title: In situ evidence for an ancient aqueous environment at Meridiani Planum, Mars.
abstract: Sedimentary rocks at Eagle crater in Meridiani Planum are composed of fine-grained siliciclastic materials derived from weathering of basaltic rocks, sulfate minerals (including magnesium sulfate and jarosite) that constitute several tens of percent of the rock by weight, and hematite. Cross-stratification observed in rock outcrops indicates eolian and aqueous transport. Diagenetic features include hematite-rich concretions and crystal-mold vugs. We interpret the rocks to be a mixture of chemical and siliciclastic sediments with a complex diagenetic history. The environmental conditions that they record include episodic inundation by shallow surface water, evaporation, and desiccation. The geologic record at Meridiani Planum suggests that conditions were suitable for biological activity for a period of time in martian history.
authors.affiliation: Department of Astronomy, Cornell University, Ithaca, NY 14853, USA. squyres@astrosun.tn.cornell.edu
authors.forename: S W
authors.initials: SW
authors.lastname: Squyres
authors.forename: J P
authors.initials: JP
authors.lastname: Grotzinger
authors.forename: R E
authors.initials: RE
authors.lastname: Arvidson
authors.forename: J F
authors.initials: JF
authors.lastname: Bell
authors.forename: W
authors.initials: W
authors.lastname: Calvin
authors.forename: P R
authors.initials: PR
authors.lastname: Christensen
authors.forename: B C
authors.initials: BC
authors.lastname: Clark
authors.forename: J A
authors.initials: JA
authors.lastname: Crisp
authors.forename: W H
authors.initials: WH
authors.lastname: Farrand
authors.forename: K E
authors.initials: KE
authors.lastname: Herkenhoff
authors.forename: J R
authors.initials: JR
authors.lastname: Johnson
authors.forename: G
authors.initials: G
authors.lastname: Klingelhöfer
authors.forename: A H
authors.initials: AH
authors.lastname: Knoll
authors.forename: S M
authors.initials: SM
authors.lastname: McLennan
authors.forename: H Y
authors.initials: HY
authors.lastname: McSween
authors.forename: R V
authors.initials: RV
authors.lastname: Morris
authors.forename: J W
authors.initials: JW
authors.lastname: Rice
authors.forename: R
authors.initials: R
authors.lastname: Rieder
authors.forename: L A
authors.initials: LA
authors.lastname: Soderblom
mesh_terms: D018559:Exobiology; D005118:Extraterrestrial Environment; D005290:Ferric Compounds; D019015:Geologic Sediments; D019369:Life; D018535:Mars; D008903:Minerals; D017640:Silicates; D018531:Spacecraft; D013057:Spectrum Analysis; D013431:Sulfates; D013455:Sulfur; D014867:Water
chemical_list: D005290:Ferric Compounds; D008903:Minerals; D017640:Silicates; D013431:Sulfates; D014867:Water; C000499:ferric oxide; D013455:Sulfur