A terrestrial brine-seepage analog for Martian slope streaks near Salar de Pedernales in the Atacama Desert, Chile

• Autores: Mushkin, Amit; Sletten, Ronal; Trombotto, Dario Tomas; Jigjidsurengiin, Batbaatar; Amit, Rivka; Halevy, Itay; Morag, Navot; Gillespie, Alan R.
• Año de publicación: 2021
• Idioma: inglés
• Tipo de recurso: documento de conferencia
• Materia: Martian slope streaks; Atacama; Desert; Salar de pedernales
• Institución: Consejo Nacional de Investigaciones Científicas y Técnicas

Martian slope streaks are elongated down-slope, low-albedo surface features that currently form within sub-annual time scales in the high-albedo (“dusty”) regions of equatorial Mars. These km-scale streaks, which can persist up to several decades on the Martian surface, present one of the most enigmatic and dynamic suites of active surface features on present-day Mars. Two categories of explanations remain in debate regarding their nature: 1) “Dry” formation models, in which surface darkening is associated with mass wasting processes, such as dust avalanches; and 2) “Wet” formation models, in which surface darkening is associated with transient wetting of the surface by either seepage of sub-surface brines or deliquescence of atmospheric moisture. Here, we report recently discovered dark slope streaks that occur in the high Atacama Desert in Chile and display a close geomorphic resemblance to the Martian streaks. Field examination of the Atacama slope streaks revealed that they formed through down-slope seepage of groundwater brines sourced from the Salar de Pedernales located 500 m away. Chemical and mineralogical analyses demonstrate that salts deposited from the Pedernales brines combined with detrital input from soils/dust are responsible for surface darkening in the Atacama case. Field-based spectral measurements in the 0.4-2.5 micron wavelength range compare to those obtained from orbit for the Martian slope streaks. In addition, high-resolution topography derived from drone imagery revealed that the Atacama streaks are rougher than their surroundings at the decimeter-scale roughness of the entire hillslope they occur on. A similar distinction was previously established between Martian slope streaks and their surrounding slopes, although on Mars these roughness variations appear to occur at lower-range sub-centimeter scales. Our study of the unique Atacama slope streaks may support “wet” formation as a viable hypothesis for some of the Martian slope streaks.
Fil: Mushkin, Amit. Geological Survey of Israel; Israel
Fil: Sletten, Ronal. University of Washington; Estados Unidos
Fil: Trombotto, Dario Tomas. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mendoza. Instituto Argentino de Nivología, Glaciología y Ciencias Ambientales. Provincia de Mendoza. Instituto Argentino de Nivología, Glaciología y Ciencias Ambientales. Universidad Nacional de Cuyo. Instituto Argentino de Nivología, Glaciología y Ciencias Ambientales; Argentina
Fil: Jigjidsurengiin, Batbaatar. University of Washington; Estados Unidos
Fil: Amit, Rivka. Geological Survey of Israel; Israel
Fil: Halevy, Itay. Weizmann Institute Of Science.; Israel
Fil: Morag, Navot. Geological Survey of Israel; Israel
Fil: Gillespie, Alan R.. University of Washington; Estados Unidos
The Geological Society of America: Connects 2021
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Estados Unidos
The Geological Society of America