Curiosity finds white rock, further evidence of wet Martian past

BBC : In addition to discovering water-formed clays on Mars’s surface, NASA’s Curiosity rover has found another sign of the planet’s wet past. On 17 January, the 1-ton rover rolled over a rock and broke it open. Looking back at the rock, the rover’s cameras revealed that the inside of the rockâmdash;dubbed Tintinaâmdash;is startlingly white. That color indicates that the rock was formed of hydrated minerals. Hydrated minerals, such as those that make up Tintina and the ones found in drilling samples, are signs that water flowed freely in that area of Gale Crater. It appears that sediments were carried down the slopes of the crater and deposited by a network of streams that flowed into a lake or pond. The water itself probably came from snow melt at a time when water ice was present near Mars’s equator.