The Opportunity Rover's Athena Science Investigation at Meridiani Planum, Mars

• Published in: Science (American Association for the Advancement of Science) Vol. 306; no. 5702; pp. 1698 - 1703
• Main Authors: Squyres, S. W., Arvidson, R. E., Bell, J. F., Brückner, J., Cabrol, N. A., Calvin, W., Carr, M. H., Christensen, P. R., Clark, B. C., Crumpler, L., D. J. Des Marais, d'Uston, C., Economou, T., Farmer, J., Farrand, W., Folkner, W., Golombek, M., Gorevan, S., Grant, J. A., Greeley, R., Grotzinger, J., Haskin, L., Herkenhoff, K. E., Hviid, S., Johnson, J., Klingelhöfer, G., Knoll, A. H., Landis, G., Lemmon, M., Li, R., Madsen, M. B., Malin, M. C., McLennan, S. M., McSween, H. Y., Ming, D. W., Moersch, J., Morris, R. V., Parker, T., Rice, J. W., Richter, L., Rieder, R., Sims, M., Smith, M., Smith, P., Soderblom, L. A., Sullivan, R., Wänke, H., Wdowiak, T., Wolff, M., Yen, A.
• Format: Journal Article
• Language: English
• Published: Johnson Space Center American Association for the Advancement of Science 03-12-2004; The American Association for the Advancement of Science
• Subjects: Atmosphere; Basaltic soils; Discovery and exploration; Evidence; Evolution, Planetary; Extraterrestrial Environment; Ferric Compounds; Geologic Sediments; Hematite; Impact craters; Landing sites; Lunar And Planetary Science And Exploration; Mars; Mars (Planet); Mars probes; Mineralogy; Minerals; Opportunities; Outcrops; Research Articles and Reports; Rocks; Sand; Sediments; Silicates; Soil composition; Soil salts; Soils; Spacecraft; Topography; Water; Wind; United States
• ISSN: 0036-8075; 1095-9203
• DOI: 10.1126/science.1106171

The Mars Exploration Rover Opportunity has investigated the landing site in Eagle crater and the nearby plains within Meridiani Planum. The soils consist of fine-grained basaltic sand and a surface lag of hematite-rich spherules, spherule fragments, and other granules. Wind ripples are common. Underlying the thin soil layer, and exposed within small impact craters and troughs, are flat-lying sedimentary rocks. These rocks are finely laminated, are rich in sulfur, and contain abundant sulfate salts. Small-scale cross-lamination in some locations provides evidence for deposition in flowing liquid water. We interpret the rocks to be a mixture of chemical and siliciclastic sediments formed by episodic inundation by shallow surface water, followed by evaporation, exposure, and desiccation. Hematite-rich spherules are embedded in the rock and eroding from them. We interpret these spherules to be concretions formed by postdepositional diagenesis, again involving liquid water.