Subduction of oceanic crust buries an average thickness 300–500 m sediment that eventually dehydrates or partially melts. Progressive release fluid/melt metasomatizes the fore-arc mantle, forming serpentinite at low temperatures and phlogopite-bearing pyroxenite where slab surface reaches 700–900 °C. This is sufficiently high to melt subducted sediments before they approach depths arc magmas ar...

Li behaviour and distribution in the mantle were investigated by ion microprobe in situ measurements on co-existing olivine (ol), orthopyroxene (opx), clinopyroxene (cpx) and amphibole (amp) in xenoliths from the French Massif Central. The fertile spinel lherzolites of this study record increasing degrees of mantle metasomatism, from unmetasomatised anhydrous samples through cryptically metasom...

Chromium isotope compositions have been determined for 42 mantle-derived xenoliths from Cameroon, France, Mongolia, Russia and the USA. The samples are mainly spinel garnet lherzolites, or harzburgites, yield ?53CrNIST979 ?0.33 to 0.43‰, within range of previously reported compositions, ?0.51 0.74‰ (Xia et al., 2017). Partial melting has proposed as a process that alters ?53Cr mantle residue. N...

The origin of the Proterozoic Choghart iron oxide deposit in the Bafq mining district of Central Iran has been the subject of a long-standing dispute. Some authors believe that it was formed from magma, while others suggest metasomatic replacement of preexisting rocks. The present study on the basis of new oxygen isotope, REE and geochemical data concludes that neither of these two hypotheses c...

Fluid-rock interaction in ultramafic rocks considerably affects the chemical and isotopic composition of oceanic lithosphere. We present a geochemical petrological study serpentinites ophicalcites Northern Apennine ophiolite, Italy. This ophiolite sequence represents fragments Jurassic lithosphere that have been denuded by low angle detachment faults, exposing peridotites on ocean floor trigger...

The present bulk-rock geochemical study aims to answer some questions concerning the distribution and variability of trace elements (TEs) rare earth (REEs) in lower Cambrian–Lower Cretaceous sandstones mudstones NE Gondwana Jordan. proved that REE TE patterns both detrital authigenic, light heavy minerals are controlled principally by source-rock provenance, followed an interplay many factors: ...