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dc.contributor.advisorDavis, George H.en_US
dc.contributor.authorAhlgren, Stephen G.
dc.date.accessioned2012-10-17T22:59:03Z
dc.date.available2012-10-17T22:59:03Z
dc.date.issued1999
dc.identifier.urihttp://hdl.handle.net/10150/249273
dc.description.abstractRiedel shear zones are geometric fault patterns commonly associated with strike-slip fault systems. The progressive evolution of natural Riedel shear zones within the Navajo Sandstone of southern Utah is interpreted from the spatial evolution of small-scale, incipient Proto-Riedel Zones (PRZs) to better-developed Riedel shear zones using field mapping and three-dimensional digital modeling. PRZs nucleate as a tabular zone of localized shearing marked by en èchelon deformation bands, each of which is no more than a few mm wide and tens of cm long, and oriented at 55° - 85° to the trend of the zone. With increasing strain, deformation bands and sedimentary markers are sheared ductily through granular flow and assume a sigmoidal form. The temporal and spatial evolution of bands comprising a Riedel shear zone suggests that PRZs nucleate as transitional-compactional deformation bands under localized, supra-lithostatic fluid pressure. Subsequent bands develop under modified regional stresses as conjugate shear fractures within the strain- hardened axis of the PRZ. These antithetic driven systems are not compatible with traditional synthetic driven models of Riedel shear zones. Unlike most synthetic driven examples, these antithetic driven systems are not controlled by preexisting "basement" structures, thus their geometries reflect a primary propagation or secondary passive deformation mechanism.
dc.language.isoen_USen_US
dc.publisherThe University of Arizona.en_US
dc.rightsCopyright © is held by the author. Digital access to this material is made possible by the Antevs Library, Department of Geosciences, and the University Libraries, University of Arizona. Further transmission, reproduction or presentation (such as public display or performance) of protected items is prohibited except with permission of the author or the department.en_US
dc.subjectCapitol Reef National Parken_US
dc.subjectclastic rocksen_US
dc.subjectColorado Plateauen_US
dc.subjectcompactionen_US
dc.subjectdeformationen_US
dc.subjectfaultsen_US
dc.subjectfoldsen_US
dc.subjectJurassicen_US
dc.subjectMesozoicen_US
dc.subjectNavajo Sandstoneen_US
dc.subjectporosityen_US
dc.subjectporous materialsen_US
dc.subjectRiedel shear zonesen_US
dc.subjectsandstoneen_US
dc.subjectsedimentary rocksen_US
dc.subjectshear zonesen_US
dc.subjectsouthern Utahen_US
dc.subjectstrike-slip faultsen_US
dc.subjecttectonicsen_US
dc.subjectUnited Statesen_US
dc.subjectUtahen_US
dc.titleThe Nucleation and Evolution of Riedel Shear Zones as Deformation Bands in Porous Sandstoneen_US
dc.typetexten_US
dc.typeThesis-Reproduction (electronic)en_US
dc.contributor.chairDavis, George H.en_US
thesis.degree.grantorUniversity of Arizonaen_US
thesis.degree.levelmastersen_US
dc.contributor.committeememberChase, Clement G.en_US
dc.contributor.committeememberDeCelles, Peter G.en_US
thesis.degree.disciplineGraduate Collegeen_US
thesis.degree.disciplineGeosciencesen_US
thesis.degree.nameM.S.en_US
dc.description.noteAntevs Libraryen_US
dc.description.collectioninformationThis item is part of the Geosciences Theses collection. It was digitized from a physical copy provided by the Antevs Library, Department of Geosciences, University of Arizona. For more information about items in this collection, please email the Antevs Library, antevs@geo.arizona.edu.en_US
dc.contributor.creatorAhlgren, Stephen G.en_US
dc.identifier.georef2001-055166
refterms.dateFOA2018-08-26T21:02:47Z
html.description.abstractRiedel shear zones are geometric fault patterns commonly associated with strike-slip fault systems. The progressive evolution of natural Riedel shear zones within the Navajo Sandstone of southern Utah is interpreted from the spatial evolution of small-scale, incipient Proto-Riedel Zones (PRZs) to better-developed Riedel shear zones using field mapping and three-dimensional digital modeling. PRZs nucleate as a tabular zone of localized shearing marked by en èchelon deformation bands, each of which is no more than a few mm wide and tens of cm long, and oriented at 55° - 85° to the trend of the zone. With increasing strain, deformation bands and sedimentary markers are sheared ductily through granular flow and assume a sigmoidal form. The temporal and spatial evolution of bands comprising a Riedel shear zone suggests that PRZs nucleate as transitional-compactional deformation bands under localized, supra-lithostatic fluid pressure. Subsequent bands develop under modified regional stresses as conjugate shear fractures within the strain- hardened axis of the PRZ. These antithetic driven systems are not compatible with traditional synthetic driven models of Riedel shear zones. Unlike most synthetic driven examples, these antithetic driven systems are not controlled by preexisting "basement" structures, thus their geometries reflect a primary propagation or secondary passive deformation mechanism.


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