Tracing continental contamination along the Sunda-Banda arc transition: geochemical indicators of subduction to collision

Abstract

In subduction zones surface materials are subducted, transferring elements to the mantle (Plank and Langmuir, 1998). This is a key process modifying magma geochemistry.

The Sunda and Banda volcanic arcs in Indonesia record the northward subduction of the Indo-Australian plate beneath the Sunda plate and a progressive tectonic change from subduction to island-arc collision with the Australian continental margin.

Previous studies indicate that collisional volcanics in the Southwest Banda arc carry geochemical signatures of local subducting sediments enriched in Australian continental material (Vroon et al., 1995). Elburg, van Bergen and Foden (2004) propose that elements were transferred to the mantle from partially subducted segments of Australian continental margin. Additionally, helium isotope data   suggests continental influence may extend west beneath the active region around the island of Flores (Hilton et al., 1992).