Grant NSF-ANT-1043152. 07/01/11 – 06/30/14.
Exploring the Significance of Na-Alkaline Magmatism in Subduction Systems, a Case Study From the Ross Orogen, Antarctica
Magmas generated during subduction of oceanic lithosphere beneath active continental margins typically have a calc-alkaline chemistry. However, igneous rocks with signatures usually associated with anorogenic magmatism are increasingly being found with calc-alkaline rocks in subduction zones. These enigmatic rocks provide insight into a variety of magmatic and structural processes that are fundamental to subduction zone dynamics but processes that lead to their petrogenesis remain a matter of debate. This project will investigate the Koettlitz Glacier Alkaline Province (KGAP) in the Transantarctic Mountains, a section through a Na-alkaline province bounded to the north and south by calc-alkaline magmatism. This province potentially contains key information on the thermo-mechanical processes leading to generation of Na-alkaline rocks in subduction systems. This study will train three graduate and three undergraduate students incorporating hands-on experience with state of the art instrumentation. Each summer, four high school students will be incorporated into various aspects of the laboratory-based research through the UCSB research mentorship program. This project will stimulate refinement of in-situ LA-ICPMS methods and development of collaborative linkages with Antarctic geologists at GNS Science in New Zealand. Results will be disseminated via papers and presentations at international conferences.
Hagen-Peter, G. Cottle J.M., Tulloch, A.J., Cox, S.C. 2015. Mixing between lithospheric mantle and crustal components in a short-lived subduction-related magma system in the Dry Valleys area, Antarctica: Insights from U-Pb and Hf isotopes and whole-rock geochemistry. GSA Lithosphere. doi:10.1130/L384.1 View pdf here