PASADENA, Calif., Jan. 20, 2013 /PRNewswire-USNewswire/ -- A NASA spacecraft is providing new evidence of a wet underground environment on Mars that adds to an increasingly complex picture of the Red Planet's early evolution. (Logo: http://photos.prnewswire.com/prnh/20081007/38461LOGO ) The new information comes from researchers analyzing spectrometer data from NASA's Mars Reconnaissance Orbiter (MRO), which looked down on the floor of McLaughlin Crater. The Martian crater is 57 miles (92 kilometers) in diameter and 1.4 miles (2.2 kilometers) deep. McLaughlin's depth apparently once allowed underground water, which otherwise would have stayed hidden, to flow into the crater's interior. Layered, flat rocks at the bottom of the crater contain carbonate and clay minerals that form in the presence of water. McLaughlin lacks large inflow channels, and small channels originating within the crater wall end near a level that could have marked the surface of a lake. Together, these new observations suggest the formation of the carbonates and clay in a groundwater-fed lake within the closed basin of the crater. Some researchers propose the crater interior catching the water and the underground zone contributing the water could have been wet environments and potential habitats. The findings are published in Sunday's online edition of Nature Geoscience. "Taken together, the observations in McLaughlin Crater provide the best evidence for carbonate forming within a lake environment instead of being washed into a crater from outside," said Joseph Michalski, lead author of the paper, which has five co-authors. Michalski also is affiliated with the Planetary Science Institute in Tucson, Ariz., and London's Natural History Museum. Michalski and his co-authors used the Compact Reconnaissance Imaging Spectrometer for Mars (CRISM) on MRO to check for minerals such as carbonates, which are best preserved under non-acidic conditions.