184-3 Holocene Paleolimnology of Jackson Lake Revealed Through Carbon Geochemistry

Session: Lakes of the World Through Space and Time: Archives of Climate, Paleoenvironments, Ecosystems, Geohazards, and Economic Resources (Posters)

Poster Booth No.: 46

Presenting Author:

Abigail Portwood

Authors:

Portwood, Abigail¹, McGlue, Michael M.², Thigpen, Ryan³, Johnson, Sarah⁴, Woolery, Edward W.⁵, Brown, Summer J.⁶, Dilworth, John⁷, Rasbold, Giliane Gessica⁸, Backus, Jason S.⁹, Conner, Andrea K.¹⁰

(1) Earth and Environmental Sciences, University of Kentucky, Lexington, KY, USA, (2) Earth and Environmental Sciences, University of Kentucky, Lexington, KY, USA, (3) Earth and Environmental Sciences, University of Kentucky, Lexington, KY, USA, (4) Earth and Environmental Sciences, University of Kentucky, Lexington, KY, USA, (5) Earth and Environmental Sciences, University of Kentucky, Lexington, KY, USA, (6) Earth and Environmental Sciences, University of Kentucky, Lexington, KY, USA, (7) Earth and Environmental Sciences, University of Kentucky, Lexington, KY, USA, (8) Department of Earth, Environmental, and Atmospheric Sciences, Western Kentucky University, Bowling Green, KY, USA, (9) Kentucky Geological Survey, Lexington, KY, USA, (10) Kentucky Geological Survey, Lexington, KY, USA,

Abstract:

The hydrological systems of the American West, including the Snake River, are critical to sustaining regional ecosystems, agriculture, and municipal water resources. However, these systems face growing stress from climate change, with intensified drought, higher temperatures, and extreme events threatening long-term water availability. To better understand past hydrologic variability of the Snake River, we are exploring the deepwater sedimentary record of Jackson Lake (Grand Teton National Park, Wyoming).

Preliminary geochemical analyses of a 30 m long core collected from Jackson Lake reveal considerable variability that may be linked to changes in the Snake River, which forms a delta in the northern axis of the basin. We hypothesize that the Snake River inflow to Jackson Lake is higher during wetter paleoclimate conditions, as reflected in higher total carbon (TC) content values generated via LECO analysis. Despite short-term variability, we identify a long-term increasing trend in TC values, indicating a possible shift towards stronger Snake River inflow over the Holocene. Total inorganic carbon (TIC) values acquired via carbonate coulometry analysis support this interpretation; high TIC near the base of the record suggests limnological and climatic conditions favoring carbonate precipitation and accumulation. Water content appears to track TC, with higher values reflecting more organic matter burial owing to favorable productivity, preservation, and dilution conditions. By integrating these data with analysis of lithofacies, physical properties, and X-ray fluorescence data, the sediments in this long core may resolve uncertainties in the climatic and hydrologic record, offering potentially invaluable insights into system response with intensifying climate change.

Geological Society of America Abstracts with Program. Vol. 57, No. 6, 2025

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