There is a debate on the behavior of Re and Os during mantle metasomatism. Some argue that the mantle can acquire high 187Os/188Os (0.15 to s 1.0) either directly from metasomatic events or by the growth of 187Os from 187Re over time. However, any suggestions of subduction-related Os metasomatism producing whole-scale elevation of the mantle to 187Os/188Os values greater than 0.15 need to be su...

s CD. BODINIER, J.-L., MENZIES, M. A., SHIMIZU, N., FREY, F. A. & MCPHERSON, E. 2004. Silicate, hydrous and carbonate metasomatism at Lherz, France: contemporaneous derivatives of silicate melt–harzburgite reaction. Journal of Petrology, 45, 299–320. BONADIMAN, C., BECCALUVA, L., COLTORTI, M. & SIENA, F. 2005. Kimberlite-like Metasomatism and ‘garnet signature’ in spinel-peridotite xenoliths fr...

Two dives of the DSV Shinkai 6500 in the Mariana Trough back-arc basin in the western Pacific sampled back-arc basin mantle exposures. Reports of peridotite exposures in back-arc basin setting are very limited and the lack of samples has hindered our understanding of this important aspect of lithospheric evolution. The Mariana Trough is a slow-spreading ridge, and ultramafic exposures with asso...

a r t i c l e i n f o Keywords: silica-undersaturated volcanism 238 U-230 Th-226 Ra-210 Pb series disequilibria magma transport and residence time carbonate metasomatism volcanic hazard assessment The silica-undersaturated Nyiragongo volcanics, located in the East African Rift, have globally unique chemical compositions and unusually low viscosities, only higher than carbonatite lavas, for terr...

Mantle-derived xenoliths brought to the Earth’s Surface by basalts are important windows to understand composition, evolution and processes of the lithospheric mantle. The lithosphere of the southeastern China is dominated by peridotite or lherzolite [1, 2]. The spinel peridotite xenoliths studied are from Fangshan basalt, eastern China, which are composed of olivine, clinopyroxene, orthopyroxe...

Modern plate tectonic brings down oceanic crust along subduction zones where it either dehydrates or melts. Those hydrous fluids or melts migrate into the overlying mantle wedge trigerring its melting which produces arc magmas and thus additional continental crust. Nowadays, melting seems to be restricted to cases of young (< 50 Ma) subducted plates. Slab melts are silicic and strongly sodic (t...

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...

Geophysical imaging provides a unique perspective on metasomatism, because it allows the present day fluid distribution in the Earth’s crust and upper mantle to be mapped. This is in contrast to geological studies that investigate midcrustal rocks have been exhumed and fluids associated with metasomatism are absent. The primary geophysical methods that can be used are (a) electromagnetic method...

The development of the multi-collector ICP-MS has provided a wider range of isotopic systems (e.g. Li, Mg, Fe, Cu, Hf, Tl) that can used to place constraints on the timing of mantle metasomatism and better characterize metasomatic processes. Associated with the application of these isotopic systems has been the parallel development of in-situ isotope analysis using a laser ablation microprobe a...