Martian Mountain Mystery

A digital elevation model of Gale Crater shows the pattern of mid-latitude Martian craters with interior sedimentary mounds.

Credit: University of Texas at Dallas / NASA

“The role of turbulence cannot be overstated,” Anderson said. “Since sediment movement increases non-linearly with drag imposed by the aloft winds, turbulent gusts literally amplify sediment erosion and transport.”

The location — and mid-latitude Martian craters in general — became of interest as NASA’s Curiosity rover landed in Gale Crater in 2012, where it has gathered data since then.

“The rover is digging and cataloging data housed within Mount Sharp,” Anderson said. “The basic science question of what causes these mounds has long existed, and the mechanism we simulated has been hypothesized. It was through high-fidelity simulations and careful assessment of the swirling eddies that we could demonstrate efficacy of this model.”

The theory Anderson and Day tested via computer simulations involves counter-rotating vortices — picture in your mind horizontal dust devils — spiraling around the crater to dig up sediment that had filled the crater in a warmer era, when water flowed on Mars.

“These helical spirals are driven by winds in the crater, and, we think, were foremost in churning away at the dry Martian landscape and gradually scooping sediment from within the craters, leaving behind these off-center mounds,” Anderson said.

Credit: University of Texas at Dallas

That simulations have demonstrated that wind erosion could explain these geographical features offers insight into Mars’ distant past, as well as context for the samples collected by Curiosity.

“It’s further indication that turbulent winds in the atmosphere could have excavated sediment from the craters,” Anderson said. “The results also provide guidance on how long different surface samples have been exposed to Mars’ thin, dry atmosphere.”

This understanding of the long-term power of wind can be applied to Earth as well, although there are more variables on our home planet than Mars, Anderson said.

“Swirling, gusty winds in Earth’s atmosphere affect problems at the nexus of landscape degradation, food security and epidemiological factors affecting human health,” Anderson said. “On Earth, however, landscape changes are also driven by water and plate tectonics, which are now absent on Mars. These drivers of landscape change generally dwarf the influence of air on Earth.”

Computational resources for the study were provided by the Texas Advanced Computing Center at UT Austin. Day’s role in the research was supported by a Graduate Research Fellowship from the National Science Foundation.

 

 

Contacts and sources:

University of Texas at Dallas