More evidence for subsurface water and ancient hot springs on Mars

Two more pieces of the water-on-Mars puzzle in the last few days… the Mars rover Spirit has found new evidence of liquid water having trickled down into the soil in the relatively recent past, while the Mars Reconnaissance Orbiter has found an old volcanic cone which would have been warm and wet even after most of Mars had already started to change to the cold, dry place we see today.

Churned up soil showing sulfate layers below surface sand and dust.
Credit: NASA/JPL-Caltech/Cornell University

When Spirit became stuck in the sand last year, the wheels churned up the soil during extraction attempts, which turned out to be a blessing in disguise. The revealed layers below the surface indicated that small amounts of water, perhaps from frost or snow, trickled down into the soil, likely sometime within the last few hundreds of thousands of years (recently, geologically-speaking) and on an on-going basis. See also the published paper here.

Hydrothermal mineral deposits on the volcanic cone in Nili Patera.
Credit: NASA/JPL-Caltech/MSSS/JHU-APL/Brown University

Meanwhile, the deposits of hydrated silica on an old volcanic cone in Nili Patera, photographed by the Mars Reconnaissance Orbiter, are thought to be the best evidence yet for ancient hydrothermal vents (fumaroles or hot springs). On Earth, such places are prime areas of habitability for microbes. They would also have been habitable places on Mars, but were they actually inhabited? The deposits are similar to ones found at hydrothermal vents in Iceland. The Mars rover Spirit had also previously found similar deposits directly in the soil (another tie-in to the other findings discussed above), evidence that fumaroles or hot springs were once present at its landing site.

Watch Curiosity grow

The next Mars rover, Curiosity, is being built right now in the clean room at NASA’s Jet Propulsion Laboratory in Pasadena, CA and you can watch the progress live on the new webcam!.

Curiosity is scheduled to be launched late next year and land on Mars in August 2012. It is also much larger than the two previous rovers, Spirit and Opportunity, at 10 feet long, 9 feet wide and 7 feet tall. It is nuclear powered, so not dependent on solar panels for energy and hosts a geology lab, including rock-vaporizing lasers and the cameras can take both high-resolution photos and video. It will search for evidence of past or present conditions suitable for life.

Into the depths of a Martian canyon

Valles Marineris is a huge rift valley on Mars, a canyon system dwarfing the Grand Canyon on Earth. A portion of it, Melas Chasma, is featured in new images from the Mars Express spacecraft. In this spot, the canyon is about 9 kilometres (5.6 miles) deep, and sulphate deposits are evidence of a former lake. There are also other water-cut channels in the immediate vicinity. There are additional and larger images, including 3D perspectives, here.

Credit: ESA/DLR/FU Berlin (G. Neukum)

Perhaps the proposed Martian airplane will fly over this area for even better views…?

Extensive carbonate deposits reported on Mars

According to a new paper published in Nature Geoscience, large deposits of carbonates have been found buried about six kilometres (four miles) below the surface of Leighton crater (exposed by the original impact), near the huge shield volcano in the Syrtis Major region. Small deposits have been found before on the surface, including recently by the rover Spirit, but much larger amounts would be additional evidence of a warmer, wetter ancient Mars, with a thicker atmosphere of carbon dioxide. Notably, carbonates are formed in non-acidic (alkaline) liquid water. So this finding would again reinforce the idea of ancient lakes, seas or oceans on the surface. But were those waters cold or warm? What about those icebergs? It seems like every time another piece of the puzzle is found, it just raises more questions…

Ancient Martian icebergs?

Images from the Mars Reconnaissance Orbiter have provided evidence of possible icebergs in the ancient Martian past. It has long been speculated that the northern smoother plains were once the bottom of an ocean; now, clusters of boulders and chains of pits or craters have been found there which are very similar to those on Earth, in areas where icebergs have scraped the bottom of the ocean, depositing rock fragments.

Credit: HiRISE

Of course, if there were icebergs, then there must have been oceans or seas. The findings support a more recent theory, of a cold and wet early Mars. So perhaps more like the Arctic ocean rather than the tropics, but still significant in terms of possible life.

And now, the case of the disappearing methane

First, as posted a few days ago, there was the mystery of seemingly missing methane on an exoplanet. Now there’s another methane-related riddle, on Mars. First detected in 2003, the gas is being continually produced, but the origin is still unknown. It could be either geological or biological, and is concentrated in three areas in the northern hemisphere, regions of previous volcanic activity and underground water ice. The amount also varies with the seasons, increasing in the spring, more so in the summer, peaking in autumn and then rapidly decreasing in winter. That pattern could fit with either still-occurring hydrothermal activity or biology, ie. microbes, or both.

The new puzzle though is why the methane has now been observed to remain in the atmosphere for less than a Martian year. It was expected to last longer, so something is destroying it relatively quickly, faster than expected for a photochemical process (destruction by sunlight). As stated in the article, perhaps chemicals from the soil, being alofted into the atmosphere by winds.

So both the origin and demise of the Martian methane are currently unknown. Hopefully more answers can come from the upcoming Mars Science Laboratory rover (Curiosity) and the ExoMars missions, both of which are equipped to analyse the methane in more detail…

Opportunity rover now halfway to Endeavour crater

The Opportunity rover passed the halfway mark this week on its long journey from Victoria crater to the huge 22 kilometre (14 mile) diameter Endeavour crater. A fitting first post for the new blog, as it is of course in Meridiani Planum where Opportunity has been travelling since 2004… It will be interesting as we get closer, because clay minerals have been found around the rim of the crater by the Mars Reconnaissance Orbiter; clay minerals form in non-acidic (alkaline) liquid water, so this would be yet another indicator of different surface conditions in the ancient Martian past…

The halfway point to Endeavour… Credit: NASA/JPL-Caltech

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