Description
- Abstract:
- Orbital and landed investigations of Mars have revealed a variety of secondary minerals on the surface consistent with past surface or subsurface liquid water and more habitable conditions. Studies of water-rock interactions on Earth can lead to a better understanding of these processes and help constrain past environments on Mars. This thesis characterizes the mineral assemblages formed through high temperature aqueous alteration and later diagenesis and weathering in metamorphic, volcanic, and impact environments through case studies at three Mars-relevant field sites. This work utilizes hyperspectral imaging to map mineralogies of thick sections and hand samples in combination with other laboratory analyses and then scales the results to outcrops. Chapter 1 maps iron oxidation state and coordination at an ancient serpentinite in Norbestos, Quebec, Canada, as a proxy for production of hydrogen, which can sustain microbial communities, and uses stable isotope analyses of carbonates to reconstruct aqueous conditions during serpentinization. The results have implications for the preservation of potential biosignatures in serpentine-bearing rocks on Mars. Chapters 2 and 3 investigate an outcrop of lacustrine pillow lavas in Meriden, Connecticut, USA, that were hydrothermally altered after emplacement and then altered further by diagenesis. Through a suite of coordinated analyses, the history of alteration of these pillow lavas has been unraveled. In addition, the variety of types of alteration and secondary mineralogies and the pervasive, low-grade alteration at the site have implications for any similar sites on Mars. Chapter 4 maps the mineral assemblages at a calcite-marcasite vug at the Haughton impact structure, Devon Island, Nunavut, Canadian High Arctic. This vug formed in the post-impact hydrothermal system and has since weathered at low temperatures to form a variety of oxides and sulfates. Spectral mapping of the vug shows an evolution in the chemistry, temperature, and redox state with alteration. Finally, Chapter 5 synthesizes these results and highlights some geological applications of hyperspectral imaging at the thick section, hand sample, and outcrop scales. The results of this thesis have implications for understanding past aqueous environments on Mars and for use of similar technologies on future planetary missions.
- Notes:
- Thesis (Ph.D. -- Brown University (2015)
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Citation
Greenberger, Rebecca Naomi,
"High Temperature Aqueous Alteration and Diagenesis: Unexpected Insights with Imaging Spectroscopy from Microns to Meters"
(2015).
Earth, Environmental and Planetary Sciences Theses and Dissertations.
Brown Digital Repository. Brown University Library.
https://doi.org/10.7301/Z0PC30R2
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Earth, Environmental and Planetary Sciences Theses and Dissertations
Theses and Dissertations for the Earth, Environmental and Planetary Sciences department....