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GEOREF RECORD

Structural evolution of folded thrusts and duplexes on a first-order anticlinorium in the Valley and Ridge Province of Pennsylvania

Richard P. Nickelsen
Structural evolution of folded thrusts and duplexes on a first-order anticlinorium in the Valley and Ridge Province of Pennsylvania (in Geometries and mechanism of thrusting, with special reference to the Appalachians, Gautam Mitra (editor) and Steven F. Wojtal (editor))
Special Paper - Geological Society of America (1988) 222: 89-106

Abstract

The Jacks Mountain anticlinorium is a high, continuous structure in the Pennsylvania Valley and Ridge Province midway between the Blue Mountain and Allegheny structural fronts. Evolution of its northwest limb proceeded through a number of structural stages that may be characteristic of the first-order anticlines of the middle Appalachians. Prior to major folding, faults rising to the northwest off the proposed Antes-Coburn detachment developed in sequence as the Stone Mountain duplex, the Bearpen Hollow thrust and the Potlicker Flat thrust, all cutting Silurian rocks. These were later passively folded to northwest dips during growth of the anticlinorium above the contracting and imbricating Cambro-Ordovician duplex. The northwest limb near the Stone Mountain duplex underwent later-stage layer-parallel extension and steep out-of-sequence reverse or strike-slip faulting, which were caused by the larger amounts of limb rotation and fold flattening at this part of the anticlinorium. Faults associated with this later event have mineralized pressure-solved breccias, suggesting that different deformation conditions prevailed. Evaluation of the poorly exposed Antes-Cobura detachment has not provided structural evidence of a systematic transport direction, but allows interpretation of this zone as both an early floor thrust for imbricates rising to the northwest into overlying Silurian rocks and a later boundary zone between parts of the stratigraphic section undergoing unequal layer-parallel shortening.


ISSN: 0072-1077
EISSN: 2331-219X
Coden: GSAPAZ
Serial Title: Special Paper - Geological Society of America
Serial Volume: 222
Title: Structural evolution of folded thrusts and duplexes on a first-order anticlinorium in the Valley and Ridge Province of Pennsylvania
Title: Geometries and mechanism of thrusting, with special reference to the Appalachians
Author(s): Nickelsen, Richard P.
Author(s): Mitra, Gautameditor
Author(s): Wojtal, Steven F.editor
Affiliation: Bucknell Univ., Dep. Geol., Lewisburg, PA, United States
Affiliation: Univ. Rochester, Dep. Geol. Sci., Rochester, NY, United States
Pages: 89-106
Published: 1988
Text Language: English
Publisher: Geological Society of America (GSA), Boulder, CO, United States
ISBN: 0-8137-2222-5
References: 27
Accession Number: 1989-011618
Categories: Structural geology
Document Type: Serial
Bibliographic Level: Analytic
N39°43'00" - N42°17'60", W80°31'60" - W74°40'00"
Secondary Affiliation: Oberlin Coll., USA, United States
Country of Publication: United States
Secondary Affiliation: GeoRef, Copyright 2017, American Geosciences Institute.
Update Code: 1989
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