Boron cycling in the Central Andean subduction zone: evidence for recycled components

ROSIE JONES; LINDA KIRSTEIN; RICHARD HINTON; SIMONE KASEMANN; TIM ELLIOTT; VANESA D. LITVAK

Florencia

Conferencia; Goldschmidt 2013 Conference; 2013

The Geochemical Society

Subduction zones, such as the active Andean margin, form large recycling systems and are the main producers of new continental crust. Some of the material which enters the subduction zone, including terreginous and pelagic sediment and oceanic crust, is recycled to the continental crust via arc magmatism, and some re-equilibrates with the mantle. Boron has been identified as an ideal tracer for mass transfer in subduction zones, especially of recycled slab components. Central Andean arc magmas received a greater influence from slab derived fluids after the intersection of the Juan Fernandez Ridge and subsequent shallowing of the Nazca plate. This work demonstrates boron isotope ratios can be used in combination with high resolution U-Pb dating and major and trace element geochemistry to provide new insights into arc processes in changing geodynamic settings.