I. Spectroscopic and geochemical characterization of Mars analog alteration materials
A tremendous body of geochemical and morphological evidence, amassed through Martian ground and orbiter missions, points to the past existence of liquid water on the surface of Mars. A major goal of the Mars Exploration program is to understand the environmental conditions under which water existed on Mars, and whether those environments could have sustained life. Alteration mineralogy, as identified on Mars by in situ and orbital spectrosopic measurements, can often constrain the environment of formation and its properties, including the pH and chemistry of fluids and the fluid/rock ratio. However, the instrument suites available on Mars rover missions are limited, and we can't (yet) return Martian samples to the lab for detailed analysis. Therefore, to fully understand the alteration mineralogy we observe on Mars, it is useful to study analogous materials in terrestrial environments in a known geologic context.
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Clockwise from top left, the Gertrude Weise high-silica deposits at Gusev Crater, Mars; silica coatings on spatter basalt, 1974 Kilauea flow, Hawaii; SEM image of Fe-Ti spherules on the surface of the Hawaiian basalt; cross sectional view of the coating, from bottom to top: basalt substrate, darker silica coating, bright thin Fe-Ti oxide layer, epoxy. |
My recent focus has been the study of Hawaiian silica coatings, as an analog for high-silica deposits discovered by the Spirit rover at Home Plate. These coatings form on very young (~30 y.o.) basaltic flows near volcanic vents. I have studied in detail the micro-morphological, chemical, spectral and oxygen isotopic properties of these materials using a variety of analytical techniques. The purpose of this study is to determine the formation mechanism of the coating and to develop a set of characteristic observations for the interpretation of secondary silica on Mars.
Abstracts and Publications:- Chemtob, S. M., B. L. Jolliff, G. R. Rossman, J. M. Eiler, and R. E. Arvidson (2010) Silica coatings in the Ka’u Desert, Hawaii, a Mars analog terrain: a micro-morphological, spectral, chemical and isotopic study. JGR, 115, E04001, doi:10.1029/2009JE003473.
- Seelos, K. D., R. E. Arvidson, B. L. Jolliff, S. M. Chemtob, R. V. Morris, D. W. Ming, and G. A. Swayze (2010) Silica in a Mars analog environment: Ka’u Desert,Kilauea Volcano, Hawai’i. JGR, 115, E00D15, doi:10.1029/2009JE003347.
- Chemtob, S. M., G. R. Rossman, J. M. Eiler, and B. L. Jolliff (2009) Silica coatings on the 1974 Kilauea flow: new SEM and SIMS results and implications for Mars. LPSC XL, #2156. (talk)
- S. M. Chemtob, B. L. Jolliff, and R. E. Arvidson (2006) Si- and Ti- rich surface coatings on Hawaiian basalt and implications for remote sensing on Mars. LPSC XXXVI, #1443. (poster)