As the Curiosity rover advances across Mars, the planet’s watery past becomes clearer and sharper. In early 2017, scientists announced the discovery of possible dried cracks in the Gail crater, which 3.5 billion years ago were filled with lakes. A new study confirms this assumption and offers fresh data on the ancient Martian climate.
Now there is confidence that it is dirt. Dried cracks appear only where the wet sediment is exposed to air. In addition, their location closer to the center of the ancient lake, and not to the edge, hints that the levels of lakes rise and fall sharply over time.
The researchers focused on a stone slab called the “Old Soaker”. Intersected by polygons, which are identical in appearance to the terrestrial effects of drying. With the help of Curiosity, it was possible to obtain a physical and chemical analysis of the formation.
Image of a Squid Cove plate mined by a Curiosity rover on the 1555th sol. The red surface is covered with ridges protruding from the residual sediment filling cracks in the dried-up Gale crater about 3.5 billion years ago. Covers 60 cm wide
There is evidence that polygons bounded by one layer of rock and sediments filling cracks between them are created from exposure to air, and not by other mechanisms, such as thermal and hydraulic fractures. And although researchers have guessed this since the landing of Curiosity in 2012, it is only now that we managed to directly see this feature.