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 Himalaya-Tibetan orogen has become the paradigm for continental collision and is central to deciphering continental tectonics. Neogene extension in the orogen is not predicted by plate tectonic theory, and its significance is widely debated. In the Himalaya, north-south extension is restricted to the Southern Tibetan Detachment System (STDS), which juxtaposes the High Himalayan Crystalline ...

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...

Introduction. About 100 m of impactites (suevitetype breccias) have been drilled at the ICDP drill site Yax-1 within the Chicxulub impact structure (see [1] for more information). Post-impact hydrothermal alteration including alkali metasomatism and devitrification of impact melt glass has significantly modified the mineralogy and chemistry of the impact breccia lithologies. Hydrothermal altera...

the study area is located in the central iranian tectono-magmatic zone, which is known for its world-class ioa-type iron ore deposits. the advanced space borne thermal emission and reflection radiometer (aster) and landsat enhanced thematic mapper plus (etm+) image-processing techniques, were used in satellite imagery through conventional and also modern processing methods including band ratios...

New mineralogical and geochemical data from a suite of glass ± from the mantle (Deines & Gold, 1973; Nelson et al., 1988). However, controversy remains as to whether such apatite ± amphibole ± phlogopite ± carbonate-bearing spinel magmas represent (1) direct partial melts of carbonatewehrlite, lherzolite and harzburgite xenoliths from the Newer Volbearing mantle peridotite (i.e. primary carbona...

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...