Sign on

SAO/NASA ADS Astronomy Abstract Service

· Find Similar Abstracts (with default settings below)
· Electronic Refereed Journal Article (HTML)
· Full Refereed Journal Article (PDF/Postscript)
· Full Refereed Scanned Article (GIF)
· Also-Read Articles (Reads History)
·
· Translate This Page
Title:
Mineralogy, petrology, and shock history of lunar meteorite Sayh al Uhaymir 300: A crystalline impact-melt breccia
Authors:
Hudgins, J. A.; Walton, E. L.; Spray, J. G.
Publication:
Meteoritics & Planetary Science, vol. 42, Issue 10, p.1763-1779
Publication Date:
00/2007
Origin:
ADS
Bibliographic Code:
2007M&PS...42.1763H

Abstract

Sayh al Uhaymir (SaU) 300 comprises a microcrystalline igneous matrix (grain size <10 μm), dominated by plagioclase, pyroxene, and olivine. Pyroxene geothermometry indicates that the matrix crystallized at ˜1100 °C. The matrix encloses mineral and lithic clasts that record the effects of variable levels of shock. Mineral clasts include plagioclase, low- and high-Ca pyroxene, pigeonite, and olivine. Minor amounts of ilmenite, FeNi metal, chromite, and a silica phase are also present. A variety of lithic clast types are observed, including glassy impact melts, impact-melt breccias, and metamorphosed impact melts. One clast of granulitic breccia was also noted. A lunar origin for SaU 300 is supported by the composition of the plagioclase (average An95), the high Cr content in olivine, the lack of hydrous phases, and the Fe/Mn ratio of mafic minerals. Both matrix and clasts have been locally overprinted by shock veins and melt pockets. SaU 300 has previously been described as an anorthositic regolith breccia with basaltic components and a granulitic matrix, but we here interpret it to be a polymict crystalline impact-melt breccia with an olivine-rich anorthositic norite bulk composition. The varying shock states of the mineral and lithic clasts suggest that they were shocked to between 5-28 GPa (shock stages S1-S2) by impact events in target rocks prior to their inclusion in the matrix. Formation of the igneous matrix requires a minimum shock pressure of 60 GPa (shock stage >S4). The association of maskelynite with melt pockets and shock veins indicates a subsequent, local 28-45 GPa (shock stage S2-S3) excursion, which was probably responsible for lofting the sample from the lunar surface. Subsequent fracturing is attributed to atmospheric entry and probable breakup of the parent meteor.

Printing Options

Print whole paper
Print Page(s) through

Return 600 dpi PDF to Acrobat/Browser. Different resolutions (200 or 600 dpi), formats (Postscript, PDF, etc), page sizes (US Letter, European A4, etc), and compression (gzip,compress,none) can be set through the Printing Preferences


More Article Retrieval Options

HELP for Article Retrieval
Bibtex entry for this abstract   Preferred format for this abstract (see Preferences)
   

Find Similar Abstracts:

Use: Authors
Title
Abstract Text
Return: Query Results Return    items starting with number
Query Form
Database: Astronomy
Physics
arXiv e-prints