Flocks, J. ., U.S. Geological Survey, St. Petersburg, USA, firstname.lastname@example.org
Twichell, D. ., U.S. Geological Survey, Woods Hole, USA, email@example.com
Baldwin, W. ., U.S. Geological Survey, Woods Hole, USA, firstname.lastname@example.org
Miner, M. ., University of New Orleans, New Orleans, USA, email@example.com
Kulp, M. ., University of New Orleans, New Orleans, USA, firstname.lastname@example.org
INFLUENCE OF ANTECEDENT GEOLOGY ON BARRIER ISLAND DEVELOPMENT, NORTHERN CHANDELEUR ISLANDS, LOUISIANA
A dense network of high-resolution seismic profiles collected around the northern Chandeleur Islands reveals three seismic facies that dominate the shallow (<100 m) stratigraphy. The first is an acoustically transparent lens-shaped unit with discontinuous reflectors, interpreted as distributary channel deposits associated with the St. Bernard complex of the Mississippi Delta. Stratigraphically adjacent to the first is a unit defined by low-angle parallel reflectors, interpreted to represent fine-grained interdistributary deposits. These two units underlie a seaward-thinning acoustically transparent unit, interpreted as the offshore extent of the barrier sand sheet. The distributary facies occupies the southern part of the northern Chandeleurs. The interdistributary facies comprise the northern portion and includes an erosional surface immediately seaward of the islands. The overlying barrier sand sheet is narrow along the southern part of the study area and is broadest and thickest at the northern end of the islands. The occurrence and thickness of the barrier sand correlate well with the spatial distribution of the underlying deltaic deposits, indicating a subsurface influence on the recent barrier-island development.
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