The BGS Lexicon of Named Rock Units — Result Details

Archerbeck Beds

Computer Code: AKB Preferred Map Code: notEntered
Status Code: Index Level
Age range: Asbian Substage (CR) — Asbian Substage (CR)
Lithological Description: Alternating limestones, calcareous mudstones and mudstones with some calcareous sandstones. The strata contain a marine fauna of polyzoa, corals, brachiopods and bivalves.
Definition of Lower Boundary: Conformable contact with a thick seatearth lying c.90m above the Kinmont Limestone.
Definition of Upper Boundary: Conformable contact with unfossiliferous sandstones and mudstones c.15m below the base of the Cornet Limestone.
Thickness: c.100m. Limestones form up to 33% of the thickness.
Geographical Limits: Confined to the Langholm district.
Parent Unit: Tyne Limestone Formation (TYLS)
Previous Name(s): Archerbeck Limestone Formation [Obsolete Name And Code: See AKB And TYLS] (ARLS)
Alternative Name(s): none recorded or not applicable
Stratotypes:
Partial Type Section  In the Liddel Water, 0.7km southeast of Harelawslack, Langholm, Scotland. 
Type Section  Archerbeck Borehole from 520m to 621m depth from the surface; registered No. NY 47 NW/14, Langholm (1:50k Sheet 11 [Scotland], Langholm.) 
Reference(s):
Lumsden G I, Tulloch W, Howells M F and Davies A. 1967. The geology of the neighbourhood of Langholm. Memoir of the Geological Survey, Sheet 11 (Scotland). 
1:50K maps on which the lithostratigraphical unit is found, and map code used:
none recorded or not applicable