The Story of the Jurassic Coast

For centuries, Earth scientists have gravitated towards the beguiling cliffs and beaches of Dorset and East Devon, creating a wealth of scientific understanding that has flowed from the shores of the Jurassic Coast. This story continues today. The international importance of the geological heritage along the Jurassic Coast was recognised in 2001 when it became a World Heritage Site.

The significance of the Jurassic Coast as a World Heritage Site lies in its unique geology. Exposed along its 95 miles of cliffs and foreshore ledges, are rocks that provide a near-complete record of the Triassic, Jurassic and Cretaceous periods of geological time. 

Between roughly 260 and 65 million years ago, layers of sediment built up here almost continuously. As environmental conditions changed over millions of years, different types of sedimentary rocks were laid down. The exquisite fossils that the rock layers contain provide insight into the web of life at different points in Earth’s history. Together, the sequence of rock layers and fossils along the Dorset and East Devon coast can be read like a book, describing the evolution of this area over the course of 185 million years. 

Today, the diversity of rock types across the coastline has given rise to many different coastal landscapes, from sheer golden cliffs, to massive complex landslides. It has been described as an outdoor laboratory for the study of coastal landforms. 

Take a Walk Through Time

Starting at the western end of the Jurassic Coast, at Orcombe Point in East Devon, the red Triassic rocks are around 260 million years old. Travelling eastward is a Walk Through Time, as beneath your feet and in the cliffs the rocks get progressively younger until you reach the eastern end of the Site, at Studland Bay in Dorset, where the white Cretaceous Chalk is around 70 million years old. 

On the way you will pass rocks laid down in deserts, tropical seas, forests and lagoons. As you move across the different rock types you will encounter the richly varied landscape, a result of sandstone, mudstone and limestone being shaped by natural processes into hills, valleys, bays, beaches, arches, stacks and landslides. Even the buildings change, as the unique character of each town and village is strongly derived from their use of whatever local building stone was and is available to them. By stopping at museums and visitor’s centres along the way you will see the extraordinary wealth of fossils that have been and continue to be recovered from the shoreline of the World Heritage Site. These relics of prehistoric habitats and ecosystems help chart the evolution of life across the Triassic, Jurassic and Cretaceous. 

This remarkable journey is made possible by the particular way the geology of the Jurassic Coast formed. Watch this video to learn more.

The importance of erosion

The coast is where land, sea and sky meet. It is a dynamic landscape where drama is found both in its nature and in how we as human beings interact with it. Conservation of the Jurassic Coast World Heritage Site starts with the rock exposures, fossils and natural landforms that form the basis of its Outstanding Universal Value. The coastline we know today was created by the natural process of erosion. Over time it has exposed world-class geology and palaeontology and created iconic and much-loved landforms, such as Chesil Beach, Durdle Door, Lulworth Cove and Ladram Bay. Natural change is ongoing and part of the evolving story of the Jurassic Coast. 

Allowing natural erosion to continue is the most effective way to maintain the Outstanding Universal Value of the Jurassic Coast and safeguard its World Heritage Status. However, this can be in conflict with the needs or desires of coastal communities to protect themselves from flooding and coastal retreat. A pragmatic approach to resolving this conflict where it arises usually leads to positive outcomes. This is often best done through collaboration in order to find an acceptable balance between the needs of people and the needs of the natural environment.

Defining our Outstanding Universal Value

There are five key attributes of the Dorset and East Devon Coast that underpin its status as a World Heritage Site. These are the key characteristics that have been recognised as being globally significant, transcending national and cultural boundaries, and having common importance for present and future generations of all humanity. 

1. Stratigraphy (the rock record) and structure
   The Site includes a near-continuous sequence of Triassic, Jurassic and Cretaceous rock exposures, representing almost the entire Mesozoic Era (between 251 and 66 million years ago), or approximately 185 million years of Earth history. Because the overall tilt or ‘dip’ of the rocks is gently to the east, each section of coast contains its own unique part of the story that add up to the whole; a globally significant site.
    

2. Palaeontological record
   The Site contains a diverse range of internationally important Mesozoic fossil localities, including key areas for Triassic reptiles, and for Jurassic and Cretaceous mammals, reptiles, fish and insects. These chart virtually one third of the entire evolution of complex life forms. The ammonite zonation is also important as these animals changed rapidly through time and can therefore be used to date the relative ages of the rocks and place them in a time context with other sites.
    

3. Geomorphological features (landforms) and processes
   A wide range of significant geomorphological features and processes are also represented within the Site. It is renowned for its demonstration of landsliding, and of beach formation and evolution in relation to changing sea level, including raised beaches and offshore peat deposits. The coast demonstrates spectacularly how geological structure controls the evolution of bays and headlands and how erosion on a discordant and concordant coastline creates these features. There are also superb examples of the formation of caves, arches and sea stacks.
    

4. Ongoing scientific investigation and educational use, and role in the history of science
   The coast played a key role in the development of the Earth sciences over the last two centuries and continues to provide an outdoor classroom for teaching, and an unparalleled resource for ongoing research. The continuous rock sequence contained in the naturally eroding cliffs allows scientists to test existing theories and generate new ones. Fossils new to science continue to be found through responsible collecting efforts, and thus contribute to maintaining the OUV of this Site. The ability to study erosional processes is also important, and is also now benefiting from the application of new monitoring techniques.
    

5. Underlying geomorphological processes in the setting of the Site
   The reasons for the form, diversity and quality of the coastal landscape are found in the underlying geology and the geomorphological processes acting on it. Much of the landscape is dominated by relic features and dates back to a time of active processes under very different climatic conditions from today. The long-term preservation of the Site’s OUV depends on the maintenance of dynamic natural processes in the setting, and the awareness that processes acting in the land or sea setting may impact on the Site itself.