178 Paleontology, Diversity, Extinction, Origination

Tuesday, 21 October 2025
8:00 AM - 12:00 PM
HBGCC, 305

New Evidence of Deciduous and Evergreen Conifers in Late Cretaceous Antarctic Forests

Paper number: 178-4
Program: Technical Sessions
Time: 9:00 AM – 9:15 AM

Authors

Abstract

The temperate forests of the Late Cretaceous of Antarctica comprised an enigmatic ecosystem with no direct modern analogue due to the combination of consistently above-freezing temperatures and the presence of a polar light regime. These dynamics lead to the hypothesis that seasonality in this environment was controlled at least in part by light dynamics in addition to climate. The impact of light-availability-based seasonality and other stresses associated with prolonged exposure and absence of sunlight on the paleoenvironment of southern temperate polar forests is still unclear. However, anatomical signals from permineralized fossil wood, ubiquitous in the Late Cretaceous strata of James Ross Island, provide valuable insights into leaf abscission and retention in conifers, a cycle that can be strongly influenced by seasonality. Quantitative measurements of tracheids in gymnosperm wood allow a technique called the Cumulative Sum of Deviation from the Mean (CSDM) curve to be used, which estimates the seasonal timing of leaf retention and abscission in conifers. Using this method, the first unambiguously deciduous conifer in the Late Cretaceous of Antarctica is reported. New evergreen conifer specimens are also present, with estimated leaf retention times ranging from 1–5 years. These new data on temperate polar forest dynamics add to scientific understanding of the impacts of past greenhouse climates and can inform future polar climate predictions.

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

doi: 10.1130/abs/2025AM-414051

© 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.