Joints and decollement zones in Middle Devonian shales. Evidence for multiple deformation events in the central Appalachian Plateau

Journal Article · Fri Apr 01 04:00:00 EST 1994 · Geological Society of America, Bulletin; (United States)

DOI:https://doi.org/10.1130/0016-7606(1994)106<0447:JADCZI>2.3.CO;2· OSTI ID:7015919

Evans, M A ^[1]

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1. Georgia Southern Univ., Statesboro, GA (United States)

Fractures in oriented Middle Devonian shale cores from the Appalachian Plateau province provide evidence for multiple deformation events associated with the Alleghanian orogeny, post-orogenic stress relaxation, and neotectonic ( ) stresses. The orientation, distribution, and mineral paragenesis of these fractures are used to establish the timing, regional extent, and stress orientation of each deformation event. During the Alleghanian orogeny, the Middle Devonian shale section was a regional decollement zone in the central Appalachian Plateau province. The decollement extends from the Appalachian Structural Front to northwestern Pennsylvania and east-central Ohio. It is defined by abundant joints, veins, and slick-ensided fractures localized within multiple zones of organic-rich brown and black shale. These zones are distributed over tens to hundreds of meters of the Middle Devonian shale section. The shale cores record a continuous counterclockwise rotation of the maximum compressive stress direction in the west-central Appalachians during the Alleghanian orogeny. Three stages are recognized. 68 refs., 10 figs., 3 tabs.

• OSTI ID: 7015919
• Journal Information: Geological Society of America, Bulletin; (United States), Journal Name: Geological Society of America, Bulletin; (United States) Vol. 106:4; ISSN 0016-7606; ISSN BUGMAF
• Country of Publication: United States
• Language: English

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