Geography Colloquium Speaker—Wednesday, February 12

Speaker: Dr. Jessica Oster (Vanderbilt University, Department of Earth and Environmental Sciences)
Topic: Glacial and Deglacial Precipitation History of Western North America from Proxy Records and Paleoclimate Models

Abstract: In this presentation, I will discuss ongoing work to understand how the amount and source of precipitation varied in western North America over the past 35,000 years, including a new multi-proxy speleothem record from Lake Shasta Caverns in northern California. At 40.8°N, this cave is situated within the transition zone between regions in the northwestern and southwestern United States that demonstrate different precipitation responses to both modern and paleoclimatic drivers. This speleothem record demonstrates the non-stationarity of the transition zone location over the last glacial period and varied regional responses to Dansgaard-Oeschger events, Heinrich Events, and glacial interglacial changes. Covariation of speleothem ∂18O, an indicator of moisture source, with ∂13C and trace elements, indicators of moisture amount, allow separate investigation of how changes in moisture source and moisture amount influenced hydroclimate over this period. I will also describe initial results from a new study to understand the patterns and drivers of hydroclimatic change across the deglaciation using isotope-enabled climate models. This combined approach, using speleothem records and isotope-enabled climate models supports not only the reconstruction of past changes in atmospheric circulation, temperature, and precipitation but also the investigation of how these changes occurred and are recorded in paleoclimate archives.

February 12, 2020
Where: Mackay Science Room 321, UNR
Time: 4 PM–5 PM