title: Ancient impact and aqueous processes at Endeavour Crater, Mars.
abstract: The rover Opportunity has investigated the rim of Endeavour Crater, a large ancient impact crater on Mars. Basaltic breccias produced by the impact form the rim deposits, with stratigraphy similar to that observed at similar-sized craters on Earth. Highly localized zinc enrichments in some breccia materials suggest hydrothermal alteration of rim deposits. Gypsum-rich veins cut sedimentary rocks adjacent to the crater rim. The gypsum was precipitated from low-temperature aqueous fluids flowing upward from the ancient materials of the rim, leading temporarily to potentially habitable conditions and providing some of the waters involved in formation of the ubiquitous sulfate-rich sandstones of the Meridiani region.
authors.affiliation: Department of Astronomy, Cornell University, Ithaca, NY 14853, USA. squyres@astro.cornell.edu
authors.forename: S W
authors.initials: SW
authors.lastname: Squyres
authors.forename: R E
authors.initials: RE
authors.lastname: Arvidson
authors.forename: J F
authors.initials: JF
authors.lastname: Bell
authors.forename: F
authors.initials: F
authors.lastname: Calef
authors.forename: B C
authors.initials: BC
authors.lastname: Clark
authors.forename: B A
authors.initials: BA
authors.lastname: Cohen
authors.forename: L A
authors.initials: LA
authors.lastname: Crumpler
authors.forename: P A
authors.initials: PA
authors.lastname: de Souza
authors.forename: W H
authors.initials: WH
authors.lastname: Farrand
authors.forename: R
authors.initials: R
authors.lastname: Gellert
authors.forename: J
authors.initials: J
authors.lastname: Grant
authors.forename: K E
authors.initials: KE
authors.lastname: Herkenhoff
authors.forename: J A
authors.initials: JA
authors.lastname: Hurowitz
authors.forename: J R
authors.initials: JR
authors.lastname: Johnson
authors.forename: B L
authors.initials: BL
authors.lastname: Jolliff
authors.forename: A H
authors.initials: AH
authors.lastname: Knoll
authors.forename: R
authors.initials: R
authors.lastname: Li
authors.forename: S M
authors.initials: SM
authors.lastname: McLennan
authors.forename: D W
authors.initials: DW
authors.lastname: Ming
authors.forename: D W
authors.initials: DW
authors.lastname: Mittlefehldt
authors.forename: T J
authors.initials: TJ
authors.lastname: Parker
authors.forename: G
authors.initials: G
authors.lastname: Paulsen
authors.forename: M S
authors.initials: MS
authors.lastname: Rice
authors.forename: S W
authors.initials: SW
authors.lastname: Ruff
authors.forename: C
authors.initials: C
authors.lastname: Schröder
authors.forename: A S
authors.initials: AS
authors.lastname: Yen
authors.forename: K
authors.initials: K
authors.lastname: Zacny
mesh_terms: D002133:Calcium Sulfate; D005118:Extraterrestrial Environment; D055593:Geological Phenomena; D018535:Mars; D019110:Meteoroids; D017640:Silicates; D018531:Spacecraft; D014867:Water; D015032:Zinc
chemical_list: D017640:Silicates; C060346:basalt; D014867:Water; D015032:Zinc; D002133:Calcium Sulfate