Abstract
Data collected by Phoenix Lander's Thermal and Evolved Gas Analyzer (Phoenix-TEGA) indicate carbonate thermal decomposition at both low and high temperatures. The high-temperature thermal decomposition is consistent with calcite, dolomite, or ankerite, (3-6. wt.%) or any combination of these phase or, presumably, solid solutions of these phases having intermediate composition. The low-temperature thermal decomposition is consistent with the presence of magnesite or siderite, their solid solutions, or any combination of magnesite and siderite, and possibly other carbon-bearing phases (e.g., organics). The carbonate concentration for the low temperature release, assuming magnesite-siderite, is ~1.0. wt.%. This revised interpretation of the Phoenix-TEGA data resulted from new laboratory measurements of carbonate decomposition at a Phoenix-like 12. mbar atmospheric pressure. Phoenix carbonate was inherited in ejecta from the Vastitas Borealis and Scandia regions, inherited from material deposited by aeolian processes, and/or formed in situ at the Phoenix Landing site (pedogenesis). Inherited carbonate implies multiple formation pathways may be represented by carbonates at the Phoenix Landing site. Soil carbonates and associated moderate alkalinity indicate that the soil pH is favorable for microbial activity at the Phoenix Landing site and presumably throughout the martian northern plains.
Original language | English (US) |
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Pages (from-to) | 290-296 |
Number of pages | 7 |
Journal | Icarus |
Volume | 218 |
Issue number | 1 |
DOIs | |
State | Published - Mar 2012 |
Keywords
- Instrumentation
- Mars, Polar geology
- Mars, Surface
- Mineralogy
- Regoliths
ASJC Scopus subject areas
- Astronomy and Astrophysics
- Space and Planetary Science