Meeting:Abstract 2013 CSDMS meeting-027

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Insights into late Quaternary events on the Beaufort Shelf and Slope from sea level and stratigraphic modeling

Philip Hill, Geological Survey of Canada Sidney , Canada. phill@nrcan.gc.ca

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Kim Picard, Geoscience Australia Canberra NO STATE, Australia. kim.picard@ga.gov.au

Andrew Wickert, University of Colorado Boulder Colorado, United States. Andrew.Wickert@colorado.edu

[[Image:|300px|right|link=File:]]Notice: Kim Picard is 1st author; Phil Hill 2nd author; Andrew Wickert 3rd author

This work aims to improve the late Quaternary stratigraphic framework for the outer shelf and slope of the Beaufort Sea and to assist in the assessment of geohazards, particularly those related to slope instability. Slope failures have been identified on the upper slope, but the age and triggers of slope failure are poorly understood. Existing conceptual models of late Quaternary stratigraphy of the Beaufort shelf and slope are quite generalized and based on a poorly constrained relative sea level curve. Sea level and stratigraphic modeling are used to test the relationships between glaciation, sea level and sedimentation. The results of the work suggest that glacio-isostatic effects cause the relative sea level (RSL) curve to vary significantly across the Beaufort Shelf particularly in the cross-shelf direction. Stratigraphic modeling with a variable RSL input successfully reproduces depositional patterns in the Mackenzie Trough including distinctive highstand and lowstand wedges and a retrogradational transgressive systems tract. However on the eastern shelf, more pronounced isostatic depression is required to match the known stratigraphy, suggesting deviation from the assumed ice loads or crustal properties in the model. Two outburst floods documented to have occurred in the region would have had a marked effect on shelf edge and slope sedimentation. Modeling suggests significant progradation of the shelf edge and rapid deposition on the slope and outer shelf at lowstand and in the early stage of transgression.