Reported middle Paleozoic fossils and new geochronological data from the southern and central Appalachians: Disposable outrageous hypothesis or justification for major revision of tectonic history
- Univ. of Tennessee, Knoxville, TN (United States). Dept. of Geological Sciences Oak Ridge National Lab., TN (United States)
Recently published interpretations of fossil fragments from the Walden Creek Group (Ocoee Supergroup) suggesting that these rocks are middle Paleozoic (Devonian to Early Carboniferous), and new geochronological data that yield late Paleozoic age dates on rocks and major faults in the Blue Ridge and piedmont, if taken alone, would permit speculation that most of the deformation and metamorphism affecting this part of the orogen is Alleghanian. The two Ordovician clastic wedges (Sevier, Llanvirn, and Martinsburg, Caradoc-Ashgill) and the Carboniferous-Permian wedge(s), along with many radiometric ages on plutons, indicate uplift and sediment dispersal from the interior of the southern and central Appalachians (SCA) that may have resulted from Taconian and Alleghanian deformation. Combining the reproducible fossil evidence, including that from Alabama and a recently discovered crinoid fragment from the upper part of the Murphy belt sequence, with the most current geochronological data requires that peak metamorphism and penetrative deformation be at least Devonian or younger at the southwestern end of the orogen, and Late Ordovician or younger in the Carolinas and northern Georgia. Zircon ages reported from large thrust and dextral strike-slip faults bounding the Pine Mountain window indicate all of the faults there may be Alleghanian, except the younger sinistral Mesozoic faults, and requires that both metamorphism and penetrative deformation there also be Alleghanian. As in New England, the southern Appalachian Alleghanian metamorphic core is now known to be much more extensive. The older data require that the Taconian and perhaps the Acadian orogenies were significant events in the SCA, but these new data reconfirm the dominance of Alleghanian continent-continent collision processes here.
- OSTI ID:
- 5879444
- Report Number(s):
- CONF-9303211-; CODEN: GAAPBC
- Journal Information:
- Geological Society of America, Abstracts with Programs; (United States), Vol. 25:2; Conference: 28. annual Geological Society of America (GSA) Northeastern Section meeting, Burlington, VT (United States), 22-24 Mar 1993; ISSN 0016-7592
- Country of Publication:
- United States
- Language:
- English
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Age and position of the sedimentary basin of the Ocoee Supergroup western Blue Ridge tectonic province, southern Appalachians
Related Subjects
APPALACHIAN MOUNTAINS
GEOLOGIC HISTORY
GEOLOGY
ALABAMA
FOSSILS
GEOLOGIC DEPOSITS
GEOLOGIC FAULTS
GEOLOGIC FORMATIONS
ISOTOPE DATING
NORTH CAROLINA
ORIGIN
OROGENESIS
PALEONTOLOGY
PLATE TECTONICS
SOUTH CAROLINA
AGE ESTIMATION
DEVELOPED COUNTRIES
GEOLOGIC FRACTURES
GEOLOGIC STRUCTURES
MOUNTAINS
NORTH AMERICA
TECTONICS
USA
580000* - Geosciences