COMPARISON OF SYNCHROTRON AND ROVER-BASED CHARACTERIZATIONS OF MARTIAN ANALOG CLAY SAMPLES
Abstract/Contents
- Abstract
- Robotic, teleoperated spacecraft and rovers have been sent in mankind’s quest to explore the solar system. With many unresolved questions about its past and present habitability, Mars has been a focus for many exploratory missions. Scientists and researchers have developed orbiters, landers, and rovers to analyze the geological and geochemical processes on Mars in an attempt to answer these questions. Though their instruments continue to improve, it is important to recognize the limit of their capabilities so accurate conclusions can be drawn. Here, we compare the performances of synchrotron and rover-based instruments on characterizing Martian analog clays. The samples from Griffith Park, California were studied using x-ray fluorescence (XRF), x-ray absorption near-edge structure (XANES) spectroscopy, and x-ray diffraction (XRD) instruments to provide detailed elemental maps, determine the iron oxidation and coordination states, and determine the mineral phases present, respectively. At the Stanford Synchrotron Radiation Lightsource facility, elemental maps were produced of our Griffith Park sample. These maps were used to identify specific points at which to gather iron K-edge XANES spectra. By comparison, the Mapping Alpha-particle X-ray Fluorescence spectrometer, an arm-based XRF device, produced elemental maps at significantly lower resolution from which only broad conclusions can be made about a certain area. By isolating the XANES pre-edge and measuring its intensity and energy centroid, an abundance of octahedral Fe3+ and Fe2+ was shown to exist, agreeing well with previous results. However, our analysis also finds the first detection of tetrahedral Fe3+ in these rocks. To determine the mineral phases present in Griffith Park samples, x-ray diffraction experiments were conducted. The results reveal that labradorite and saponite are present within the Griffith Park samples, matching similar plagioclase and tioctahedral smectite discoveries by Treiman et al.. However, our results show a 0.4 degree shift in the 02l diffraction peak locations. This may be caused by variations in clay hydration which will affect interlayer lattice spacings, and/or differences in composition.
Description
| Type of resource | text |
|---|---|
| Date created | April 2018 |
Creators/Contributors
| Primary advisor | Brown, Jr., Gordon E |
|---|---|
| Advisor | Mao, Wendy |
| Degree granting institution | Stanford University, Department of Geological Sciences |
| Author | Tarantino, Paul Michael |
Subjects
| Subject | martian analog clays |
|---|---|
| Subject | XRD |
| Subject | XRF |
| Subject | XANES |
| Subject | School of Earth Energy & Environmental Sciences |
| Subject | Stanford Department of Geological Sciences |
| Genre | Thesis |
Bibliographic information
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- This work is licensed under a Creative Commons Attribution Non Commercial 3.0 Unported license (CC BY-NC).
Preferred citation
- Preferred Citation
- Tarantino, Paul Michael. (2018). COMPARISON OF SYNCHROTRON AND ROVER-BASED CHARACTERIZATIONS OF MARTIAN ANALOG CLAY SAMPLES. Stanford Digital Repository. Available at: https://purl.stanford.edu/zq683cy4022
Collection
Master's Theses, Doerr School of Sustainability
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- paulmt@stanford.edu
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