The BGS Lexicon of Named Rock Units — Result Details

Blackhall Till Formation

Computer Code: BHTI Preferred Map Code: notEntered
Status Code: Full
Age range: Devensian Stage (QD) — Devensian Stage (QD)
Lithological Description: Dark grey to greyish brown, locally reddish brown, very stiff, stony sandy silty clay diamicton with sparse fragments of shell. It contains clasts mostly of Carboniferous lthologies in southern Northumberland, with far-travelled rocks from the Southern Uplands and, south of Blyth, from the Lake District too; local Permian lithologies predominate south of the Tyne. Generally becomes more clayey and plastic upwards. Includes local lenses of sand and gravel.
Definition of Lower Boundary: Either rests directly on bedrock or as a sharp, subhorizontal, planar to gently undulating contact with limestone-rich gravel of the Limekiln Gill Gravel Formation.
Definition of Upper Boundary: Generally a sharp, uneven, erosional contact with overlying red fine-grained sand of the Peterlee Sand Formation along the Durham coast.
Thickness: Up to 15m
Geographical Limits: Coast of County Durham and southern Northumberland.
Parent Unit: North Sea Coast Glacigenic Subgroup (NSG)
Previous Name(s): Durham Lower Till [Obsolete Name and Code: Use BHTI] (-3214)
Alternative Name(s): Blackhall Member
Stratotypes:
Type Section  Cliff sections in the vicinity of, and south of Black Halls Rocks, Peterlee, County Durham. Francis, 1970. 
Reference(s):
Smith, D B and Francis, E A. 1967. Geology of the country between Durham and West Hartlepool. Memoir of the Geological Survey of Great Britain, Sheet 27 (England and Wales). 
Bridgland, D R, Horton, B P and Innes, J B. 1999. The Quaternary of northeast England. Field Guide. Quaternary Research Assocation, London. 
Thomas, G S P. 1999. Northern England. 91-98 in Bowen, D Q (Editor), A revised correlation of Quaternary and Neogene deposits in the British Isles. Geological Society Special Report No.23. 
Huddart, D. 2002. Warren House Gill. 51-56 in Huddart, D and Glasser, N F (editors), Quaternary of Northern England. Geological Conservation Review Series, No.25. [Peterborough: Joint Nature Conservation Committee.] 745pp. 
Francis, E A. 1970. Quaternary. 134-152 in Johnson, G A L, Geology of Durham County. [Newcastle: Natural History Society of Northumberland, Durham and Newcastle-upon-Tyne.] 152pp. 
1:50K maps on which the lithostratigraphical unit is found, and map code used:
none recorded or not applicable