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Fluvial to Lacustrine Facies Transitions in Gale Crater, MarsNASA's Curiosity rover has documented predominantly fluvial sedimentary rocks along its path from the landing site to the toe of the Peace Vallis alluvial fan (0.5 km to the east) and then along its 8 km traverse across Aeolis Palus to the base of Aeolis Mons (Mount Sharp). Lacustrine facies have been identified at the toe of the Peace Vallis fan and in the lowermost geological unit exposed on Aeolis Mons. These two depositional systems provide end members for martian fluvial/alluvial-lacustrine facies models. The Peace Vallis system consisted of an 80 square kilometers alluvial fan with decimeter-thick, laterally continuous fluvial sandstones with few sedimentary structures. The thin lacustrine unit associated with the fan is interpreted as deposited in a small lake associated with fan runoff. In contrast, fluvial facies exposed over most of Curiosity's traverse to Aeolis Mons consist of sandstones with common dune-scale cross stratification (including trough cross stratification), interbedded conglomerates, and rare paleochannels. Along the southwest portion of the traverse, sandstone facies include south-dipping meter-scale clinoforms that are interbedded with finer-grained mudstone facies, interpreted as lacustrine. Sedimentary structures in these deposits are consistent with deltaic deposits. Deltaic deposition is also suggested by the scale of fluvial to lacustrine facies transitions, which occur over greater than 100 m laterally and greater than 10 m vertically. The large scale of the transitions and the predicted thickness of lacustrine deposits based on orbital mapping require deposition in a substantial river-lake system over an extended interval of time. Thus, the lowermost, and oldest, sedimentary rocks in Gale Crater suggest the presence of substantial fluvial flow into a long-lived lake. In contrast, the Peace Vallis alluvial fan onlaps these older deposits and overlies a major unconformity. It is one of the youngest deposits in the crater, and requires only short-lived, transient flows.
Document ID
20150003056
Acquisition Source
Johnson Space Center
Document Type
Conference Paper
Authors
Sumner, Dawn Y. (California Univ. Davis, CA, United States)
Williams, Rebecca M. E. (Planetary Science Inst. Tucson, AZ, United States)
Schieber, Juergen (Indiana Univ. Bloomington, IN, United States)
Palucis, Marisa C. (California Inst. of Tech. Pasadena, CA, United States)
Oehler, Dorothy Z. (Oak Ridge Associated Universities, Inc. Houston, TX, United States)
Mangold, Nicolas (Laboratoire de Planetologie et Geodynamique de Nantes (LPG) Nantes, France)
Kah, Linda C. (Tennessee Univ. Knoxville, TN, United States)
Gupta, Sanjeev (Imperial Coll. of London London, United Kingdom)
Grotzinger, John P. (California Inst. of Tech. Pasadena, CA, United States)
Grant, John A., III (Smithsonian Institution Washington, DC, United States)
Edgar, Lauren A. (Arizona State Univ. Tempe, AZ, United States)
Dietrich, William E. (California Univ. Berkeley, CA, United States)
Date Acquired
March 17, 2015
Publication Date
May 3, 2015
Subject Category
Lunar And Planetary Science And Exploration
Report/Patent Number
JSC-CN-33088
Meeting Information
Meeting: 2015 Joint Assembly
Location: Montreal, Canada
Country: Canada
Start Date: May 3, 2015
End Date: May 7, 2015
Sponsors: American Geophysical Union, Mineralogical Association of Canada, Canadian Geophysical Union, Geological Association of Canada
Distribution Limits
Public
Copyright
Public Use Permitted.

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