Geology Commons^™

Electron Backscatter Diffraction Analysis Of Olivine In Ureilite Meteorites: Evaluation Of The Partially Magmatic Catastrophic Disruption Model Of The Ureilite Parent Body (Upb), James Karl Frye

Dissertations and Theses

Past studies of olivine have yielded insights into crystallographic slip systems and how they are activated thermally. Using this information in conjunction with Electron Backscatter Diffraction (EBSD) analysis and metrics developed for chondrites, I constrained the thermal environment and the cooling rate for four ureilite meteorites in an attempt to test the model of catastrophic disruption of the ureilite parent body while it was partly molten. Present evidence for deformation, along with thermal metrics, were examined in order to conclude the following: Deformation of the meteorites took place at high temperatures followed by swift cooling, leaving little time for annealing. …

Characterization And Interpretation Of Feldspathic Chromite Assemblages (Fcas) In Four Ordinary Chondrites: An Electron Backscatter Diffraction (Ebsd) Study, Kimberly Louisa Maccini

Dissertations and Theses

Feldspathic Chromite Assemblages (FCAs) are chemically distinctive assemblages rich in Na, Al, and Cr that are found in a variety of chondrites. They consist of concentrations of chromite associated mainly with feldspathic material, either feldspar or the glassy material known as maskelynite. Professor Alan Rubin (2003) has proposed that some FCAs formed by shock melting, but the origin of different types of feldspathic chromite assemblages are unclear and have not been studied with more modern techniques such as Electron Backscatter Electron Diffraction (EBSD).

Here EBSD was used to study FCAs in four metamorphosed ordinary chondrites of different shock stages, including …

Assessment Of Cluster Chondrite Accretion Temperature Using Electron Backscatter Diffraction And Implications For Chondrule Formation Models, Secana Portia Goudy

Dissertations and Theses

This thesis studies ordinary chondrites with cluster chondrite lithologies using electron backscatter diffraction so as to measure the temperatures of their olivine grains during deformation, for the purpose of constraining the accretion temperatures of cluster chondrites and creating new constraints on chondrule formation models. Samples analyzed with the technique are shock classified in this thesis as S1 and are type 3, so the deformation analyzed is interpreted to represent the temperatures of the chondrules during accretional deformation. It is found that the studied samples are primarily composed of chondrules at hot temperatures (>850°C) during deformation, mixed with a questionable …