Chronology of Advance and Recession Dynamics of the Southern Green Bay Lobe of the Laurentide Ice Sheet, South-Central Wisconsin, USA

Authors

Eric C. Carson, University of Wisconsin-MadisonFollow
John W. Attig, University of Wisconsin-Madison
J. Elmo Rawling III, University of Wisconsin-MadisonFollow
Paul R. Hanson, University of Nebraska - LincolnFollow
Stefanie E. Dodge, University of Wisconsin-Madison

ORCID IDs

Eric Carson

Date of this Version

2020

Citation

Quaternary Research 95 (2020), pp. 142–153.

doi: 10.1017/qua.2020.8

Comments

Copyright © 2020 University of Washington. Published by Cambridge University Press. Used by permission.

Abstract

We used a combination of accelerator mass spectrometry (AMS) radiocarbon dating, optically stimulated luminescence (OSL) age estimates, and stratigraphic data from cores collected along the southern margin of the Green Bay Lobe (GBL) of the Laurentide Ice Sheet to provide new information on the timing and dynamics of the end of advance of the GBL and the dynamics of the ice sheet while very near its maximum position. Coring at multiple sites along the margin of the GBL indicate that ice had reached a stable position near its maximum extent by 24.7 ka; that ice advanced several kilometers to the Marine Isotope Stage 2 maximum position sometime shortly after 21.2 ka; and that ice remained at or beyond that position through the time interval represented by an OSL age estimate of 19.2 ± 3.2 ka. The timeline developed from these chronological data is internally consistent with, and further refines, AMS radiocarbon ages and OSL age estimates previously published for the southern margin of the GBL. It also provides new chronological control on the expansion of the GBL from its late Marine Isotope Stage (MIS) 3 extent to its MIS 2 maximum.