Basaltic Rocks Analyzed by the Spirit Rover in Gusev Crater

Abstract

The Spirit landing site in Gusev Crater on Mars contains dark, fine-grained, vesicular rocks interpreted as lavas. Pancam and Mini-Thermal Emission Spectrometer (Mini-TES) spectra suggest that all of these rocks are similar but have variable coatings and dust mantles. Magnified images of brushed and abraded rock surfaces show alteration rinds and veins. Rock interiors contain Յ25% megacrysts. Chemical analyses of rocks by the Alpha Particle X-ray Spectrometer are consistent with picritic basalts, containing normative olivine, pyroxenes, plagioclase, and accessory FeTi oxides. Mössbauer, Pancam, and Mini-TES spectra confirm the presence of olivine, magnetite, and probably pyroxene. These basalts extend the known range of rock compositions composing the martian crust.Rocks at the Spirit landing site are finegrained with irregular vesicles and vugs, suggesting a volcanic origin. The rocks are angular and strewn across the surface, which suggests they were ejected from nearby Bonneville crater (1) by an impact event (2).Pancam and Mini-Thermal Emission Spectrometer (Mini-TES) spectra of rock surfaces indicate two end members, represented by dark-and light-toned rocks, with most rocks falling between these extremes. Three representative rocks, Adirondack, Humphrey, and Mazatzal, located several hundred meters apart, have been analyzed with the Athena instruments (3). Pancam images (4) show that Adirondack and Humphrey are partly coated and that Mazatzal is uniformly coated by light-toned material (Plates 9A, 10A, and 11A). Pancam spectra (Fig. 1) of the dark portions of Adirondack and Humphrey are consistent with the presence of olivine, which has a broad (composite) absorption band near 1000 nm. A weak band center near 930 nm suggests the presence of pyroxene or contamination by ferric oxides.The long-wavelength portion of Mini-TES spectra of dark rock surfaces resembles the Mars Global Surveyor (MGS)-TES spectra of

The evolution of a heterogeneous Martian mantle: Clues from K, P, Ti, Cr, and Ni variations in Gusev basalts and shergottite meteorites

“…In contrast to the shergottites, these basalts contain fewer conspicuous crystals (McSween et al, 2004;Squyres et al, 2006) and more likely represent primary melts (Monders et al, 2007) than accumulated crystal mushes. Alkali abundances are variable in Gusev basalts (from below detection limits to 1.2 wt.% K 2 O; McSween et al, 2006aMcSween et al, , 2006bMcSween et al, , 2008 over narrow ranges in SiO 2 and MgO concentrations (Fig.…”

“…Although relatively dust-free surfaces were examined, surface contamination is possible for these rock classes. Even so, we do not normalize APXS results of the basalts to relatively volatile-free compositions (0.3 wt.% SO 3 and no Cl) as has been convention set by McSween et al (2004;2006a;2006b) because all rocks have relatively low S and Cl concentrations (b3 wt.% SO 3 ). RATted rock interiors contain higher SO 3 (1-2 wt.%) than the renormalizing value of 0.3 wt.% and calculated S solubility (0.27-0.54 wt.% SO 3 ; Righter et al, 2009).…”

“…Over the last 5 years in Gusev Crater, the Mars Exploration Rover Spirit has encountered mainly volcanic rocks, including diverse, relatively unaltered basaltic lavas first, in the Gusev Plains and later, in the Columbia Hills McSween et al, 2004McSween et al, , 2006aMcSween et al, , 2006b. Major and minor element compositions of rock surfaces (abraded, brushed, and "as is") were determined by APXS (Table 1).…”

Quantitative compositional analysis of martian mafic regions using the MEx/OMEGA reflectance data 1. Methodology, uncertainties and examples of application

“…Previous remote sensing and in situ measurements indicate that the mafic regions are dominantly basaltic, composed mostly of feldspar and pyroxene (Bandfield et al, 2000;Hamilton et al, 2001;McSween et al, 2004McSween et al, , 2006aMcSween et al, , 2006b. Two major divisions in crustal composition were recognized on the basis of their Thermal InfraRed (TIR) spectral signatures obtained by the Mars Global Surveyor / Thermal Emission Spectrometer (TES) instrument (Bandfield et al, 2000): 1) Surface Type 1, which occurs primarily in the southern highlands, and 2) Surface Type 2, which is found primarily in the northern lowlands.…”

Assessing extraterrestrial regolith material simulants for in-situ resource utilisation based 3D printing

“…the Moon, Mars etc. ), that would function autonomously and utilise indigenous materials as feedstock [8][9][10][11]. Previous studies have demonstrated that the application of a Powder Bed Fusion 3D printing process can manufacture structures/components from multi component ceramics that closely simulate Lunar and Martian regolith [12,13].…”