PUBLICATIONS Journal of Geophysical Research: Planets RESEARCH ARTICLE Orbital evidence for more widespread carbonate- 10.1002/2015JE004972 bearing rocks on Mars Key Point: James J. Wray1, Scott L. Murchie2, Janice L. Bishop3, Bethany L. Ehlmann4, Ralph E. Milliken5, • Carbonates coexist with phyllosili- 1 2 6 cates in exhumed Noachian rocks in Mary Beth Wilhelm , Kimberly D. Seelos , and Matthew Chojnacki several regions of Mars 1School of Earth and Atmospheric Sciences, Georgia Institute of Technology, Atlanta, Georgia, USA, 2The Johns Hopkins University/Applied Physics Laboratory, Laurel, Maryland, USA, 3SETI Institute, Mountain View, California, USA, 4Division of Geological and Planetary Sciences, California Institute of Technology, Pasadena, California, USA, 5Department of Geological Sciences, Brown Correspondence to: University, Providence, Rhode Island, USA, 6Lunar and Planetary Laboratory, University of Arizona, Tucson, Arizona, USA J. J. Wray,
[email protected] Abstract Carbonates are key minerals for understanding ancient Martian environments because they Citation: are indicators of potentially habitable, neutral-to-alkaline water and may be an important reservoir for Wray, J. J., S. L. Murchie, J. L. Bishop, paleoatmospheric CO2. Previous remote sensing studies have identified mostly Mg-rich carbonates, both in B. L. Ehlmann, R. E. Milliken, M. B. Wilhelm, Martian dust and in a Late Noachian rock unit circumferential to the Isidis basin. Here we report evidence for older K. D. Seelos, and M. Chojnacki (2016), Orbital evidence for more widespread Fe- and/or Ca-rich carbonates exposed from the subsurface by impact craters and troughs. These carbonates carbonate-bearing rocks on Mars, are found in and around the Huygens basin northwest of Hellas, in western Noachis Terra between the Argyre – J.