May 12, 2022
Fossil Coast Drinks Co is delighted to announce that its expressions of gin, gin liqueur, and rum spirit are now available to buy at the Lulworth Estate Heritage Centre.
The coastline between Lulworth Cove and Durdle Door has been influenced by its geology. This coastline is defined as a concordant coastline where bands of differing rock types run parallel to the coast and in this case the harder outer rock is Portland limestone.
Lulworth Cove, Stair Hole and folded limestone strata known as the "Lulworth crumple"
Lulworth Cove is a near-circular bay created by coastal erosion. Around 10,000 years ago a river of glacial meltwater from the ice age flooded and removed the softer clay and sand rocks behind the Portland limestone until the sea broke through. As you travel further east to Durston Head and Studland Bay the coastline becomes discordant where the bands of the same rock run perpendicular to the coast creating a series of headlands and bays because of the rocks differing resistance to erosion.
Heading west from Lulworth Cove there is a steep walk along the South West Coast Path up Hambury Tout towards Durdle Door. As you walk the path and look down to your left is Dungy Head with its dangerous cliff edges and the start of St Oswald’s Bay.
As you reach the summit of Hambury Tout take a minute. On a clear day and looking out to sea you should see the 6 Km silhouette of the Isle of Portland running from the Port to Portland Bill’s lighthouse, the southernmost point of Dorset.
The Isle of Portland is an impressive place for geology and is essentially an "island of limestone" with a mix of Kimmeridge Clay and Portland Sand.
Each of these layers have a combined fossil record that includes giant ammonites (Titanites), bivalves, gastropods, ostracods, fossil trees, fossil soils, early mammals and dinosaur footprints.
As you sweep around the coastline past the seaside town of Weymouth you will see that the coastline ahead is again influenced by its geology including the steep chalk cliffs. In the distance you will notice a small natural arch known as Bat’s Hole and a series of offshore limestone outcrops and small rocky islets with the nearest called The Bull followed by The Blind Cow, The Cow, and The Calf.
Before you approach Durdle Door you will notice that it is flanked by a steep and rocky projecting headland with steps down to an enclosed cove known as The Man o’ War. Apparently, this is a popular sandy beach in the Summer as well as good for fishing, swimming, snorkelling and diving, the water is protected from swells by a partially submerged offshore reef. Seals are known to visit.
Among the most iconic and photographed geological landmarks along the Jurassic Coast is Durdle Door (Durdle meaning "drill"). The softer Purbeck limestones and Wealden sandstones and siltstones have been eroded by the sea leaving a natural limestone arch of steeply dipping Portland Stone.
Durdle Door
Approximately between 145 – 150 million years ago during the Jurassic period the limestone was deposited as sediment in the shallow warm seas. At this time the sea bed was flat until between 65 and 7 million years ago when the Alpine orogeny, or Alpine mountain building event occurred creating the Alps, Pyrenees and Carpathian Mountains in Europe. In fact, this event has never stopped by movements today are nominal.
The Alpine orogeny led to intense metamorphism, warping and crumpling of stacked-up layers of sedimentary rock that became vertically uplifted creating geological features such as the Weald-Artois Anticline in Southern England/Northern France.
As modern-day Dorset was over 1,000 km from the collision zone of the Alpine orogeny it did not create any mountains but instead uplifted and folded rocks into what is knowns as the Purbeck Monocline or the northernmost 'ripple' of the Alpine orogeny. This ripple continues under the sea towards The Needles of the Isle of Wight as the Purbeck-Isle of Wight Disturbance.
This geological fold in the southern part of England is best seen at Lulworth Cove, Man O War Bay and Durdle Door, but the most dramatic example is at Stair Hole in the ‘Lulworth Crumple’. Within the folds there are ring-shaped imprints of fossilised ancient trees.