Paleozoic Accretionary History of the North American Plate Margin (Central and Southern Appalachians): Constraints from the Age, Origin, and Distribution of Granitic Rocks

  1. John W. Hillhouse
  1. A. Krishna Sinha,
  2. Eric A. Hund and
  3. John P. Hogan

Published Online: 18 MAR 2013

DOI: 10.1029/GM050p0219

Deep Structure and Past Kinematics of Accreted Terranes

Deep Structure and Past Kinematics of Accreted Terranes

How to Cite

Sinha, A. K., Hund, E. A. and Hogan, J. P. (1989) Paleozoic Accretionary History of the North American Plate Margin (Central and Southern Appalachians): Constraints from the Age, Origin, and Distribution of Granitic Rocks, in Deep Structure and Past Kinematics of Accreted Terranes (ed J. W. Hillhouse), American Geophysical Union, Washington, D. C.. doi: 10.1029/GM050p0219

Author Information

  1. Department of Geological Sciences, Virginia Polytechnic Institute and State University, Blacksburg

Publication History

  1. Published Online: 18 MAR 2013
  2. Published Print: 1 JAN 1989

ISBN Information

Print ISBN: 9780875904542

Online ISBN: 9781118666609

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Keywords:

  • Geology, Structural—Congresses;
  • Geodynamics—Congresses;
  • Earth—Crust—Congresses

Summary

The relationship between generation of thermal anomalies (magmatism) and terrane accretion can be identified through spatial and temporal distribution of igneous rocks. Compositional variations observed within discrete magmatic provinces provide information about tectonic setting. The earliest Paleozoic magmatism (∼520–490 m.y.) is predominantly of tonalitic affinity and defines a continental margin island arc environment. Collapse of this magmatic arc (∼460–440 m.y.) and subsequent crustal thickening is recorded in the generation of magmas with primary epidote. The Silurian-Devonian (∼420–370 m.y.) is marked by parallel belts of plutonism. The peraluminous trondhjemitic plutons in the western overthrust terrane are modelled as being formed by delayed decompressional melting and not the result of a subduction process. Igneous activity in the Charlotte belt is trimodal (gabbro-granite-syenite) and is interpreted to be the result of transtensional environments created by strike-slip accretion of the Carolina Slate belt. The Permo-Carboniferous (∼330–270 m.y.) igneous activity is dominated by granite magmatism related to oblique subduction and closure of the proto-Atlantic ocean. New radiometric ages and chemistry of plutons presented here suggest that the Paleozoic thermal (magmatic) evolution of the central and southern Appalachians is consistent with amalgamation of at least three distinct plates over a 200 m.y. interval, while the compositional diversity in the nature of magmatism also records three distinct tectonic settings (convergent, tensional, overthrust).