Carbonate precipitation can occur where groundwater enters lakes and supplies chemicals missing from the lake, creating carbonate mounds called tufa mounds or microbialites. These precipitates can often be associated with microbes that either create micro-environments that encourage precipitation or act as templates for precipitation. These types of environments may be the places where early life started, and scientists are interested in the mechanisms of how mineral precipitation interacts with these microbes. In studies at Big Soda Lake, Nevada, and Lake Clifton, Western Australia, thermal imagery in combination with X-ray diffraction, scanning electron microscopy, and chemical analyses have been used to determine the relation between microbes living in and around the carbonate and silica deposits and the role that groundwater plays in initiating carbonate precipitation. Thermal imagery allows the use of temperature contrast between groundwater and lake water to determine where the tufa mounds are actively forming. These studies are important for determining the mechanisms that may provide clues to the origins of life on Earth and may help determine ways to store carbon dioxide quickly.
Thermal image of a tufa mound with groundwater (warmer temperature, orange color) flowing from the top of the mound. The contrast in temperature is small (a few degrees centigrade) but is reliably detectable with the thermal imagery, which shows that the mound is active.