Publication Date:
2004-12-04
Description:
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.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Squyres, S W -- Arvidson, R E -- Bell, J F 3rd -- Bruckner, J -- Cabrol, N A -- Calvin, W -- Carr, M H -- Christensen, P R -- Clark, B C -- Crumpler, L -- Marais, D J Des -- 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 -- Klingelhofer, 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 Jr -- Richter, L -- Rieder, R -- Sims, M -- Smith, M -- Smith, P -- Soderblom, L A -- Sullivan, R -- Wanke, H -- Wdowiak, T -- Wolff, M -- Yen, A -- New York, N.Y. -- Science. 2004 Dec 3;306(5702):1698-703.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Department of Astronomy, Space Sciences Building, Cornell University, Ithaca, NY 14853, USA. squyres@astro.cornell.edu〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/15576602" target="_blank"〉PubMed〈/a〉
Keywords:
Atmosphere
;
Evolution, Planetary
;
Extraterrestrial Environment
;
Ferric Compounds
;
Geologic Sediments
;
*Mars
;
Minerals
;
Silicates
;
Spacecraft
;
Water
;
Wind
Print ISSN:
0036-8075
Electronic ISSN:
1095-9203
Topics:
Biology
,
Chemistry and Pharmacology
,
Computer Science
,
Medicine
,
Natural Sciences in General
,
Physics
