The Jurassic Coast The Dorset and East Devon

The Jurassic Coast. The Dorset and East Devon World Heritage Coast. All pictures © Alan Holiday 2003

World Heritage Coast Education Strategy Worbarrow Bay from Worbarrow Tout

An opportunity to study the past and present and look into the future. Chesil Beach late spring sunset

Why was the site designated? • The coast has 185 million years of outstanding geology more or less continuously exposed over 95 miles (135 km. ) of coastline. Worbarrow Bay from Worbarrow Tout.

Map of the World Heritage coast from Orcombe Rocks to the Old Harry Rocks. World Heritage Site Bid Document Access points and service centres – gateway towns to the W. H. C.

The extent of the World Heritage Site. • The Dorset and East Devon World Heritage Site extends from Orcombe Rocks, east of the Exe Estuary in Devon, to the Old Harry Rocks, between Swanage and Studland, in Dorset.

Aerial photo of Orcombe Rocks. Aerial photograph from multimap. com

Cliffs east of Orcombe Rocks showing bedding and a fault

A World Class Coastal Section. Triassic rocks at Ladram Bay, Devon. Cretaceous Chalk at the Old Harry Rocks. The rocks exposed are of Mesozoic age (255 m. a. to 65 m. a. ) formed at a very important time for the evolution of life on earth.

The Ballard Down coast looking towards the Old Harry Rocks.

• The geological time scale with particular reference to World Heritage Sites. The part of geological time represented by the W. H. C. is shaded and stands out over other geologically important World Heritage sites. World Heritage Site Bid Document

The importance of the fossils: • Many World Class fossil sites are found within the Site, including those at Lyme Regis and Charmouth. There are many possibilities for studying fossils, their evolution and importance to geologists as well as their aesthetic value.

• and Kimmeridge. (Steve Etches Collection)

Coastal Features. • Many important, sometimes unique, coastal features such as Lulworth Cove, Chesil Beach and the Fleet occur along this section of coastline. Ideal opportunities for field work for students of all ages…. .

Aerial view of Fleet at Abbotsbury …. also relating landscape features to maps and aerial images. Aerial photography from Dorset, photographic atlas

Lulworth Cove & Stair Hole evidence of major geological events and modern processes. Classic landforms and processes.

Aerial view of Lulworth Cove Aerial photograph from Dorset, photographic atlas How does the relative hardness of the rock control the form of the Cove?

Land slips. • There also important examples of land slips such as that at Black Ven, the largest in Europe, and the area between Lyme Regis and Axmouth, the first land slip described in technical literature. Black Ven from Charmouth

The Undercliff area between Lyme Regis & Axmouth. An ideal opportunity to study modern processes & their impact on the landscape and the local human geography.

Undercliff aerial view showing proximity to Lyme Regis. Aerial photograph from multimap. com

The development of scientific knowledge: • The area has been very important for the development of scientific knowledge, especially in Victorian times, at a time when geology was at the forefront of science. This resulted from the work of such people as Mary Anning, Henry de la Beche and more recently W. J. Arkell. World Heritage Site Bid Document Opportunities to study social history

Present day role in education. • The coast has an important role in education at present with large numbers of students of all ages coming to the area to study coastal landforms and geology. Students studying the Inferior Oolite at Burton Bradstock

Out of season tourism. • Out of season tourism is an important development as demonstrated by Rockwatch and other events. What benefits will such out of season tourism provide for the local economy? Study opportunities for students of all ages!

Very varied geology: • All the rocks in the area are sedimentary in origin but were formed in very varied conditions ranging from arid continental to tropical marine, to lagoonal, to tropical continental and back to marine. How can we explain these changing conditions? They can be related to plate tectonic processes.

Budleigh Salterton, east Devon. • At Budleigh Salterton, the orange coloured sediments • were deposited in arid and semi-arid conditions by rivers (perhaps similar to the River Nile in northern Sudan and Egypt) and as sand dunes. These sedimentary rocks now dip gently to the east and are found at 1600 metres below east Dorset and form one of the reservoir rocks for the Wytch Farm Oilfield. There are opportunities to relate modern desert environments to ancient ones exposed in the East Devon cliffs. How does the geology affect the development of modern resources? Why do the rocks dip to the east, what has caused the overall pattern of rocks?

Lyme Regis. • The cliffs either side of Lyme Regis are of Blue Lias, the base of the Jurassic, and formed of interbedded limestone and clay. These beds are often very fossiliferous. What can we tell from the fossil content, how do they help us understand the past?

Seatown and Golden Cap. • As the rocks dip to the east, progressively younger rocks are seen along the coast, various Lower Jurassic rocks are seen including the Belemnite Marl and Belemnite Stone at Seatown. Why are some rocks more fossiliferous than others?

Golden Cap: • The classic Dorset feature of Golden Cap occurs because younger “golden” Cretaceous sandstone rests on older Jurassic grey clay. There is a time gap of around 100 million years, known as an unconformity by geologists. Why is the geological record incomplete?

West Bay, evidence of varying conflicts. Aerial photograph from Dorset, photographic atlas There are opportunities to study recent changes with the civil engineering project at West Bay and the importance of tourism on coastal towns.

West Bay continued • Sometimes important features can be covered up by further coastal protection. What are arguments for and against such developments.

Burton Bradstock. • At Burton Bradstock and West Bay distinctive sandstone cliffs occur showing honeycomb weathering. The sandstone dips to the east and also forms a reservoir rock for the Wytch Farm Oilfield. Opportunities to study modern weathering processes and resources.

Burton Cliff. • Over a period of time the sandstone cliff weathers with harder beds standing out and weaker beds being worn away until cliff falls produce a fresh surface. Opportunities to study rock forming processes and rock properties such as porosity and permeability as well as mass movement.

Cogden Beach. • Further east there is a change to clay cliffs and the beginning of Chesil Beach is apparent. Pea grit forms the beach at Burton Bradstock and becomes progressively coarser towards Portland. • Compare and contrast the cliffs – what processes are involved in their formation, what are the rates of process? • How did the beach sediment form – study of attrition and related processes.

Abbotsbury: • At Abbotsbury, Chesil Beach protects the Fleet coastline from erosion. Concern has been raised that the erosion of Chesil Beach will lead to serious erosion problems in south Dorset. There are opportunities to study wildlife and natural vegetation – shingle and salt marsh plant communities – how do they colonise such inhospitable habitats?

The Fleet: • Along the Fleet there are various interesting fossil collecting sites including Herbury and Tidmoor Point. At Herbury the Boueti Bed occurs on the beach yielding fossil brachiopods. How to fossils relate to modern organisms – the evolution of some groups and not others.

Examples of fossils collected at Herbury.

Portland: • Portland shows interesting geology along the coast and in the disused quarries, such as Tout Quarry. In this picture Portland Sand Portland Stone are seen as well as evidence of land-slips. Visits to quarries, different methods of stone extraction, volumes, mass, density of stone, how much removed? how much left? how long? resource implications.

Aerial photo of north west Portland Aerial photograph from Dorset, photographic atlas An opportunity to study the conflicts between the World Heritage Coast, extractive industry and tourism