Timing and Dynamics of the Initiation of Subduction: South Island, New Zealand

California Institute Of Technology, Pasadena CA

Investigators

Abstract

Gurnis EAR-0003558 This collaborative study will document the evolution of a nascent subduction zone along the Fiordland margin of southwest New Zealand with the objective of constraining the dynamics of subduction initiation. Using the finite element method, the investigators will model the history of vertical motion and gravity in order to determine the classes of dynamic models most consistent with the uplift history and modern structure of the region. (U-Th)/He dating by the investigators and exposure dating by New Zealand collaborators will place limits on erosional denudation associated with bedrock uplift. During year 1, the team will obtain helium ages for previously collected bedrock samples. During the Austral summer (year 2), they will collect new samples along the coast of the southernmost fiords with a chartered boat and at high elevations with a helicopter. Helium thermochronometric ages for these samples will be used to test the dynamic models. This is a collaborative project with NZ colleagues R. Sutherland (IGNS) and P. Kamp (Waikato University) who have complementary funding from the Royal Society of NZ.