Searching for the source regions of martian meteorites using MGS TES: Integrating martian meteorites into the global distribution of igneous materials on Mars

Abstract

Abstract-The objective of this study was to identify and map possible source regions for all 5 known martian meteorite lithologies (basalt, lherzolite, clinopyroxenite, orthopyroxenite, and dunite) using data from the Mars Global Surveyor Thermal Emission Spectrometer (MGS TES). We deconvolved the TES data set using laboratory spectra of 6 martian meteorites (Los Angeles, Zagami, ALH A77005, Nakhla, ALH 84001, and Chassigny) as end members, along with atmospheric and surface spectra previously derived from TES data. Global maps (16 pixels/degree) of the distribution of each meteorite end member show that meteorite-like compositions are not present at or above TES detectability limits over most of the planet's dust-free regions. However, we have confidently identified local-scale (100s-1000s km 2 ) concentrations of olivine-and orthopyroxene-bearing materials similar to ALH A77005, Chassigny, and ALH 84001 in Nili Fossae, in and near Ganges Chasma, in the Argyre and Hellas basin rims, and in Eos Chasma. Nakhla-like materials are identified near the detection limit throughout the eastern Valles Marineris region and portions of Syrtis Major. Basaltic shergottites were not detected in any spatially coherent areas at the scale of this study. Martian meteorite-like lithologies represent only a minor portion of the dust-free surface and, thus, are not representative of the bulk composition of the ancient crust. Meteorite-like spectral signatures identified above TES detectability limits in more spatially restricted areas (<tens of km) are targets of ongoing analysis.

Basalt weathering rates on Earth and the duration of liquid water on the plains of Gusev Crater, Mars

“…Mineral compositions on Mars range from intermediate to ferroan olivine and intermediate to calcic plagioclase (Bandfield, 2002;McSween et al, 2004). Both high and low Ca pyroxenes have been detected (Mustard et al, 1997;Hamilton et al, 2003;Bibring et al, 2005;McSween et al, 2006). Glass of a basaltic andesite composition, documented in a Martian meteorite (Greshake et al, 2004), would dissolve only slightly more slowly than the basalt glass dissolution line on Figure 2.…”

The SNC meteorites: basaltic igneous processes on Mars

“…The basaltic and andesitic-like signatures dominate the surface of Mars with only relatively minor olivine-rich or haematite-rich areas. However, Hamilton et al (2000Hamilton et al ( , 2003 and Bibring & Erard (2001) noted that the basaltic TES spectra do not closely match those of the shergottites. Furthermore, Wyatt & McSween (2002) and Wyatt et al (2004) modified the deconvolution mineralogy, significantly decreasing the estimated feldspar in both terrane types.…”

“…Peridotitic shergottites may have crystallized in situ as plutonic or intrusive material at deeper crustal levels. Hamilton et al (2003) reported the results of a search using TES data for spectral signatures close to those of the SNC types. Although some olivine-and orthopyroxene-rich areas were identified, no fits to the laboratory SNC spectra were found.…”

Color imaging of Mars by the High Resolution Imaging Science Experiment (HiRISE)

“…13). This spectrally diverse area of Mars has been mapped in detail using previously available orbital spectral and visible datasets, and has become well known for both its mafic (Hamilton et al, 2003;Hoefen et al, 2003;Hamilton and Christensen, 2005;Tornabene et al, 2008) and hydrated silicate mineral diversity (Mangold et al, Table 3 Laboratory mineral spectra used in study. See Fig.…”