title: Unique meteorite from early Amazonian Mars: water-rich basaltic breccia Northwest Africa 7034.
abstract: We report data on the martian meteorite Northwest Africa (NWA) 7034, which shares some petrologic and geochemical characteristics with known martian meteorites of the SNC (i.e., shergottite, nakhlite, and chassignite) group, but also has some unique characteristics that would exclude it from that group. NWA 7034 is a geochemically enriched crustal rock compositionally similar to basalts and average martian crust measured by recent Rover and Orbiter missions. It formed 2.089 ± 0.081 billion years ago, during the early Amazonian epoch in Mars' geologic history. NWA 7034 has an order of magnitude more indigenous water than most SNC meteorites, with up to 6000 parts per million extraterrestrial H(2)O released during stepped heating. It also has bulk oxygen isotope values of Δ(17)O = 0.58 ± 0.05 per mil and a heat-released water oxygen isotope average value of Δ(17)O = 0.330 ± 0.011 per mil, suggesting the existence of multiple oxygen reservoirs on Mars.
authors.affiliation: Institute of Meteoritics, University of New Mexico, Albuquerque, NM 87131, USA. agee@unm.edu
authors.forename: Carl B
authors.initials: CB
authors.lastname: Agee
authors.forename: Nicole V
authors.initials: NV
authors.lastname: Wilson
authors.forename: Francis M
authors.initials: FM
authors.lastname: McCubbin
authors.forename: Karen
authors.initials: K
authors.lastname: Ziegler
authors.forename: Victor J
authors.initials: VJ
authors.lastname: Polyak
authors.forename: Zachary D
authors.initials: ZD
authors.lastname: Sharp
authors.forename: Yemane
authors.initials: Y
authors.lastname: Asmerom
authors.forename: Morgan H
authors.initials: MH
authors.lastname: Nunn
authors.forename: Robina
authors.initials: R
authors.lastname: Shaheen
authors.forename: Mark H
authors.initials: MH
authors.lastname: Thiemens
authors.forename: Andrew
authors.initials: A
authors.lastname: Steele
authors.forename: Marilyn L
authors.initials: ML
authors.lastname: Fogel
authors.forename: Roxane
authors.initials: R
authors.lastname: Bowden
authors.forename: Mihaela
authors.initials: M
authors.lastname: Glamoclija
authors.forename: Zhisheng
authors.initials: Z
authors.lastname: Zhang
authors.forename: Stephen M
authors.initials: SM
authors.lastname: Elardo
mesh_terms: D002244:Carbon / Q000032:analysis; D003460:Crystallization; D007501:Iron / Q000032:analysis; D008345:Manganese / Q000032:analysis; D018535:Mars; D019110:Meteoroids; D009656:North America; D010103:Oxygen Isotopes / Q000032:analysis; D055110:Radiometric Dating; D014867:Water / Q000032:analysis / Q000737:chemistry*
chemical_list: D010103:Oxygen Isotopes; D014867:Water; D008345:Manganese; D002244:Carbon; D007501:Iron