Occupation of a relict distributary system by a new tidal inlet, Quatre Bayou Pass, Louisiana
Levin, D.R. (1995). Occupation of a relict distributary system by a new tidal inlet, Quatre Bayou Pass, Louisiana, in: Flemming, B.W. et al. (Ed.) Tidal Signatures in Modern and Ancient Sediments. Special Publication of the International Association of Sedimentologists, 24: pp. 71-84
In: Flemming, B.W.; Bartholomä, A. (Ed.) (1995). Tidal Signatures in Modern and Ancient Sediments. Special Publication of the International Association of Sedimentologists, 24. Blackwell Science: Oxford. ISBN 0-86542-978-2. 358 pp., more
In: Special Publication of the International Association of Sedimentologists. Blackwell: Oxford. ISSN 0141-3600; e-ISSN 2054-6610, more
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| Abstract |
It has long been suspected that some Louisiana tidal inlets occupy old distributary channels because they do not migrate significant distances alongshore. Historical information coupled with an intensive coring programme supports this contention for Quatre Bayou Pass (QBP), a tide-dominated inlet located in the microtidal Barataria Bight, Louisiana. Cat Bayou, a levee-bound distributary channel, was mapped on the east side of the QBP opening in 1842. Coincident with levee breeches prior to 1886, the backbarrier marsh became channelized producing more efficient conduits for Barataria Bay tidal flux.. By 1934, the Cat Bayou channel was largely abandoned and a narrow, meandering, 8-m deep channel was established on the west side of the inlet opening. Vibracores reveal that the thalweg of this inlet is anchored in place by erosion-resistant channel walls of a relict distributary. There was no core evidence that the channel had migrated to its new position. Apparent coastwise migration of the inlet thalweg is related to the degree of meander in the evacuated channel system. During transgression the inlet throat is resituated within the antecedent meander position. Subsurface recognition of this phenomenon requires identification of marine sediments filling a non-migratory channel that incises delta plain fades. |
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