Depth through thought

OUCC News 13th November 2008

Volume 18, Number 19

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Editor: Andrew Morgan

Trips this term:

Giovani and the giant crystals

Tim Guilford

Some time ago I watched a thoroughly preposterous film called “The Core” in which the usual motley array of humans (“Terranauts”) burrowed to the centre of the earth to blow it up. For reasons I forget, this was supposed to be good for America and therefore the rest of humankind. The plot doesn’t matter much (its easily lost), but at one point the burrowing machine plunges headlong into a giant geode containing the most absurdly oversize crystals you can imagine. At this point my ability to suspend disbelief and simply enjoy the special effects began to wear off. There’s impossible and there’s really impossible.

Last night at the Exploration Club OUCC jointly hosted an Italian speaker internationally renowned for his pioneering approach to cave science and exploration. We were taken on an incredible journey, beautifully illustrated with picture and video, through polar karst systems in Antarctica (where it was until recently believed that caves couldn’t form because it is too cold), to glacial pitches and tunnels on the Patagonian ice sheet, to a mixture of the most wonderful and most miserable underground spaces on the planet. Always Giovani Badino had a fascinating scientific story to tell, always in an engaging and showmanly style. “The underground is too big for us”, he exclaimed as he showed us his calculations of the probable many millions of kilometres of undiscovered cave passage on earth worked out from known densities and areas of karst. “It is impossible!” Heartening indeed for those of us who are always on the brink of giving up cave exploration for want of finding anything new. Then Giovani starts to tell us about the sounds that caves make, and shows how in principle it may be possible to determine the size of undiscovered underground systems from the pattern of resonance that air movements generate inside the system. He makes careful measurements of the frequency of these reverberations after opening and shutting a steel entrance in a cave in Italy, literally playing the mountain as perhaps the largest musical instrument on earth.

Suddenly I start to see those shifting elusive draughts in the boulder choke digs deep in Draenen in another light. Are we digging in a giant bagpipe?

Then we are into underground weather, and learn how even the legendary and oft-repeated stability of the cave has its informative meteorological perturbations if you measure temperature to the nearest 100th of a degree. We learn about clouds in caves (actually, I abseiled through one once in Spain, so I am beginning to believe all this), and the potential erosive effects of air movements depositing moisture on the cave walls, all back-up by meticulous calculations of lapse rates and energetic exchange through the system. Giovani is a professor of Physics at the University of Turin, and member of La Venta, an organisation that aims to broaden the concept of cave exploration and science beyond its traditional frontiers.

Suddenly, I am back in my crap film about American Terranauts. Only these are real cavers, dressed in pioneering ice-suits and back-packs that provide cool air to their face masks. The kit is all that allows them the survive more than a few minutes in the searing heat and high humidity of a cave beneath the limestone hills of Naica in Mexico. The kit is all home-made. These people are nutters, obviously, so what are they doing? They are exploring and surveying Los Cristales, a macrogeode chamber discovered during a mineral mining operation.

They are surrounded by the largest and most perfectly formed gypsum crystals imaginable. There are 170 of them in all, the biggest more than 11 metres long.

This place makes Lechuguilla look like the Mendips. The scene is simply unbelievable, just like my film The Core, except that it’s real. (editor: here is an article in National Geographic with pictures The giant crystals formed where thermal upwelling carry mineral rich waters into the limestone caverns, and have been exposed because of the water pumping operations that allow the miners to work below the water table. It is an awesomely beautiful place, and it is decaying. It is decaying because it lives under hot water far away from us and our damaging activities. One day, perhaps, the mine will shut and the chamber will fill again. In the meantime, Giovani and his team are hell-bent on documenting this unique phenomenon and learning as much as possible about what it can teach us about the earth’s before it decays or sinks back into oblivion. Why go to the moon?

This was Giovani’s first visit to Britain, and with a dinner in Christ Church Hall, followed by his first English pint in the KA, I hope it left a good impression. His talk, well attended by OUCC if a little thinly by OUEC (plus some members of the Italian Society), certainly left an impression on me. He also generously donated to the club library a pamphlet on Los Cristales, and a wonderfully illustrated book of his own called Caves of Sky. Take a look. If he ever gets to read this, let him know that we all thoroughly enjoyed his talk, his company, and sense of scientific adventure.