title: Jarosite and hematite at Meridiani Planum from Opportunity's Mossbauer Spectrometer.
abstract: Mossbauer spectra measured by the Opportunity rover revealed four mineralogical components in Meridiani Planum at Eagle crater: jarosite- and hematite-rich outcrop, hematite-rich soil, olivine-bearing basaltic soil, and a pyroxene-bearing basaltic rock (Bounce rock). Spherules, interpreted to be concretions, are hematite-rich and dispersed throughout the outcrop. Hematitic soils both within and outside Eagle crater are dominated by spherules and their fragments. Olivine-bearing basaltic soil is present throughout the region. Bounce rock is probably an impact erratic. Because jarosite is a hydroxide sulfate mineral, its presence at Meridiani Planum is mineralogical evidence for aqueous processes on Mars, probably under acid-sulfate conditions.
authors.affiliation: Institut für Anorganische und Analytische Chemie, Johannes Gutenberg-Universität, Staudinger Weg 9, D-55128 Mainz, Germany. phil.christensen@asu.edu
authors.forename: G
authors.initials: G
authors.lastname: Klingelhöfer
authors.forename: R V
authors.initials: RV
authors.lastname: Morris
authors.forename: B
authors.initials: B
authors.lastname: Bernhardt
authors.forename: C
authors.initials: C
authors.lastname: Schröder
authors.forename: D S
authors.initials: DS
authors.lastname: Rodionov
authors.forename: P A
authors.initials: PA
authors.lastname: de Souza
authors.forename: A
authors.initials: A
authors.lastname: Yen
authors.forename: R
authors.initials: R
authors.lastname: Gellert
authors.forename: E N
authors.initials: EN
authors.lastname: Evlanov
authors.forename: B
authors.initials: B
authors.lastname: Zubkov
authors.forename: J
authors.initials: J
authors.lastname: Foh
authors.forename: U
authors.initials: U
authors.lastname: Bonnes
authors.forename: E
authors.initials: E
authors.lastname: Kankeleit
authors.forename: P
authors.initials: P
authors.lastname: Gütlich
authors.forename: D W
authors.initials: DW
authors.lastname: Ming
authors.forename: F
authors.initials: F
authors.lastname: Renz
authors.forename: T
authors.initials: T
authors.lastname: Wdowiak
authors.forename: S W
authors.initials: SW
authors.lastname: Squyres
authors.forename: R E
authors.initials: RE
authors.lastname: Arvidson
mesh_terms: D005118:Extraterrestrial Environment; D005290:Ferric Compounds; D019015:Geologic Sediments; D058085:Iron Compounds; D017616:Magnesium Compounds; D018535:Mars; D008903:Minerals; D017640:Silicates; D018531:Spacecraft; D015204:Spectroscopy, Mossbauer; D013431:Sulfates; D014867:Water
chemical_list: D005290:Ferric Compounds; D058085:Iron Compounds; D017616:Magnesium Compounds; D008903:Minerals; D017640:Silicates; D013431:Sulfates; C060346:basalt; C492331:jarosite; D014867:Water; C092478:pyroxene; C000499:ferric oxide; C034475:olivine