The last eruption in Tenerife was in 1905 – a blink of the eye in geological time – and the island’s landscape is dominated by its volcanic past. Andy talked in particular about two caving trips, one with a surveying team and one with a group of artists (from the International Society of Spelaeological Art), to explore lava tubes on the island. In particular, they explored the extensive Cueva del Viento - Sobrado system in the north-west of the island. This is the fifth largest lava tube in the world; the top four being in Hawaii. Lava tubes are distinctive caves formed by lava flowing below the surface.
The lava inside the tubes is not all black as you might expect, but coloured, often yellow, by minerals and bacterial growth. Tree roots grow down from the roof of some of the caves, giving a surrealistic look to the photos. The rock is hard and jagged, with characteristic features including shelves, bubble bursts and, more rarely, stalactite forms.
The talk was illustrated with some spectacular photos, both above and below ground, with a few sequences set to music. Andy also showed sketches that the artists did underground, giving a different perspective to the caves.
On the second visit, Andy and his party got to the top of the 3,718m peak of Mount Teide. The photos looking down at the caldera wall and the distant coastline certainly made me want to revisit the otherworldly beauty of the volcanos of Tenerife.
Before the talk, the Cardiff Naturalists Society held its AGM.
The next indoor meeting, which is about Antarctica, is on Monday 14 October, is at the same place: The Cardiff School of Management building on Metropolitan University’s Llandaff Campus (Room 0023) at 7.30pm. The new program can be found elsewhere on this blog: http://cardiffnaturalists.blogspot.co.uk/p/programme.html