147 Climate, Ocean and Environmental Changes Through Earth History: From Marine and Terrestrial Proxies to Model Assessments (Posters)

This session brings together marine and terrestrial proxies and modelling to reconstruct rapid ocean, environment, and climate events, and shifts between long-term climate/ocean/environment states, within the context of normal variability throughout Earth history.

Monday, 20 October 2025
8:00 AM - 5:30 PM
HBGCC, Hall 1

Insights into the Deglacial in Southwestern North America from a Lacustrine Record in Northeastern Arizona

Paper number: 147-18
Program: Technical Sessions
Time: 8:45 AM – 8:45 AM

Authors

Abstract

During the last glacial maximum, southwest North America was wetter than the present, and as deglaciation progressed, shifts in the seasonal precipitation regimes occurred. However, the relative contribution of summer and winter precipitation, as well as their underlying mechanisms and forcings remain uncertain because long continuous paleoclimate records from this region are relatively rare. Here, we present a new reconstruction of past climate changes spanning the past ca. 40,000 years from Potato Lake on the Mogollon Rim in northeast Arizona using leaf wax 𝛿D and branched glycerol dialkyl glycerol tetraethers. Paleotemperatures estimated using the MBT’5Me index show ca. 6.5˚C of cooling during the last glacial, and an early Holocene thermal maximum that is ca. 1˚C warmer than the preindustrial.  Deglacial warming occurs gradually and starts early, beginning at immediately after the last glacial maximum (LGM) at ca.21-22 ka.  A slight cooling of ca. 1˚C occurs synchronously with the Younger Dryas stadial.  In contrast, 𝛿Dwax values peak during  the LGM, but do not change significantly until ca. 16.3 ka, when they decrease abruptly. The differences between the 𝛿Dwax and temperature reconstructions suggests a decoupling between temperature and atmospheric dynamics during the deglacial, reflecting differences in the underlying processes driving precipitation and temperature changes at that time.

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

doi: 10.1130/abs/2025AM-413793

© Copyright 2025 The Geological Society of America (GSA), all rights reserved. Permission is hereby granted to the author(s) of this abstract to reproduce and distribute it freely, for noncommercial purposes. Permission is hereby granted to any individual scientist to download a single copy of this electronic file and reproduce up to 20 paper copies for noncommercial purposes advancing science and education, including classroom use, providing all reproductions include the complete content shown here, including the author information. All other forms of reproduction and/or transmittal are prohibited without written permission from GSA Copyright Permissions.