Tag Archives: Silurian

“A Volcano… in Somerset”

One thing I hate about some science articles in magazines and newspapers is where a whole article is expanded to a huge length in order to basically say “No”. The problem of course being that questions like “Was Darwin Wrong?” are the ones that get the readers in, not statements like “Darwin proven right, again”. This all being said I’m about to do exactly this myself, for which I apologise in advance.

So you may be wondering what the deuce the title of this article is referring to, well in short it’s all about this newspaper story from This Is Somerset: ‘We could be sitting on a Mendip volcano’ says Somerset expert.

The article is almost a year old, but it’s so bad I can’t let it get away with itself.

So according to the gentleman quoted in the article, he believes that if oil and gas companies are to be allowed to begin Fracking operations in the Mendip hills, it may re-activate an extinct volcano whose vent is situated at Moon’s Hill Quarry, near Stoke St Michael. I’m not going to attack the man for being wrong, he’s a non-specialist policy maker trying to protect his community from a harmful industry. I’m not going to attack the journalist for sensationalism because to use a tired metaphor – “sex sells”. Though we know not who the journalist is – quite telling in my opinion – the article has no actual person attached to it so we may never know.

What I will attack is the fact that our mystery journalist has thrown caution to the wind and not actually asked an expert – a geologist, volcanologist, or even the good folks at the Somerset Earth Science Centre (actually AT Moon’s Hill) – for clarification of whether or not there is a risk at all.

Now I’m no volcanologist, I’m a newly minted geologist far more interested in fossils and sediments than the very-hot-gooey-stuff that comes out of the ground; yet I can still explain why this article is nothing more than silly scaremongering. The volcanic plug at Moon’s Hill is very, very old, and a quick search online will bring you to websites explaining the geology of the place, at least one of which even gives you the geological setting for the now extinct volcano – it was a subduction zone volcano. This is a vital piece of information and one completely missing from the article in question.

Why is it vital I hear you whisper ever so quietly? Because there is no subducting margin anywhere near the Mendip hills any more… the nearest being in the Mediterranean sea. So I ask you… where is this huge accumulation of molten rock supposed to come from? It certainly hasn’t been hanging around unfed and unheated since the Silurian period some 425 million years ago, it would have cooled and hardened into a very, very solid rock by now.

Added to which, the rocks of this region have been shifted monumentally since the plug was emplaced. By what mechanism could such a huge quantity of molten rock so close to the surface as to be disturbed by Fracking; be kept from exploding or seeping out during the folding and faulting that produced the Mendips in the first place? If there is one, I haven’t come across it yet.

And finally, you might be thinking to yourself that the hot spring at Bath is mentioned in the article, if there’s no magma down there, how does it get heated up? An excellent question but one with a clean cut answer. Anywhere you dig on the planet, as you get deeper the ground gets warmer, by a whole 25 degrees centigrade per kilometre (77 degrees Farenheit) – even without a huge mass of molten magma near the surface. As the waters at Bath are a mere 46 degrees centigrade, that’s not a long distance the water would have to sink through the earth’s crust to attain that temperature and then rise back to the surface.

Yesterday I was fortunate enough to attend a science writing master class in London, and one of the biggest things that was stressed was that in science writing you have to produce something that will grab the interest of the reader, and also be right. Sadly while this article does the former, it is manifestly wrong, and all the more so for not asking the right questions of anyone who could have answered them.

Ben Brooks
06/10/2012

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