Other
Scientific paper
Dec 2004
adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2004agufm.p13b..03z&link_type=abstract
American Geophysical Union, Fall Meeting 2004, abstract #P13B-03
Other
5410 Composition, 5415 Erosion And Weathering, 5470 Surface Materials And Properties, 5494 Instruments And Techniques
Scientific paper
The Alpha-Particle X-ray Spectrometers (APXS) are part of the instrument suites of both Mars Exploration Rovers, Spirit and Opportunity, which landed on Mars at Gusev crater and Meridiani Planum in the beginning of 2004. They are in-situ instruments for the determination of major and minor elements of soils, rocks, and outcrops. Soils at these landing sites are chemically characterized by high sulfur and chlorine contents, similar to soils at previous landing sites. Abundances of major and minor elements of all soils are very similar, strongly supporting the concept of global distribution and thorough mixing of soils on Mars. Locally, minor deviations from average soil composition are observed. These are attributed to the addition of local components to "global soil". In one trench at Gusev crater magnesium and sulfur concentrations increase with depth and give direct evidence for magnesium sulfate, possibly formed by weathering of olivine under acidic conditions, and local redistribution processes. Rocks at Gusev crater plains are primitive magnesium-rich basaltic rocks with normative olivine. They are coated to varying degrees with soil/dust and alteration rinds. Highly mobile elements are enriched in these outer layers. Outcrop materials at the base of the Colombia Hill site are possibly basaltic or volcaniclastic rocks. They are chemically highly altered as reflected by very high concentrations of water soluble elements (S, Cl, and Br), observed even after removal of a more than 8 mm thick surface layer. Apparently, the alteration extends to much greater depth. Outcrops at the Opportunity landing site were analyzed in Eagle crater and Endurance crater. These are light-toned sedimentary rocks of siliciclastic materials with up to 40 weight percent of sulfates. Based on mass balance calculations, in addition to Mg-sulfate and jarosite, other sulfates, e.g., Ca- and Al-bearing sulfates must be present. Outcrop rocks in Eagle crater are enriched in bromine relative to chlorine to varying degrees. Rocks in Endurance crater are stratigraphically layered sediments, possibly deposited under aqueous and aeolian conditions. The silicate to sulfate ratio of these units increases with depth. Vein fillings have high bromine concentrations. The chemical composition of rocks, soils and outcrops analyzed at both landing sites provides clear evidence for water-rock interaction and the presence of water over an extended period of time.
ACS Science Team
Zipfel Jutta
No associations
LandOfFree
Chemical Composition of Rocks and Soils at Gusev and Meridiani Landing Sites of the Mars Exploration Rovers: APXS Results and Implications. does not yet have a rating. At this time, there are no reviews or comments for this scientific paper.
If you have personal experience with Chemical Composition of Rocks and Soils at Gusev and Meridiani Landing Sites of the Mars Exploration Rovers: APXS Results and Implications., we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Chemical Composition of Rocks and Soils at Gusev and Meridiani Landing Sites of the Mars Exploration Rovers: APXS Results and Implications. will most certainly appreciate the feedback.
Profile ID: LFWR-SCP-O-1646840