Type
Text
Type
Dissertation
Advisor
Advisors: Rogers, Deanne; Philips, Brian L.; Glotch, Timothy D.; Nekvasil, Hanna; Horgan, Briony H.
Date
2017-12-01
Keywords
Geochemistry, Alteration, Chemistry, Geology, Mars, Spectroscopy, Sulfates
Department
Department of Geosciences | Dissertation
Language
en
Source
This work is sponsored by the Stony Brook University Graduate School in compliance with the requirements for completion of degree.
Identifier
http://hdl.handle.net/11401/78313
Publisher
The Graduate School, Stony Brook University: Stony Brook, NY.
Format
application/pdf
Abstract
The abundance and species of chemical alteration products on planetary surfaces are related to the starting composition of unaltered protolith, the style and duration of alteration processes, the fluid composition, and fluid-to-rock ratio, and ultimately, the preservation of those products in rocks and soils. Thus, detection and interpretation of alteration mineral assemblages on Mars is critical to deciphering the history of the Martian surface. This dissertation reports investigations into the characterization of altered synthetic Martian materials and natural analogs followed by the comparison of their spectral properties with remotely-sensed data. For the first time, direct infrared spectral analyses of glasses with Martian compositions, altered under controlled conditions, are presented in order to assess surface weathering and regolith development on Mars. Basaltic glass with rover analyzed compositions (Irvine, Backstay, and Pathfinder) were synthesized and altered under controlled, cation-conservative, acid-sulfate conditions. These experiments provided constraints on how infrared spectral features vary as a function of pH and composition for Martian surface material. A volatile-containing Irvine composition was also included to observe how chlorine and water affect the spectral and chemical characteristics of unaltered/altered basaltic glass. Furthermore, hydrothermally-altered basalt from Hawaii was spectrally characterized here in order to provide a better understanding of the properties of open-system alteration relative to closed-system. Combined, these data sets provide a spectral library that includes mixtures of unaltered and altered material, poorly crystalline phases, combinations of various grain sizes, and alteration coatings that are difficult to capture with a standard mineral library. The generated libraries were compared with remotely-sensed data sets (TES and CRISM) which allowed for assessment of alteration at both global and local scales on Mars. Both TES and OMEGA data sets exhibit strong evidence for acid weathered glass in the northern lowlands of Mars, with additional potential detections in Terra Meridiani, Vallis Marineris, and Mawrth Vallis. Because lander/rover measurements have observed isochemically altered, acid-sulfate weathering at disparate locations, the lack of previous orbital detections is in conflict with the rover data. This is attributed primarily to later reworking of soils, which would redistribute the alteration products and dilute their surface abundance. The fine-grained nature of alteration materials may also contribute to their spectral obscuration. The ubiquitous spectral signatures of acid weathering in the northern lowlands suggest a more recent, ongoing process to maintain concentrated alteration materials at the surface. | 279 pages
Recommended Citation
Roth, Marcella, "Aqueous Alteration of Glass on the Martian Surface: A Comparison of Remotely-Acquired and Experimental Data Sets" (2017). Stony Brook Theses and Dissertations Collection, 2006-2020 (closed to submissions). 3807.
https://commons.library.stonybrook.edu/stony-brook-theses-and-dissertations-collection/3807