Barriers on the brink? The complex intertwined roles of geologic framework, sediment availability and sea-level rise in island evolution

By: , and 
Edited by: Julie D. RosatiPing Wang, and Tiffany M. Roberts

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Abstract

Sensitivity experiments in the North Carolina Outer Banks (OBX) have previously revealed that substrate sand proportion, followed by substrate slope, sea-level rise rate and sediment-loss rate are the most important factors in determining how barrier islands respond to sea-level rise. High sediment-loss rates and low substrate sand proportions cause barriers to be smaller and more deeply incised. Thus, as sea level rise rates increase, more deeply incised barriers do not need to migrate as far landward as larger, less-incised barriers to liberate sand from the shoreface. However, if the combination of sand losses and substrate sand proportions requires a barrier to migrate landward faster than the shoreface can erode to replenish losses, a barrier will change state and begin to disintegrate. Because the substrate of the OBXis sand-rich, these barriers are likely to persist in the near-term. In contrast, model simulations for the Chandeleur Islands, Louisiana suggest sediment loss rates are too high and/or substrate sand proportions are too low to be matched by liberation of shoreface sand. These simulations further suggest that a state change, from a landward-migrating barrier system to a subaqueous shoal complex, is either already underway or imminent.

Additional publication details

Publication type Conference Paper
Publication Subtype Conference Paper
Title Barriers on the brink? The complex intertwined roles of geologic framework, sediment availability and sea-level rise in island evolution
ISBN 978-981-4355-52-0
DOI 10.1142/9789814355537_0021
Year Published 2011
Language English
Publisher World Scientific
Contributing office(s) Woods Hole Coastal and Marine Science Center
Description 14 p.
Larger Work Type Book
Larger Work Subtype Conference publication
Larger Work Title The proceedings of the Coastal Sediments 2011
First page 272
Last page 285
Conference Title Coastal Sediments 2011
Conference Location Miami, FL
Conference Date May 2-6, 2011