The BGS Lexicon of Named Rock Units — Result Details
Hopwas Breccia Formation
Computer Code: | HPBR | Preferred Map Code: | HpBr |
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Status Code: | Full | ||
Age range: | Cisuralian Epoch (PLC) — Early Triassic Epoch (TE) | ||
Lithological Description: | A coarse breccia composed of locally derived material and up to 10% Carboniferous limestone clasts, interbedded with sandstones and subordinate mudstone beds. | ||
Definition of Lower Boundary: | Unconformable on Carboniferous and older rocks and also on the Permian Clent and Nechells breccias, which contain a greater variety of extrabasinal clasts (Smith and others, 1974). | ||
Definition of Upper Boundary: | Overlain by red sandstones of the Polesworth Formation. | ||
Thickness: | Variable, but thicknesses of 30m are recorded (Smith and others, 1974). | ||
Geographical Limits: | South Staffordshire, Warwickshire and Leicestershire coalfields area (Hains and Horton, 1969). | ||
Parent Unit: | Sherwood Sandstone Group (SSG) | ||
Previous Name(s): | Barr Beacon Beds [Obsolete Name And Code: Use HPBR]
(ARBC)
Moira Breccia [Obsolete Name And Code: Use MOI] (MOB) |
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Alternative Name(s): | none recorded or not applicable | ||
Stratotypes: | |||
Type Section | Near village of Hopwas, Leicestershire. Outcrop of breccias composed of locally derived material, described originally by Barrow and others, 1919. | ||
Reference(s): | |||
Smith, D B, Brunstrom, R G W, Manning, D I, Simpson, S and Shotton, F W. 1974. A correlation of Permian rocks in the British Isles. Geological Society of London Special Report No. 5. | |||
Hains, B A and Horton, A.1969. British Regional Geology: Central England. 3rd edition. (London: HMSO). | |||
Worssam, B C and Old, R A, 1988. Geology of the country around Coalville. Memoir of the British Geological Survey, Sheet 155 (England and Wales) | |||
Barrow, G, Gibson, W, Cantrill, T C, Dixon, E E L, and Cunningham, C H. 1919. The geology of the country around Lichfield. Memoir of the Geological Survey of Great Britain. | |||
1:50K maps on which the lithostratigraphical unit is found, and map code used: | |||
E155 E154 |