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California seventh-graders spot possible lava tube skylight on Mars 24 June 2010

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There’s no scale with the NASA/JPL image of the Martian surface on the left, but the black dot inside the red square is a large hole in the surface of Mars, about 190 x 160 metres in size and about 115 metres deep. It is situated on the slopes of Pavonis Mons, a volcano in the equatorial region of Mars, and may well be a skylight – an opening in the roof of a lava tube created during past volcanic activity (more on Martian lava tube caves here). It was spotted by a group of seventh-grade science students at Evergreen Middle School, Cottonwood, California, who have been taking part in the Mars Student Imaging Project run by NASA and Arizona State University. ‘The Mars Student Imaging Program is certainly one of the greatest educational programs ever developed’, says the students’ science teacher, Dennis Mitchell. ‘It gives the students a good understanding of the way research is conducted and how that research can be important for the scientific community. This has been a wonderful experience’.

Image credit: NASA/JPL-Caltech/ASU.

News
7th-graders discover mysterious cave on Mars – MSNBC, 21 June 2010
Mars cave opening found by 7th graders – CBS News, 22 June 2010
Teen project one-ups NASA, finds hole in Mars cave – AFP, 23 June 2010

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Olympus Mons and our ‘life on Mars’ obsession 5 March 2009

Posted by admin in geoscience, Mars, solar system.
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Over the past 24 hours quite a few stories have appeared in the media about a paper in the journal Geology on Olympus Mons, the giant Martian volcano. Can you spot what they have in common?

Here’s a hint: the ‘big question’ in the last headline is ‘whether the Red Planet had – or still supports – life’. Life on Mars is clearly what the Geology paper is all about.

It isn’t, of course. The paper concerned, Patrick K. McGovern & Julia K. Morgan, ‘Volcanic spreading and lateral variations in the structure of Olympus Mons, Mars’ (discussed here at The Volcanism Blog three weeks ago) is, as its title indicates, about the geology of Olympus Mons – specifically, why the volcano is the shape it is. The ‘big question’ of life gets a mention in the final paragraph.

An implication of the paper’s thesis – that Olympus Mons is underlain by clay sediments – is that there might be a reservoir of water beneath the volcano in which conditions suitable for thermophilic life might have been maintained. They only mention it in passing.

I suppose it’s understandable that Martian life is always going to have a higher media profile than Martian sedimentary geology. Is that healthy for science, though? And is there a danger that our Martian discoveries are always going to be viewed through the distorting lens of our ‘life on Mars’ obsession?

  • Patrick K. McGovern & Julia K. Morgan, ‘Volcanic spreading and lateral variations in the structure of Olympus Mons, Mars’, Geology, vol. 37, no. 2 (February 2009), pp. 139-142. [Link to abstract only]

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Olympus Mons, lopsided giant 11 February 2009

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Mosaic of Olympus Mons (NASA/NSSDC).

Olympus Mons, the largest mountain and the largest volcano we know of in the Solar System, is a huge shield volcano on Mars. It rises 23km above the Martian plain, is approximately 600km in diameter, and is lopsided, like a vast unsuccessful cake. The gently-sloping north-west flank of the volcano extends much further from the central caldera complex than does the steeply-sloping south-eastern flank; these flanks are also upwardly concave, showing an overall increase in the steepness of slope towards the centre, and are divided from the surrounding terrain by steep scarps, features not found in other sectors. A new paper on Olympus Mons in the February 2009 issue of Geology looks at the possible reasons for what it calls these ‘substantial asymmetries in its structure’. From the abstract:

The NW-SE asymmetries are aligned with the regional slope from the Tharsis rise, but an understanding of the underlying causes has remained elusive. We use particle dynamics models of growing, spreading volcanoes to demonstrate that these flank structures could reflect the properties of the basement materials underlying Olympus Mons. We find that basal slopes alone are insufficient to produce the observed concave-upward slopes and asymmetries in flank extent and deformation style that are observed at Olympus Mons; instead, lateral variations in basal friction are required. These variations are most likely related to the presence of sediments, transported and preferentially accumulated downslope from the Tharsis rise. Such sediments likely correspond to ancient phyllosilicates (clays) recently discovered by the Mars Express mission.

Thus the north-west flank of the edifice spreads more easily across the thickened sediments downhill from the Tharsis rise, while the south-east flank encounters the high-friction zone of the elevated pre-sediment basement which inhibits its spread. Result: a lopsided volcano. The sediments beneath forming the low-friction basal zone beneath Olympus Mons would need to be good at retaining water, making clays the obvious candidates, and the authors note that the spectral signatures of clay materials have been detected by the Mars Express OMEGA imaging spectrometer.

In the last, four-sentence, paragraph of the paper the authors suggest that ‘[these] results have implications for extant life on Mars’. The erupted lavas of Olympus Mons could have trapped a water reservoir in the sediments beneath: ‘This deep reservoir, warmed by geothermal gradients and magmatic heat and protected from adverse surface conditions, would be a favored environment for the development and maintenance of thermophilic organisms’. Hence the headline at Australia’s ABC Science today: ‘Martian volcano could shelter life’.

  • Patrick K. McGovern & Julia K. Morgan, ‘Volcanic spreading and lateral variations in the structure of Olympus Mons, Mars’, Geology, vol. 37, no. 2 (February 2009), pp. 139-142. [Link to abstract only]

Image: mosaic of Olympus Mons created with the medium-resolution black and white MDIM combined with a low resolution color image mosaic acquired on the 735 orbit of Viking 1 on 22 June 1978. Image Processing by Jody Swann/Tammy Becker/Alfred McEwen, using the PICS (Planetary Image Cartography System) image processing system developed at the U.S. Geological Survey in Flagstaff, Arizona (NASA/NSSDC image).

News
Volcanic spreading and lateral variations in structure of Olympus Mons, Mars – ScienceDaily, 3 February 2009
Martian volcano could shelter life – ABC Science, 11 February 2009

Information
ESA – Mars Express – home page for the ESA Mars Express mission
Unravelling part of Olympus Mons’ geologic history – HiRISE High Resolution Imaging Science Experiment (University of Arizona)
Volcanic Geology of Mars – from Albert T. Hsui, University of Illinois (Urbana-Champaign)
Highest and lowest points on Mars – Geology.com (on Olympus Mons and the Hellas Impact Crater)
Olympus Mons – Mike Dunford at The Questionable Authority shows just how big Olympus Mons is

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Mars – plate tectonics with a single plate? 22 December 2008

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A new study of Mars (reports Scientific American) suggests that, although the Red Planet does not have plate tectonics on Earth’s model with an outer layer of multiple plates moving relative to each other and to the inner structure of the planet, it does have in effect plate tectonics with a single plate. The entire Martian lithosphere, the theory argues, rotates relative to the inner core. This rotating outer shell could explain the apparent case of volcanic migration that produced the Tharsis Rise, suggests study author Shijie Zhong of the University of Colorado at Boulder:

This would help to explain the apparent movement of the volcanic activity that formed the Tharsis Rise. ‘For Mars, observationally we know the Tharsis volcanism really started in the so-called highlands, this thickened crust area, and then with time migrated toward the equator’ before stabilizing somewhat about four billion years ago, Zhong says. ‘This particular observation has been known for quite a while with no clear explanation’.

The same process, Zhong muses, may be found in other bodies such as the Moon and Mercury, long thought to have static and dull inner lives compared to the dynamic Earth.

  • Shijie Zhong, ‘Migration of Tharsis volcanism on Mars caused by differential rotation of the lithosphere’, Nature Geoscience, published online 14 December 2008 (link is to abstract only).

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Nicaraguan volcanoes and life on Mars 29 September 2008

Posted by admin in Cerro Negro, current research, Mars, Nicaragua, solar system.
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‘Although volcanoes on Mars today are dormant or extinct’, says the summary of this Astrobiology Magazine story, ‘in the distant past the Red Planet was literally a hotbed of volcanic activity’. Yes, literally a hotbed. ‘Cerro Negro, an active volcano in Nicaragua, offers clues to what the martian era of fire and brimstone may have been like – and what types of organisms could have lived in that superheated world’.

It seems Cerro Negro, the youngest volcano in Central America (born April 1850), offers Martian-type basalts that can provide terrestrial analogs to possible conditions in and around the volcanoes of Mars back in the ‘martian era of fire and brimstone’. To find out more, take a look at ‘Nicaraguan volcano provides insight into early Mars’ at Astrobio.net.

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