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Vis-NIR Spectral Characterization of Si-rich Deposits at Gusev Crater, Mars
| Content Provider | Semantic Scholar |
|---|---|
| Author | Rice, Melissa S. Bell, James Wang, Aihui H. Cloutis, Edward A. |
| Copyright Year | 2008 |
| Abstract | Introduction: During its investigations in the Inner Basin of the Columbia Hills, the Mars Exploration Rover (MER) Spirit has discovered high concentrations of amorphous silica in several locations [1]. In a topographic lowland d믭 "Silica Valley", Spirit's Alpha Particle X-Ray Spectrometer (APXS) measured a composition of >90% silica at the soil feature "Gertrude Weise" (Fig. 1), a record for Mars [1]. Mini Thermal Emission Spectrometer (Mini-TES) results from these targets are consistent with opaline silica [2]. Light-toned nodular outcrops also have been found to have high silica (up to ~72% silica at "Elizabeth Mahon" [1]), and they have been identified near three separate deposits of sulfur-rich soil [3]. On Earth, deposits of amorphous SiO2 are common surface manifestations of high-T geothermal systems [e.g., 4], and thus Spirit's discovery may provide clues to the past habitability of Mars. Pancam Spectral Characteristics: Spirit's Pancam instrument [5,6] has been used to collect Vis-NIR relative reflectance spectra of the high-Si deposits in 11 unique wavelengths from 430 to 1009 nm. Both the bright soils at Gertrude Weise and light-toned nodules (within "Silica Valley" and near S-rich soils) show a distinct feature: a negative spectral slope from 934 to 1009 nm (corresponding to Pancam's R6 and R7 filters; Fig. 3) [3]. The "white" soil at the S-rich Tyrone deposit also exhibits this feature, but the "yellow" soil within the same deposit does not. Mini-TES spectra of the "white" soil show evidence for amorphous silica [7]; APXS measurements were not made at the Tyrone site, however, so the specific compositional difference between these two color units is not well constrained. With the exception of the Tyrone "white" materials, all high-Si soils and nodules are also characterized by a flat spectrum between 864 nm and 934 nm, indicating that the absorption band related to the Si-rich materials is |
| File Format | PDF HTM / HTML |
| Alternate Webpage(s) | https://www.lpi.usra.edu/meetings/lpsc2008/pdf/2138.pdf |
| Language | English |
| Access Restriction | Open |
| Content Type | Text |
| Resource Type | Article |
