Problem of water in the upper mantle: Antigorite breakdown

Abstract

The subducting oceanic crust has a heterogeneous composition but mainly is composed of a mixture of anhydrous dolerite and gabbro with mafic green schist (albite + epidote + chlorite + actinolite) and amphib� olite [1]. An increase in pressure and temperature results in rock dehydration in the subducting oceanic crust [2]. As this takes place, dehydration proceeds successively depending on phase transitions in hydrous phases (chlorite, lawsonite, amphibole, phengite, zoisite–clinozoisite, and others). The sub� ducting oceanic crust contains >5 wt % Н2О at the ini�