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Geology Gallery
Geological Map of the Cromer Area
Key
The rocks around Cromer are of international 1 Overstrand 5 Telegraph Hill importance, not least because the Cromer Forest- Glacial Till bed Formation at West Runton is the ‘type locality’ 2 Cromer 6 Holt Holocene for the Cromerian Stage. The Chalk and Crag Overstrand Chalk Raft deposits which can be seen along the beaches of The huge chalk rafts 3 Sheringham 7 Cley Glacial Sand and North Norfolk are also of world importance. Above that dominate the cliffs Gravel these sediments however, are the glacial deposits at Overstrand. 4 Weybourne 8 Blakeney which were laid down starting approximately 500,000 years ago, during the Ice Age. These form Wroxham Crag most of the cliffs that you can see along the coast Formation at Trimingham, Sidestrand and Overstrand. Exaggerated relief geological map of Cromer and the surrounding area.
Pleistocene Cromer Forest-bed The Cromer Ridge is a huge glacial feature which 1 Showing the Cromer Ridge, which at Formation forms the highest point in Norfolk. The ridge is about 100 metres above sea level, is the what’s left of the terminal moraine, formed as the highest point in the whole of Norfolk. glacier retreated. The eastern part of the ridge is Alluvial sand and a push moraine. This is best seen at Overstrand, gravel which has a 60 metre cross-section through the S ridge, showing spectacular ‘rafts’ of chalk which E White Chalk Group were pushed into their current position by glacial 5 W movement. N 2 6
The western part of the ridge is composed of 3 Lower Cretaceous outwash sands and gravels deposited by rivers at Sandstone the glacier edge. This is best seen at Telegraph Hill. At the view point there is a steep northward- 4 facing slope which would have been the glacier Lias Mudstone margin, this rests on the flat-lying outwash gravel surface of Kelling Heath. There are also a series of circular hills known as kames between Telegraph Hill and the sea. 7 Mercia Mudstone
Sherwood Sandstone 8 Group
Metamorphosed Glossary: Mudstone, Siltstone and Sandstone Triassic Cromerian Stage = a stage within the Pleistocene Silurian Permo- Triassic Jurassic Cretaceous Period, from 866,000 to 478,000 years ago. Ice coverage in the Crag deposits = a series of marine deposits at Glacial Till British Isles during the the base of the Pleistocene in Norfolk, Suffolk and most recent glaciation Essex. Crag is a local word for shelly sand. Cromer Forest-bed (between about 110,000 Formation Glacial deposits = the rocks, soil and other White Chalk to 10,000 years ago). sediment picked up and transported by glaciers. Wroxham Crag Beach Sand Formation and Gravel The Cromer Ridge is one Terminal moraine = sediments deposited by a feature caused by the glacier at its end when the ice was at its maximum movement of ice during extent. this glaciation. Outwash = glacial sediments deposited by meltwater at the terminus of a glacier. West Runton Cliffs Push moraine = a broad arc-shaped ridge of Photograph of the cliffs at West Runton material pushed along by an advancing glacier. beach, highlighting the major geological Kame = sand and gravel hills formed as glaciers. formations. retreat. © Martin Warren