Mission Control To Curiosity Rover: Drill, Baby, Drill!

Look closely at this photo of the “Sheepbed” locality, taken by Curiosity rover, and you’ll see well-defined veins filled with whitish minerals believed to be calcium sulfate. These veins form when water circulates through fractures, depositing minerals along the sides of the fracture, to form a vein. Scale at top. Click to enlarge. Credit: NASA/JPL-Caltech/MSSS

Curiosity rover has done it again – found even more evidence for soaking, seeping, swirling waters on Mars. We’ve seen earlier images of water-rolled pebbles and sedimentary outcrops, but this week NASA shared a new set of photos from the Yellowknife Bay site showing alternating, thin layers of rock that could only have formed in a stream bed. Other pictures show mineral veins deposited by flowing water in rock fractures. What’s remarkable it how similar these rocks look to their counterparts on Earth.

This set of images shows the similarity of sulfate-rich veins seen on Mars by Curiosity to sulfate-rich veins seen on Earth. The view on the left is a mosaic of two shots from the remote micro-imager on the ChemCam instrument. Credit: NASA/JPL-Caltech

Scientists have been studying Yellowknife through Curiosity’s eyes looking for an ideal spot to test the rover’s drill for the first time. If engineers deem it safe, the rover will inch up to “John Klein”, a flat-lying expanse of bedrock laced with pale mineral veins, and fire up its drill sometime in the next few days. The location is named after former Mars Science Laboratory deputy project manager John W. Klein who died in 2011.

This picture shows inclined layering known as cross-bedding in an outcrop called “Shaler”. Currents mold the sediments into small underwater dunes that migrate downstream. When exposed in cross-section, evidence of this migration is preserved as tilted layers or strata. The bottom of the large outcrop is about 3 feet across. Click to enlarge. Credit: NASA/JPL-Caltech/MSSS

The first powdered rock samples will be used to scrub the drill clean of any earthly contamination. Later samples will be fed into Curiosity’s miniature chem lab to analyze the rock’s mineral and chemical makeup. Thanks to a zap from the rover’s ChemCam laser, we already know one of the veins contains high levels of calcium, sulfur and hydrogen, likely from the mineral calcium sulfate, better known as gypsum.

Not only has the robot returned photos of cross-bedded outcrops (layers of sediments deposited by rivers) and mineral veins, but using the closeup camera, scientists have found grains of sandstone the size of “peppercorns” in other rock formations nearby.

The “John Klein” site in Yellowknife Bay, a broad depression in Gale Crater on Mars. Sometime in the next few days, the rover will use its drill to gather a rock sample. The drill can bore as deep as two inches into rock. Click for large, annotated photo. Credit:

“Still others are siltstone, with grains finer than powdered sugar. These differ significantly from pebbly conglomerate rocks in the landing area,” according to the NASA release. Siltstones were originally layers of mud that were later compressed into rock by geological forces.

All these signs point to a much wetter past on the Red Planet. Pouring over the new pictures, it doesn’t take much imagination to envision the floor of Gale Crater crossed by streams and dotted with small lakes. For water to be stable on the surface of Mars long enough to build the rocks we’re now finding, the planet must have had a much thicker atmosphere and warmer temperatures in the past. A denser atmosphere provides pressure needed to prevent water from boiling away.

Curiosity photographed a transparent mineral grain measuring a couple millimeters across embedded in coarse-grained sandstone. Some Internet users have dubbed it “the Mars Flower”. Credit: NASA-JPL/Caltech

Transport yourself to a remote time when the brown Martian sky was blue and the air almost humid. At your feet a stream swirls along, carrying away tiny pebbles and grains of sand. While oxygen may only have been present in trace amounts in the ancient Martian air, you could listen to the sound of running water and maybe even hear one of Mars’ many volcanoes rumbling in the distance. Tell me this wasn’t a world ripe for microscopic life.

6 Responses

  1. H.Bob

    Possibly “ripe” for microscopic life, but we don’t know how organic life is sparked yet. It would certainly be amazing if Curiosity were to find some evidence !

    1. astrobob

      The veined rocks get me excited because we have similar looking rocks here in Duluth, Minn. except instead of calcium sulfate, they’re lined with calcite and other minerals.

      1. Giorgio Rizzarelli

        That’s great, Bob!

        I did a bit of research and discovered (probably you knew) that there are entire dunes of that mineral, gympsum, on Mars, in the North cap sand zone. Here’s a great pic: http://jtintle.wordpress.com/2008/10/16/saltating-gypsum-into-dark-polar-dunes/
        Also this phenomenon has an Earth analog, at White Sands National Monument in New Mexico.

        I also read that a bright vein deposited by water, gypsum or something similar, was found already by MER, about 1 year ago. I remember the pic:

        1. astrobob

          Yes, that’s right. You jogged my memory. I remember that big vein seen by the other rover. If I recall, it was a single, fat one. These Curiosity rocks show multiples. Just one more indication of water erosion.

          1. Giorgio Rizzarelli

            Yes of course, now there are multiple veins, inside rock and the composition is confirmed by the better MSL instruments. It’s a marvellous pic. Go on Curiosity…

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