NASA’s one-ton Curiosity rover has beamed back thousands of photos of amazing landscapes within Gale Crater since landing in August 2012. And that’s after driving only 3.8 miles, probably the distance to the nearest grocery store for many of us.
Earlier this month, the rover entered the Kimberley, a rise within the crater dotted with three buttes – Mounts Remarkable, Joseph and Christine – that exposes several varieties of rock scientists are eager to study. The area will be the focus of exploration for weeks to come before Curiosity resumes its journey to the slopes of Mount Sharp, a broad peak that rises 3 miles (5 km) from the crater’s floor.
The Kimberley is strewn with some of the most beautiful sandstones yet seen on Mars. Sandstones form when water or wind carries along grains of sand until depositing them in a layer at the bottom of a stream or on the ground as in a desert. Minerals within the pore spaces between the sand grains cement the grains together to create sandstone. Sometimes layers of deposited sand can build up one atop another helping to further compact the material into stone.
Cement materials vary greatly. Clay minerals build sandstones that crumble with a rap of a hammer and more quickly erode in the Martian winds. Quartz cement creates a tougher rock more resistant to erosion. If you’ve ever marveled at the sight of a western, canyon-filled landscape, you’re seeing the varying resistance of sandstone to erosion at work. The same thing happens on Mars:
“A major issue for us now is to understand why some rocks resist erosion more than other rocks, especially when they are so close to each other and are both likely to be sandstones,” said Michael Malin of Malin Space Science Systems, San Diego. Malin added that variations in cement material of sandstones could provide clues to different types of wet environmental conditions in the area’s history.
At Yellowknife Bay, Curiosity’s last major waypoint, erosion had exposed both sandstones and a lower layer of mudstone that was once part of an ancient lake bottom. The rover will be tooling around the Kimberley for a while – why not join the exploration by periodically checking out the Mars raw image archive?