opal – Australian Science

Could Australian Terrain Help Train Future Mars Explorers?

Elizabeth Howell — Mon, 08 Jul 2013 00:01:32 +0000

Researchers simulate Mars exploration during a 2008 NASA Desert RATS (Research and Technology Studies) exercise in Arizona. Credit: NASA

How do you rehearse for a Martian space trip? Simulations can only bring astronauts so far when they’re figuring out a mission. A typical person training for the International Space Station can expect a combination of classroom work, spacewalk rehearsals in the water, and robotic arm training using articles that are very close to the real deal.

Exploring another world is a complex problem yet again. Astronauts in the Apollo mission received hundreds of hours in geology training, for example, and flew to areas ranging from Meteor Crater in Arizona to the site of a huge crater in Sudbury, Ont. Today, NASA and other research institutions carry out Mars mission research at two Mars Society sites in Canada and Utah, among other locations.

Turns out Australia’s challenging environment could also be a good analog for the Red Planet. The Great Artesian Basin, which stretches across much of the east side of the continent, is the site of “acidic weathering” that could be similar to what was experienced on Mars, a new study says. Perhaps future Martian trainees could add Australia to their list of destinations.

A map of the Great Artesian Basin. Credit: Wikimedia Commons

The tough environment has an economic link to Australia: precious opals, the national gemstone of the country. The May 2013 paper in the Australian Journal of Earth Sciences suggests not only a way that opals form.

There’s a bit of a mystery behind opal formation, which Markus Hammonds documented in a past Australian Science article. Also, their formation could point to similarities to the Red Planet.

“Interestingly, acidic oxidative weathering has been documented at the surface of Mars, which shares an intriguing set of attributes with the Great Artesian Basin,” stated the scientific paper.

These characteristics include sandstones that appear very similar between the locations, a “drying out” period that created clay and opaline silica, and even a similar red color, the paper noted. The opals themselves were formed after the acidic weathering dried out the landscape amid the Eromanga Sea receding about 100 million years ago.

A sample of precious opal. Credit: Wikimedia Commons

So what are the implications of this link between Australia and Mars?

It could help us better understand geological features. Rovers on Mars keep stumbling across evidence of minerals that formed in water, “including opal-bearing mineral assemblages”, the paper noted. Research on the Red Planet is thus helping us to better understand how opal formed in Australia, it added, and how the area was dehydrated during the Late Cretaceous.

It could teach us more about each planet’s history. Both areas are very red, suggesting that “oxidative weathering played an important role during and after the dehydration of Mars’ surface”, the paper stated. From a wider perspective, comparative planetology between Mars and Earth could help us understand how a planet can lose much of its atmosphere (as Mars did) or hang on to it (as Earth has, so far.)

Australia could be a good training ground for budding Martian scientists. This finding has already generated a lot of interest in the greater space community (it was picked up by a NASA astrobiology publication, for example) and will likely bring about more research into the links. This could potentially bring Australia to more prominence as a potential training ground for Mars exploration. Geologists could train for searching on Mars by searching in the Great Artesian Basin.

Human Mars exploration is likely still years away, but at the very least, Australia could be a spot where technology is tested out and Martian geological exploration is simulated. The Mars Society has talked about putting in a “Mars-OZ” base in Australia, for example.

There are substantial risks to the journey — this Australian Science article by Sharon Harnett explains more about the hazards associated with radiation and cardiovascular damage, among other risks. There’s a lot we need to figure out. But as more findings like this recent one are released, interest in Australia as an analog environment is bound to increase.

Cite this article:
Howell E (2013-07-08 00:01:32). Could Australian Terrain Help Train Future Mars Explorers?. Australian Science. Retrieved: May 03, 2024, from http://australianscience.com.au/space/could-australian-terrain-help-train-future-mars-explorers/

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The post Could Australian Terrain Help Train Future Mars Explorers? appeared first on Australian Science.

What do Mars and Australia have in common?

Markus — Tue, 11 Jun 2013 00:29:45 +0000

If you’re expecting a punchline to that title, then guess again. It’s no joke. Surprisingly, Australia shares some remarkably similar geology to our neighbouring planet. Specifically the Red Centre, the arid heart of Australia, is the most Mars-like place on Earth!

It’s possible that people may have mused on the similarities already. After all, with its strikingly rich colours, the Red Centre (more often known as the Outback) certainly looks like few other places on Earth. Without any vegetation, the colour of the soil and rocks in the region could easily resemble Mars in places. But evidently, this resemblance is more than just skin deep. The clue that lead to this fascinating realisation? Another of Australia’s most beautiful and iconic of things – opals.

A view from the top of Uluru, showing it’s distinctive red colour. Credit: Binarysequence/Wikimedia Commons

Patrice Rey at the University of Sydney’s School of Geosciences was investigating how opals formed. It may be surprising to learn that opals are found in few other places on Earth, with roughly 90% of all opals worldwide having originated in Australian mines. Beautiful and sought after, there’s been a lot of mystery behind opals for a long time – specifically about how they form, why they’re found at such shallow depths under the Australian soil, and why they’re found nearly nowhere else on Earth.

The story of these beautiful sparkly gemstones, it turns out, began around 100 million years ago. At the time, most of central Australia was covered by the Eromanga Sea. In times past, this huge epicontinental (inland) sea covered what is now known as the Eromanga Basin – spanning an area of one million square kilometres and reaching into much of what is now Queensland, the Northern territories, South Australia and New South Wales.

During the Cretaceous period, when dinosaurs still ruled our planet, this sea would have been teeming with prehistoric life. But much like the dinosaurs, the Eromanga Sea was doomed. Around 100 million years ago, the climate of Earth began to change and the sea began to dry out. The sea dried out rapidly on geological timescales, to cover a much smaller area. The result was that the chemistry of the surrounding rocks began to change.

As the Eromanga Sea dried out, pyrite minerals in the surrounding rocks began to release sulfuric acid, causing acid weathering on a huge scale – quite possibly the largest Earth has ever seen. The opaline silica which was created in the Australian rocks during this process would later go on to form into opals. But the big clue is the acid weathering – we only know of one other place in the Solar System where this has happened in the past. Planet Mars.

While the predicament of prehistoric Australia is, as far as we know, unique on Earth, Mars actually shares a lot in common with this event. Except on Mars, we believe that the drying out of seas happened on a global scale. Hints of this were detected in 2008, when NASA’s twin Mars rovers, Spirit and Opportunity, detected several telltale clues in the Martian soil.

The surface of Mars was found to hold opaline silica, iron oxides, and certain types of clay. All of these clues led areologists* to conclude that the surface of Mars had been subject to huge amounts of acid weathering. The exact same type of acid weathering which Rey and his fellow researchers have now discovered to have happened in Australia!

An opal doublet from Andamooka, South Australia. Credit: CRPeters/Wikimedia Commons

If you’re thinking that this means that there may be Martian opals waiting to be discovered somewhere on the planet next door, it’s hard to say. But it’s certainly a possibility! There is, however, one final step in the formation of opals. The opaline silica which was found on Mars is not yet true opal. In Australia, the surrounding rock has an impressive capability to neutralise acid. This means that after the ground in Australia became riddled with opaline silica, the surrounding conditions quickly went from acid to alkaline. When this happens before the silica trapped in rock cavities dehydrates and solidifies – voila! Opals! Of course, there’s a good chance that Mars may be home to some kinds of rock which can also neutralise acid the same way.

So only time will tell. Perhaps someday in the future, Martian colonists may be using Mars opals to create the first ever jewellery made elsewhere in the Solar System!

*An areologist studies the geology of Mars, seeing as technically the “geo” in geology refers to planet Earth.

Could there be opals hiding under the Martian soil? Credit: NASA/JPL

Cite this article:
Hammonds M (2013-06-11 00:29:45). What do Mars and Australia have in common?. Australian Science. Retrieved: May 03, 2024, from http://australianscience.com.au/geology/what-do-mars-and-australia-have-in-common/

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