P2C2: Evaluating Mean Annual Precipitation in the Southwestern United States (US) during the Pliocene-Pleistocene Transition Using Nitrate D17O Anomalies

Purdue University, West Lafayette IN

Investigators

Abstract

This project aims to develop a new precipitation record in Southwestern US during the Pliocene-Pleistocene transition (1-3 Million years). The researchers suggest to use a new isotopic tracer of precipitation: soil nitrate 17O anomalies. The analyses will be carried out on sediment samples collected from the Confidence Hills paleo- lake deposits in Death Valley, CA. This type of arid environment is suitable for nitrates deposition. The main objective is to assess quantitative changes in mean annual precipitation using soil nitrate 17O anomalies and link it to qualitative markers of climate variations such as shifts in depositional environments. The new data will serve as a test bed for model simulations of Pliocene-Pleistocene changes in precipitation. The potential Broader Impacts include developing a long quantitative precipitation record, testing and applying a new isotopic tracer for precipitation reconstruction from terrestrial sediments, and providing a critical data input at deep time-scales (1-3 Million years) to test Pliocene-Pleistocene climate models. Two undergraduate and one graduate student (PhD student to be recruited from tribal undergraduate colleges) will be mentored through the project. A Native American K-12 student field trip is incorporated in to the project and will be led by two native American students from Purdue University. This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.