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34 results on '"Ruff, S. W"'

1. Mineralogy at Meridiani Planum from the Mini-TES Experiment on the Opportunity Rover

Author

Christensen, P. R., Wyatt, M. B., Glotch, T. D., Rogers, A. D., Anwar, S., Arvidson, R. E., Bandfield, J. L., Blaney, D. L., Budney, C., Calvin, W. M., Fallacaro, A., Fergason, R. L., Gorelick, N., Graff, T. G., Hamilton, V. E., Hayes, A. G., Johnson, J. R., Knudson, A. T., McSween, H. Y., Mehall, G. L., Mehall, L. K., Moersch, J. E., Morris, R. V., Smith, M. D., Squyres, S. W., Ruff, S. W., and Wolff, M. J.

Published
2004

2. Basaltic Rocks Analyzed by the Spirit Rover in Gusev Crater

Author

McSween, H. Y., Arvidson, R. E., Bell, J. F., Blaney, D., Cabrol, N. A., Christensen, P. R., Clark, B. C., Crisp, J. A., Crumpler, L. S., Farmer, J. D., Gellert, R., Ghosh, A., Gorevan, S., Graff, T., Grant, J., Haskin, L. A., Herkenhoff, K. E., Johnson, J. R., Jolliff, B. L., Klingelhoefer, G., Knudson, A. T., McLennan, S., Milam, K. A., Moersch, J. E., Morris, R. V., Rieder, R., Ruff, S. W., de Souza, P. A., Squyres, S. W., Wänke, H., Wang, A., Wyatt, M. B., Yen, A., and Zipfel, J.

Published
2004

3. Initial Results from the Mini-TES Experiment in Gusev Crater from the Spirit Rover

Author

Christensen, P. R., Ruff, S. W., Fergason, R. L., Knudson, A. T., Anwar, S., Arvidson, R. E., Bandfield, J. L., Blaney, D. L., Budney, C., Calvin, W. M., Glotch, T. D., Golombek, M. P., Gorelick, N., Graff, T. G., Hamilton, V. E., Hayes, A., Johnson, J. R., McSween, H. Y., Mehall, G. L., Mehall, L. K., Moersch, J. E., Morris, R. V., Rogers, A. D., Smith, M. D., Squyres, S. W., Wolff, M. J., and Wyatt, M. B.

Published
2004

4. Ancient Aqueous Environments at Endeavour Crater, Mars

Author

Arvidson, R. E., Squyres, S. W., Bell, J. F., Catalano, J. G., Clark, B. C., Crumpler, L. S., de Souza, P. A., Fairén, A. G., Farrand, W. H., Fox, V. K., Gellert, R., Ghosh, A., Golombek, M. P., Grotzinger, J. P., Guinness, E. A., Herkenhoff, K. E., Jolliff, B. L., Knoll, A. H., Li, R., McLennan, S. M., Ming, D. W., Mittlefehldt, D. W., Moore, J. M., Morris, R. V., Murchie, S. L., Parker, T. J., Paulsen, G., Rice, J. W., Ruff, S. W., Smith, M. D., and Wolff, M. J.

Published
2014

5. Ancient Impact and Aqueous Processes at Endeavour Crater, Mars

Author

Squyres, S. W., Arvidson, R. E., Bell, J. F., Calef, F., Clark, B. C., Cohen, B. A., Crumpler, L. A., de Souza, P. A., Farrand, W. H., Gellert, R., Grant, J., Herkenhoff, K. E., Hurowitz, J. A., Johnson, J. R., Jolliff, B. L., Knoll, A. H., Li, R., McLennan, S. M., Ming, D. W., Mittlefehldt, D. W., Parker, T. J., Paulsen, G., Rice, M. S., Ruff, S. W., Schröder, C., Yen, A. S., and Zacny, K.

Published
2012
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7. Amorphous Phases on the Surface of Mars

Author

Rampe, E. B, Morris, R. V, Ruff, S. W, Horgan, B, Dehouck, E, Achilles, C. N, Ming, D. W, Bish, D. L, and Chipera, S. J

Subjects
Lunar And Planetary Science And Exploration
Abstract

Both primary (volcanic/impact glasses) and secondary (opal/silica, allophane, hisingerite, npOx, S-bearing) amorphous phases appear to be major components of martian surface materials based on orbital and in-situ measurements. A key observation is that whereas regional/global scale amorphous components include altered glass and npOx, local scale amorphous phases include hydrated silica/opal. This suggests widespread alteration at low water-to-rock ratios, perhaps due to snow/ice melt with variable pH, and localized alteration at high water-to-rock ratios. Orbital and in-situ measurements of the regional/global amorphous component on Mars suggests that it is made up of at least three phases: npOx, amorphous silicate (likely altered glass), and an amorphous S-bearing phase. Fundamental questions regarding the composition and the formation of the regional/global amorphous component(s) still remain: Do the phases form locally or have they been homogenized through aeolian activity and derived from the global dust? Is the parent glass volcanic, impact, or both? Are the phases separate or intimately mixed (e.g., as in palagonite)? When did the amorphous phases form? To address the question of source (local and/or global), we need to look for variations in the different phases within the amorphous component through continued modeling of the chemical composition of the amorphous phases in samples from Gale using CheMin and APXS data. If we find variations (e.g., a lack of or enrichment in amorphous silicate in some samples), this may imply a local source for some phases. Furthermore, the chemical composition of the weathering products may give insight into the formation mechanisms of the parent glass (e.g., impact glasses contain higher Al and lower Si [30], so we might expect allophane as a weathering product of impact glass). To address the question of whether these phases are separate or intimately mixed, we need to do laboratory studies of naturally altered samples made up of mixed phases (e.g., palagonite) and synthetic single phases to determine their short-range order structures and calculate their XRD patterns to use in models of CheMin data. Finally, to address the timing of the alteration, we need to study rocks on the martian surface of different ages that may contain glass (volcanic or impact) with MSL and future rovers to better understand how glass alters on the martian surface, if that alteration mechanism is universal, and if alteration spans across long periods of time or if there is a time past which unaltered glass remains.

Published
2014

9. ABSTRACTS: Ancient Aqueous Environments at Endeavour Crater, Mars

Author

Arvidson, R. E., Squyres, S. W., Bell, J. F., III, Catalano, J. G., Clark, B. C., Crumpler, L. S., de Souza, P. A., Jr., Fairén, A. G., Farrand, W. H., Fox, V. K., Gellert, R., Ghosh, A., Golombek, M. P., Grotzinger, J. P., Guinness, E. A., Herkenhoff, K. E., Jolliff, B. L., Knoll, A. H., Li, R., McLennan, S. M., Ming, D. W., Mittlefehldt, D. W., Moore, J. M., Morris, R. V., Murchie, S. L., Parker, T. J., Paulsen, G., Rice, J. W., Ruff, S. W., Smith, M. D., and Wolff, M. J.

Published
2014

10. Evidence for a Noachian-Aged Ephemeral Lake in Gusev Crater, Mars

Author

Ruff, S. W, Niles, P. B, Alfano, F, and Clarke, A. B

Subjects
Lunar And Planetary Science And Exploration
Abstract

Gusev crater was selected as the landing site for the Spirit rover because of the likelihood that it contained an ancient lake. Although outcrops rich in Mg-Fe carbonate dubbed Comanche were discovered in the Noachian-aged Columbia Hills, they were inferred to result from volcanic hydrothermal activity. Spirit encountered other mineral and chemical indicators of aqueous activity, but none was recognized as definitive evidence for a former lake in part because none was associated with obvious lacustrine sedimentary deposits. However, water discharge into Martian crater basins like Gusev may have been episodic, producing only small amounts of sediment and shallow ephemeral lakes. Evaporative precipitation from such water bodies has been suggested as a way of producing the Mg- and Fe-rich carbonates found in ALH84001 and carbonates and salts in some nakhlites a hypothesis we examine for the Comanche carbonate.

Published
2014

11. Quantifying the Complete Mineral Assemblages in Rocks of GUSEV Crater, Mars

Author

McSween, H. Y, Ruff, S. W, Morris, R. V, and Gellert, R

Subjects
Geophysics
Abstract

Determining the complete mineralogy of Mars rocks by remote sensing has remained a challenge, because of inherent limitations in the minerals that can be detected and uncertainties in spectral modeling. A subset of the igneous rocks of Gusev crater provide a unique opportunity to determine modal mineralogy, because of limited alteration and the analytical capabilities of the Athena instrument package. Here we estimate the absolute (wt. %) abundances of Fe-bearing minerals from Moessbauer spectra (previously reported only as "areas for component subspectra"), and compare these results to the normative mineralogy calculated from APXS elemental analyses. We also test our preferred mineralogy by comparison of Mini-TES spectra with synthetic thermal emission spectra.

Published
2007

12. The Rocks of Gusev Crater as Viewed by Mini-TES

Author

Ruff, S. W, Christensen, P. R, and Blaney, D. L

Subjects
Lunar And Planetary Science And Exploration
Abstract

We are developing the means to separate atmospheric spectral features from rock spectra. Measurements made in the late afternoon when the temperature difference between the rocks and sky is the greatest provide spectra that are least impacted by downwelling radiance. Additionally, the long wavelength range of Mini-TES spectra contain spectral features that are least effected by contributions from the atmosphere due to its relative transparency in this range. Mini-TES spectra have thus been used to reveal the geological diversity in Gusev crater and will continue to be a rich source of mineralogical information as Spirit continues its traverse.

Published
2005

13. A Rover's-Eye View in the Thermal Infrared: Spectral Adjacency Effects

Author

Horton, K. A, Moersch, J. E, Lucey, P. G, and Ruff, S. W

Subjects
Lunar And Planetary Science And Exploration
Abstract

Due to the unique perspective of thermal infrared spectral measurements of geologic targets taken obliquely from a planetary rover or fixed lander, we have conducted several series of experiments designed to explore the various interferences which may arise from the local environment. Additional information is contained in the original extended abstract.

Published
2002

14. Geological Characterization of Remote Field Sites Using Visible and Infrared Spectroscopy: Results from the 1999 Marsokhod Field Test

Author

Johnson, J. R, Ruff, S. W, Moersch, J, Roush, T, Horton, K, Bishop, J, Cabrol, N. A, Cockell, C, Gazis, P, and Newsom, H. E

Subjects
Lunar And Planetary Science And Exploration
Abstract

The 1999 Marsokhod Field Experiment (MFE) provided an opportunity to test the suitability of rover-borne visible/near-infrared and thermal infrared field spectrometers to contribute to the remote geological exploration of a Mars analog field site.

Published
2000

15. Mars' 'White Rock' Feature Lacks Evidence of an Aqueous Origin

Author

Ruff, S. W, Christensen, P. R, Clark, R. N, Kieffer, H. H, Malin, M. C, Bandfield, J. L, Jakosky, B. M, Lane, M. D, Mellon, M. T, and Presley, M. A

Subjects
Lunar And Planetary Science And Exploration
Abstract

The Thermal Emission Spectrometer on board the Mars Global Surveyor has observed "White Rock" and the data do not indicate the presence of evaporite minerals. We suggest it is a deposit of compacted or weakly cemented aeolian sediment.

Published
2000

16. Mineralogy and chemistry of altered Icelandic basalts: Application to clay mineral detection and understanding aqueous environments on Mars

Author

Ehlmann, B. L., Bish, D. L., Ruff, S. W., and Mustard, J. F.

Abstract

We used a suite of techniques, including those emulating compositional data sets obtained from Mars orbit and obtainable at the Mars surface, to examine aqueous alteration of basaltic rocks from Iceland as a mineralogic and geochemical analog for Noachian environments on Mars. A sample suite was collected for laboratory measurement of (1) whole-rock visible/near-infrared (VNIR) reflectance and thermal infrared (TIR) emission spectra; (2) VNIR and TIR reflectance spectra of particle-size separates derived from the bulk rock and from materials extracted from fractures/vesicles; (3) X-ray diffraction (XRD) patterns for determination of quantitative modal mineralogy; (4) major element chemistry using flux fusion of whole-rock powders; and (5) electron microprobe analyses of minerals in thin sections. Conclusions about aqueous alteration can be influenced by technique. For these basalts, whole-rock chemical data showed scant evidence for chemical fractionation, but TIR, VNIR, and XRD measurements identified distinctive assemblages of hydrous silicate minerals, differing by sample. XRD provided the most complete and accurate quantitative determination of sample mineralogy. However, VNIR spectroscopy was the technique most useful for determining composition of low-abundance smectite clays, and TIR spectroscopy was the most useful for recognizing hydrated silicates in thin surface coatings. High spatial resolution mineralogical and chemical data sets were useful for understanding the texture and distribution of alteration products and variations in fluid chemistry. No single approach provides a complete assessment of the environment of alteration, demonstrating the importance of employing multiple, synergistic mineralogical and geochemical techniques and instruments in exploration of rock strata from aqueous paleoenvironments on Mars.

Published
2012

17. Addendum: Evidence for magmatic evolution and diversity on Mars from infrared observations

Author

Christensen, P. R., McSween, Jr, H. Y., Bandfield, J. L., Ruff, S. W., Rogers, A. D., Hamilton, V. E., Gorelick, N., Wyatt, M. B., Jakosky, B. M., Kieffer, H. H., Malin, M. C., and Moersch, J. E.

Abstract

Author(s): P. R. Christensen; H. Y. McSween, Jr; J. L. Bandfield; S. W. Ruff; A. D. Rogers; V. E. Hamilton; N. Gorelick; M. B. Wyatt; B. M. Jakosky; H. H. [...]

Published
2005
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19. Spirit Mars Rover Mission to the Columbia Hills, Gusev Crater: Mission overview and selected results from the Cumberland Ridge to Home Plate.

Author

Arvidson, R. E., Ruff, S. W., Morris, R. V., Ming, D. W., Crumpler, L. S., Yen, A. S., Squyres, S. W., Sullivan, R. J., Bell, J. F., Cabrol, N. A., Clark, B. C., Farrand, W. H., Gellert, R., Greenberger, R., Grant, J. A., Guinness, E. A., Herkenhoff, K. E., Hurowitz, J. A., Johnson, J. R., and Klingelhöfer, G.

Published
2008
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20. Meteorites on Mars observed with the Mars Exploration Rovers.

Author

Schröder, C., Rodionov, D. S., McCoy, T. J., Jolliff, B. L., Gellert, R., Nittler, L. R., Farrand, W. H., Johnson, J. R., Ruff, S. W., Ashley, J. W., Mittlefehldt, D. W., Herkenhoff, K. E., Fleischer, I., Haldemann, A. F. C., Klingelhöfer, G., Ming, D. W., Morris, R. V., de Souza, P. A., Squyres, S. W., and Weitz, C.

Published
2008
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30. ON THE TRAIL OF MARTIAN CARBONATES.

Author

Ruff, S. W., Hamilton, V. E., Rogers, A. D., Edwards, C. S., Horgan, B., and Niles, P. B.

Subjects
CARBONATE minerals, CARBONATES, CARBONATE rocks, MARTIAN meteorites, MARTIAN atmosphere, METEORITES, PLANETARY science, CARBONIC acid
Published
2019

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