In today’s Academic Minute, Dr. Deanne Rogers of Stony Brook University discusses the evidence for subterranean water on Mars.
Deanne Rogers is an assistant professor in the Department of Geosciences at Stony Brook University. Her researcher uses remote sensing techniques and laboratory spectroscopy to investigate planetary surface processes. She earned her Ph.D. at Arizona State University.
Dr. Deanne Rogers – Subterranean Water on Mars
Did Mars ever have lakes? Or oceans? Concentrated salt deposits at Meridiani Planum, a vast dune-covered plain spanning over 600 miles in diameter and investigated by the NASA Mars Exploration Rover over the last decade, point to repeated episodes of groundwater rising to the surface and rapidly evaporating over three and a half billion years ago. The minerals found by the rover suggested highly acidic waters, though, and in limited amounts--not conducive to life. But what about elsewhere? Why would groundwaters only emerge on the surface in Meridiani Planum?
Groundwater flow models suggest that waters may have risen to the surface in other topographic lows, such as basins formed by meteor impact. So why not look there? Using infrared data from a NASA satellite, we have found evidence of water in one of those basins, but this time, the minerals point to mild water conditions – perhaps similar to hard tap water on Earth. What’s more, layered materials found in the crater point to deposition under water. So, unlike the Meridiani Planum salts, these minerals were formed in a lake – standing water that did not evaporate rapidly enough without first filling the bottom of the basin. Where did the water come from? There are no channels leading into the crater that would suggest river flow—the water must have come from below.
For the past two decades, the search for habitable environments on Mars has been focused on locations at the surface, due to limited sensing capabilities of satellites and rovers. But on Earth, nearly fifty percent of the total biomass is comprised of microbial life found underground. With increasing evidence for extensive groundwater on ancient Mars, and harsh conditions at the surface, perhaps we should be looking for signs of life way below the rover’s wheels.