Additional martian hydrothermal sites considered in NASA's site selection studies include channels along the margins of impact crater melt sheets and the slopes of ancient volcanoes. Canyon floor of the Valles Marineris on Mars. Geologists believe the lakebed sediments have been deposited over the original canyon wall. Please credit image to NASA Ames Home Page. Canyon floor of the Valles Marineris on Mars.
Geologists believe the lakebed sediments have been deposited over the original canyon wall.
Please credit image to NASA Ames Home Page. With the great age of the meteorite, this clearly supports the search for an ancient record of life in martian rocks, particularly if we can return samples from the right places. Mars may harbor the best preserved rock record anywhere in the solar system. The 4.56 billion year age reported for ALH84001 suggests the record for Mars extends back to the very earliest history of that planet. This record has been erased on Earth by plate tectonics, a process that apparently never occurred on Mars.