Silica in a Mars analog environment: Ka'u Desert, Kilauea Volcano, Hawaii
| Autor: | Raymond E. Arvidson, Gregg A. Swayze, Kimberly D. Seelos, Douglas W. Ming, Richard V. Morris, Bradley L. Jolliff, S. M. Chemtob |
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| Jazyk: | angličtina |
| Rok vydání: | 2010 |
| Předmět: |
Atmospheric Science
Lava Soil Science Mineralogy Context (language use) Pyroxene Aquatic Science engineering.material Oceanography Geochemistry and Petrology Earth and Planetary Sciences (miscellaneous) Earth-Surface Processes Water Science and Technology Basalt geography geography.geographical_feature_category Olivine Ecology Paleontology Forestry Mars Exploration Program Hematite Geophysics Volcano Space and Planetary Science visual_art visual_art.visual_art_medium engineering Geology |
| Popis: | Airborne Visible/Near-Infrared Imaging Spectrometer (AVIRIS) data acquired over the Ka'u Desert are atmospherically corrected to ground reflectance and used to identify the mineralogic components of relatively young basaltic materials, including 250–700 and 200–400 year old lava flows, 1971 and 1974 flows, ash deposits, and solfatara incrustations. To provide context, a geologic surface units map is constructed, verified with field observations, and supported by laboratory analyses. AVIRIS spectral end-members are identified in the visible (0.4 to 1.2 μm) and short wave infrared (2.0 to 2.5 μm) wavelength ranges. Nearly all the spectral variability is controlled by the presence of ferrous and ferric iron in such minerals as pyroxene, olivine, hematite, goethite, and poorly crystalline iron oxides or glass. A broad, nearly ubiquitous absorption feature centered at 2.25 μm is attributed to opaline (amorphous, hydrated) silica and is found to correlate spatially with mapped geologic surface units. Laboratory analyses show the silica to be consistently present as a deposited phase, including incrustations downwind from solfatara vents, cementing agent for ash duricrusts, and thin coatings on the youngest lava flow surfaces. A second, Ti-rich upper coating on young flows also influences spectral behavior. This study demonstrates that secondary silica is mobile in the Ka'u Desert on a variety of time scales and spatial domains. The investigation from remote, field, and laboratory perspectives also mimics exploration of Mars using orbital and landed missions, with important implications for spectral characterization of coated basalts and formation of opaline silica in arid, acidic alteration environments. |
| Databáze: | OpenAIRE |
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