Barrier island evolution and reworking by inlet migration along the Mississippi-Alabama gulf coast
- Univ. of New Orleans, LA (USA)
The five barrier islands along the Mississippi-Alabama coast are located 10 to 14 mi (16 to 23 km) offshore and separate Mississippi Sound from the Gulf of Mexico. The barrier islands in the chain are, from east to west: Dauphin Island, Petit Bois Island, Horn Island, Ship Island, and Cat Island. The islands are low sand bodies situated on a relatively broad Holocene sand platform that extends 70 mi (113 km) from Dauphin Island on the east to Cat Island on the west. The platform varies in thickness from 25 to 75 ft (7.6 to 23 m) and rests on Holocene marine clays or on Pleistocene sediments. The barrier island chain predates the St. Bernard lobe of the Mississippi delta complex, which began to prograde about 3,000 years ago, and continued until it was abandoned approximately 1,500 years ago. In contrast to the other islands, Cat Island at the western down-drift end of the Mississippi-Alabama barrier island chain is characterized by more than 12 prominent east west-oriented progradational linear ridges. The ridge system of Cat Island is interpreted as a relict of an earlier stage in the life cycle of the barrier platform when there was a more robust littoral drift system and an abundant sediment supply During the Pre-St. Bernard Delta period of vigorous sedimentation, all of the islands in the barrier chain probably exhibited progradational ridges similar to those now found only on Cat Island. Presently, only vestigial traces of these progradational features remain on the islands to the east of Cat Island. Unlike Cat Island, which has been protected and preserved by the St. Bernard Delta, the other barrier islands have been modified and reworked during the past 1,500 years by processes of island and tidal inlet migration, accompanied by a general weakening of the littoral drift and a reduction of the available sediment supply.
- OSTI ID:
- 5835529
- Report Number(s):
- CONF-9010204-; CODEN: AABUD
- Journal Information:
- AAPG Bulletin (American Association of Petroleum Geologists); (USA), Vol. 74:9; Conference: Gulf Coast Association of Geological Societies and Gulf Coast Section of SEPM (Society of Economics, Paleontologists, and Mineralogist) meeting, Lafayette, LA (USA), 17-19 Oct 1990; ISSN 0149-1423
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
GULF COAST
GEOMORPHOLOGY
ISLANDS
ALABAMA
ALLUVIAL DEPOSITS
CLAYS
GULF OF MEXICO
MIGRATION
MISSISSIPPI
QUATERNARY PERIOD
REDUCTION
RIFT ZONES
SAND
SEDIMENTATION
SEDIMENTS
ATLANTIC OCEAN
CARIBBEAN SEA
CENOZOIC ERA
CHEMICAL REACTIONS
FEDERAL REGION IV
GEOLOGIC AGES
GEOLOGIC DEPOSITS
GEOLOGIC STRUCTURES
GEOLOGY
NORTH AMERICA
SEAS
SURFACE WATERS
USA
580000* - Geosciences