The BGS Lexicon of Named Rock Units — Result Details
Benscliffe Breccia Member
| Computer Code: | CMBA | Preferred Map Code: | CMBA |
|---|---|---|---|
| Status Code: | Full | ||
| Age range: | Ediacaran Period (AD) — Ediacaran Period (AD) | ||
| Lithological Description: | Grey, very thickly bedded, massive andesitic and dacitic volcanic breccia, grading to lapilli tuff, with subordinate beds of fine-, medium- and coarse-grained andesitic to dacitic tuff. | ||
| Definition of Lower Boundary: | Not seen, but inferred to be a sharp contact on grey, laminated volcaniclastic siltstones of the Blackbrook Reservoir Formation. | ||
| Definition of Upper Boundary: | Grades up into medium- and coarse-grained tuff, with subordinate lapilli tuff beds, and pale grey, laminated to bedded tuffaceous mudstones, siltstones and sandstones of the Beacon Hill Formation. In the west it thickens and merges laterally with the Charnwood Lodge Formation (lower part). | ||
| Thickness: | 20-100m | ||
| Geographical Limits: | The unit extends from Hanging Stone (above), southwards to Benscliffe Wood and, northwards, and is last seen at Rhododendron Hill (SK 4980 1693), Nanpantan. | ||
| Parent Unit: | Beacon Hill Formation (CMBH) | ||
| Previous Name(s): | Benscliffe Agglomerate [Obsolete Name and Code: Use CMBA, BENS]
(-2596)
Felsitic agglomerate [Obsolete Name and Code: Use CMBA, BENS] (-3204) Benscliffe Breccia Member [Obsolete Code: Use CMBA] (BENS) |
||
| Alternative Name(s): | none recorded or not applicable | ||
| Stratotypes: | |||
| Reference Section | Small exposures around Hanging Stone, Charnwood Lodge Nature Reserve. | ||
| Type Section | Crags in Benscliffe Wood, commonly called the 'Pillar Rock'. | ||
| Reference(s): | |||
| Carney, J N. 1994. Geology of the Thringstone, Shepshed and Loughborough districts (SK41NW, SK41NE and SK51NW). British Geological Survey Technical Report WA/94/08. | |||
| 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) | |||
| Watts, W W, 1947. Geology of the ancient rocks of Charnwood Forest, Leicestershire. Leicester: Leicester Literary and Philosophical Society. | |||
| Moseley, J and Ford, T D, 1985. A stratigraphic revision of the Late Precambrian rocks of Charnwood Forest, Leicestershire. Mercian Geologist, Vol.10(I), 1-18. | |||
| 1:50K maps on which the lithostratigraphical unit is found, and map code used: | |||
| E155 E141 | |||