Halogen Bearing Amphiboles, Aqueous Fluids, and Melts in Subduction Zones: Insights on Halogen Cycle From Electrical Conductivity

Amphiboles are hydrous minerals that formed in the oceanic crust via hydrothermal alteration. The partial substitution of halogens for OH? makes amphibole one principal hosts Cl and F subducting slab. In this study, we investigated electrical conductivity a suite halogen bearing at 1.5 GPa up to 1,400 K. discontinuous behavior indicates dehydration ?915 This is followed by induced melting temperatures above 1,070 We find released aqueous fluids have an ?0.1 S/m. high likely explain anomalously observed certain subduction zone settings. order magnitude greater than pure similar conditions due partitioning into fluids. also noted subsequent dehydration, secondary phases form breakdown primary amphibole. Chemical analyses these indicate they repositories Cl. Hence, infer upon amphibole, first partitioned then back mineral phases. These transport deep Earth may part concentration ocean island basalt.