New Research Reveals Warmer, Wetter Mars Existed

June 04, 2010 - News Release

Scientists including a University of Guelph physicist have found new evidence of warmer, wetter conditions on early Mars that might have suited life on the red planet.

In a Science paper published recently online, the team says carbonate-rich rocks detected by a robotic rover suggest that the red planet had a denser, CO2-rich atmosphere and water more than three billion years ago.

Carbonate rock usually forms after atmospheric carbon dioxide mixes in the right conditions with water.

"It's the very first huge evidence for carbonate-heavy rocks on Mars," said physics professor Ralf Gellert, co-author of the new paper along with scientists from the United States and Germany.

Lead author Dick Morris, a planetary scientist at NASA's Johnson Space Centre in Houston, said: “Substantial carbonate deposits are evidence for habitable conditions because they originate under wet near-neutral conditions.”

Morris assembled the data received from instruments on the Spirit rover, which arrived on Mars in 2004. Spirit encountered the so-called Comanche rock outcrop in the Gusev crater in late 2005.

At first, scientists saw nothing special in that outcrop.

But one rover instrument had picked up evidence of iron-bearing carbonate. Analysis of data from other devices, including an alpha particle X-ray spectrometer (APXS), showed excess light elements such as carbon, nitrogen and oxygen and helped to quantify the carbonate in the rocks.

Referring to how Morris pieced together information from the rover's instruments, Gellert — lead scientist for the APXS — said: "It's a nice detective story."

In 2007, Guelph physicist Iain Campbell detected the first on-the-spot evidence of significant amounts of bound water still existing on Mars, formed by different processes in acidic conditions. Speaking of the new find, Gellert said carbonate-rich rock would probably have formed earlier in a more neutral aqueous environment.

Two years ago, Gellert and his Guelph team calibrated and delivered to NASA an improved version of the APXS for another science rover due to reach Mars in 2012. That rover will probably visit other sites containing possible evidence of more neutral water from the planet’s remote past.

Prof. Ralf Gellert
Department of Physics
519-824-4120, Ext. 53992

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