NASA Logo

NTRS

NTRS - NASA Technical Reports Server

Back to Results
Mineralogical Comparison of Olivine in Shergottites and A Shocked L Chondrite: Implications for Shock Histories of Brown OlivineMost Martian meteorites are heavily shocked, exhibiting numerous shock features, for example undulatory extinction of olivine and pyroxene, the presence of diaplectic glass ("maskelynite") and the formation of shock melt. Among these shock features, olivine darkening ("brown" olivine) is unique in Martian meteorites because no other meteorite group shows such a feature. Although the presence of brown olivine in shergottites was reported thirty years ago, detailed observation by TEM has not been performed until the NWA 2737 chassignite was discovered, whose olivine is darkened, being completely black in hand specimen. Fe metal nano-particles were found in NWA 2737 olivine which are considered to have been formed by olivine reduction during heavy shock. Subsequently, magnetite nano-particles were also found in other Martian meteorites and the coexistence of Fe metal and magnetite nano-particles was reported in the NWA 1950 shergottite and some Fe metal nano-particles were mantled by magnetite. Therefore, the formation process of nano-particles seems to be complex. Because "brown" olivine is unique to Martian meteorites, they have a potential to constrain their shock conditions. In order to better understand the shock history of Martian meteorites, we compared olivine in several shergottites with that in a highly-shocked L chondrite which contains ringwoodite.
Document ID
20150001926
Acquisition Source
Johnson Space Center
Document Type
Conference Paper
Authors
Takenouchi, A.
(Tokyo Univ. Hongo, Japan)
Mikouchi, T.
(Tokyo Univ. Hongo, Japan)
Yamaguchi, A.
(National Inst. of Polar Research Tokyo, Japan)
Zolensky, M. E.
(NASA Johnson Space Center Houston, TX, United States)
Date Acquired
February 23, 2015
Publication Date
March 16, 2015
Subject Category
Lunar And Planetary Science And Exploration
Report/Patent Number
JSC-CN-32786
Meeting Information
Meeting: Lunar and Planetary Science Conference
Location: The Woodlands, TX
Country: United States
Start Date: March 16, 2015
End Date: March 20, 2015
Sponsors: NASA Headquarters, Lunar and Planetary Inst., Universities Space Research Association
Distribution Limits
Public
Copyright
Public Use Permitted.
No Preview Available