The BGS Lexicon of Named Rock Units — Result Details
Burrington Oolite Subgroup
| Computer Code: | BO | Preferred Map Code: | notEntered |
|---|---|---|---|
| Status Code: | Pending Upgrade | ||
| Age range: | Chadian Substage (CI) — Arundian Substage (CJ) | ||
| Lithological Description: | Massive pale grey ooidal limestones and ooidal/crinoidal limestones. Beds of coarse crinoidal limestone in lower part and calcite mudstones in uppermost part. Locally dolomitised in lowermost part. | ||
| Definition of Lower Boundary: | Taken at gradational junction of sparsely crinoidal dolomite of underlying Black Rock Limestone Subgroup and the ooidal limestone [locally dolomitised] of the Burrington Oolite Subgroup. In the eastern Mendip Hills, taken at the incoming of the ooidal limestones above the coarse crinoidal limestones of the Vallis Limestone Formation. Both contacts need further investigation. | ||
| Definition of Upper Boundary: | Taken at the incoming of calcite mudstones and dark splintery limestones of the Clifton Down Limestone Formation above the ooidal and ooidal/crinoidal limestones of the Subgroup. | ||
| Thickness: | 210m at Burrington Combe to 230m at Wells, thinning to a feather edge in the eastern Mendip Hills. | ||
| Geographical Limits: | Mendip Hills [ST 50 55] and Western-super-Mare [ST 30 60] area. Passes north into the Gully Oolite, Clifton Down Mudstone and Goblin Combe Oolite formations. Passes west into Gully Oolite, Caswell Bay Mudstone, High Tor Limestone and Goblin Combe Oolite formations. Passes east into Vallis Limestone Formation and supposedly the Black Rock Limestone Subgroup, but this needs further investigation. | ||
| Parent Unit: | Pembroke Limestone Group (PEMB) | ||
| Previous Name(s): | Clifton Down Group [Obsolete Name And Code: See PEMB]
(CDGP)
Burrington Oolite Formation [Obsolete Name and Code: Use BO] (-3234) |
||
| Alternative Name(s): | none recorded or not applicable | ||
| Stratotypes: | |||
| Partial Type Section | Burrington Combe, Burrington, Somerset. Unit is 210m thick and comprises oolitic and crinoidal limestone. Most of the unit seen except for contact with overlying Clifton Down Limestone Formation. Contact with underlying Black Rock Limestone Subgroup seen. | ||
| Type Section | Burrington Combe: from quarry by the public toilets, south to the quarry up valley from Aveline's Hole. | ||
| Reference(s): | |||
| Waters, C N, Waters, R A, Barclay, W J, and Davies, J R. 2009. Lithostratigraphical framework for Carboniferous successions of Southern Great Britain (Onshore). British Geological Survey Research Report, RR/09/01. 184pp. | |||
| Kellaway, G A and Welch, F B A. 1993. Geology of the Bristol district. Memoir of the British Geological Survey Special Sheet [England and Wales]. | |||
| Green, G W and Welch F B A, 1965. The geology of the country around Wells and Chedder. Memoir of the Geological Survey of England and Wales, Sheet 280. | |||
| Kellaway, G A and Welch, F B A. 1955. The Upper Old Red Sandstone and Lower Carboniferous rocks of the Bristol and the Mendips compared with those of Chepstow and the Forest of Dean. Bulletin of the Geological Survey of Great Britain, No.9, p.1-21. | |||
| 1:50K maps on which the lithostratigraphical unit is found, and map code used: | |||
| E280 E281 E279 | |||