GSA Connects 2022 meeting in Denver, Colorado

Paper No. 269-20
Presentation Time: 2:00 PM-6:00 PM

A GLACIAL-GEOLOGIC RECORD OF ICE RETREAT IN NORTH-CENTRAL MAINE, USA


MILES, Maraina1, HALL, Brenda L.1, LOWELL, Thomas V.2 and PUTNAM, Aaron1, (1)School of Earth and Climate Sciences and The Climate Change Institute, University of Maine, Orono, ME 04469, (2)Department of Geology, University of Cincinnati, Cincinnati, OH 45221

The termination of the last ice age (17.8-11.7 ka) provides a unique view into how the global climate system functions during times of rapid warming. Extreme seasonality, with unequal temperature changes in summer and winter, may have been a key feature of abrupt climate changes during the termination in the North Atlantic region. To begin to sort out seasonal variation, we aim to develop a record of summer temperature fluctuations from the glacial-geologic record of north-central Maine. Here, we present the results of glacial-geomorphic mapping and 10Be exposure ages of glacially transported boulders on moraines, including a newly discovered moraine in the lowlands south of Katahdin. Our preliminary 10Be dates suggest significant ice-surface lowering 16 – 15 ka, during the latter part of Heinrich Stadial 1 (HS1: 17.8 - 14.7 ka), which may indicate warmer than average summer temperatures during this time. We will discuss the implications of our results with regard to the seasonality hypothesis.