Introduction to Hydrous Mantle

What is/are Hydrous Mantle?

Hydrous Mantle - Progressively more hydrous mantle-derived mafic magmas feed this chamber from below, providing heat, H2O, S and metals, but no unique “fertile” Cu-rich magma was involved in the formation of the deposit. ^[1] The slab window opening induced upwelling of anhydrous mantle and formation of the Fe-Ti gabbro dykes. ^[2] Helens dominantly formed by partial melting of metabasaltic lower crust, the geochemical and thermal models of this thesis indicate that the dacites are derived by fractional crystallization from a hydrous mantle-derived endmember with a maximum of 20-30% assimilation of pre-existing crustal material. ^[3] The coincidence of (1) the depth of a rheological transition, marked granular to porphyroclastic textures, and (2) the depth of a phase transition, from subsolidus hydrous peridotite to a hydrous mantle with melt in localized pockets, is the remarkable feature of the LAB beneath Ichinomegata. ^[4] We use phase equilibria and trace element modelling to characterize the Hf–Nd isotopic evolution of a chain of melting from anhydrous mantle through hydrated basalt to TTG. ^[5] Progressively more hydrous mantlederived mafic magmas feed this chamber from below, providing heat, H2O, S and metals, but no unique “fertile” Cu-rich magma was involved in the formation of the deposit. ^[6]