Photos: Wagifa Island on the southeastern side of Goodenough island: This island is entirely volcanic in origin and part of a lineament of historic volcanic rocks that are despite their calc-alkaline character not directly associated with a subduction zone.

The Eastern peninsula of Papua New Guinea sits in a complex geotectonic setting. An area where arc magmatism coincides with continental rifting and ocean spreading. Volcanic centers north of the peninsula are aligned with elevated seismic activity, yet a clearly defined plate boundary is not observed. Furthermore, the youngest exhumed ultra-high-pressure (UHP) rocks on Earth are associated with this area.

Understanding the volcanism in this areas and the timing of tectonic events requires a good control on the processes of magma generation.

We investigate nominally anhydrous minerals of mafic lavas to obtain estimates for primitive mantle melt water concentrations to distinguish between magma generation as a result of fluid addition through previously subducted oceanic lithosphere or of extension and decompression melting. By employing magma geothermobarometery on the primitive magmas we provide data for the thermal conditions at the depth from which the UHP rocks must have been exhumed, thus constraining geodynamic exhumation models.

collaborator and post-doc advisor: Terry Plank