Durdle Door is a natural limestone arch on the Jurassic Coast near Lulworth in Dorset, England.
It is privately owned by the Welds, a family who owns 12,000 acres (50 km2) in Dorset in the name of the Lulworth Estate and open to the public. The name Durdle is derived from the Old English word ‘thirl' meaning bore or drill. The coastline around Durdle Door is controlled by its geology—by the contrasting hardnesses of the rocks, and the local patterns of faults and folds. The arch has formed on a concordant coastline where bands of rock run parallel to the shoreline. Originally a band of resistant Portland limestone ran along the shore, the same band that appears one mile along the coast as forms the narrow entrance to Lulworth Cove. Behind this is a 120-metre (390 ft) band of weaker, easily eroded rocks, and behind this is a stronger and much thicker band of chalk, forming the Purbeck Hills. These steeply dipping rocks are part of the geological structure known as the Lulworth crumple, itself part of a broader monocline (a kinked type of geological fold) that built the Alps during the mid-Cenozoic. Around this part of the coast nearly all of the limestone has been removed by sea erosion, whilst the remainder forms the small headland which includes the arch. Erosion at the western end of the limestone band has resulted in the arch formation. UNESCO teams monitor the condition of both the arch and adjacent beach. The 120-metre (390 ft) isthmus which joins the limestone to the chalk is made of a 50-metre (160 ft) band of Portland limestone, a narrow and compressed band of cretaceous Wealden clays and sands, and then narrow bands of greensand and sandstone. In Man O' War Bay, immediately east of Durdle Door, the band of Portland and Purbeck limestone has not been entirely eroded away, and is visible above the waves as Man O'War Rocks. Similarly, offshore, the eroded limestone outcrop forms a line of small rocky islets called (from east to west) The Bull, The Blind Cow, The Cow, and The Calf. As the coastline in this area is generally an eroding landscape, the
Size: 4912px × 7360px
Location: Durdle Door, Dorset
Photo credit: © Philip Chapman / Alamy / Afripics
License: Royalty Free
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Keywords: arch, arthur, bay, beach, bore, cenezoic, chalk, clay, coast, coastline, concordant, crumple, door, dor, dorset, drill, durdale, durdle, erosion, estate, greensand, hardy, jurassic, limestone, lulworth, man, monocline, moule, owar, purbeck, sandstone, thirl, unesco, wealden, weld
