The BGS Lexicon of Named Rock Units — Result Details

Stackpole Limestone Formation

Computer Code: STPL Preferred Map Code: notEntered
Status Code: Pending Upgrade
Age range: Arundian Substage (CJ) — Holkerian Substage (CQ)
Lithological Description: Pale grey, thick-bedded skeletal and oolitic limestones; scattered cherts and silicified fossils; local dolomitisation. Dark grey, thinner-bedded limestones are common in the lower part. Pale grey oncolitic limestones and calcite mudstones are common in the uppermost part. Deposited in front barrier, barrier and back barrier settings.
Definition of Lower Boundary: Taken at the gradational boundary between the dark grey interbedded wackestones and mudstones of the underlying Pen-y-holt Limestone Formation and the pale grey thick-bedded skeletal and oolitic limestones of the Formation. Boundary taken at base of first oolitic limestone.
Definition of Upper Boundary: Taken at the outgoing of pale grey calcite mudstones of the Formation and the incoming of mottled [pseudobrecciated] skeletal packstones and palaeokarstic surfaces of the overlying Oxwich Head Limestone Formation.
Thickness: 260m at type locality in southwest Pembrokeshire.
Geographical Limits: Castlemartin area [SR 95 98], southwest Pembrokeshire. Its relationship with the coeval Hunts Bay Oolite Subgroup to north and east is uncertain and needs further investigation.
Parent Unit: Pembroke Limestone Group (PEMB)
Previous Name(s): none recorded or not applicable
Alternative Name(s): none recorded or not applicable
Stratotypes:
Partial Type Section  Variable accessible sea cliffs between Stackpole Quay and Barafundle Bay, Castlemartin, southwest Pembrokeshire. Entire unit seen and mainly comprises pale grey skeletal and oolitic limestones. Contacts with underlying Pen-y-holt Limestone Formation and overlying Oxwich Head Limestone Formation seen. 
Reference(s):
Dixon, E E L, 1921. The Geology of the South Wales Coalfield, Part XIII , the country around Pembroke and Tenby, being an account of the region comprised in sheets 244 and 245. Memoir of the Geological Survey of Great Britain (HMSO). 
George, T N, Johnson, G A L, Mitchell, M, Prentice, J E, Ramsbottam, W H C, Sevastopulo, G D and Wilson, R B. 1976. A correlation of the Dinantian rocks of the British Isles. Special Report of the Geological Society of London, No 7. 
1:50K maps on which the lithostratigraphical unit is found, and map code used:
E244 E245