HR: 0800h
AN: P31B-0428    [Abstracts]
TI: Reconstruction of Eolian Bedforms from Cross-Bedded Strata at Victoria Crater, Meridiani Planum, Mars
AU: * Hayes, A G
EM: hayes@gps.caltech.edu
AF: California Institute of Technology, Division of Geological and Planetary Sciences. Mail Code 150-21, Pasadena, CA 91125, United States
AU: Grotzinger, J P
EM: grotz@gps.caltech.edu
AF: California Institute of Technology, Division of Geological and Planetary Sciences. Mail Code 150-21, Pasadena, CA 91125, United States
AU: Squyres, S W
EM: squyres@astro.cornell.edu
AF: Cornell University, Astronomy Department, Ithaca, NY 14853, United States
AU: Lewis, K
EM: klewis@gps.caltech.edu
AF: California Institute of Technology, Division of Geological and Planetary Sciences. Mail Code 150-21, Pasadena, CA 91125, United States
AU: Metz, J
EM: Joannah@gps.caltech.edu
AF: California Institute of Technology, Division of Geological and Planetary Sciences. Mail Code 150-21, Pasadena, CA 91125, United States
AU: Bell, J F
EM: jfb8@cornell.edu
AF: Cornell University, Astronomy Department, Ithaca, NY 14853, United States
AU: Athena Science Team, T
AB: Outcrop exposures imaged by the Opportunity rover at Meridiani Planum have depicted cross-bedded strata with geometries and scales similar to eolian and subaqeous deposits on Earth. On Earth preserved cross-strata are rich in geologic information, providing insight into the depositional environment and sediment transport directions. The high-resolution stratigraphy of these cross-bedded strata can be used to reconstruct sedimentary bedforms on Mars to infer formation process and describe the depositional environment. Meter-scale cross bedding at Victoria Crater is similar to terrestrial eolian deposits and is interpreted as a dry dune field. Sets of cross-strata in the Cape St. Vincent and Cape St. Mary sections of Victoria Crater are comparable to Jurassic-age eolian deposits of the western US. The Opportunity Rover has spent ~300 sols traversing 90 degrees of the rim of Victoria crater, obtaining images of rock outcrops exposed by several promontories along the way. The outcrops at the Cape St. Mary and Cape St. Vincent promontories, which are located at opposite ends of the traverse, have proven to be the best examples of meter scale cross-bedding observed on Mars to date. Super-resolution imaging techniques and long baseline stereo observations were utilized during an extended imaging campaign of both outcrop faces. Cape St. Mary is characterized by meter-scale trough-style cross bedding, suggesting sinuous crested dunes with scour pits migrating perpendicular to the outcrop face. Cape St. Vincent, which is striking 110° away from Cape St. Mary, has layering indicative of a single climbing bedform with dune heights of several meters. The findings at Cape St. Mary and Cape St. Vincent are combined with other bedding faces to produce an eolian deposition model for layering exposed at Victoria Crater. Any depositional model used to explain the bedding must conform to an observed N-S paleo-flow direction. In addition to bedded layering, a bright band is observed which lies on an equipotential surface and is ubiquitous around the crater. The super-resolution images of Cape St. Vincent show that bedforms can be followed through the layer, suggesting that it is diagenetic in origin.
DE: 5415 Erosion and weathering
DE: 5464 Remote sensing
DE: 5470 Surface materials and properties
DE: 6225 Mars
SC: Planetary Sciences [P]
MN: 2007 Fall Meeting