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Title: 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

Abstract

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 sinistralmore » 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.« less

Authors:
 [1]
  1. Univ. of Tennessee, Knoxville, TN (United States). Dept. of Geological Sciences Oak Ridge National Lab., TN (United States)
Publication Date:
OSTI Identifier:
5879444
Report Number(s):
CONF-9303211-
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: 25:2; Conference: 28. annual Geological Society of America (GSA) Northeastern Section meeting, Burlington, VT (United States), 22-24 Mar 1993; Journal ID: ISSN 0016-7592
Country of Publication:
United States
Language:
English
Subject:
58 GEOSCIENCES; 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

Citation Formats

Hatcher, Jr, R D. 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. United States: N. p., 1993. Web.
Hatcher, Jr, R D. 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. United States.
Hatcher, Jr, R D. 1993. "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". United States.
@article{osti_5879444,
title = {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},
author = {Hatcher, Jr, R D},
abstractNote = {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.},
doi = {},
url = {https://www.osti.gov/biblio/5879444}, journal = {Geological Society of America, Abstracts with Programs; (United States)},
issn = {0016-7592},
number = ,
volume = 25:2,
place = {United States},
year = {Mon Mar 01 00:00:00 EST 1993},
month = {Mon Mar 01 00:00:00 EST 1993}
}

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