Showing papers by "S. W. Squyres published in 2012"
01 Jan 2012
TL;DR: In this article, the authors used the Microscopic Imager and Panoramic Camera to investigate the role of surface processes in the geologic history of the Victoria crater on Mars.
Abstract: The Mars Exploration Rover Opportunity has investigated bedrock outcrops exposed in several craters at Meridiani Planum, Mars, in an effort to better understand the role of surface processes in its geologic history. Opportunity has recently completed its observations of Victoria crater, which is 750 m in diameter and exposes cliffs up to ∼15 m high. The plains surrounding Victoria crater are ∼10 m higher in elevation than those surrounding the previously explored Endurance crater, indicating that the Victoria crater exposes a stratigraphically higher section than does the Endurance crater; however, Victoria strata overlap in elevation with the rocks exposed at the Erebus crater. Victoria crater has a well-developed geomorphic pattern of promontories and embayments that define the crater wall and that reveal thick bedsets (3–7 m) of large-scale cross-bedding, interpreted as fossil eolian dunes. Opportunity was able to drive into the crater at Duck Bay, located on the western margin of Victoria crater. Data from the Microscopic Imager and Panoramic Camera reveal details about the structures, textures, and depositional and diagenetic events that influenced the Victoria bedrock. A lithostratigraphic subdivision of bedrock units was enabled by the presence of a light-toned band that lines much of the upper rim of the crater. In ascending order, three stratigraphic units are named Lyell, Smith, and Steno; Smith is the light-toned band. In the Reference Section exposed along the ingress path at Duck Bay, Smith is interpreted to represent a zone of diagenetic recrystallization; however, its upper contact also coincides with a primary erosional surface. Elsewhere in the crater the diagenetic band crosscuts the physical stratigraphy. Correlation with strata present at nearby promontory Cape Verde indicates that there is an erosional surface at the base of the cliff face that corresponds to the erosional contact below Steno. The erosional contact at the base of Cape Verde lies at a lower elevation, but within the same plane as the contact below Steno, which indicates that the material above the erosional contact was built on significant depositional paleotopography. The eolian dune forms exposed in Duck Bay and Cape Verde, combined with the geometry of the erosional surface, indicate that these outcrops may be part of a larger-scale draa architecture. This insight is possible only as a result of the larger-scale exposures at Victoria crater, which significantly exceed the more limited exposures at the Erebus, Endurance, and Eagle craters.
27 citations
01 Mar 2012
TL;DR: Karunatillake et al. as mentioned in this paper smoothed the midlatitudes smoothed with a Gaussian kernel and highlighted the hydration states between 2.5 and 4, areally representing approximately 77% of the subsurface.
Abstract: mid-latitudes smoothed with a Gaussian kernel. The bulk of the hydration states highlighted yellow are between 2.5 and 4, areally representing approximately 77% of the subsurface. THE HYDRATION STATE OF SULFATES ON MARS Suniti Karunatillake, Olivier Gasnault, Scott M. McLennan, A. Deanne Rogers, James. J. Wray, Steven W. Squyres, and William V. Boynton, 324 Sci&Tech BLDG., Rider University, NJ 08610 (wk43@cornell.edu); Université de Toulouse [UPS], F-31000 Toulouse, France; Stony Brook University, NY 11794; Georgia Institute of Technology, GA 30332; Cornell University, NY 14853; University of Arizona, AZ 85721.
4 citations