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Title: Pre-Mesozoic terranes and the tectonic framework of the Gulf Coastal Plain

Abstract

Pre-Mesozoic rocks beneath the Gulf Coastal Plain reflect the late Precambrian (Pc)-Cambrian (Cb) rifted continental margin and the late Paleozoic Appalachian-Ouachita orogen (AOO). The AL promontory of Pc continental crust is bounded by a NW-striking transform margin (AL-OK transform) and a NE-striking rifted margin (southern Blue Ridge rift). Terrane accretion during the AOO differed markedly on the orthogonal adjacent sides of the AL promontory (ALp). Late Paleozoic compressional fabrics and terrane-boundary sutures, as well as extensional fabrics of the older rifted margin, influenced the geometry of Mesozoic extension and opening of the Gulf of Mexico. Along the SW side of the ALp, arc-continent collision resulted in accretion of an arc and subduction complex onto the margin of N American crust. The Ouachita allochthon includes off-shelf passive-margin rocks in an accretionary prism and synorogenic turbidites that represent a forearc basin and trench. Carbonate-shelf strata of the N American passive margin remained in place beneath the Ouachita allochthon. Along the southeast side of the ALp, passive-margin carbonate-shelf rocks are imbricated in the Appalachian thrust belt and bordered by an internal metamorphic belt of accreted terranes; both are underlain by relatively shallow Pc basement. The SE-dipping Suwannee-Wiggins suture terminates the shallow continental crust,more » truncates previously accreted terranes, and forms the boundary between N America and the Suwannee terrane. Mesozoic extensional structures include NE-and NW-striking fault systems. A NE-striking Triassic graben overlies the Suwannee-Wiggins suture, suggesting that Mesozoic extension used the Late Paleozoic compressional fabric of the suture. A NW-striking system of Triassic fault-bounded basins coincides with the trace of the Cb AL-OK transform fault, suggesting that the older crustal boundary controlled the location of a Mesozoic transform/transfer fault system.« less

Authors:
 [1]
  1. Univ. of Kentucky, Lexington, KY (United States). Dept. of Geological Sciences
Publication Date:
OSTI Identifier:
6077511
Report Number(s):
CONF-9304188-
Journal ID: ISSN 0016-7592; CODEN: GAAPBC
Resource Type:
Conference
Journal Name:
Geological Society of America, Abstracts with Programs; (United States)
Additional Journal Information:
Journal Volume: 25:4; Conference: 42. annual Geological Society of America (GSA) Southeastern Section meeting, Tallahassee, FL (United States), 1-2 Apr 1993; Journal ID: ISSN 0016-7592
Country of Publication:
United States
Language:
English
Subject:
58 GEOSCIENCES; CONTINENTAL CRUST; TECTONICS; US GULF COAST; GEOLOGIC FAULTS; GEOLOGIC STRUCTURES; MESOZOIC ERA; OROGENESIS; RIFT ZONES; SUBDUCTION ZONES; DEVELOPED COUNTRIES; EARTH CRUST; GEOLOGIC AGES; GEOLOGIC FRACTURES; NORTH AMERICA; USA; 580000* - Geosciences

Citation Formats

Thomas, W A. Pre-Mesozoic terranes and the tectonic framework of the Gulf Coastal Plain. United States: N. p., 1993. Web.
Thomas, W A. Pre-Mesozoic terranes and the tectonic framework of the Gulf Coastal Plain. United States.
Thomas, W A. Mon . "Pre-Mesozoic terranes and the tectonic framework of the Gulf Coastal Plain". United States.
@article{osti_6077511,
title = {Pre-Mesozoic terranes and the tectonic framework of the Gulf Coastal Plain},
author = {Thomas, W A},
abstractNote = {Pre-Mesozoic rocks beneath the Gulf Coastal Plain reflect the late Precambrian (Pc)-Cambrian (Cb) rifted continental margin and the late Paleozoic Appalachian-Ouachita orogen (AOO). The AL promontory of Pc continental crust is bounded by a NW-striking transform margin (AL-OK transform) and a NE-striking rifted margin (southern Blue Ridge rift). Terrane accretion during the AOO differed markedly on the orthogonal adjacent sides of the AL promontory (ALp). Late Paleozoic compressional fabrics and terrane-boundary sutures, as well as extensional fabrics of the older rifted margin, influenced the geometry of Mesozoic extension and opening of the Gulf of Mexico. Along the SW side of the ALp, arc-continent collision resulted in accretion of an arc and subduction complex onto the margin of N American crust. The Ouachita allochthon includes off-shelf passive-margin rocks in an accretionary prism and synorogenic turbidites that represent a forearc basin and trench. Carbonate-shelf strata of the N American passive margin remained in place beneath the Ouachita allochthon. Along the southeast side of the ALp, passive-margin carbonate-shelf rocks are imbricated in the Appalachian thrust belt and bordered by an internal metamorphic belt of accreted terranes; both are underlain by relatively shallow Pc basement. The SE-dipping Suwannee-Wiggins suture terminates the shallow continental crust, truncates previously accreted terranes, and forms the boundary between N America and the Suwannee terrane. Mesozoic extensional structures include NE-and NW-striking fault systems. A NE-striking Triassic graben overlies the Suwannee-Wiggins suture, suggesting that Mesozoic extension used the Late Paleozoic compressional fabric of the suture. A NW-striking system of Triassic fault-bounded basins coincides with the trace of the Cb AL-OK transform fault, suggesting that the older crustal boundary controlled the location of a Mesozoic transform/transfer fault system.},
doi = {},
url = {https://www.osti.gov/biblio/6077511}, journal = {Geological Society of America, Abstracts with Programs; (United States)},
issn = {0016-7592},
number = ,
volume = 25:4,
place = {United States},
year = {1993},
month = {3}
}

Conference:
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