The Accretionary Wedge #13: Geology in Spaaaace!


The September 2008 edition of the geoscience blog carnival The Accretionary Wedge, was hosted by The topic is “Geology in Spaaaace!” and the original can be found here.

The unprecedented threat of alien geology must weigh heavy on the minds of human Earth geologists. This month’s Accretionary Wedge (issue 13), opens the alien riddled can of worms that is Geology in Spaaaaace.

Greetings human Earth geologists and geologically interested beings of all kinds. This month’s Accretionary Wedge is dedicated to posts about, from an earthling’s perspective, Geologeeeeeeee in Spaaaaaace. In a manner befitting a species such as homo sapiens, posts will be tackled from a heliocentric perspective, starting with Venus and moving out to the entire universe. Behold the fearful wonder that is Geology in Space!

(note: if you’re reading this in an RSS reader, you’ll probably be missing out on the artwork I did for this post. Make sure you click through to get the full visual experience)


A world of beauty, or a galactic volcano in sediment’s clothing? Only Hypocentre of Hypo-thesis can distil the ancient doom of the Cambrian on Venus!

Something catastrophic may (or may not*) have happened during the Cambrian on Venus.

Maria Brumm of Green Gabbro gives cibophobics another reason to fear cakes, as she compares a plum clafoutis to Venetian impact craters in What Planet is my Clafoutis From?

Like so many moments of culinary inspiration, this plum clafoutis is nothing like what I was thinking of prior to actually wandering into the kitchen to make dinner.


The Earth. A pale blue dot suspended in a sunbeam. The target of jealous and tyrannical alien invaders. And impacts! Geology Happens relays the shocking facts about Impacts from Space!

I am cheating somewhat since my post is about a phenomenon that happens here on earth as well as in space. That is the idea of impact craters.

Tuff Cookie from Magma Cum Laude tells of impactors too in Rocks in from space. Could this be the first wave of yet another alien invasion?

Anyway, spending so much time at the museum – around the meteorites, among other things – was one of the reasons I became a geologist.


The constant, unending invasions from Mars during the 1900s should have been horrifying enough, but now SamStag from cryology and co. makes us quiver in fear at the prospect of Rockglaciers from Mars !!! Will the red menace ever be defeated!?

From all planets and minor objects of the solar system, most similarities to features of periglacial regions on Earth can be found on the red neighbour – Mars.

And if the thought of glacial processes on Mars didn’t send shivers down your spine, Brian from Clastic Detritus informs us of Fluvial Deposits on Mars! Walk for your lives!

High-resolution mapping of planet surfaces (including Earth) from orbiting spacecraft is revealing the beauty and complexity of erosional and depositional landforms.

The Asteroid Belt

The inner Solar System could have bore five terrestrial planets. The smoldering remains of planet 4.5 are what make up the asteroid belt, where material unchanged since the dawn of the Solar System remains. Though there’s no perceived threat of alien attack from the asteroid belt, who can really be sure? Silver Fox of Looking for Detachment discusses Mining the Asteroid Belt, in what can only be described as a preemptive attack to deprive potential invaders of potential resources. Potentially.

But first off, mining in space – in the asteroid belt or anywhere else – is not likely to happen anytime soon, IMO. Numerous people, however, have been looking into it, perhaps at least as long as we have been actively exploring space, beginning with our 1960’s race to the moon.


The gaseous bully of the Solar System offers up intrigue for the bravest of volcanologists. And Dave Schumacher of Geology News gives us the terrifying details of Extraterrestrial Volcanism on Io! Will the space bound geo horrors never cease!?

What is all the lava that erupts on Io composed of? Scientists do not know for certain the composition of the lava, but based on spectrometer data, Io’s surface is covered with a mix of hot, basaltic or ultramafic silicates and a sulfur dioxide frost.


The unfolding story of Titan should surely serve as a warning! Peter Polito over at Geology News regales us with tales of Titan Channels: What we know four and half years later.

One of the most fascinating things about the surface of Titan is that five years ago we knew nothing about it.  But with the arrival of Cassini and Huygens that has all changed.

Lockwood of Outside The Interzone also contemplates the channels of Titan and low temperature freeze-ray geology, as well as details of the moons of Enceladus, Europa and Miranda in A Fine Piece of Ice:

We knew there was a chance a chance of methane/ethane preciptation, we knew there was a chance of liquids on Titan. But the idea that dendritic drainage might form at 178 below zero Celsius never crossed my mind.


Disregarded as a fully qualified planet, could the menace of an atmosphere make Pluto a body of geological interest? Yes! And Chris from Pools and Riffles heralds in the new threat of the Geology of Pluto.

The hardest thing about studying the geology of Pluto is the distance. Pluto is at a minimum 4.28 billion km from earth. A little to far for a rock hammer. At that distance, even satellites have problems.

The Entire Solar System

Cosmochemists (as I could claim to be), like the big picture. The REALLY big picture. Chuck at Lounge of the Lab Lemming tells us of the radioactive horrors that endured when the solar system was dragged kicking and screaming into the galaxy, in Isotope Park.

When’s the last time your non-geological friends told you their 6 year old loves 60Fe?

The Entire Universe

MJC Rocks of Geotripper contemplates scarring the children of today with thought of the universe-sized scorpions and bears, but not as part of some sort of dome, in Done with Domes.

The ancients thought of the cosmos this way, and they made stories to go with the random arrangements of stars that formed bears and hunters and scorpions.

And speaking of space in its entirety:

How long could you survive in the vacuum of space?

You have read it. You cannot unread it. Stay tuned for more exciting geological tales in next month’s Accretionary Wedge. Your very survival could depend on it!

For those wondering, no I didn’t manage to get my thesis in on time. I’ve got a 4 week extension, though, so it’s not far off.

In the title comic book cover, illustrations of the Earth split in twain, the characters floating in space, and the terrifying martian are from various covers of the comic book series Mystery in Space and © DC Comics.

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