Portland Stone Formation | |
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Stratigraphic range: | |
Type | Geological formation |
Unit of | Portland Group |
Sub-units | Dorset: Portland Chert Member, Portland Freestone Member
Vale of Wardour: Tisbury Member, Wockley Member, Chilmark Member Vale of Pewsey: No formal subdivision |
Underlies | Lulworth Formation |
Overlies | Portland Sand Formation |
Thickness | up to 38 metres (120 ft) in Dorset |
Lithology | |
Primary | Limestone |
Other | Siltstone, Sandstone |
Location | |
Region | England |
Country | United Kingdom |
Type section | |
Named for | Isle of Portland |
Location | Clay Ope, West Weare Cliff |
Thickness at type section | 25 metres |
Portland stone is a limestone geological formation (formally named the Portland Stone Formation[1]) dating to the Tithonian age of the Late Jurassic that is quarried on the Isle of Portland in Dorset, England.[1] The quarries are cut in beds of white-grey limestone separated by chert beds. It has been used extensively as a building stone throughout the British Isles, notably in major public buildings in London such as St Paul's Cathedral and Buckingham Palace. Portland stone is also exported to many countries, being used for example at the United Nations headquarters in New York City.