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Weathering of Basaltic Rocks from the Gusev Plains up into the Columbia Hills from the Perspective of the MER Mossbauer SpectrometerRocks on the ejecta blanket of Bonneville crater and along Spirit s traverse over the Gusev plains towards the Columbia Hills are angular and strewn across the surface. They have a basaltic composition [1,2], and their Mossbauer spectra are dominated by an olivine doublet [1]. The ubiquitous presence of abundant olivine in rocks and in surrounding soil suggests that physical rather than chemical weathering processes currently dominate the plains at Gusev crater [1]. However, MB spectra of rocks and outcrops in the Columbia Hills suggest more aggressive alteration processes have occurred. Ascending into the hills, Spirit encountered outcrop and rocks exhibiting layered structures. Some scattered rocks at the foot of the Columbia Hills appeared "rotten" or highly altered by physical and/or chemical processes (fig. 1). Mossbauer spectra of those rocks show a decrease in olivine accompanied by an increase in the Fe-oxides magnetite, hematite, and nanophase Fe3+ -oxides (fig. 2), suggesting that chemical weathering processes in the presence of water have altered these rocks and outcrops.
Document ID
Document Type
Conference Paper
Schroeder, C.
(Mainz Univ. Germany)
Klingelhoefer, G.
(Mainz Univ. Germany)
Morris, R. V.
(NASA Johnson Space Center Houston, TX, United States)
Rodionov, D. S.
(Mainz Univ. Germany)
deSouza, P. A.
(CVRD Group Vitoria, Brazil)
Ming, D. W.
(NASA Johnson Space Center Houston, TX, United States)
Yen, A. S.
(Jet Propulsion Lab., California Inst. of Tech. Pasadena, CA, United States)
Gellert, R.
(Max-Planck-Inst. fuer Chemie Mainz, Germany)
Bell, J. F., III
(Cornell Univ. Ithaca, NY, United States)
Date Acquired
September 7, 2013
Publication Date
January 1, 2005
Publication Information
Publication: Lunar and Planetary Science XXXVI, Part 18
Subject Category
Funding Number(s)
Distribution Limits
Public Use Permitted.
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