PP048-01
Clumped Isotope Constraints on Changes in Paleotemperature and Past Hydroclimates: A Case Study from the Northwestern Great Basin, Lake Surprise, California

Wednesday, 16 December 2020: 19:00
Virtual
Lauren Santi1,2, Alexandrea Jay Arnold2, Daniel Enrique Ibarra3, Chloe Whicker2,4, John Arthur Mering5,6, Rico Bathan Lomarda7, Juan Manuel Lora2,8 and Aradhna K Tripati9, (1)GSI Environmental Inc., Houston, TX, United States, (2)University of California Los Angeles, Los Angeles, CA, United States, (3)Brown University, Earth, Environmental and Planetary Sciences, Providence, RI, United States, (4)University of Michigan, Ann Arbor, CA, United States, (5)University of California, Los Angeles, Earth, Planetary, and Space Sciences, Los Angeles, CA, United States, (6)University of Waikato, Hamilton, New Zealand, (7)University of California Los Angeles, Chemistry & Biochemistry, Los Angeles, United States, (8)Yale University, Department of Earth and Planetary Sciences, New Haven, CT, United States, (9)University of California Los Angeles, Department of Earth, Planetary, and Space Sciences, Department of Atmospheric and Oceanic Sciences, Institute of the Environment and Sustainability, Institute of Geophysics and Planetary Physics, Los Angeles, CA, United States
Recorded Presentation
Abstract:
During the Last Glacial Maximum (LGM) and subsequent deglaciation, the Great Basin in the southwestern United States was covered by numerous extensive closed-basin lakes, in stark contrast with the predominately arid climate observed today. This transition from lakes in the Late Pleistocene to modern arid­ity implies large changes in the regional wa­ter balance. Whether these changes were driven by increased precipitation rates due to changes in atmospheric dynamics, decreased evaporation rates resulting from temperature depression and summer insolation changes, or some combination of the two remains uncer­tain. In a recently published paper (Santi et al., 2020), we use a novel geochemical proxy for paleotemperature, clumped isotope analysis, to report thermodynami­cally derived estimates of changes in tempera­ture, precipitation, and evaporation rates, as well as the isotopic composition of lake water, using clumped isotope data from an ancient lake in the northwestern Great Basin, Lake Surprise, California. Compared to modern climate, mean annual air temperature at Lake Surprise was 4.7 °C lower during the Last Glacial Maximum, with decreased evapora­tion rates and similar precipitation rates to modern. In addition to presenting data from Lake Surprise, this presentation will review a few related areas of research from the Tripati Lab, including recent advances in temperature calibrations using modern samples, and application of clumped isotopes in both regional paleotemperature reconstruction and as a tool for understanding other paleoclimate variables, i.e. precipitation and evaporation rates. It also will describe application of clumped isotope analysis to carbonate sediments from other post-LGM lake basins in North and South America to study spatial and temporal trends, underscoring the utility of this climate proxy in disentangling complex paleoclimate signals.
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