Mesozoic Tectonic Evolution of the Pamir: An Analysis of the Structural Style, Magnitude, and Timing of Crustal Shortening and Terrane Accretion

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dc.contributor.advisorRobinson, Alexander C.
dc.contributor.committeeMemberLapen, Thomas J.
dc.contributor.committeeMemberMurphy, Michael A.
dc.contributor.committeeMemberImrecke, Daniel B.
dc.creatorVillarreal, Dustin P. 1986-
dc.creator.orcid0000-0002-0954-2338
dc.date.accessioned2019-12-17T03:28:17Z
dc.date.createdDecember 2019
dc.date.issued2019-12
dc.date.submittedDecember 2019
dc.date.updated2019-12-17T03:28:17Z
dc.description.abstractThe timing for suturing of Gondwanan crustal fragments and the magnitude and timing of subsequent upper crustal deformation in the Pamir Mountains are not well resolved. To investigate these issues, I conducted three studies. First, to address the timing of terrane accretion, a provenance analysis of clastic deposits within the Southern Pamir was done. The clastic deposits are the Late Triassic Rhaetian Lokzun Group Flysch and the Early Jurassic Darbasatash Group that have well-constrained stratigraphic ages and lie directly below and above the angular unconformity, respectively. Petrographic results and U-Pb analysis for both successions suggest sediment was sourced from the Northern Pamir’s Permian–Triassic Karakul-Mazar accretionary arc complex, which indicates accretion occurred by the end of the Triassic. Second, it has commonly been suggested that the Tanymas fault accommodated Cenozoic convergence between India and Asia. However, this interpretation is due in large part to uncertainty of ages associated with the Tanymas fault. Mapping of deposits in the footwall of the Tanymas thrust fault and ages from detrital zircon U-Pb analysis, Muscovite 40Ar/39Ar ages, and zircon fission track analysis show that the deposits are related to shortening (syn-orogenic) and are Early-mid Cretaceous. This age for displacement along the Tanymas fault is similar to what has been documented along the Rushan-Pshart suture and in the fold and thrust belt of the Southern Pamir. Third, the Southern Pamir Fold and Thrust Belt has been suggested to have accommodated ~50 km of upper crustal shortening and has recently been interpreted to be Cretaceous in age. Through geologic mapping and forward modeling of the fold and thrust belt, we suggest that only ~4.25 km (~7.5%) of upper crustal shortening has been accommodated within the fold and thrust belt, significantly lowering the amount of upper crustal shortening in the Southern Pamir. The modeling results also suggests that the fold and thrust belt is both propagating and verging to the south. These results imply that the Northern Pamir was elevated and thickened prior to accretion of the Gondwana terranes and that upper crustal shortening within the Central Pamir and Southern Pamir was the result of Cretaceous retroarc deformation.
dc.description.departmentEarth and Atmospheric Sciences, Department of
dc.format.digitalOriginborn digital
dc.format.mimetypeapplication/pdf
dc.identifier.urihttps://hdl.handle.net/10657/5551
dc.language.isoeng
dc.rightsThe author of this work is the copyright owner. UH Libraries and the Texas Digital Library have their permission to store and provide access to this work. Further transmission, reproduction, or presentation of this work is prohibited except with permission of the author(s).
dc.subjectPamir
dc.subjectCimmerian
dc.subjectGondwana
dc.subjectTanymas
dc.subjectPaleotethys
dc.titleMesozoic Tectonic Evolution of the Pamir: An Analysis of the Structural Style, Magnitude, and Timing of Crustal Shortening and Terrane Accretion
dc.type.dcmiText
dc.type.genreThesis
local.embargo.lift2021-12-01
local.embargo.terms2021-12-01
thesis.degree.collegeCollege of Natural Sciences and Mathematics
thesis.degree.departmentEarth and Atmospheric Sciences, Department of
thesis.degree.disciplineGeology
thesis.degree.grantorUniversity of Houston
thesis.degree.levelDoctoral
thesis.degree.nameDoctor of Philosophy

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