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DOI	10.1306/04282017325
	Documenting the geometry and magnitude of shortening at the Allegheny Front: Lycoming County; Pennsylvania; United States
	Ace A.; McQuarrie N.; Sak P.B.; Grundy R.; Lavergne B.
发表日期	2020
ISSN	0149-1423
起始页码	2379
结束页码	2399
卷号	104 期号:11
英文摘要	Based on limited geophysical and outcrop data, shortening of the strata in the Appalachian Plateau above the Silurian salt detachment was interpreted to have occurred by layer-parallel shortening (LPS) plus gentle folding. Recently acquired high-quality, three-dimensional seismic reflection and well data reveal that strata from the Silurian Salina Group and the Devonian Marcellus Shale shortened through a variety of macroscale mechanisms in the Appalachian Plateau region of Lycoming County, Pennsylvania. Geometries evident in the seismic reflection profiles and repeated stratigraphy in gamma-ray log surveys indicate north- and south-dipping wedge-style thrust faults with offsets ranging from 60 to 550 m (195 to 1800 ft). Through kinematically restored and balanced cross sections, we show that the 10%-15% LPS calculated from the rocks exposed at the surface of the Appalachian Plateau is equal to the magnitude of interpreted macroscale shortening in the Silurian-Lower Devonian units immediately above the Silurian Salina Group. Previously collected seismic reflection profiles extending south of the Nittany anticlinorium into the Valley and Ridge reveal wedge-style thrust faulting in Ordovician through Silurian units and wedging of the northernmost horses (a volume of rock completely enclosed by thrust faults) of the Cambrian-Ordovician duplex of the fold-thrust belt under the southern plateau edge. These structures allow us to interpret a pathway of triangle zones (a combination of two thrusts with the same detachment and with opposing vergence such that they form a triangular zone) that transfer slip from the basal decollement in the Cambrian Waynesboro Formation to the overlying Ordovician Reedsville detachment and then to the Silurian salt detachment in the Appalachian Plateau. Copyright © 2020. The American Association of Petroleum Geologists. All rights reserved.
英文关键词	Gamma rays; Radioactivity logging; Seismic waves; Seismology; Stratigraphy; Balanced cross sections; Fold-thrust belts; Layer parallel shortenings; Marcellus shales; Seismic reflection profiles; Seismic reflections; Thrust faulting; Valley and Ridge; Faulting; crustal shortening; decollement; detachment fault; Devonian; duplex; folding; geometry; geophysical method; magnitude; outcrop; Silurian; stratigraphy; Allegheny Front; Appalachian Plateau; Lycoming County; Pennsylvania; United States; West Virginia; Equidae; Salina
语种	英语
来源期刊	AAPG Bulletin
文献类型	期刊论文
条目标识符	http://gcip.llas.ac.cn/handle/2XKMVOVA/168682
作者单位	Department of Geology and Environmental Science, University of Pittsburgh, Pittsburgh, PA, United States; Department of Earth Sciences, Dickinson College, Carlisle, PA, United States; Earth and Environmental Systems Institute, Pennsylvania State University, State CollegePA, United States; Inflection Energy LLC, Denver, CO, United States
推荐引用方式 GB/T 7714	Ace A.,McQuarrie N.,Sak P.B.,et al. Documenting the geometry and magnitude of shortening at the Allegheny Front: Lycoming County; Pennsylvania; United States[J],2020,104(11).
APA	Ace A.,McQuarrie N.,Sak P.B.,Grundy R.,&Lavergne B..(2020).Documenting the geometry and magnitude of shortening at the Allegheny Front: Lycoming County; Pennsylvania; United States.AAPG Bulletin,104(11).
MLA	Ace A.,et al."Documenting the geometry and magnitude of shortening at the Allegheny Front: Lycoming County; Pennsylvania; United States".AAPG Bulletin 104.11(2020).