15 Current Research in Lacustrine Sedimentary Records and Processes for Understanding Climate and Environmental Change (Posters)

Sunday, 17 March 2024
1:30 PM - 5:30 PM
Armory Ballroom

DEVELOPING A RECORD OF UPLAND DEGLACIATION AT TERMINATION 1 FROM SMITH AND SKY PONDS, NEW HAMPSHIRE

Paper number: 15-13
Program: Theme Sessions
Time: 1:30 PM – 5:30 PM

Authors

Abstract

Globally, Termination 1 was a major climate transition with rising CO2 and a warming climate which resulted in the rapid collapse of ice sheets. In the Northeastern United States the recession of the Laurentide ice sheet is well known in some locations. For example, in the Connecticut River Valley detailed varve records not only indicate past ice position but also retreat rates. However, the retreat in upland areas is poorly understood due to discontinuous archives of ice extent, and ice dynamics may have been complex in upland areas. The changing climate and associated ice sheet retreat resulted in massive landscape changes, shifts in vegetation structure and composition, and the lifeways of native peoples. Here, we present lake sediment core records from Sky and Smith Ponds in central and southwest New Hampshire that were collected in summer 2023 to investigate deglaciation, climate, and ecological changes across Termination 1. Termination 1 is contained in the lower third of the two ~6 m-long core records, as evidenced by transitions from clastic glacial sediments to organic-rich gyttja. We employ visual stratigraphy, magnetic susceptibility (MS), spectrophotometry, X-ray fluorescence (XRF) core scanning, and pollen to track depositional changes that reflect deglaciation and related environmental change. Radiocarbon dating of plant macrofossils provides age control. To place this work in a broader context, we are working to compare our records of environmental change with similar existing records to understand ice retreat and upland climate and vegetation changes. These data are the foundation for understanding human lifeways in the Northeast during Termination 1 in response to large regional shifts in climate and vegetation.

Geological Society of America Abstracts with Programs. Vol. 56, No. 1

doi: 10.1130/abs/2024NE-397486

© Copyright 2024 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.