NASA's Mars Reconnaissance Orbiter has provided new evidence of a wet underground environment on Mars, according to NASA.

Researchers analyzing spectrometer data from the orbiter, which looked down on the floor of the 57-mile wide and 1.4-mile deep McLaughlin Crater, think the crater once allowed underground water that 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," NASA reported.

The above photo of layered rocks on the floor of McLaughlin Crater, taken by the High Resolution Imaging Science Experiment camera on NASA's Mars Reconnaissance Orbiter, shows sedimentary rocks that contain spectroscopic evidence for minerals formed through interaction with water.

Image credit: NASA/JPL-Caltech/Univ. of Arizona