The role of shear heating in producing crystal-poor obsidian Public Deposited

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  • March 22, 2019
Creator
  • Curry, Adam Charles
    • Affiliation: College of Arts and Sciences, Department of Geological Sciences
Abstract
  • The reasons for obsidian's lack of phenocrysts (2 vol%) contain plagioclase and sanidine but sometimes lack quartz. Crystal-poor samples contain dominantly rounded phenocrysts indicative of resorption, whereas phenocrysts in crystal-rich samples contain sharp, defined corners. Thermal models of ascending, high-silica magma were run using COMSOL Multiphysics to assess temperature increases caused by shear heating, which could potentially resorb crystals. Models show large (>300 K) temperature increases at the conduit edges capable of resorbing crystals. Though model dike geometry is unrealistic, obsidian mineralogy and thermal modeling are consistent with shear heating-induced resorption during ascent of high-silica magmas.
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  • In Copyright
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  • Includes one supplemental Excel file.
Advisor
  • Glazner, Allen F.
Degree
  • Master of Science
Graduation year
  • 2013
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