Abstract
JOURNAL OF GEOPHYSICAL RESEARCH,
VOL. 111,
E03S05,
16 PP., 2006
doi:10.1029/2006JE002675
Composition of northern low-albedo regions of Mars: Insights from the Mars Odyssey Gamma Ray Spectrometer
Department of Astronomy, Cornell University, Ithaca, New York, USA
Department of Astronomy, Cornell University, Ithaca, New York, USA
Hawai'i Institute of Geophysics and Planetology, University of Hawai'i, Honolulu, Hawaii, USA
Lunar and Planetary Laboratory, University of Arizona, Tucson, Arizona, USA
Centre d'Etude Spatiale des Rayonnements, Centre National de la Recherche Scientifique, Université Paul Sabatier Toulouse, Toulouse, France
Computer Sciences Corporation, Lanham, Maryland, USA
Institute of Meteoritics, University of New Mexico, Albuquerque, New Mexico, USA
Department of Physics, Catholic University of America, Washington, D. C., USA
Lunar and Planetary Laboratory, University of Arizona, Tucson, Arizona, USA
Lunar and Planetary Laboratory, University of Arizona, Tucson, Arizona, USA
Lunar and Planetary Laboratory, University of Arizona, Tucson, Arizona, USA
Department of Hydrology and Water Resources, University of Arizona, Tucson, Arizona, USA
Lunar and Planetary Laboratory, University of Arizona, Tucson, Arizona, USA
Department of Geosciences, Stony Brook University, Stony Brook, New York, USA
Lunar and Planetary Laboratory, University of Arizona, Tucson, Arizona, USA
Analysis of data acquired by the Mars Global Surveyor Thermal Emission Spectrometer (TES) instrument led to the identification of two distinct surface types.“Surface type 1,” lying mostly within southern low-albedo terrain, is likely to be composed of basalt. However, there are several competing mineralogical models for “surface type 2,” which is found primarily in northern low-albedo terrain. We attempt to identify which models better agree with element concentrations determined through the Gamma Subsystem (GS) of the Gamma Ray Spectrometer (GRS) instrument suite aboard the Mars Odyssey spacecraft. We have binned GS data over threshold regions derived from maps of surface types 1 and 2 and examined the spatial correlation of element concentrations with surface type 2. The elements we have examined are Cl, Fe, H, K, Si, and Th. Our results show that K concentration, Th concentration, and the areal abundance of surface type 2 are strongly correlated, with significant enrichment of both K and Th in regions representative of surface type 2. In addition, Si does not appear to be significantly enriched in surface type 2. These results are more consistent with surface type 2 originating from a compositionally distinct mantle source than the aqueous alteration of basalts.
Received 9 January 2006; accepted 30 June 2006; published 13 December 2006.
Citation: (2006), Composition of northern low-albedo regions of Mars: Insights from the Mars Odyssey Gamma Ray Spectrometer, J. Geophys. Res., 111, E03S05, doi:10.1029/2006JE002675, [printed 112(E3), 2007].
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