The BGS Lexicon of Named Rock Units — Result Details

Blackhall Limestone

Computer Code: BLLS Preferred Map Code: BLLS
Status Code: Full
Age range: Brigantian Substage (CX) — Brigantian Substage (CX)
Lithological Description: A pale to dark grey, crinoidal, bioclastic, earthy to hard limestone, interpreted to be of marine origin, with thicker occurrences comprising calcareous mudstone and lime mudstone beds, thinly bedded above and massive below. In the Glasgow area, the lower leaf of the limestone is a brownish grey ostracodal limestone.
Definition of Lower Boundary: Generally seen as a conformable change from marine mudstone underlying the Blackhall Limestone above a thin coal or seatearth within the Lower Limestone Formation, that forms the top of the Inchinnan Limestone cycle.
Definition of Upper Boundary: Generally seen as a conformable change to thick marine mudstone containing the Neilson Shell Bed fauna that passes up into deltaic arenaceous deposits of the Lower Limestone Formation.
Thickness: From 0.45m to 3.70m in the Airdrie, Falkirk and Glasgow districts, whereas in interpreted on-shelf settings such as around Midlothian, it can be 15m to 18m.
Geographical Limits: Throughout the outcrop and subcrop of the Lower Limestone Formation in the Midland Valley of Scotland, but locally absent in Ayrshire and Strathclyde, on highs largely created by the Clyde Plateau Volcanic Formation.
Parent Unit: Lower Limestone Formation (LLGS)
Previous Name(s): Middle Skateraw Limestone [Obsolete Name And Code: Use BLLS] (MSKL)
Douglas Wee Limestone [Obsolete Name And Code: Use BLLS] (DWLS)
Middle Skateraw Limestone And Upper Skateraw Limestone (Undifferentiated) [Obsolete Name And Code: Use BLLS] (MUSKL)
North Greens Limestone [Obsolete Name And Code: Use BLLS] (NOGL)
Charlestown Main Limestone [Obsolete Name And Code: Use BLLS] (CNMA)
Tartraven Limestone [Obsolete Name And Code: Use BLLS] (TAR)
Dockra Limestone [Obsolete Name And Code: Use BLLS] (DOLS)
Upper Skateraw Limestone [Obsolete Name And Code: Use BLLS] (USKL)
Alternative Name(s): none recorded or not applicable
Stratotypes:
Reference Section  Measured as 1.12m in two leaves, with a base at a depth of 204.83m in the Wester Gartshore Colliery Underground Borehole, NS67SE/99, at Kintilloch, northwest of Airdrie, at NS 6823 7239. Blackhall is in east Paisley. 
Reference(s):
Hinxman, L W, Anderson, E M and Carruthers, R G. 1920. The economic geology of the Central Coalfield of Scotland, Area IV; Paisley, Barrhead, Renfrew. Memoir of the Geological Survey, Scotland. 
Robertson, T, Simpson J B and Anderson J G C. 1949. The Limestones of Scotland. Special reports on the mineral resources of Great Britain. Vol.35. Memoir of the Geological Survey. 
Browne, M A E, Dean, M T, Hall, I H S, McAdam, A D Monro, S K and Chisholm, J I. 1999. A lithostratigraphical framework for the Carboniferous rocks in the Midland Valley of Scotland. British Geological Survey Research Report, RR/99/07. 
Cameron, I B, Aitken, A M, Browne, M A E and Stephenson, D. 1998. Geology of Falkirk District. Memoir of the British Geological Survey Sheet 31E (Scotland). 
Hall, I H S, Browne, M A E and Forsyth, I H. 1998. Geology of the Glasgow district. Memoir of the British Geological Survey, Sheet 30E (Scotland). 
Lexique Stratigraphique International. 1971. Volume 1, Europe, Fascicule 3a, England, Wales and Scotland, Part 3a VII, Lower Carboniferous (Dinantian). 
Forsyth, I H, Hall, I H S and McMillan, A A. 1996. Geology of the Airdrie district. Memoir of the British Geological Survey, Sheet 31W (Scotland). 
1:50K maps on which the lithostratigraphical unit is found, and map code used:
S031 S031 S023 S032 S049 S040 S030 S030 S039 S040 S041 S032