Wednesday, 1 July 2009

Charnwood Charnia!

Greetings Folks!

A quick search in Google for interesting articles about the geology of Charnwood reveals this humble blog as high as third on the list! So if my single blog on the subject last month is enough to shoot this venue to such stratospheric heights I think it proves that there is just not enough written on the subject!

As mentioned last time, the area of Charnwood in the East Midlands contains some of the oldest rocks in Britain, of pre-cambrian age. In 1957 frond shaped fossils were detected in these rocks suggesting the presence of complex, multicellular life in the pre-cambrian era.

A cast of the 'Charnia', the first accepted complex Precambrian organism. (From Wikipedia)

It is quite staggering to think that right on my own (new) doorstep are rocks that contain evidence of the earliest known multicellular life form on earth! The Charnia is one of the organisms found to have been present in the Ediacaran Period of the Neoproterzoic era which was the last era of the Pre-cambrian at 575Ma to 545Ma.

Strangely, the Ediacaran Period gave rise to a distinct form of life that only lasted in this relatively short timespan, before what became known as the 'Cambrian explosion. Few of the characteristics of the Charnian biota were carried forward into the Cambrian explosion of lifeforms, so alas they were a short lived phenomenon! Why they disappeared so abruptly hasn't fully been explained, but some believe it my have been due to the emergence of competition from other lifeforms, the emergence of predators or simply a change in the environment.

Prior to the discovery of the Charnia in 1957, it was believed that no life forms existed prior to the Cambrian. The humble fossil shown above brought about a hasty rethink! What is particularly interesting about the fossils of this period is that they are all soft bodied. Such creatures generally don't fossilise, so there must have been something about the global conditions of this time that allowed such delicate creatures to be preserved in such numbers.

The Leicestershire City Council Museums and Galleries website suggests this interpretation of what the Charnia may have looked like all those years ago:-

How the Charnia may have looked 575 Ma to 545 Ma.

This weekend sees Ruth and I getting away for a couple of days to Matlock Bath in Derbyshire, home of The Heights of Abraham, a scary cable car ride and some interesting caverns. I'll take the camera and post up a few photos next week if you're lucky!

Until then, take care!

Cheers, Alyn

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