Stratigraphy and tectonic development of the southern Ouachita thrust belt - implications of new subsurface data, Arkansas
Recent drilling in southwest Arkansas has provided new constraints on the age, facies and tectonics of the buried Southern Ouachita thrust belt. Results are consistent with Pennsylvanian collision of the North American craton with an island arc/continental fragment via a south-dipping subduction zone. Reprocessing of the Ouachita COCORP seismic line further supports this geometry. Ouachita facies rocks south of the Benton Uplift consist of deformed Mississippian and Lower Morrowan clastics deposited in a forearc basin setting. Early to middle Ordovician flora found in core and cuttings suggest reworking and sourcing from an older terrane. A transgressive sequence up to 4500' thick that ranges from marginal marine clastics to open marine carbonates overlies the thrust belt. This sequence is significantly different from time-equivalent rocks of the Frontal Ouachitas where the Atoka consists of 15-20,000' of turbidites that have been involved in thrusting. This indicates that the Ouachita orogeny terminated much earlier to the south than to the north. Palynological analysis from this post-orogenic section identified marine acritarchs and scolecodonts with South American affinities. Their presence suggests deposition south of the North American craton on an exotic basement complex with both a northern and southern provenance. A remnant of this exotic southern terrane apparently remained attached to the North American craton following Triassic rifting and the opening of the Gulf of Mexico.
- Research Organization:
- Arco Exploration Company, Denver, CO (USA)
- OSTI ID:
- 6462071
- Report Number(s):
- CONF-8510489-
- Journal Information:
- Geol. Soc. Am., Abstr. Programs; (United States), Journal Name: Geol. Soc. Am., Abstr. Programs; (United States) Vol. 17; ISSN GAAPB
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
580201* -- Geophysics-- Seismology & Tectonics-- (1980-1989)
ARKANSAS
DRILLING
EXPLORATORY WELLS
FEDERAL REGION VI
GEOLOGIC FAULTS
GEOLOGIC FRACTURES
GEOLOGIC STRUCTURES
GEOLOGY
GEOMETRY
MATHEMATICS
NORTH AMERICA
OROGENESIS
PALYNOLOGY
PLATE TECTONICS
STRATIGRAPHY
SUBDUCTION ZONES
TECTONICS
USA
WELL DRILLING
WELLS