This Keck project is an interdisciplinary investigation of biologically mediated precipitation of dolomite and other carbonate minerals in Deep Springs Lake, CA. Elucidating the mechanisms of modern dolomite precipitation is a fundamental and longstanding problem in sedimentology and Earth history. Students and faculty will develop an integrated suite of field and laboratory data utilizing techniques in microbiology, aqueous geochemistry, sedimentology, mineralogy, and isotope geochemistry. During the project, participants will have the opportunity to perform cutting-edge geobiological research, including one week of fieldwork in a modern alkaline playa lake and three weeks of lab research at the sponsoring institutions.
The 2013 project will investigate the impact of Tropical Storm Irene on sediment transport in the Deerfield River Basin. This record-breaking storm dumped 180-250 mm of rain within a 24-hour period causing extensive flooding throughout the watershed. Numerous mass wasting events helped contribute to an anomalously high sediment load.
This project focuses on the tectonic evolution of the Chugach-Prince William terrane in Southeast Alaska, and it is a continuation of our 2011, and 2012 projects. This thick accretionary complex is dominated by Campanian-Paleocene (c. 75-55 Ma) trench fill turbidites likely derived from a volcano-plutonic complex. Near-trench plutons of the Sanak-Baranof belt imprinted a distinctive thermal event on these rocks and are a key indicator of plate position between 61-50 Ma. The primary study area for 2013 is the Sitka Graywacke in Sitka, Alaska, and the nearby and presumed metamorphosed equivalent, Baranof Schist in Whale Bay in the South Baranof Wilderness Area. Student projects will be focused on metamorphism and thermal evolution of these rocks, and sedimentary provenance including U/Pb dating of detrital zircon.
In this project, we will collect specimens so that field relations can be considered as part of the magnetic/geochemical provenance problem. There is also a more general archaeological/anthropological perspective involving sourcing theory, technological choices, and economic models for the students to balance the strictly geological aspects of this project.