Can the magmatic conditions of the Martian nakhlites be discerned via
investigation of clinopyroxene and olivine crystallographic
Deformation is a near ubiquitous process that is observed within nearly
all naturally forming rocks, terrestrial and extra-terrestrial. Large
area electron backscatter diffraction (EBSD) is a technique that enables
slip-systems (a form of plastic deformation) to be inferred at a
comparable scale to representative texture analysis (≥100 crystals).
Extensive laboratory and studies on naturally occurring samples have
identified preferential extrinsic parameters for specific slip-system
signatures within olivine and clinopyroxene for mantle conditions.
Slip-systems in both olivine and augite (high Ca-clinopyroxene) for 21
large area EBSD datasets sourced from 16 different Martian nakhlite
meteorites were analysed and assessed against these parameters. When
investigating the high and low deformation regions within the samples 10
of the 21 sections exhibited a shift in the slip-system patterns between
the low and high deformation regions. The secondary signatures
identified within the low deformation regions are inferred to relate to
emplacement deformation. Thus, these samples exhibit both shock and
emplacement signatures. The observed variations in deformation patterns
for the two main regimes of deformation indicate heterogeneous sampling
of the nakhlite ejecta crater. Our findings indicate that shock
deformation is prevalent throughout the nakhlites, and that great care
needs to be taken when interpreting slip-deformation of crystals within
apparent lower deformation regions.