The recent discovery of cracks on the surface of Mars by NASA’s Curiosity rover last year have been analyzed by scientists to realize that these lakes could have dried up 3.5 billion years ago.
In early 2017, the desiccation cracks were found in Gale Crater, which was believed to have been filled by lakes 3.5 billion years ago. “We are now confident that these are mudcracks,” declared lead author Nathaniel Stein, a geologist at the California Institute of Technology in Pasadena, US.
These cracks form when wet sediment is exposed to air, their position closer to the centre of the lake bed rather than the edge suggests that lake levels went up and down over time.
“The mudcracks show that the lakes in Gale Crater had gone through the same type of cycles that we see on Earth,” Stein said. Traces of water once on Mars was not a new finding but the fact that the mudcracks are found, it may further lead to “to our understanding of this ancient lacustrine system”, said Stein, whose paper was published in the journal Geology.
“This research is just a chapter in a story that Curiosity has been building since the beginning of its mission,” he said.
For the study, the team examined a table-sized slab of rock nicknamed “Old Soaker”, which is a crisscrossing with polygons similar to desiccation features found on Earth.
The scientists found that the polygons are confined to a single layer of rock and with sediment filling the cracks between them, which is usually formed from exposure to air, and not due to hydraulic fracturing.