HiRISE imaging of impact megabreccia and sub-meter aqueous strata in Holden Crater, Mars
- John A. Grant1,
- Rossman P. Irwin III1,
- John P. Grotzinger2,
- Ralph E. Milliken2,
- Livio L. Tornabene3,
- Alfred S. McEwen3,
- Catherine M. Weitz4,
- Steven W. Squyres5,
- Timothy D. Glotch6 and
- Brad J. Thomson6
- 1Center for Earth and Planetary Studies, National Air and Space Museum, Smithsonian Institution, Washington, D.C. 20560, USA
- 2Division of Geological and Planetary Sciences, California Institute of Technology, Pasadena, California 91125, USA
- 3Lunar and Planetary Laboratory, University of Arizona, Tucson, Arizona 85721, USA
- 4Planetary Science Institute, Tucson, Arizona 85719, USA
- 5Department of Astronomy, Space Sciences Building, Cornell University, Ithaca, New York 14853, USA
- 6Jet Propulsion Laboratory, California Institute of Technology, Pasadena, California 91109, USA
Abstract
High Resolution Imaging Science Experiment (HiRISE) images of Holden crater, Mars, resolve impact megabreccia unconformably overlain by sediments deposited during two Noachian-age phases of aqueous activity. A lighter-toned lower unit exhibiting phyllosilicates was deposited in a long-lived, quiescent distal alluvial or lacustrine setting. An overlying darker-toned and often blocky upper unit drapes the sequence and was emplaced during later high-magnitude flooding as an impounded Uzboi Vallis lake overtopped the crater rim. The stratigraphy provides the first geologic context for phyllosilicate deposition during persistent wet and perhaps habitable conditions on early Mars.
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- Accepted 28 October 2007.
- Received 6 August 2007.
- Revision received 18 October 2007.
- The Geological Society of America, Inc.
