Mesozoic basin development beneath the southeastern US coastal plain: evidence from new COCORP profiling
New COCORP profiling on the Georgia coastal plain indicates that the Triassic/Early Jurassic South Georgia basin is a composite feature, which includes several large half-grabens separated by intervening regions where the Triassic/Early Jurassic section is much thinner. Two half-grabens imaged on the profiles have apparent widths of 125 and 40 km, and at their deepest points contain about 5 km of basin fill. Both basins are bounded on their south flanks by major normal faults that dip moderately steeply toward the north, and are disrupted internally by subsidiary normal faults within the basin fill sequences. The orientation of the main basin-bounding faults suggests that they might have reactivated Paleozoic south-vergent structures formed on the south side of the Alleghenian suture. Evolution of the South Georgia basin appears to follow a model of initial, rapid rifting followed by flexural subsidence. The major episode of normal faulting, and hence extension, within the South Georgia basin occurred prior to extrusion of an areally extensive sequence of Early Jurassic basalt flows. This sequence is traceable across most of the width of the South Georgia basin in western Georgia, and may extend as far east as offshore South Carolina. Jurassic strata above the basalt horizon are notably less faulted and accumulated within a broadly subsiding basin that thins both to the north and south. The occurrence of the basalt relatively late in the rift sequence supports the hypothesis that the southeastern US may have been a major area of incipient spreading after Pangea had begun to separate.
- Research Organization:
- Cornell Univ., Ithaca, NY (USA)
- OSTI ID:
- 6197805
- 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
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Related Subjects
GEORGIA
SEDIMENTARY BASINS
GEOLOGIC FAULTS
SEISMIC SURVEYS
STRATIGRAPHY
BASALT
COASTAL REGIONS
GEOLOGIC HISTORY
GEOLOGIC MODELS
JURASSIC PERIOD
PLATE TECTONICS
RIFT ZONES
TRIASSIC PERIOD
FEDERAL REGION IV
GEOLOGIC AGES
GEOLOGIC FRACTURES
GEOLOGIC STRUCTURES
GEOLOGY
GEOPHYSICAL SURVEYS
IGNEOUS ROCKS
MESOZOIC ERA
NORTH AMERICA
ROCKS
SURVEYS
TECTONICS
USA
VOLCANIC ROCKS
580201* - Geophysics- Seismology & Tectonics- (1980-1989)
580100 - Geology & Hydrology- (-1989)