Mars would have been warmer and wetter some 3.7 billion years ago, say scientists.
NASA rovers have shown Martian landscapes littered with loose rocks from impacts or layered by catastrophic floods, rather than the smooth contours of soils that soften landscapes on Earth. However, recent images from Curiosity from the impact Gale Crater.
University of Oregon geologist Gregory Retallack said that recent images from Curiosity from the impact Gale Crater reveals that Earth-like soil profiles with cracked surfaces lined with sulfate, ellipsoidal hollows and concentrations of sulfate comparable with soils in Antarctic Dry Valleys and Chile's Atacama Desert.
The newly discovered soils provide more benign and habitable soil conditions than known before on Mars. Retallack noted that their dating to 3.7 billion years ago puts them into a time of transition from "an early benign water cycle on Mars to the acidic and arid Mars of today."
Retallack added that Steven Benner of the Westheimer Institute of Science and Technology in Florida has speculated that life is more likely to have originated on a soil planet like Mars than a water planet like Earth.
The study is published in the journal Geology.