This week's geology-related news (that I found on the BBC...)

So here's a round up of the geology related news stories this week (week beginning 8th July 2013) so you don't need to go and find them yourself:

So starting off with a quick one, a volcano:

Video footage of the Popocatepetl eruption has been captured by Mexican military aircraft. The footage (for those to lazy to click the link) shows a smoking single vent at the top of the volcano:
http://www.bbc.co.uk/news/world-latin-america-23267354

Lake Vostok:

For several years an Antarctic drilling programme has being happening over the sub-glacial Lake Vostok. The task undertaken has not been insignificant as the teams only operate during the summer months and battle against extreme colds in their quest to drill through 4 kilometres of ice to the lake that lies 200 m below sea level.

But the big news is that the lake may contain all manner of extremophiles and possibly even fish! The energy source of such creatures maybe from nutrient rich hydrothermal vents on the lake bed.

It's all quite a thought when considering the environments that might be suitable for life on other worlds or, closer to home, the moons of Jupiter and Saturn, Europa and Enceladus (respectively).

http://www.bbc.co.uk/news/science-environment-23230864

(As aside this article mentions tardigrades, for more info. see: http://www.youtube.com/watch?v=6H0E77TdYnY)

The blue planet of silicate rain:

I'm going to pause for a second and let you wrap your head around the implications of an environment that has liquid sand as rain instead of water or light hydrocarbons (a more celestially common substance to find in a planet's rain).

Not so for HD 189733b which orbits it's sun extremely closely 65 light years for our own blue planet.

Where as our blue sky colour comes from the refraction of light in our atmosphere when light is refracted through silicate rain in an atmosphere over 1000 degrees centigrade it produces a stunning azure blue colour.

The planet was observed crossing its sun (which is one of many ways astronomers now have for detecting planets) and joins the myriad of exotic worlds that we are only just discovering.

http://www.bbc.co.uk/news/science-environment-23275607

(For more info. on exo-planets check out this video: http://www.youtube.com/watch?v=zFPnOUSdMdc)

Journey to the centre of the Earth...:

So the core. We know it's hot, dense and made or some sort of iron alloyed with... err... something. Ok, here's the thing, we actually know very little for sure about the Earth's core and considering that the core is approximately a third of the Earth's volume and takes up half the radius that's pretty embarrassing. Anything we do know is from seismic waves which have the unfortunate property of not being particularly good at being able to distinguish what the wave speed is actually being affected by.
Here are the following factors that can control wave speed of a seismic wave (from, say, a nice big earthquake):
Mineral composition, mineral phase, mineral density, melt fraction, mineral alignment and, finally, temperature.

Yeah, it's a wonder we know anything at all.

Anyway, the big news is there's some new theory about the structure of the Earth's core, for more information see this nice article here:

http://www.bbc.co.uk/news/science-environment-23180271

If you go down to the woods today...:

And finally, scientists have discovered a 50,000 year old forest that was totally submerged and covered until Hurricane Katrina in the Gulf of Mexico removed the sediments. Now it's a race against time to discover as much about the forest as possible before the sea water does its work and rots the forest away to nothing...

http://www.escapistmagazine.com/news/view/125801-Scientists-Discover-50-000-Year-Old-Underwater-Forest

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Hopefully I'll have so more science-y news for you next week otherwise I'll just have to wax-geological about this article I'm currently reading about the rheology  of suspended solids in solution.

I keep up to date with the latest news in nuclear technology.... I'm a dedicated follower of fission.

Popocatepetl- The smoking Mountain

Aside from having one of the greatest volcano names on the planet (it's up there with Batu Tara (Indonesia) and Erta Ale (Ethiopia) as one of those volcano names that just trip off the tongue in a delightful ribbon of phonetic sounds), Popocatepetl has an interesting mythology and geology to go along with its frequent activity.

Popocatepetl has been recently in the news (with some very pretty images accompanying it (see below)) for increased activity which has disrupted the airspace over Mexico City (which is approximately 60 km North-West of the volcano). The activity has included near-continuous explosions on Saturday 6th July, gas and ash emissions. As of writing (Monday 8th) reports are that the volcano is on yellow alert (phase 3 of 5) with a 12 km exclusion zone. Sunday 7th saw intermittent eruptions with a steam and ash plume 3 km high.

(Figure 1, reference below)

Like many ridiculously photogenic stratovolcanoes (kind of like the ridiculously photogenic Syrian rebel (dft.ba/-5rebel1) only more deadly), Popocatepetl was formed due to the collision of two plate boundaries, the North American Plate (which the volcano sits upon) and the Cocos Plate that is being subducted beneath it. Fluids are liberated from the subducting plate causing the mantle above the plate to melt and rise up through the crust. This magma mixes with other components creating an Andasitic magma which is viscous, volatile rich leading to explosive eruptions.

(Figure 2, reference below)

 

But let's now talk about some interesting trivia to do with our dear friend El Popo. I've been recently reading a book called 'Melting the Earth: The history of ideas on volcanic eruptions' by Haraldur Sigurdsson which apart from being the most compulsively readable geological text I've read since Prof. Gillian Foulger's 'Plates Vs. Plumes: A geological Controversy' recounts the local creation myth of Popocatepetl amongst other things.

So without too much plagiarism I shall now summarise said Aztec myth: 

 

The two mountains Popocatepetl and Iztaccihuatl (The Woman in White) were worshiped by the Aztec people as gods.

 

The Smoking Mountain (Popocatepetl) was a warrior who fell in love with the daughter of the emperor, Princess Izraccihuatl. The warrior went away to war and upon his victory headed home to claim his beloved sweetheart. However, enemies of the warrior sent word to the Princess that far from coming home victorious he had been killed. Heartbroken, the Princess died soon after of grief.

Upon discovering his deceased love Popocatepetl built two great mountains. He laid his 'sleeping woman' right on the peak of Iztaccihuatl (La Mujer Dormida, which means 'the sleeping woman') and on the other he forever stands guard bearing her funeral torch.

(I get something of a Romeo and Juliet vibe from this story personally...)

 

As far as explanations for the firry wrath of the great mountains near Mexico City (the flaming torch and insatiable wrath of a great immortal warrior) it certainly beats some of the other ideas early people had about volcanoes (if only in style!) For instance, for a great number of years it was thought that earthquakes and volcanoes were caused by great winds in the caverns beneath the earth! Combine that with some thoughts on the winds being caused by the combustion of brimstone (sulphur) and you've a recipe for some humorous wind-related jokes. (Except I'm far to high brow to make such jokes!)

 

Anyway, that's all for now, if you want to keep up with other volcano related activity I highly recommend the Smithsonian weekly report (the webpage has recently had a nice shiny overhaul) at: http://volcano.si.edu/weekly_report.cfm

or for daily updates on volcanoes practically as it happens check out the Volcano Discovery website:

http://www.volcanodiscovery.com/volcanoes.html



In an attempt to get myself doing this during the doldrums of the holidays expect to see more posts soon!

I'm so cool, I'm obsidian...

References:

Help with working out which plate the volcano is on: http://answers.yahoo.com/question/index?qid=20061211100617AAirLaW
Figure 1: http://www.telegraph.co.uk/news/worldnews/centralamericaandthecaribbean/mexico/9218197/Mexico-City-on-alert-as-Popocatepetl-volcano-spews-rock-and-ash.html
Figure 2: http://www.platetectonics.com/book/images/Subduction2.gif
Volcano monitoring information: http://www.volcanodiscovery.com/popocatepetl/news.html
More information on Popocatepetl: http://en.wikipedia.org/wiki/Popacatapetl
Further information on the myth of Popocatepetl and Iztaccihuatl: http://en.wikipedia.org/wiki/Iztacc%C3%ADhuatl