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dc.contributor.advisorWalker, J. Douglas
dc.contributor.advisorStockli, Daniel F.
dc.contributor.authorBidgoli, Tandis S.
dc.date.accessioned2016-01-04T02:16:55Z
dc.date.available2016-01-04T02:16:55Z
dc.date.issued2014-08-31
dc.date.submitted2014
dc.identifier.otherhttp://dissertations.umi.com/ku:13589
dc.identifier.urihttp://hdl.handle.net/1808/19590
dc.description.abstractThe current form of the Pacific-North American plate boundary is the result of a complex evolution from a subduction zone to a transform boundary. Changes in the kinematics and dynamics of the plate boundary have predictable consequences for deformation within the central Basin and Range (CBR). However, uncertainties in the timing, magnitude, and spatial distribution of extension and later transtension have made reconstructions of Cenozoic intraplate deformation difficult. This study investigates the Cenozoic history of the CBR through a province-wide (U-Th)/He thermochronologic study of 16 fault-bounded ranges. Thermochronologic data are integrated with published geologic and structural data in order to determine a detailed history of extensional deformation in the region, and the timing and spatial progression of the transition to transtensional deformation. These data are used to address two main questions. (1) How closely in time do the structural style and fault kinematics of intraplate deformation match changes in plate motion? (2) If the timing is very different, either locally or regionally, are there other dynamic processes that must be considered during the Cenozoic tectonic evolution of the western U.S.? These questions are addressed in this dissertation by results presented in 5 chapters. Chapter 1 provides an introduction and the plate tectonic setting. Chapter 2 focuses on the timing of onset, magnitude of exhumation, and spatial distribution of strain associated with the Castle Cliffs, Tule Springs, and Mormon Peak detachments, three significant low-angle normal faults in the eastern part of the CBR. Chapter 3 evaluates the middle Miocene to recent exhumation history of the Slate Range, located in the southwestern part of the CBR. Chapter 4 uses low- to moderate-temperature thermochronology data to evaluate space-time patterns of Miocene to Pliocene strain within the Death Valley area and the geodynamic drivers of that deformation. Chapter 5 focuses on evidence and possible mechanisms for Late Cretaceous to early Cenozoic cooling over a large portion of the western CBR. Zircon and apatite (U-Th)/He cooling ages from this study suggest that Basin and Range extension initiated at the eastern edge of the CBR at ~18 Ma and migrated westward with time. Extension in the western part of the CBR is overprinted by distinctly younger episodes of cooling that signal the onset of transtension associated with the development of the eastern California shear zone. For areas west of Death Valley, the initiation of dextral transtension occurs simultaneously at 3-4 Ma, matching the inferred timing of lithospheric delamination in the central and southern Sierras. The results suggest that the Cenozoic pattern of strain reflects a progression from plate boundary kinematics to intraplate drivers like lithospheric delamination. This study also sheds light on the development of the Nevadaplano, a broad plateau in the hinterland of the Late Cretaceous to early Cenozoic Sevier retroarc fold-thrust belt. The new (U-Th)/He ages, combined with published thermochronology data, show that there are two distinct periods of pre-Miocene cooling that affect the western CBR and Mojave Desert. The first is a Late Cretaceous cooling event that may be related to widespread extension, crustal refrigeration, and/or erosion associated with Laramide flat-slab subduction. The second event corresponds to a pulse of exhumation during the Eocene that may be related to rapid erosion following major shifts in global climate. Collectively, the data suggest the rapid tectonic exhumation of the Nevadaplano occurred in the latest Cretaceous, whereas erosional beveling and stabilization of the plateau was dominantly an early to middle Eocene phenomenon related to a changing climate
dc.format.extent238 pages
dc.language.isoen
dc.publisherUniversity of Kansas
dc.rightsCopyright held by the author.
dc.subjectGeology
dc.subjectapatite
dc.subjectextension
dc.subjectthermochronology
dc.subjecttranstension
dc.subject(U-Th)/He
dc.subjectzircon
dc.titleLow-temperature thermochronometric constraints on Cenozoic intraplate deformation in the central Basin and Range
dc.typeDissertation
dc.contributor.cmtememberTaylor, Michael H.
dc.contributor.cmtememberMoeller, Andreas
dc.contributor.cmtememberStearns, Leigh
dc.contributor.cmtememberEgbert, Stephen
dc.thesis.degreeDisciplineGeology
dc.thesis.degreeLevelPh.D.
dc.rights.accessrightsopenAccess


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