Curiosity rover finds cute little rock 'lizard' on Mars

Feb 19, 2020
The rocks being studied are estimated to have been three billion years old. The Curiosity Rover has yet to find any " clay-heavy layers". The maximum amount of clay reported, to date, is ~30%, with most sediments studied having much less than that. And no shales have been seen. These sedimentary rocks require the erosion and slow deposition of clays and other minerals (quartz) from pre-existing clay sources.