The direction of the coil can tell planetary geologists how the lava was moving as it flowed, and reveals that the surface of the vast area is coated with lava. More than 5000 cubic kilometers worth of lava pooled in the Cerberus Palus on Mars, forming a giant lava lake.
Ryan spotted these coils with the HiRISE (High Resolution Imaging Science Experiment) instrument, a camera on board the Mars Reconnaissance Orbiter that takes detailed images of Mars’ surface, and which planetary geologists use to study the planet’s history and composition. Ryan performed his analysis using more than 100 high resolution images beamed back by the NASA's Mars Reconnaissance Orbiter. Ryan said the large spiral coils there, in the Elysium volcanic province of Mars, range from five to 30 meters (16 to 100 feet) wide and could not have been formed by ice- or water-related processes.Now high-resolution images beamed back by NASA's Mars Reconnaissance Orbiter of the Red Planet have revealed 269 spirals of lava that researchers say cannot be explained by ice-related activity. "This is the first time lava coils have been identified on an extraterrestrial setting," study lead author Andrew Ryan at Arizona State University told SPACE.com. "The most surprising thing about these features when I first saw them was how well-preserved they are."
Their excellent preservation, along with the lack of craters in the cooled lava, suggests the volcanic eruption didn’t take place all that long ago.
|A small lava coil on pahoehoe flow, Kilauea Volcano, Hawai`i(see the pocket knife for scale.) Credit: W.W. Chadwick|
Cooling lava on Mars can form patterns like snail shells when the lava is pulled in two directions at once. Such patterns, rare on Earth, have never before been seen on Mars.
The lava left behind telltale coils as seen on some parts of Earth, like on the Big Island of Hawaii and in submarine lava flows near the Galapagos Rift on the floor of the Pacific Ocean, said the findings in the journal Science. They usually form along slow-moving shear zones in a flow; for example, along the margins of a small channel, and the direction of the flow can be determined from a lava coil.
Mars is the home of the largest known volcano in the solar system, Olympus Mons, which towers over Mars' western hemisphere. At 16 miles (25 km) high, it is about three times as tall as Mount Everest, Earth's highest mountain.
But don’t start a Martian volcano watch just yet. It will probably be millions of years before the Red Planet has another eruption.