Characteristics and Origin of an Erosionally Resistant Unit in the Mars Science Laboratory Landing Ellipse (Gale Crater, Mars), Based on Analyses of Surface Data and Orbital Images

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dc.contributor.author Jacob, Samantha
dc.date.accessioned 2017-12-18T21:03:59Z
dc.date.available 2017-12-18T21:03:59Z
dc.date.issued 2015-05
dc.description M.S. University of Hawaii at Manoa 2015.
dc.description Includes bibliographical references.
dc.description.abstract The data coming from the multitude of orbiters and landed missions exploring the surface of Mars has proven that Mars had a very geologically active past. Almost every geologic process that is known to have occurred on Earth has also been identified in the deposits on the surface of Mars. The big picture scientists are now asking is, was Mars habitable? The Mars Science Laboratory (MSL) mission was sent to Gale Crater to investigate the answer to this resounding question. In August 2012, the MSL rover Curiosity safely landed in Gale Crater armed with the scientific instruments necessary to help verify whether or not Gale Crater could have ever hosted a habitable environment. Prior to landing, the Curiosity landing ellipse was mapped into six geomorphic units based on their geomorphic characteristics as seen in orbital images. The goal of this research is to understand the extent and geologic origin of the Cratered Surface (CS), one of the six geomorphic units identified in the Curiosity landing ellipse. The CS is a nearly horizontal, erosionally resistant unit that covers ~24% of the surface within the landing ellipse. In HiRISE images, the CS exposures are identified by their high crater density and meter scale erosional scarps. Variations in morphological and topographical characteristics, and crater density of the CS exposures highlighted natural subdivisions. The five CS sub-units identified in this study are CS_Flat, CS_Infill1, CS_Infill2, CS_Bedded1, and CS_Bedded2. Curiosity has imaged and analyzed four out of five sub-units with the Mastcam and ChemCam instruments, CS_Infill2 will not be visited by Curiosity. The various CS sub-units appear to be made of similar fine-grained, erosionally resistant material. Most of the CS float rocks chosen to be analyzed by the ChemCam instrument have grain sizes smaller than the resolution limit of the camera, which indicates that the grains are ~45 μm or smaller. The in situ outcrops of the CS sub-units have a range of lithologies, from massive to very fine bedding. Chemically, the CS targets show concentrations of Na, K, and Al indicative of an alkaline phase in the mineralogy of the CS. The physical characteristics of the CS, as seen in the orbital HiRISE images and the Curiosity Mastcam images, are not distinct to one depositional environment. Additionally, the physical variations of the CS sub-units would suggest that there are multiple depositional environments represented by the CS exposures. The commonly observed erosional scarp and the ability to retain large numbers of sub-km craters indicate that the CS has either undergone lithification after deposition or is composed of an innately erosionally resistant material. Comparisons of the physical characteristics of the CS material to terrestrial outcrops have illuminated fluvial, lacustrine, aeolian, and volcanic flow processes that could have deposited the CS material. While a sedimentary origin is the most likely scenario, a volcanic origin cannot be conclusively ruled out. The geochemical signature of the CS material allow for the mineralogy and composition to be understood, however, it provides little support in narrowing down the possibilities of the geologic origin of the CS sub-units.
dc.identifier.uri http://hdl.handle.net/10125/50930
dc.language.iso eng
dc.publisher [Honolulu] : [University of Hawaii at Manoa], [May 2015]
dc.relation Theses for the degree of Master of Science (University of Hawaii at Manoa). Geology & Geophysics
dc.title Characteristics and Origin of an Erosionally Resistant Unit in the Mars Science Laboratory Landing Ellipse (Gale Crater, Mars), Based on Analyses of Surface Data and Orbital Images
dc.type Thesis
dc.type.dcmi Text
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