Website Feedback | Publication Request | Contact Us | 
| 
| 
| 
Jurassic Coast
Durdle Door - The natural arch
Location: Durdle Door near Lulworth
Rock Type: Limestone
Age: Jurassic 140 million years old
Features of Note: Natural rock arch, ripple marks and Fossil Forest remnants.
The geology in detail
Hard layers of Portland Limestone have been folded on this part of the coast so that they appear almost vertical and these form the seaward edge of the small promontory here that includes the arch known as Durdle Door. The type of rock is known as an Oolitic Limestone and is made up of tiny balls of calcium carbonate and is famously quarried on Portland. On parts of the vertical face of the landward side of the arch there are preserved ripple marks, formed where the water was shallow enough so that the sea bed was disturbed by the waves. There are also holes that would have once contained fossil wood.
The ancient environment
Oolitic limestones are known to form in shallow warm seas very like those found in the Bahamas today, where modern oolitic sand forms on the sea bed.
The rock arch
The impressive arch of Durdle Door formed due to the effect of the erosive power of the sea on the vertical layers of different types of rock. At some point in the past the sea would have begun to breach the hard Portland Limestone and form a string of caves along the coast. The much softer rocks behind would have quickly been eroded away creating caves and natural arches. Eventually the arches collapsed leaving stacks, which would in turn be broken and washed away by the power of the waves. And so, the Portland stone was slowly stripped from the coast, Durdle Door is part of only a small strip that is left here. The remnants of old arches can still be seen in the form of ‘stumps' of limestone only just visible in the waves. One day that is all that will remain of Durdle Door.Loading...
Orcombe Point - The beginning of the story
The western end of the World Heritage Site and the oldest rocks on the Jurassic Coast. Striking Red sandstones and mudstones can be seen in the cliff and the ‘geoneedle' on top of Orcombe point marks the start of the ‘walk through time'.
Budleigh Pebble Beds - Mountains and rivers
An incredible river deposit of pebbles from
across the channel and sandstones with ancient plant roots.
Ladram Bay - Sea stacks and the E.Devon AONB
Ladram Bay is a picturesque beach characterised by several
high sea stacks. It is one of the highlights of the East Devon Area of
Outstanding Natural Beauty (AONB)
Sidmouth - Desert dweller in the Otter Sandstone
Sidmouth is a traditional British seaside town bounded
within a wedge of red sandstone.
Beer - A story of stone Part 1
Beer is a picturesque fishing village and a source for
the famous Beer Stone.
Lyme Regis - World famous fossil site
Lyme Regis is famous worldwide for the abundant and
well preserved fossils that are found there eroded from the local cliffs.
Charmouth - World famous fossil site
Charmouth is famous worldwide for the abundant and
well preserved fossils that are found there eroded from the local cliffs.
Golden Cap - The highest view on the south coast
Golden Cap is the highest point on the south
coast and gives a fantastic viewpoint of this western part of the World
Heritage Site.
Chesil Beach - Finest barrier beach in Europe
Chesil Bank is one of the finest examples of a barrier
beach in Europe. Its formation is a direct
result of impact of the Ice ages on the geology and coastal processes of West Dorset.
Osmington Mills - Traces of life
Fantastic trace fossils can be seen on the beach at
Osmington Mills. Some of the best along the whole of the Jurassic Coast.
Durdle Door - The natural arch
Durdle Door, a huge natural rock arc, is an internationally
famous landmark and one of the most characteristic and spectacular features
along the Jurassic
Coast.
Lulworth Cove & Crumple - a geography pilgrimage
Lulworth Cove is a quintessential location for
the study of different rates of erosion in the formation of bays and headlands.
It is also a beautiful and popular tourist destination.
Old Harry Rocks - The end of the story
This is the eastern end of the Jurassic Coast
and where the youngest rocks on the world Heritage Site are exposed. Brilliant
white chalk has been eroded into steep cliffs and the famous collection of sea
stacks known as ‘Old Harry Rocks'.
Copyright 2011 Jurassic Coast
Copyright 2011 Jurassic Coast