Sponsor
Portland State University. Department of Geology
First Advisor
Alex M. Ruzicka
Date of Publication
Fall 12-8-2014
Document Type
Thesis
Degree Name
Master of Science (M.S.) in Geology
Department
Geology
Language
English
Subjects
Chondrites (Meteorites) -- Inclusions -- Analysis, Meteorites -- Analysis, Solar system -- Origin -- Research
DOI
10.15760/etd.2069
Physical Description
1 online resource (v, 161 pages)
Abstract
Our inventory of material from the early solar system includes large, igneous-textured inclusions in O chondrites, whose origin and relationship to their host meteorite is unclear. These inclusions occur in approximately 4% of O chondrites, and are mineralogically, petrographically, and chemically diverse. Petrographic and chemical data from 29 inclusions from 23 host meteorites were collected with optical light and scanning electron microscopy, allowing for the determination of major phase modal abundance and major element bulk chemistry. No correlation between any inclusion property and host meteorite type were found, but some trends were observed. Nine of the inclusions show strong evidence, such as radial variations in texture and chemistry, for having crystallized as a free-floating droplet in a space environment, and may share the same formation process as chondrules. One inclusion is almost certainly shock-melted material that intruded into the host material. Thirteen inclusions have bulk chemistry patterns that suggest the material was vapor fractionated; the remaining sixteen are essentially chondritic, i.e., unfractionated. Broadly, the data support the conclusions of Ruzicka et al. (1998, 2000), which divided large inclusions into Na-poor (vapor fractionated) and Na-rich (unfractionated) groups, suggesting at least two different origins. There is no evidence that any of the inclusions studied formed by igneous differentiation.
Rights
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Persistent Identifier
http://archives.pdx.edu/ds/psu/13163
Recommended Citation
Armstrong, Katherine, "Chemical and Petrographic Survey of Large, Igneous-Textured Inclusions in Ordinary Chondrites" (2014). Dissertations and Theses. Paper 2070.
https://doi.org/10.15760/etd.2069