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dc.contributor.advisorLaubach, Stephen E. (Stephen Ernest), 1955-en
dc.contributor.advisorEichhubl, Peteren
dc.creatorKaylor, Autumn Leighen
dc.date.accessioned2012-02-17T16:35:25Zen
dc.date.available2012-02-17T16:35:25Zen
dc.date.created2011-12en
dc.date.issued2012-02-17en
dc.date.submittedDecember 2011en
dc.identifier.urihttp://hdl.handle.net/2152/ETD-UT-2011-12-4453en
dc.descriptiontexten
dc.description.abstractOpening-mode fracture shapes are typically the result of brittle deformation and proportional growth in fracture height, length, and width. Based on the typical fracture shape, it is assumed that fracture tips are free to propagate in all directions. Some natural rock fractures have been shown to form as a result of slow non-elastic deformation processes. Such fractures may propagate to a finite length or height and accommodate further growth by aperture widening only. To determine the growth conditions of a fracture in the Triassic-Jurassic La Boca Formation of northeastern Mexico and to test fracture growth models, I combined fluid inclusion microthermometry and SEM-based cathodoluminescence cement texture analysis to determine the relative timing of fracture cement precipitation and related fracture opening for five samples collected along its trace. Fracture growth initiated at a minimum age of 70 Ma as two separate fractures with branching fracture tips that coalesced to a single continuous fracture under prograde burial conditions at a minimum age of 54 Ma. At this stage, fracture growth was accommodated by both propagation (i.e. increase in trace length) and by an increase in aperture during maximum burial and early exhumation. Samples collected at the fracture tips recorded temperatures reflecting fracture opening starting with maximum burial at a minimum age of 48 Ma at one tip and of 38 Ma at the other tip. Synkinematic fluid inclusions in crack-seal cement track continued fracture opening close to the fracture tips without a concurrent increase in trace length after 38 Ma until about 21 Ma. I attribute the observed change in fracture growth mechanism to a change in material response. The stage in aperture increase without propagation corresponds to an increase in elastic compliance or in non-elastic flow properties. Non-elastic flow can be attributed to solution-precipitation creep of the host rock. Dissolution of host quartz grains and subsequent quartz precipitation is consistent with the abundance of quartz fracture cement formed during exhumation. Cement textures from fractures in the La Boca Formation mimic those found in subsurface core, which allows application of the results to a variety of geologic environments.en
dc.format.mimetypeapplication/pdfen
dc.language.isoengen
dc.subjectFracture growthen
dc.subjectFluid inclusionen
dc.subjectDiagenesisen
dc.subjectCathodoluminescenceen
dc.subjectTriassicen
dc.subjectNortheastern Mexicoen
dc.subjectFracture cementen
dc.subjectLa Boca Formationen
dc.subjectQuartzen
dc.subjectJurassicen
dc.titleA fluid inclusion and cathodoluminescence approach to reconstruct fracture growth in the Triassic-Jurassic La Boca Formation, Northeastern Mexicoen
dc.date.updated2012-02-17T16:36:10Zen
dc.identifier.slug2152/ETD-UT-2011-12-4453en
dc.contributor.committeeMemberCatlos, Elizabethen
dc.contributor.committeeMemberKetcham, Richarden
dc.description.departmentGeological Sciencesen
dc.type.genrethesisen
thesis.degree.departmentGeological Sciencesen
thesis.degree.disciplineGeological Sciencesen
thesis.degree.grantorUniversity of Texas at Austinen
thesis.degree.levelMastersen
thesis.degree.nameMaster of Science in Geological Sciencesen


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