Date of Award
Summer 8-15-2017
Degree Name
Doctor of Philosophy (PhD)
Degree Type
Dissertation
Abstract
This dissertation presents three studies applying orbital remote sensing, rover-based compositional and morphological observations, and laboratory references to understand the conditions in which aqueous alteration occurred on ancient Mars. Chapters 2 and 3 present detailed analysis of Compact Reconnaissance Imaging Spectrometer for Mars (CRISM) hyperspectral observations over the Opportunity and Curiosity rover exploration sites, processed using a robust radiative transfer model to obtain the spectral character of the surface and a log-maximum likelihood algorithm to retrieve the best estimates of the spectral signal in the presence of noise and better spatial projections.
Chapter 2 analyzes overlapping CRISM observations of the rim of Endeavour Crater, where the Opportunity rover is exploring, and reports the detection of Fe3+-Mg smectite minerals exposed in the floor of a cross-cutting valley. Opportunity was commanded to drive to the valley to obtain in-situ observations of the smectite-bearing outcrops detected from CRISM observations. The rover measurements demonstrate that the smectites likely formed isochemically from the impact breccia in the rim, and fluid flowed preferentially along bedding or fracture joints in the rim of the crater. Chapter 3 presents detailed CRISM-based analysis of the mineralogy evident in the strata in Gale Crater where the Curiosity has explored and is planning to go. Particularly, Curiosity is approaching the point at which phyllosilicate-bearing layers transition to sulfate-bearing units, and the results from this work have been used to identify outcrops that the rover is preparing to investigate the units and determine the environmental settings in which they formed.
The final chapter of this dissertation is based upon rover observations and earth analog characterizations. Finding manganese oxides on Mars motivated an effort to better characterize manganese oxides using methods analogous to those available on the rovers, so Chapter 4 details a survey of earth-based manganese oxide samples intended to be used as reference data for comparison to detections made on Mars.
Language
English (en)
Chair and Committee
Raymond E. Arvidson
Committee Members
Bradley Jolliff, Jeffrey Catalano, Joseph O'Sullivan, Edward Guinness,
Recommended Citation
Fox, Valerie, "Aqueous alteration of Endeavour and Gale Craters, Mars, using orbital remote sensing and rover-based measurements" (2017). Arts & Sciences Electronic Theses and Dissertations. 1246.
https://openscholarship.wustl.edu/art_sci_etds/1246
Comments
Permanent URL: https://doi.org/10.7936/K7N58KS7