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The tectono-thermal evolution of the Central Appalachian Orogen; accretion of a peri-Gondwanan(?) Ordovician arc

Howell Bosbyshell, LeeAnn Srogi, Gale C. Blackmer, William S. Schenck, Ryan Mathur and Victor Valencia
The tectono-thermal evolution of the Central Appalachian Orogen; accretion of a peri-Gondwanan(?) Ordovician arc (in Tripping from the fall line; field excursions for the GSA annual meeting, Baltimore 2015, David K. Brezinski (editor), Jeffrey P. Halka (editor) and Richard A. Ortt (editor))
Field Guide (Geological Society of America) (2015) 40: 35-59

Abstract

Recent detrital zircon results in both the central Appalachians and New England demonstrate that middle Ordovician, "Taconic" island arcs, long considered to be peri-Laurentian, are built upon or associated with rock of Gondwanan affinity. This trip will visit granulite-facies orthogneiss of the Wilmington Complex, a 475-480 Ma magmatic arc, and the adjacent Wissahickon Formation. The Wissahickon Formation is intruded by and interlayered with meta-igneous rocks with arc affinity and contains detrital zircon populations characteristic of both Gondwanan and Laurentian sources. The Chester Park Gneiss, now known to have detrital zircon age spectra which match the Gondwana-derived Moretown Terrane in New England, is also featured. The trip will examine contact relationships between arc and Laurentian rocks and a newly discovered location where metapelitic rock contains garnet with crystallographically oriented rutile inclusions, possibly indicative of ultrahigh-temperature or ultrahigh-pressure metamorphism. We will discuss similarities between rocks of the central and northern Appalachians and evaluate a new model wherein the central Appalachian rocks were originally part of the Taconic arc in New England and were translated by strike-slip deformation to their present position in the orogen.


ISSN: 2333-0937
EISSN: 2333-0945
Serial Title: Field Guide (Geological Society of America)
Serial Volume: 40
Title: The tectono-thermal evolution of the Central Appalachian Orogen; accretion of a peri-Gondwanan(?) Ordovician arc
Title: Tripping from the fall line; field excursions for the GSA annual meeting, Baltimore 2015
Author(s): Bosbyshell, HowellSrogi, LeeAnnBlackmer, Gale C.Schenck, William S.Mathur, RyanValencia, Victor
Author(s): Brezinski, David K.editor
Author(s): Halka, Jeffrey P.editor
Author(s): Ortt, Richard A., Jr.editor
Affiliation: West Chester University, Department of Geology & Astronomy, West Chester, PA, United States
Affiliation: Maryland Geological Survey, Baltimore, MD, United States
Pages: 35-59
Published: 2015
Text Language: English
Publisher: Geological Society of America, Boulder, CO, United States
References: 120
Accession Number: 2016-007656
Categories: Structural geologyIgneous and metamorphic petrology
Document Type: Serial
Bibliographic Level: Analytic
Illustration Description: illus. incl. 3 tables, geol. sketch maps
N39°42'00" - N40°04'60", W75°30'00" - W75°12'00"
Secondary Affiliation: Pennsylvania Geological Survey, USA, United StatesDelaware Geological Survey, USA, United StatesJuniata College, USA, United StatesWashington State University, USA, United States
Country of Publication: United States
Secondary Affiliation: GeoRef, Copyright 2017, American Geosciences Institute.
Update Code: 201604
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