Temporal evolution of the Mariana Arc: Mantle wedge and subducted slab controls revealed with a tephra perspective

Abstract

Tephras recovered by deep-sea drilling from fore-arc to back-arc locations across the Mariana Volcanic Arc record the last 34 Myr of the system's evolution. Major and trace element abundances and Sr-Nd-Pb-Hf isotope ratios have been determined for tephra with high temporal precision and an average inter-tephra layer interval of ~1 Myr. Temporal variations of source-sensitive radiogenic isotopes and large-ion lithophile elements (LILE) are mostly decoupled from unchanging modes observed in silica and, with the exception of K, other archetypical crust-forming major elements. Modeling confirms that the temporal isotopic and elemental abundance trends are controlled by subducted slab and mantle ..