9 Glacial Landscapes as Recorders of Geomorphic Process and Climate Change (Posters)

Monday, 21 March 2016
8:00 AM - 12:00 PM
Convention Hall

RECONSTRUCTING THE GLACIAL HISTORY OF THE HUNAFLOI BAY REGION IN NORTHWEST ICELAND USING COSMOGENIC 36CL SURFACE EXPOSURE DATING

Paper number: 9-3
Program: Theme Sessions
Time: 8:00 AM – 12:00 PM

Authors

Abstract

Current knowledge of ice sheet geometry and extent in Iceland during the Last Glacial Maximum (LGM) and subsequent deglaciation is based on a combination of marine-based records, terrestrial evidence, and glaciological model simulations. Ongoing studies, including recently published 36Cl exposure ages of bedrock surfaces and moraines in the West Fjords (Vestfirðir), have continued to expand on available glacial records, but critical details regarding the timing and nature of deglaciation remain unresolved. One long-standing question concerns whether a restricted ice cap on the Vestfirðir peninsula existed independently from the main Iceland ice sheet during the LGM, or if the two ice sectors coalesced into one large ice complex. In this study, we are developing a suite of 36Cl surface exposure ages on glacially scoured bedrock from Vestfirðir and around Húnaflói Bay to further define the pattern and chronology of ice sheet margin retreat in northwest Iceland during the last deglaciation. Sample sites are distributed specifically in the region where the two ice sectors may or may not have been merged during the LGM, and hence provide an opportunity to directly evaluate hypothesized ice sheet configurations. Dated ice margin positions from this study will be combined with ice sheet surface profiles derived from previously dated tuyas in the Northern Volcanic Zone, in order to place empirical constraints on ice sheet geometry across northern Iceland during the last deglaciation. Additionally, the new 36Cl ages will be considered within the context of properties of streamlined landforms in the valleys of Viðidalur, Vatnsdalur, and Svínadalur, south of Húnaflói Bay, which support the presence of paleo-ice stream activity in northern Iceland. The improved terrestrial chronology of glacial thinning, retreat, and ice stream activity in this region will inform future glaciological modeling studies in Iceland.

Geological Society of America Abstracts with Programs. Vol. 48, No. 1

doi: 10.1130/abs/2016NE-272423

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