London: After 40 years, scientists claim to have solved mysteries of climate change on Mars - using data from NASA`s Mars Reconnaissance Orbiter (MRO).
The Shallow Radar, or SHARAD, instrument aboard MRO revealed sub-surface geology allowing scientists to reconstruct the formation of a large chasm and a series of spiral troughs on the northern ice cap of Mars.
"SHARAD is giving us a beautifully detailed view of ice deposits,
whether at the poles or buried in mid-latitudes, as they changed on
Mars over the last few million years," said Rich Zurek, MRO project
scientist at NASA`s Jet Propulsion Laboratory in Pasadena, Calif.
Researchers have found that the ice caps on Mars have been formed as a result of other forces apart from the ice flow itself.
Analysing radar data on a computer, scientists can peel back the layers like an onion to reveal how the ice cap evolved over time.
One of the most distinctive features of the northern ice cap is Chasma Boreale, a canyon about as long as Earth`s Grand Canyon but deeper and wider.
Some scientists believe Chasma Boreale was created when volcanic heat melted the bottom of the ice sheet and triggered a catastrophic flood.
Others suggest strong polar winds carved the canyon out of a dome of ice.
Other enigmatic features of the ice cap are troughs th1at spiral outward from the center like a gigantic pinwheel, possibly cause due to increased solar heating in certain areas and lateral heat conduction.
Jack Holt, of the University of Texas at Austin``s Institute for Geophysics and lead author of the paper focusing on Chasma Boreale, said: "Nobody realized that there would be such complex structures in the layers.
"The layers record a history of ice accumulation, erosion and wind transport. From that, we can recover a history of climate that``s much more detailed than anybody expected."
Roberto Seu, SHARAD team leader at the University of Rome, said: "These anomalous features have gone unexplained for 40 years because we have not been able to see what lies beneath the surface.
"It is gratifying to me that with this new instrument we can finally explain them."
The findings appear in the journal Nature.