Dorset and East Devon Coast

• Official Name: Dorset and East Devon Coast
• Location: England, United Kingdom
• Type: Natural
• Year of Inscription: 2001

Comprised of a 95-mile (132-kilometer) stretch of coastline abutting the English Channel, the Dorset and East Devon coast is the United Kingdom (UK)’s first natural landform to earn recognition as a United Nations Educational, Scientific, and Cultural Organization (UNESCO) World Heritage Site. As of the mid-2020s, it is also the UK’s only natural site to hold the prestigious status.

The Dorset and East Devon Coast consists primarily of exposed rock forms and cliff faces from the Triassic, Jurassic, and Cretaceous periods of the Mesozoic Era. It is also known as the Jurassic Coast, as many of its unique and heavily studied features date from the Jurassic period. The eight separate regions included in the UNESCO-recognized property provide an atypically clear record of localized rock formation processes that cover a period of geologic time spanning 185 million years. They have also yielded multiple highly valuable fossil sites that provide a compelling record of the evolutionary characteristics of Mesozoic life. Geologists and geomorphology specialists widely consider the Dorset and East Devon Coast to be one of the world’s most valuable research sites, and earth science experts have extensively studied the area’s rock formations and fossil deposits for more than three centuries. The Dorset and East Devon Coast also holds high knowledge transfer value, as it has been used as an instructional tool for emerging generations of geologists and geomorphologists for many decades.

In addition to their research value, many of the coast’s rock formations have a dramatic and picturesque character that contributes significantly to the site’s natural beauty. The area covered under World Heritage Site status features very little urban or commercial development, leading conservationists to classify it as one of the UK’s best-preserved natural regions. It was inscribed as a World Heritage Site in December 2001 and is managed by the Jurassic Coast Partnership in cooperation with Dorset and Devon County Councils. The Jurassic Coast Partnership maintains a detailed plan for protecting the site from both natural and anthropomorphic forces, including erosion, tourism and commercial activity, fossil recovery projects, and climate change.

History

During the Mesozoic Era, which began about 252 million years ago and ended 66 million years ago, what is now the English Channel was covered by a group of sedimentary basins. One such basin, now known as the Wessex Basin, amassed a succession of sediment layers between the late stages of the Paleozoic Era’s Permian period and the Cenozoic Era’s Paleogene period. The Permian and Paleogene periods bookend the three periods of the Mesozoic Era.

The rocks that formed in the Wessex Basin between the Permian and Paleogene periods now cover a land area spanning more than 7,700 square miles (20,000 square kilometers) of southern England. In the Dorset Coast area, the Wessex Basin rock forms become miles thick, aligning into three layered stacks. The basal (oldest) stacks date to the Permian and Triassic periods and are known as “red beds.” These stacks formed in desert-like climate conditions. In the middle, rocks from the Jurassic and early Cretaceous periods accumulated and deepened as the primordial continent of Pangaea began to rift under tectonic forces. These mid-layer rocks include limestone, marine mudstone, and sandstone. The chalky rocks that comprise the uppermost layer of the Dorset Coast Wessex Basin became part of the present-day landforms in the late Cretaceous and early Paleogene periods.

Around the middle of the Cretaceous period, ongoing tectonic shifts guided these three layers of sediment into a slight east-facing downward slope. A combination of natural erosion and rising sea levels then pushed the chalky, sandy rocks and clays that make up the uppermost level of the Wessex Basin to the apex of these sloping layers. These layers met with deeper, older layers of rock in what geologists call an “unconformity,” a technical term that describes continuous surface contact between two strata layers that formed during different geological timeframes. At certain points of the Dorset and East Devon Coast, the ancient Permian and Triassic stacks comprise the surface layer. At others, the surface-level rocks date to the Jurassic, early Cretaceous, late Cretaceous, and early Paleogene periods. Further erosion dating to the current Quaternary period of geologic time formed the modern landscape.

The Dorset and East Devon Coast is also known as the Jurassic Coast because its most famous segment dates to the Jurassic period. This segment of the Wessex Basin contains one of the world’s most detailed records of cyclical increases and decreases in sea level, which covers six complete cycles and etched the associated geological events in sandstone, limestone, and mudstone. It also hosts a rich and diverse fossil record of plant, animal, and marine life from the Jurassic period, including the remains of dinosaurs. The Wessex Basin’s fossil record was famously studied by Mary Anning (1799–1847), an amateur paleontologist who overcame challenges, including poverty and a lack of formal education, to become one of the most accomplished fossil collectors in English history. Anning’s discoveries prompted major revisions to the scientific understanding of geologic history and the evolution of life on Earth.

Portions of the Jurassic Coast protected under World Heritage Site status have also experienced multiple landslides, with one major such event taking place in 1839. The cumulative effect of these landslides has had a profound impact on the natural habitats found in the Dorset and East Devon Coast, making it one of the most important nature reserves in the UK from the viewpoint of plant and animal conservationism.

The Dorset and East Devon Coast is home to numerous famous sights that have achieved iconic status for their depictions on postcards and in nature photography. Examples include a landform known as Old Harry Rocks, which consists of chalky, porous structures that formed from the fossilized remains of ancient algae dating to the Cretaceous period, along with Durdle Door and Lulworth Cove. Durdle Door is a picturesque arch-shaped rock form, while Lulworth Cove is a U-shaped embayment formed by erosion forces originating in the English Channel.

Significance

In 2000, Dorset County Council prepared a comprehensive profile of the Dorset and East Devon Coast as part of its bid to have the property recognized as a World Heritage Site. The document characterized the landscape as one of the world’s most important and comprehensive surface-level geological records, noting that it played an important role in the founding of geology as an earth science and the later evolution of the geomorphology specialization. It additionally notes the critical scientific importance of the plant, animal, and marine fossil records preserved in the successive rock layers that comprise the property. The Dorset County Council also described the site’s coastal features as an archetypal example of the coastal land and rock formation processes, emphasizing its central role in shaping the academic development of many core principles of geological science.

UNESCO found Dorset County Council’s argument compelling, accepting the Dorset and East Devon Coast as a World Heritage Site in 2001 under selection criterion (vii). UNESCO maintains a list of ten criteria under which a proposed property can qualify for World Heritage Site status, with criterion (vii) covering particularly important visible examples of the Earth’s evolutionary and natural history.

In its official profile of the Dorset and East Devon Coast, UNESCO acknowledges the singular character of the nearly continuous layered sequences of ancient rock formations that comprise the site. The property captures 185 million years of Earth’s natural history in striking and unusually complete detail, and its fossil collections have made major contributions to the scientific understanding of life during the Mesozoic Era. These marine and terrestrial animal fossils include a wealth of both vertebrates and invertebrates, marking one of the most diverse localized fossil records in the world.

Given longstanding recognition of the site’s scientific importance, very little urban or commercial development has impacted the natural character of the Dorset and East Devon Coast. However, expert observers have registered multiple concerns about the property’s future. Due to its direct exposure to the turbid waters of the English Channel, the Dorset and East Devon Coast erodes at an unusually high rate. While this does not pose any immediate known near-term risk to the site’s integrity, it necessitates thorough and constant monitoring by experts to ensure that any natural changes are properly tracked in the site’s official scientific record. Climate change and the increase in extreme weather events may accelerate this erosion. Furthermore, the International Union for Conservation of Nature (IUCN) notes that offshore exploratory permits known as oil concessions have been approved for the English Channel waters adjacent to the site’s coastline. In the IUCN’s view, these concessions hold the potential to result in oil extraction activities within relative proximity of the World Heritage Site property, which could pose risks related to pollution and contamination in the event of a disaster.

Bibliography

Blyth, Jo. “Jurassic Coast: Why You Should Visit This Spectacular Part of Britain This Year.” Country Living Magazine, 10 May 2022, www.countryliving.com/uk/travel-ideas/staycation-uk/a39810981/jurassic-coast. Accessed 6 Dec. 2024.

Cook, Terri. “Travels in Geology: Mesozoic Masterpiece: England's Jurassic Coast.” Earth Magazine, 5 June 2018, www.earthmagazine.org/article/travels-geology-mesozoic-masterpiece-englands-jurassic-coast. Accessed 6 Dec. 2024.

“Dorset and East Devon Coast.” International Union for Conservation of Nature World Heritage Outlook, worldheritageoutlook.iucn.org/explore-sites/wdpaid/900632. Accessed 6 Dec. 2024.

“Dorset and East Devon Coast.” UNESCO World Heritage Centre, whc.unesco.org/en/list/1029. Accessed 6 Dec. 2024.

Eylott, Marie-Claire. “Mary Anning: The Unsung Hero of Fossil Discovery.” The Natural History Museum, London, www.nhm.ac.uk/discover/mary-anning-unsung-hero.html. Accessed 6 Dec. 2024.

“Nomination of the Dorset and East Devon Coast for Inclusion in the World Heritage List.” Dorset County Council, 2000, whc.unesco.org/uploads/nominations/1029.pdf. Accessed 6 Dec. 2024.

“Views Sought on How Jurassic Coast Is Looked After.” British Broadcasting Corporation, 3 Nov. 2013, www.bbc.com/news/uk-england-24769434. Accessed 6 Dec. 2024.

“World Heritage Sites.” Dorset Council, www.dorsetcouncil.gov.uk/countryside-coast-parks/countryside-management/countryside-site-designations/world-heritage-sites. Accessed 6 Dec. 2024.