Sedimentary Processes in High-Altitude Salars

Astrobiologists have provided a description of two environments in the Andes Mountains of northeastern Chile that host acid brines. The high-altitude locations, Salar Gorbea and Salar Ignorado, are salt pans formed from the repeated evaporation of water. The harsh conditions present in these salars, and the organisms that thrive in their waters, could help scientists understand mechanisms that life as we know it could use to survive on other worlds in the Solar System.

The surface and groundwater pH of Salar Gorbea and Salar Ignorado was found to be as low as 1.8, and the salinity was as high as 290‰ of the total dissolved solids (TDS). Both sites are surrounded by active volcanoes and the sometimes extremely acidic, volcanogenic groundwater seeps up to form small pools at the surface. The team found microbial mats associated with both the lowest- and highest-pH waters.

The study provides the first comprehensive look at the sedimentary processes in Salar Gorbea and Salar Ignorado, and compares the findings to other saline lakes around the world. Based on their observations, the team believes that Salar Gorbea and Salar Ignorado could serve as terrestrial analogs for some martian sedimentary systems, paving the way for further study of the microbial ecology present at the research sites.

The paper, “The Physical and Chemical Sedimentology of Two High-Altitude Acid Salars in Chile: Sedimentary Processes In An Extreme Environment,” was published in the journal Journal of Sedimentary Research. The work was supported by NASA Astrobiology through the Exobiology Program.

Additional Information:
WVU geologist receives NASA grant to research environments similar to Mars (West Virginia University)