Sunday, 25 July 2010

The Lizard Peninsula- a geological wonder

A trip to the Lizard is a must for anyone exploring Cornwall after an MEI Conference. Lizard Point is the most southerly point of mainland Britain and is only 23 miles from Falmouth by road.

Approaching Lizard Point

The geology of the Lizard is totally different from the rest of Cornwall, very complex and, until the discovery of plate tectonics, a total enigma. Cornwall's geology is very much linked to the formation of Pangea over 300 million years ago, and as the Rheic Ocean closed the Variscan oregeny deformed and metamorphosed the Devonian slates and shales into the hard rock known locally as killas.

I am not a geologist, so I tend to use simple analogies to describe geological events, and I can only describe the formation of the Lizard as bulldozing of the earth's crust and mantle by the unimaginable tectonic forces.  As the Rheic Ocean finally closed, another analogy is that the underlying mantle was squeezed upwards like a pip from a piece of fruit, until it broke through the earth's crust to form the Lizard, a complete sequence of rocks from the mantle to the crust- igneous rocks, volcanic lava and ocean sediments- a total mess which would confound geologists for ages! One of the rocks, peridotite,  was rich in iron and magnesium and was metamorphosed by the tremendous heat generated into serpentine, one of the Lizard's most famous and attractive rocks.

Kynance Cove

There are many wonderful walks on the Lizard, but I would highly recommend the short walk to Kynance Cove, one of Cornwall's most beautiful and most photographed beaches. This is also the best place to see serpentine in all its glory, as the cliffs here are composed of this mineral, which also gives the sea a lovely turquoise colour.


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1 comment:

  1. The Lizard is indeed a beautiful place, and the National Trust has just voted Kynance Cove the best picnic site in Britain.

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