1.A diverse landscape. A false color image highlights the complex geology of the Northeast Syrtis Major region on Mars. NASA/JPL/University of Arizona Credit: NASA/JPL/University of Arizona
2. A detailed map shows the the various geologic units exposed at Northeast Syrtis.
Credit: Mike Bramble/Mustard Lab
Mineral deposits in a region on Mars called Northeast Syrtis Major suggest a plethora of once-habitable environments. By mapping those deposits in the region’s larger geological context, the research could help set the stage for a possible rover mission in 2020. Using the highest resolution images available from NASA’s Mars Reconnaissance Orbiter, the study maps the extent of those key mineral deposits across the surface and places them within the region’s larger geological context.
“When we look at this in high resolution, we can see complicated geomorphic patterns and a diversity of minerals at the surface that I think is unlike anything we’ve ever seen on Mars,” said Mike Bramble, a Ph.D. student at Brown. “Within a few kilometers, there’s a huge spectrum of things you can see and they change very quickly.” If NASA ultimately decides to land at Northeast Syrtis, the work would help in providing a roadmap for the rover’s journey.
Northeast Syrtis sits between 2 giant Martian landforms – an impact crater 2,000 kilometers in diameter, Isidis Basin, and a large volcano called Syrtis Major. The impact basin formed about 3.96 billion years ago, while lava flow from the volcano came later, about 3.7 billion years ago. Northeast Syrtis preserves the geological activity that occurred in the 250 million years between those 2 events. Billions of years of erosion, mostly from winds howling across the region into the Isidis lowlands, have exposed that history on the surface.
Within Northeast Syrtis are the mineral signatures of 4 distinct types of watery and potentially habitable past environments. Those minerals had been detected by prior research, but the new map shows in detail how they are distributed within the region’s larger geological context. That helps constrain the mechanisms that may have formed them, and shows when they formed relative to each other.
The lowest and the oldest layer exposed at Northeast Syrtis has the kind of clay minerals formed when rocks interact with water that has a fairly neutral pH. Next in the sequence are rocks containing kaolinite, a mineral formed by water percolating through soil. The next layer up contains spots where the mineral olivine has been altered to carbonate – an aqueous reaction that, on Earth, is known to provide chemical energy for bacterial colonies. The upper layers contain sulfate minerals, another sign of a watery, potentially life-sustaining environment.
Understanding the relative timing of these environments is critical. They occurred around the transition between the Noachian and Hesperian epochs – a time of profound environmental change on Mars. “We know that these environments existed near this major pivot point in Mars history, and in mapping their context we know what came first, what came next and what came last,” Mustard said. “So now if we’re able to go there with a rover, we can sample rock on either side of that pivot point, which could help us understand the changes that occurred at that time, and test different hypotheses for the possibility of past life.”
And finding signs of past life is the primary mission of the Mars2020 rover. NASA has held three workshops in which scientists debated the merits of various landing targets for the rover. Mustard and Bramble have led the charge for Northeast Syrtis, which has come out near the top of the list at each workshop. Last February, NASA announced that the site is one of the final three under consideration. https://news.brown.edu/articles/2017/04/syrtis
Recent Comments