Source and dispersal of silt on northern Gulf of Mexico continental shelf
The surficial sediment on the continental shelf of the northern Gulf of Mexico is characterized by abundant silty clay which was deposited during the late Pleistocene lowstand and reworked during and after the Holocene transgression. The purposes of this study were to determine the sources of the silt fraction in this surficial sediment by quartz grain roundness and surface texture analysis, and to determine the effects of modern shelf currents upon the distribution of silt. Areal variations in quartz grain roundness and surface texture define six silt provinces on the northern Gulf of Mexico continental shelf. The Mississippi province is the largest province and stretches from the Chandeleur Islands to Matagorda Bay. It is characterized by a mixture of rounded grains that were derived from the sedimentary rocks of the Gulf coastal plain and the Mid-Continent, and angular, fractured grains that were derived from glacial deposits in the northern United States. A comparison of the areal distribution of these six provinces with the late Pleistocene paleogeography of the continental shelf shows evidence for varying degrees of shore-parallel transport of silt by modern shelf currents.
- OSTI ID:
- 5924338
- Report Number(s):
- CONF-880301-
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
020200* -- Petroleum-- Reserves
Geology
& Exploration
ATLANTIC OCEAN
CARIBBEAN SEA
CONTINENTAL MARGIN
CONTINENTAL SHELF
CRYSTAL STRUCTURE
CURRENTS
GEOLOGIC DEPOSITS
GRAIN BOUNDARIES
GULF OF MEXICO
MICROSTRUCTURE
ORIGIN
ROCKS
SEAS
SEDIMENTARY ROCKS
SILT
SITE CHARACTERIZATION
SURFACE WATERS
WATER CURRENTS