Preservation of coastal stratigraphy during the Holocene transgression, southwest Louisiana continental shelf
Compiled curves for the Gulf of Mexico show that sea level during the Holocene transgression rose continuously at varying rates on a scale of several thousand years. Within this primary variability, shorter term oscillations of sea level are indicated by the existence of multiple preserved depositional and erosional features on the southwest Louisiana continental shelf, recognizable on high resolution seismic reflection profiles. During the late Wisconsinan withdrawal, fluvial-deltaic systems extended themselves across the exposed continental shelf, ultimately reaching of the shelf margin. Initial transgression resulted in the eroding of a wave cut terrace from -100 to -70 m, a cypress stump from the northern edge of which was dated at 11,170 +/- 110 years B.P., and creating a composite fluvial system within pre-existing Late Wisconsinan stream channels. Resumed transgression reworked the Pleistocene deltaic sediments into a series of east-west trending sandy shoal deposits, each representing still stand positions. Several of these shoals are associated with east-west oriented lagoonal systems established in the submerged fluvial channels. Repeated erosion by the transgressing shoreface and reduced sediment supply caused by the eastward shift of the Mississippi depocenter has resulted in the subaqueous exposure of Pleistocene sediments being the sandy shoals and estuarine deposits. As sea level approached its present position, an early Holocene lobe of the Mississippi delta was deposited in the area. Its subsequent abandonment and reworking has produced a stratigraphic sequence resembling that on the outer shelf.
- Research Organization:
- Louisiana Geological Survey, Baton Rouge (USA)
- OSTI ID:
- 6273946
- Report Number(s):
- CONF-8510489-
- Journal Information:
- Geol. Soc. Am., Abstr. Programs; (United States), Vol. 17; Conference: 98. annual meeting of the Geological Society of America, Orlando, FL, USA, 28 Oct 1985
- Country of Publication:
- United States
- Language:
- English
Similar Records
The variety of shelf sand bodies within the transgressive systems tract as illustrated by the high-resolution sequence stratigraphy of Late Wisconsin/Holocene deposits from the continental shelf of Texas
Sedimentation and seismic stratigraphy of Sable Island Bank
Related Subjects
CONTINENTAL SHELF
SEDIMENTARY ROCKS
STRATIGRAPHY
LOUISIANA
DEPOSITION
EROSION
GEOLOGIC HISTORY
QUATERNARY PERIOD
SEA LEVEL
SEDIMENTS
SEISMIC SURVEYS
VARIATIONS
CENOZOIC ERA
CONTINENTAL MARGIN
FEDERAL REGION VI
GEOLOGIC AGES
GEOLOGY
GEOPHYSICAL SURVEYS
LEVELS
NORTH AMERICA
ROCKS
SURVEYS
USA
580100* - Geology & Hydrology- (-1989)