title: Water in SNC meteorites:  evidence for a martian hydrosphere.
abstract: The Shergotty-Nakhla-Chassigny (SNC) meteorites, purportedly of martian origin, contain 0.04 to 0.4 percent water by weight.  Oxygen isotopic analysis can be used to determine whether this water is extraterrestrial or terrestrial.  Such analysis reveals that a portion of the water is extraterrestrial and furthermore was not in oxygen isotopic equilibrium with the host rock.  Lack of equilibrium between water and host rock implies that the lithosphere and hydrosphere of the SNC parent body formed two distinct oxygen isotopic reservoirs.  If Mars was the parent body, the maintenance of two distinct reservoirs may result from the absence of plate tectonics on the planet.
authors.affiliation: Planetary Science Branch, National Aeronautics and Space Administration, Johnson Space Center, Houston, TX 77058.
authors.forename: H R
authors.initials: HR
authors.lastname: Karlsson
authors.forename: R N
authors.initials: RN
authors.lastname: Clayton
authors.forename: E K
authors.initials: EK
authors.lastname: Gibson
authors.forename: T K
authors.initials: TK
authors.lastname: Mayeda
mesh_terms: D001272:Atmosphere; D005118:Extraterrestrial Environment; D055593:Geological Phenomena; D005844:Geology; D018535:Mars; D008962:Models, Theoretical; D010103:Oxygen Isotopes; D016082:Solar System; D013696:Temperature; D014867:Water / Q000032:analysis* / Q000737:chemistry
chemical_list: D010103:Oxygen Isotopes; D014867:Water