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Title: Thermal and tectonic evolution of the central and southern Appalachians: evidence from distribution, age, and origin of granitic rocks

Abstract

The distribution and resolution of thermal events and associated igneous activity can discriminate between tectonic processes that form orogenic terrains, i.e., accretion of terranes, overthrusting of terranes versus thrust stacking within terranes. Reinterpretation of regional tectonics (Higgins et al., 1984) coupled with the authors interpretation of the age, origin, and distribution of granitic rocks suggest a very different mechanism for the evolution of the central and southern Appalachian orogenic belt. The Cambro-Ordovician magmatic arc (weakly bimodal) separated from the North American Margin by a Back arc basin, was thrust over the North American plate margin during the middle Ordovician. The Avalon terrane (Little River allochthon of Higgins et al., 1984) arrived during the late Silurian - but unlike earlier models that require subduction zone related with its arrival, the authors postulate strike-slip tectonics. The gabbro-diorite-syenite association in the Charlotte belt (Macon melange of Higgins) is probably related to grabens associated with the strike-slip accretion. Rocks of similar age (Siluro-Devonian) in the present day Blue Ridge and Inner Piedmont blocks are related to decompressional melting after the Ordovician thrusting. The high pressure metamorphism and associated melting show a range in ages indicating variations in uplift rates or thickness of the crustmore » caused by the initial overthrusting, and do not require a discrete subduction or orogenic event. The Permo-Carboniferous igneous activity, and associated uplift and thrusting with a strike-slip component are related to oblique subduction and post-subduction collision processes.« less

Authors:
; ; ;
Publication Date:
Research Org.:
Virginia Polytechnic Institute and State Univ., Blackburg (USA)
OSTI Identifier:
6070579
Report Number(s):
CONF-8510489-
Journal ID: CODEN: GAAPB
Resource Type:
Conference
Journal Name:
Geol. Soc. Am., Abstr. Programs; (United States)
Additional Journal Information:
Journal Volume: 17; Conference: 98. annual meeting of the Geological Society of America, Orlando, FL, USA, 28 Oct 1985
Country of Publication:
United States
Language:
English
Subject:
58 GEOSCIENCES; APPALACHIAN MOUNTAINS; OROGENESIS; PLATE TECTONICS; GRANITES; PETROGENESIS; AGE ESTIMATION; CAMBRIAN PERIOD; GEOLOGIC FAULTS; GEOLOGIC HISTORY; GEOLOGIC MODELS; MAGMATISM; METAMORPHISM; NORTH CAROLINA; ORDOVICIAN PERIOD; SUBDUCTION ZONES; VIRGINIA; FEDERAL REGION III; FEDERAL REGION IV; GEOLOGIC AGES; GEOLOGIC FRACTURES; GEOLOGIC STRUCTURES; IGNEOUS ROCKS; MOUNTAINS; NORTH AMERICA; PALEOZOIC ERA; PLUTONIC ROCKS; ROCKS; TECTONICS; USA; 580201* - Geophysics- Seismology & Tectonics- (1980-1989); 580300 - Mineralogy, Petrology, & Rock Mechanics- (-1989)

Citation Formats

Sinha, A K, Guy, R, Hund, E, and Tamburro, E. Thermal and tectonic evolution of the central and southern Appalachians: evidence from distribution, age, and origin of granitic rocks. United States: N. p., 1985. Web.
Sinha, A K, Guy, R, Hund, E, & Tamburro, E. Thermal and tectonic evolution of the central and southern Appalachians: evidence from distribution, age, and origin of granitic rocks. United States.
Sinha, A K, Guy, R, Hund, E, and Tamburro, E. Tue . "Thermal and tectonic evolution of the central and southern Appalachians: evidence from distribution, age, and origin of granitic rocks". United States.
@article{osti_6070579,
title = {Thermal and tectonic evolution of the central and southern Appalachians: evidence from distribution, age, and origin of granitic rocks},
author = {Sinha, A K and Guy, R and Hund, E and Tamburro, E},
abstractNote = {The distribution and resolution of thermal events and associated igneous activity can discriminate between tectonic processes that form orogenic terrains, i.e., accretion of terranes, overthrusting of terranes versus thrust stacking within terranes. Reinterpretation of regional tectonics (Higgins et al., 1984) coupled with the authors interpretation of the age, origin, and distribution of granitic rocks suggest a very different mechanism for the evolution of the central and southern Appalachian orogenic belt. The Cambro-Ordovician magmatic arc (weakly bimodal) separated from the North American Margin by a Back arc basin, was thrust over the North American plate margin during the middle Ordovician. The Avalon terrane (Little River allochthon of Higgins et al., 1984) arrived during the late Silurian - but unlike earlier models that require subduction zone related with its arrival, the authors postulate strike-slip tectonics. The gabbro-diorite-syenite association in the Charlotte belt (Macon melange of Higgins) is probably related to grabens associated with the strike-slip accretion. Rocks of similar age (Siluro-Devonian) in the present day Blue Ridge and Inner Piedmont blocks are related to decompressional melting after the Ordovician thrusting. The high pressure metamorphism and associated melting show a range in ages indicating variations in uplift rates or thickness of the crust caused by the initial overthrusting, and do not require a discrete subduction or orogenic event. The Permo-Carboniferous igneous activity, and associated uplift and thrusting with a strike-slip component are related to oblique subduction and post-subduction collision processes.},
doi = {},
url = {https://www.osti.gov/biblio/6070579}, journal = {Geol. Soc. Am., Abstr. Programs; (United States)},
number = ,
volume = 17,
place = {United States},
year = {1985},
month = {1}
}

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