Premium
Absence of olivine orientation fabric in highly shocked Martian dunite
Author(s) -
Tkalcec B. J.,
Brenker F. E.
Publication year - 2019
Publication title -
meteoritics and planetary science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.09
H-Index - 100
eISSN - 1945-5100
pISSN - 1086-9379
DOI - 10.1111/maps.13204
Subject(s) - olivine , meteorite , electron backscatter diffraction , geology , parent body , achondrite , orientation (vector space) , martian , shock (circulatory) , geochemistry , mineralogy , materials science , astrobiology , chondrite , mars exploration program , composite material , geometry , microstructure , physics , mathematics , medicine
Shock is often given as the cause for many observations in meteorites due to the assumed previous exposure of most meteorites to at least one impact event that ultimately led to their ejection from their parent body. Here we present electron backscatter diffraction ( EBSD ) results on a substantially shocked dunitic achondrite, chassignite Northwest Africa ( NWA ) 8694, and question the general culpability of shock exposure for the formation of preferred orientation fabrics of meteoritic olivine crystals. Despite the ubiquitous presence of substantial shock indicators, the EBSD results for NWA 8694 reveal an absence of preferred orientation of olivine crystals, displaying instead an overall random fabric. We propose that the passage of shock waves through olivine crystals within a solid, crystalline, dunitic rock does not produce an overall preferred orientation, nor is it likely to actively form a whole‐rock random fabric but instead has likely no bearing on the formation of olivine orientation fabrics.