The Meso-Cenozoic deformation history of Thailand and Myanmar; insights from calcite U-Pb and apatite fission track thermochronology

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dc.contributor.authorSimpson, A. D. W.
dc.contributor.schoolSchool of Physical Sciencesen
dc.coverage.spatialThailand, Myanmar
dc.date.issued2018
dc.descriptionThis item is only available electronically.en
dc.description.abstractGiven the absence of suitable dating methods, the timing of low-temperature crustal deformation is usually established by indirect methods (such as apatite fission track (AFT) thermochronology). Few studies have previously ventured into directly constraining the absolute timing of brittle deformation (such as authigenic illite dating). U-Pb dating of calcite in tectonic veins represents a new method to potentially directly date brittle deformation events (Roberts and Walker, 2016). By utilising this method in combination with apatite U-Pb and fission track thermochronology, this study sheds new light on the upper crustal deformation history of Thailand and Myanmar. U-Pb calcite ages demonstrate tectonic activity at ~216-209Ma in the Khao Kwang Fold and Thrust Belt associated with the Indosinian stage 2 collision between the Sibumasu Block and the Indochina Block. Brittle deformation along the Three Pagodas Fault Zone (TPFZ) was dated at ~45Ma and ~24Ma (and possibly as recently as ~1.3Ma). AFT thermochronology suggests exhumation in the Tin province of southern Myanmar at ~26Ma-18Ma. These dates are in agreement with previous regional AFT studies in Thailand and with calcite U-Pb dates for the TPFZ, suggesting fault reactivation in response to the India-Eurasia collision and rifting in the Andaman Sea. Calcite U-Pb ages were obtained with uncertainties as low as ~1%, which is an unprecedented precision for the timing of brittle deformation. This work further demonstrates that calcite elemental mapping, in combination with U-Pb dating, can be used to distinguish different calcite growth events. Particularly enrichments in Mn or depletions in LREE concentrations in calcite seem useful to distinguish different fluids and associated calcite (re)crystallisation events. Although further work is required to enhance our understanding of both Pb diffusion in calcite as well as geochemical tracers for calcite recrystallization, the combination of calcite U-Pb with apatite fission track thermochronology is a promising novel tool to enhance our understanding of the timing of brittle deformation.en
dc.description.dissertationThesis (B.Sc.(Hons)) -- University of Adelaide, School of Physical Sciences, 2018
dc.identifier.urihttps://hdl.handle.net/2440/133682
dc.language.isoenen
dc.provenanceThis electronic version is made publicly available by the University of Adelaide in accordance with its open access policy for student theses. Copyright in this thesis remains with the author. This thesis may incorporate third party material which has been used by the author pursuant to Fair Dealing exceptions. If you are the author of this thesis and do not wish it to be made publicly available, or you are the owner of any included third party copyright material you wish to be removed from this electronic version, please complete the take down form located at: http://www.adelaide.edu.au/legalsen
dc.subjectHonours; Geology; calcite; apatite; geochronology; Thailand; Myanmar; U-Pb dating; Khao Kwang Fold Thrust Belt; Three Pagodas Fault Zone; tin provinceen
dc.titleThe Meso-Cenozoic deformation history of Thailand and Myanmar; insights from calcite U-Pb and apatite fission track thermochronologyen
dc.typeThesisen

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