Title

Reconstructing the glacial history of the Húnaflói Bay region in northwest Iceland using cosmogenic 36Cl surface exposure dating

Date of Award

Winter 2016

Project Type

Thesis

Program or Major

Earth Sciences

Degree Name

Master of Science

First Advisor

Joseph M Licciardi

Second Advisor

Sarah M Principato

Third Advisor

Rosemarie E Came

Abstract

Understanding the evolution and timing of ice sheet geometry and extent in Iceland during the Last Glacial Maximum (LGM) and subsequent deglaciation has long been the focus of much active research. Ongoing studies including recently published 36Cl surface 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. In this study, I report a suite of 36Cl exposure ages on glacially scoured bedrock and erratics as well as striation measurements from the Húnaflói Bay region that elucidate the chronology and pattern of ice sheet margin retreat in northern Iceland during the last deglaciation. Results indicate that the ice margin retreated to positions inside the present-day coastline between 10.2-8.5 ka in northern Iceland. Dated ice margin positions reported here are combined with ice sheet surface profiles derived from previously dated tuyas in the northern volcanic zone, and reveal a consistent pattern of ice surface thinning and margin retreat across northern Iceland from ~11-10 ka. The orientations of ice flow indicators measured in this study align with streamlined landforms in three valleys south of Húnaflói Bay, supporting the presence of paleo-ice stream activity in northern Iceland which may have provided a facilitating mechanism for ice to reach the shelf-slope break. The timing of ice margin retreat in northern Iceland is concurrent with periods of rapid glacier recession in both Greenland and Norway, suggesting a common driver of deglaciation in the circum-North Atlantic region that likely involved perturbations in ocean circulation and attendant changes in temperature. The improved terrestrial chronology of glacial thinning, retreat, and ice stream activity in this region will inform future glaciological modeling studies in Iceland.

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