Abundances of Ag and Cu in mantle peridotites and the implications for the behavior of chalcophile elements in the mantle

摘要: Abstract Silver abundances in mantle peridotites and the behavior of Ag during high temperature processes have received little attention and, as a consequence, abundance bulk silicate Earth (BSE) has been poorly constrained. In order to better understand that fractionate other chalcophile elements mantle, Cu from different geological settings (n = 68) obtained by isotope dilution ICP-MS methods. peridotite tectonites few suites xenoliths which display evidence for variable extents melt depletion refertilization melts, show positive correlations with moderately incompatible such S, Se, Te Au. The mean Cu/Ag fertile (3500 ± 1200, 1s, n = 38) is indistinguishable mid ocean ridge basalts (MORB, 3600 ± 400, n = 338) MORB sulfide droplets. constant ratios indicate similar partial melting magmatic fractionation, thus should be representative Earth’s upper mantle. systematic fractionation Cu, Ag, Au, Se consistent melt–silicate partitioning apparent partition coefficients platinum group (PGE) > Au ⩾ Te > Cu ≈ Ag > Se ⩾ S. Because effects secondary processes, elements, notably but also PGE many are lower than massifs. Refertilization may change lithophile massifs, however, this seems mostly occur way. Correlations overlapping used constrain BSE at 9 ± 3 (1s) ng/g 30 ± 6 μg/g (1s), respectively. very extent cannot explained low pressure–temperature core formation if currently available metal–silicate data applied.