#35 UNESCO World Heritage Sites: The Jurassic Coast

Last weekend I visited the fantastic Jurassic Coast – a 95 mile stretch of coastline stretching from Exmouth in East Devon to Swanage in Dorset.  It is inscribed on the World Heritage List for criterion 8: “outstanding examples representing major stages of earth’s history, including the record of life, significant on-going geological processes in the development of landforms, or significant geomorphic or physiographic features”.  In the case of the Jurassic Coast, it has rocks recording 185 million years of the Earth’s history and is considered to provide a unique insight into the Earth Sciences by showing a geological ‘walk through time’ spanning the Triassic, Jurassic and Cretaceous periods.  It was England’s first natural World Heritage site and this classification puts it on a par with Australia’s Great Barrier Reef.

Visiting the various sections of the coast really was like a Geography lesson come to life – fascinating rock formations, beautiful coves, arches and stacks all demonstrating how the movement of plates and the power of the sea acts to form landscapes.  In the photo below, you can literally see layers of different rocks which were horizonal as they formed but which have been pushed up vertical by the movement of continental plates.  These rocks are of different degrees of ‘hardness’ – meaning that in the case of formations like Lulworth Cove and Durdle Door the sea has entered through small gaps in the harder rock at the front to erode the softer rock behind.  Initially this forms caves, but then as the the pressure of the waves circulates high pressure water in the caves, it erodes higher and higher until blow holes are formed.  Eventually this causes the rock above to collapse, leaving behind the arches which were once the cave entrance.  Once these too erode, the pillars of rock left behind are known as stacks.  Meanwhile, bays and coves form in the hollowed out sections behind.

Rocks pushed up by plate movement

Rocks pushed up by plate movement

Durdle Door - showing how sea erodes to form arches, stacks and coves

Durdle Door – showing how sea erodes to form arches, stacks and coves

 

 

 

 

 

 

 

 

 

 

We learnt that this land, currently located in south west England, was originally situated near to the equator, approximately where Africa is now and was desert.  As the supercontinent broke up, this part of it moved northwards and came to rest where it is today – but its geology reveals its secret history and lays bare its migration.

The Jurassic Coast is also famous for fossils, including those of both land dwelling dinosaurs and marine creatures.

Pliosaur skull - the biggest bite in the world?

Pliosaur skull – the biggest bite in the world?

We visited the Dorset County Museum to learn more about the rock formations and how the Jurassic Coast was formed, and to see fossils from the entire length of the coast spanning millions of years of evolution.  As well as the usual ammonites, shells, and fragments of dinosaur bone is the fossilised remains of this enormous Pliosaur skull – a marine reptile.  They also have a preserved dinosaur footprint, as do other local museums along the coast.

The Jurassic coast also includes the 18 miles of the unusual Chesil Beach, a barrier beach which reaches 18m high in places.  It’s a narrow strip of pebbles forming a natural barrier protecting the coastline behind it and sheltering The Fleet – a stretch of seawater which enters around the Isle of Portland and stretches along the back of Chesil Beach, providing a protected haven for birds.  Due to the movement of the waves (which moves smaller pebbles further than larger pebbles), the beach has the appearance of being graded into size; the pebbles get smaller the further east you travel.  Apparently local fishermen (and, back in the day, smugglers) can tell you where they’ve landed on the beach by the size of the pebbles.

I had a brilliant weekend visiting the area, learning about the rock formations and movement, seeing the fossils and enjoying lovely long walks along the coastline with fantastic views.  The glorious sunshine helped, of course, but I’m really glad that The List is taking me out and about to new places.  This is one area of the country I’d definitely recommend for a visit.

Further information on UNESCO World Heritage criteria and sites can be found here: http://whc.unesco.org/en/criteria/

The Jurassic Coast website is here: http://jurassiccoast.org/

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