Author's School

Graduate School of Arts & Sciences

Author's Department/Program

Earth and Planetary Sciences

Language

English (en)

Date of Award

January 2009

Degree Type

Dissertation

Degree Name

Doctor of Philosophy (PhD)

Chair and Committee

Raymond Arvidson

Abstract

Data acquired by the Mars Reconnaissance Orbiter: MRO) are used in conjunction with additional data sets to perform detailed stratigraphic and spectral analyses with the goal of identifying and mapping the mineralogy and stratigraphy of sedimentary deposits to infer the aqueous history of the Sinus Meridiani region on Mars. Datasets utilized include MRO Compact Reconnaissance Imaging Spectrometer for Mars: CRISM), MRO Context Imager, MRO High Resolution Imaging Science Experiment, Mars Express: MEX) Observatoire pour la Minéralogie, l'Eau, les Glaces et l'Activité, MEX High Resolution Stereo Camera, Mars Odyssey: ODY) Thermal Emission Imaging System, ODY Mars Orbital Camera, and ODY Mars Orbiter Laser Altimeter data. Spectral analyses focus on detection, identification, and mapping of hydrated and/or hydroxylated alteration minerals in the near infrared region between ~1.0 and 2.5 µm. An extensive analysis is presented on methods for the retrieval of atmospherically corrected CRISM surface Lambert Albedo spectra using Discrete Ordinate Radiative Transfer modeling. Sedimentary deposits indicative of a complex aqueous history occur in Sinus Meridiani. Fe/Mg phyllosilicate minerals, including Fe/Mg smectites, are detected in ancient Noachian cratered terrains. Fe/Mg smectites also occur in association with layered sedimentary deposits that unconformably overlie the Noachian cratered terrain. Both of these units predate the formation of the sulfate and hematite-bearing unit on which the Mars Exploration Rover Opportunity landed. At least one episode of intense erosion acted on the sedimentary deposits. A thick sequence of layered hydrated sulfate deposits that are texturally and spectrally distinct from the sulfate rich bedrock explored by the Opportunity Rover occurs in northern Sinus Meridiani. Detailed stratigraphic analyses indicate that these deposits are not readily explained by a simple layered stratigraphy and an unconformable facies change is inferred to have occurred. The presence of Fe/Mg smectite-bearing deposits indicates that the low pH conditions experienced by younger hematite-bearing materials are not representative of the aqueous geochemical environment that prevailed during the formation of earlier materials. The deposits in Sinus Meridiani record the transition from an open hydrologic system with near neutral pH conditions to a more arid acid-sulfate dominated ground water system.

Comments

Permanent URL: http://dx.doi.org/10.7936/K7RN35XX

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