25 Paleo-climate and -ecosystems of the Southwest and High Plains: From the Paleozoic to the Quaternary (Posters)

Many Phanerozoic climates and ecosystems serve as potential analogues for the future; others highlight the Earth system response to tectonic and climatic forcings. We invite abstracts that probe the paleoclimate/ecosystems of the US Southwest

Tuesday, 19 May 2026
8:00 AM - 5:30 PM
Alvarado D/E

Calibrating Charcoal Records to Improve Paleofire Reconstructions from Jackson Lake, Wyoming

Paper number: 25-4
Program: Technical Sessions
Time: 8:30 AM – 8:30 AM

Authors

Abstract

Over the past century, Grand Teton National Park (Wyoming, USA) has experienced many severe wildfires, including the Waterfalls Canyon Fire (1974), Yellowstone Fires (1988), Alder Fire (1999), and the Spalding Fire (2011). However, there is no long-term high-resolution fire history for Grand Teton National Park. Here, variations in charcoal accumulation preserved in Jackson Lake sedimentary records are used as proxies to reconstruct the timing, frequency, and intensity of past wildfires and to evaluate their relationship with climate variability throughout the Holocene.

This study focuses on high–temporal resolution analysis of charcoal deposition from short sediment cores collected from Jackson Lake to quantify charcoal concentrations and compare them with historical fire records. Charcoal records are commonly interpreted without regional calibrations because high-resolution wildfire datasets are not typically available. Our research overcomes this limitation by generating a well-dated charcoal dataset that can be explicitly linked to historical fire records, providing a calibration framework for interpreting longer Holocene sequences.

Twenty-two short sediment cores were collected from Jackson Lake in 2019, 2021, and 2023. Charcoal will be extracted at 1 cm intervals using 1 cm³ subsamples, processed using standard wet-sieving protocols, and counted under a stereomicroscope to calculate charcoal accumulation rates (CHAR, expressed as pieces cm−2 yr−1). Age-depth models constructed from ²¹⁰Pb and ¹³⁷Cs dating constrain the charcoal record to 1737–2023 CE (average sedimentation rate: 0.25 cm yr−1), enabling high-resolution reconstructions of documented wildfires in the past several centuries. Burned area extents and charcoal deposition at each core site are quantified relative to distance from known burn zones using satellite imagery and geospatial analysis for documented wildfire events over the past 40 years. By analyzing spatial patterns of charcoal deposition and preservation in Jackson Lake sediments and comparing them with documented historical wildfire records, we can more effectively calibrate the sedimentary charcoal record. This approach enhances the interpretation of longer sediment cores and improves reconstructions of wildfire frequency, magnitude, and spatial dynamics over time.

Geological Society of America Abstracts with Programs. Vol. 58, No. 4

doi: 10.1130/abs/2026RM-410622

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