Vertical rock strata on the west side of St Oswald's Bay, at the western end of the Purbeck Monocline
The Purbeck Monocline is a geological fold in southern England. The term 'fold' is used in geology when one or more originally flat sedimentary strata surfaces are bent or curved as a result of plastic (i.e. permanent) deformation. A monocline is a step-like fold, in which one limb is roughly horizontal. The Purbeck Monocline was formed during the late Oligocene and early Miocene epochs, about 30 million years ago. It is the northernmost 'ripple' of the Alpine Orogeny.
The Purbeck Monocline gives rise to the prominent ridge of steeply dipping Cretaceous chalk which now forms the Purbeck Hills. This chalk band runs from Swyre Head via Flower's Barrow to Old Harry Rocks. From here the fold continues under the sea to The Needles and forms the central spine of the Isle of Wight. Here it is also known as the Purbeck-Isle of Wight Disturbance.[1] The monocline continues under the English Channel as the Wight-Bray Monocline.
The Purbeck Hills run east–west through the small broad peninsula known as the Isle of Purbeck. The resistant beds of chalk and limestone form two ridges and the softer Wealden rocks between them have been eroded to form a valley.
Some visible features along the monocline include the disharmonic folds and faults, known as the Lulworth Crumple, at Stair Hole,[2] Lulworth Cove, Arish Mell and at Peveril Point further east. These features also include the polygonal thrust ridges developed in the harder rock bands at Kimmeridge Bay and related to the growth of the monocline is the fault at Ballard Down.
^Underhill, John R.; Paterson, Susan. (December 1998). "Genesis of tectonic inversion structures: seismic evidence for the development of key structures along the Purbeck-Isle of Wight Disturbance". Journal of the Geological Society. 155 (6). Geological Society: 975–992. doi:10.1144/gsjgs.155.6.0975. Retrieved 16 November 2010.
^West, Ian (2010). "Geology of Stair Hole". School of Ocean and Earth Science, Southampton University. Retrieved 16 November 2010.
The PurbeckMonocline is a geological fold in southern England. The term 'fold' is used in geology when one or more originally flat sedimentary strata...
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Dorset, England. The ridge is formed by the structure known as the PurbeckMonocline, and extends from Lulworth Cove in the west to Old Harry Rocks in...
west, to Peveril Point in the east. The sequence is affected by the PurbeckMonocline and dips moderately steeply to the north along its whole outcrop....
outcrops lie within the PurbeckMonocline, with the beds dipping moderately steeply to the north. There is a single example of Purbeck Marble being used during...
which forms the Purbeck Hills. These steeply dipping rocks are part of the Lulworth crumple, itself part of the broader PurbeckMonocline, produced by the...
oxygen-deficient environment, the Kimmeridge beds make up the major part of the PurbeckMonocline and the periphery of the Weymouth Anticline. They form a low-lying...
narrow (less than 50 metres (160 ft)) band of slightly less-resistant Purbeck limestone. Behind this are 300 to 500 metres (980 to 1,640 ft) of much...
Kimmeridge and Wytch Farm. Wytch Farm lies between the Purbeck Hills and Poole Harbour; the PurbeckMonocline defines the field's southern limit. Wytch Farm has...
Down Ballard Point The Pinnacles Parson's Barn Old Harry Rocks Purbeck Hills Isle of Purbeck Geology of Dorset Geology of the United Kingdom List of fossil...
Hampshire Basin, close to the steeply sloping monocline in the overlying chalk. The PurbeckMonocline defines the field's southern limit. The field consists...
southern boundary is marked by a monocline, the PurbeckMonocline, resulting in a near-vertical chalk ridge which forms the Purbeck Hills of Dorset, running under...
Bay Pinion Rock Dungy Head Stair Hole Lulworth Cove Lulworth Ranges PurbeckMonocline Bindon Hill Fossil Forest Mupe Bay Arish Mell Geology of Devon · Geology...
Antiforms, anticlinoria, synforms and synclinoria are variations on these. A monocline (or, rarely, a monoform) is a step-like fold, one limb of which is roughly...
sedimentary folding that affected this area. The foldings, known as the PurbeckMonocline, took place some 30 million years ago and were caused by the tectonic...
structure of southern England. Structures include; Wealden Anticline PurbeckMonocline Geology of Great Britain Gravity anomalies of Britain and Ireland...
Weald–Artois Anticline, the Hampshire Basin and the less gentle Purbeck-Wight monocline. The broadly western margin of the Chalk outcrop is marked, from...
affected by the late stages of the Alpine Orogeny, forming the Isle of Wight monocline, the cause of the steeply-dipping outcrops of the Chalk Group and overlying...
million years ago). The geological structure is dominated by a large monocline which causes a marked change in age of strata from the northern younger...
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