Definitive Evidence For Ancient Lake On Mars
2009-06-22 0:00

ScienceDaily.com

A University of Colorado at Boulder research team has discovered the first definitive evidence of shorelines on Mars, an indication of a deep, ancient lake there and a finding with implications for the discovery of past life on the Red Planet.


This is reconstructed landscape showing the Shalbatana lake on Mars as it may have looked roughly 3.4 billion years ago. Data used in reconstruction are from NASA and the European Space Agency. (Credit: G. Di Achille, University of Colorado)


Estimated to be more than 3 billion years old, the lake appears to have covered as much as 80 square miles and was up to 1,500 feet deep -- roughly the equivalent of Lake Champlain bordering the United States and Canada, said CU-Boulder Research Associate Gaetano Di Achille, who led the study. The shoreline evidence, found along a broad delta, included a series of alternating ridges and troughs thought to be surviving remnants of beach deposits.

"This is the first unambiguous evidence of shorelines on the surface of Mars," said Di Achille. "The identification of the shorelines and accompanying geological evidence allows us to calculate the size and volume of the lake, which appears to have formed about 3.4 billion years ago."

A paper on the subject by Di Achille, CU-Boulder Assistant Professor Brian Hynek and CU-Boulder Research Associate Mindi Searls, all of the Laboratory for Atmospheric and Space Physics, has been published online in Geophysical Research Letters, a publication of the American Geophysical Union.

Images used for the study were taken by a high-powered camera known as the High Resolution Imaging Science Experiment, or HiRISE. Riding on NASA's Mars Reconnaissance Orbiter, HiRISE can resolve features on the surface down to one meter in size from its orbit 200 miles above Mars.

An analysis of the HiRISE images indicate that water carved a 30-mile-long canyon that opened up into a valley, depositing sediment that formed a large delta. This delta and others surrounding the basin imply the existence of a large, long-lived lake, said Hynek, also an assistant professor in CU-Boulder's geological sciences department. The lake bed is located within a much larger valley known as the Shalbatana Vallis.

"Finding shorelines is a Holy Grail of sorts to us," said Hynek.

In addition, the evidence shows the lake existed during a time when Mars is generally believed to have been cold and dry, which is at odds with current theories proposed by many planetary scientists, he said. "Not only does this research prove there was a long-lived lake system on Mars, but we can see that the lake formed after the warm, wet period is thought to have dissipated."

Planetary scientists think the oldest surfaces on Mars formed during the wet and warm Noachan epoch from about 4.1 billion to 3.7 billion years ago that featured a bombardment of large meteors and extensive flooding.

The newly discovered lake is believed to have formed during the Hesperian epoch and postdates the end of the warm and wet period on Mars by 300 million years, according to the study.

The deltas adjacent to the lake are of high interest to planetary scientists because deltas on Earth rapidly bury organic carbon and other biomarkers of life, according to Hynek. Most astrobiologists believe any present indications of life on Mars will be discovered in the form of subterranean microorganisms.

But in the past, lakes on Mars would have provided cozy surface habitats rich in nutrients for such microbes, Hynek said.

The retreat of the lake apparently was rapid enough to prevent the formation of additional, lower shorelines, said Di Achille. The lake probably either evaporated or froze over with the ice slowly turning to water vapor and disappearing during a period of abrupt climate change, according to the study.

Di Achille said the newly discovered pristine lake bed and delta deposits would be would be a prime target for a future landing mission to Mars in search of evidence of past life.

"On Earth, deltas and lakes are excellent collectors and preservers of signs of past life," said Di Achille. "If life ever arose on Mars, deltas may be the key to unlocking Mars' biological past."

Adapted from materials provided by University of Colorado at Boulder.

Article from: ScienceDaily.com



Related Articles
Mars May Still Be A Living Planet, Methane In Atmosphere Reveals
Is there a Life On Mars Conspiracy?
Mars: Windy, Wet And Wild: Victoria Crater Unveils More Of Mars' Geologic Past
Mars explorer says we'll find life on other planets within 10 years
Should Mars be treated like a wildlife preserve?


Latest News from our Front Page

Turkey's Erdogan threatened to flood Europe with migrants: Greek website
2016-02-09 23:04
Turkish President Tayyip Erdogan threatened in November to flood Europe with migrants if European Union leaders did not offer him a better deal to help manage the Middle East refugee crisis, a Greek news website said on Monday. Publishing what it said were minutes of a tense meeting last November, the euro2day.gr financial news website revealed deep mutual irritation and distrust ...
Will Denmark Be The First Islamic Nation In Europe?
2016-02-09 23:44
Daily headlines prove that Europe is bursting at the seams with Islamists attempting to establish Sharia law and homegrown terror plots. France is ablaze with radicals, ISIS threatens they will send Spain back to the times of the Ottoman Empire, and Britain is much too concerned with appeasing Muslims that they are doing away with their own citizens’ free speech. The ...
'Hamilton' musical: All American founders non-White, but evil King George. I hate musicals!
2016-02-09 22:43
‘Hamilton’, Lin-Manuel Miranda’s musical about the life of Alexander Hamilton, one of America’s founding fathers, is being performed on Broadway. You know it’s going to have political undertones, when you read that the first act is titled: “Immigrants : We get the job done!” In addition to Alexander Hamilton, Miranda’s musical also casts Aaron Burr, George Washington, James Madison, John Laurens, Marquis Gilbert ...
Ted Nugent Posts "Anti-Semitic" Facebook Message About Gun Control
2016-02-09 22:53
Rock musician Ted Nugent posted a message about “who is really behind gun control” on Facebook that the Anti-Defamation League slammed as "anti-Semitic". More: ADL claims 26% of all world population is “anti-semitic” The ADL and domestic spying: Roy Bullock case revisited "Antisemitism on rise across Europe in worst times since the Nazis" says "expert" to the Guardian In the post, Nugent shares a ...
Illegal immigrant is arrested over murder of American nanny in Austria after she took him in to stop him being deported - and is revealed to have raped underage girl
2016-02-09 22:20
An illegal immigrant has been arrested over the murder of an American nanny who had given him shelter at her Vienna apartment. The 24-year-old Gambian had been wanted by police since the death of Lauren Mann, 25, from Grand Junction, Colorado last month. He was arrested on Thursday in Bern, Switzerland, at an asylum center there after his mobile phone use was ...
More News »