 @default.
• W2015604853 cites W2171106910 @default.
• W2015604853 cites W2171553286 @default.
• W2015604853 cites W2913452601 @default.
• W2015604853 cites W4236250717 @default.
• W2015604853 doi "https://doi.org/10.1016/j.chemgeo.2008.06.009" @default.
• W2015604853 hasPublicationYear "2008" @default.
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