Remanent magnetization in angrite NWA 4931
Name
1028749980-MIT.pdf
Description
Full printable version
Size
2.81 MB
Format
Adobe PDF
Checksum (MD5)
f77095c6a714cacdf37f6c43c10a3347
Author(s)
Berdahl, James Scott
Advisor(s)
Benjamin Weiss.
Date Issued
2008
Publisher
Massachusetts Institute of Technology
Abstract
Angrites are among the oldest known rocks and may record planetesimal dynamo activity and protoplanetary disk fields in the early solar system. Towards this goal, the natural remanent magnetism and its origin were examined in newly discovered angrite NWA 4931. Measurements were conducted on subsamples cut from various distances along a drilled core sample of the meteorite. The samples were then progressively demagnetized to isolate primary magnetization from contaminant overprints and to calculate paleofield intensity. Dust produced during the subsampling process was analyzed to determine that the mineralogical source of the magnetism was magnetite. Analyses of fusion crusted and adjacent samples showed that the exterior of the meteorite had been contaminated by a collector's hand magnet. However, the interior of the core yielded a pristine record, indicative of a paleointensity strength on the order of 25 [mu]T. These results, in light of magnetic measurements on other angrite samples, are suggestive of a core dynamo active for at least seven million years on the angrite parent body, beginning by 4564 Ma.
Description
Thesis: S.B. in Geoscience, Massachusetts Institute of Technology, Department of Earth, Atmospheric, and Planetary Sciences, 2008.
Cataloged from PDF version of thesis.
Includes bibliographical references (pages 26-27).
Subjects
Earth, Atmospheric, and Planetary Sciences.
MIT Department
Massachusetts Institute of Technology. Department of Earth, Atmospheric, and Planetary Sciences
Terms of Use
MIT theses are protected by copyright. They may be viewed, downloaded, or printed from this source but further reproduction or distribution in any format is prohibited without written permission.
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