The BGS Lexicon of Named Rock Units — Result Details

Blackbrook Group

Computer Code: CBK Preferred Map Code: CBK
Status Code: Full
Age range: Ediacaran Period (AD) — Ediacaran Period (AD)
Lithological Description: Well-bedded to laminated, grey to green volcaniclastic mudstones, siltstones, sandstones with volcaniclastic breccias and dacite lavas, the latter confined to the concealed Morley Lane Volcanic Formation.
Definition of Lower Boundary: Not seen or proved in Charnwood region.
Definition of Upper Boundary: Overlain by grey, coarse-grained tuffs, lapilli tuffs and breccias of Benscliffe Breccia Member, Beacon Hill Formation, or by similarly coarse-grained lithologies of Charnwood Lodge Volcanic Formation, to the west.
Thickness: 1750m+
Geographical Limits: Extends from the small inlier east of Grace Dieu Brook (SK 4397 1880) south-east to Ives Head and Benscliffe Wood.
Parent Unit: Charnian Supergroup (CHA)
Previous Name(s): Blackbrook Beds [Obsolete Name and Code: Use CBK] (-3281)
Blackbrook Series [Obsolete Name and Code: Use CBK] (-2669)
Blackbrook Formation [Obsolete Name and Code: Use CBK] (-2668)
Alternative Name(s): none recorded or not applicable
Stratotypes:
Type Area  Central/northern part of Charnwood Forest, between Morley Quarry and Benscliffe Wood. 
Type Area  The Blackbrook, 4 miles south-west of Loughborough, Leicestershire. 
Reference(s):
Moseley, J. 1979. The geology of the late Pre-Cambrian rocks of Charnwood Forest. Unpublished Ph.D. Thesis, University of Leicester. 
Hill, E and Bonney, T G, 1880. The Pre-Carboniferous Rocks of Charnwood Forest, part 3, conclusion. Quarterly Journal of the Geological Society, Vol.36, p.349. 
Watts, W W, 1910. The geology of Charnwood Forest. "In" Monkton, H W and Herries, R. (Editors). Geology in the field. Geologists' Association. London. 
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. 
Watts, W W, 1900. Pre-Cambrian rocks of Charnwood Forest. "In" Fox-Strangways, C. The geology of the country between Atherstone and Charnwood Forest. Memoirs of the Geological Survey, (England and Wales). 
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