Introduction: Chondrules are believed to have formed by a brief but intense heating and melting event in the early solar system. Melting erased most mineralogical information about chondrules’ precursors. A sub-group of chondrules is rich in alkali elements and was classified as Naand Al-rich chondrules [1]. We describe two Na-rich chondrules and discuss their phase relations in order to disent...

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...

Exact petrography and mineral chemistry investigations of pristine and altered rocks of the post-Eocene Panj-Kuh pluton show thatsubsequent to emplacement and crystallization, rocks were subjected to two secondary composition equivalents, sodic-calcic andpotassic alterations, respectively. Fresh rocks have syenitic composition and contain plagioclase (labradorite), K-feldspar, magmaticdiopside,...

exact petrography and mineral chemistry investigations of pristine and altered rocks of the post-eocene panj-kuh pluton show thatsubsequent to emplacement and crystallization, rocks were subjected to two secondary composition equivalents, sodic-calcic andpotassic alterations, respectively. fresh rocks have syenitic composition and contain plagioclase (labradorite), k-feldspar, magmaticdiopside,...