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The AAPG/Datapages Combined Publications Database

AAPG Bulletin


Volume: 63 (1979)

Issue: 9. (September)

First Page: 1579

Last Page: 1579

Title: Eastern Projection of Valley and Ridge Beneath Metamorphic Sequences of Appalachian Orogene: ABSTRACT

Author(s): Leonard D. Harris, Kenneth C. Bayer

Article Type: Meeting abstract


Surface and subsurface data from parts of the Appalachian Plateau, Valley and Ridge, Blue Ridge, Piedmont, and the continental shelf indicate that the Appalachian orogene is a broader feature than heretofore suggested. The orogene appears to form a continuous northeast-trending structural belt from Georgia to Canada, whose east-west dimension includes the area from the continental shelf to the limit of thrusting in the Appalachian Plateau. Seismic reflection data suggest that the entire southern part of the orogene is underlain by an eastward-dipping subhorizontal master decollement zone. Thus, the structural style of the orogene is dominated by subhorizontal thrusts that are characteristic of thin-skinned tectonics. Within the orogene, from Canada to Georgia, displacemen on subhorizontal thrusts has moved eugeosynclinal sequences (metamorphic and igneous rocks) tens of kilometers westward, burying thick sequences (4,500 to 10,500 m) of Paleozoic miogeosynclinal rocks. Limited seismic data in North Carolina and Georgia suggest that miogeosynclinal sequences project eastward in the subsurface beneath thrust plates of eugeosynclinal rocks for at least 65 km. If the eastward projection of miogeosynclinal rocks in the subsurface of North Carolina and Georgia is representative of the entire Appalachian orogene, there may be a concealed belt of Paleozoic miogeosynclinal rocks on the order of the present length and width of the Valley and Ridge. Future exploration programs for hydrocarbons within the Appalachian orogene should give careful consideration to this vast untested and unknown area.

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