Thursday, 10 April 2014 09:26
April 10, 2014
As scientists probe planets for signs of life with the help of machines designed using engineering information, new revelations about the presence of water on extraterrestrial bodies continue to multiply. Recent research realizations suggest that Gusev Crater on Mars was once a lake that underwent repeated drying and refilling, according to an Arizona State University news release.
The Comanche protuberance of Columbia Hills was discovered to harbor particularly high concentrations of magnesium-iron carbonate minerals, which were previously thought to be the result hydrothermal happenings in the area rather than the sedimentation activity that would be expected to occur in a lakebed environment.
However, upon closer inspection of the data gathered by NASA's Spirit rover after its 2004 arrival on Mars, scientists found support for the hypothesis that cooler waters caused the accumulation of volcanic minerals at Comanche.
"We looked more closely at the composition and geologic setting of Comanche and nearby outcrops," said Steve Ruff, associate research professor at the Mars Space Flight Facility in the School of Earth and Space Exploration at ASU. "There's good evidence that low temperature surface waters introduced the carbonates into Comanche rather than hot water rising from deep down."
Ruff and his colleagues wrote in an abstract of a study describing their Martian findings that the collection of magnesium-iron carbonate minerals located at Comanche may have come about through the evaporation of water that contained materials absorbed from nearby outgrowths named Algonquin.
"Comanche and a neighbor outcrop called Algonquin are remnants of the older and much more widespread tephra deposit," Ruff said in the news release. "The wind has eroded most of that deposit, also carrying away much of the evidence for an ancient lake."
Nonetheless, the team asserted in the abstract that tephra aggregates similar to Algonquin may have been drained of minerals by transient water flows, leading to the distribution and subsequent buildup of volcanic materials at Comanche.
"The lake didn't have to be big," Ruff said in the news release. "The Columbia Hills stand 300 feet high, but they're in the lowest part of Gusev. So a deep, crater-spanning lake wasn't needed."
Initial discovery and future prospects
The publication notes that the first signs of a lake at Gusev Crater were found after Spirit's entry into the Martian environment in search of sedimentary stones brought to the site by flowing water. Though the probe initially discovered volcanic materials rather than lakebed deposits, the device later revealed that nearby Columbia Hills did contain rocks that were aqueously modified.
The deployment of Spirit in the crater was prompted by the area's appearance as a potential site of an ancient lake. A river passage rupturing the southern edge of the basin provided the suggestion of the previous presence of a body of water.
Though the rover provided researchers with valuable information about the surface of Mars and the possibility of hydrous activity at Gusev Crater, Spirit stopped transmitting signals to earth in 2010 without investigating much of the region, according to the news release. Now, however, scientists are considering sending another probe to the 100-mile-wide cavity to continue the explorations started with Spirit.
"Going back to Gusev would give us an opportunity for a second field season there, which any terrestrial geologist would understand," Ruff said in the news release. "After the first field season with Spirit, we now have a bunch more questions and new hypotheses that can be addressed by going back."
Scientists know that Gusev Crater is geologically varied thanks to the data gathered by Spirit, making it a viable option for future explorations. The prior investigation of the area also makes it a suitable site for the 2020 rover mission, which will involve the collection of material samples to be sent back to earth using devices devised through engineering research and development.
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