"We think the water came from the melting of nearby sub-surface ice called permafrost, and that the permafrost melting was caused by magmatic activity that still occurs periodically on Mars to the present day."

Mars meteorite found in drawer reveals history of water on Red Planet

Source: space
Source Link: https://www.space.com/the-universe/mars/mars-meteorite-found-in-drawer-reveals-history-of-water-on-red-planet