The BGS Lexicon of Named Rock Units — Result Details

Roker Formation

Computer Code: ROD Preferred Map Code: RKR
Status Code: Full
Age range: Guadalupian Epoch (PUG) — Lopingian Epoch (PUL)
Lithological Description: Cream, oolitic dolostone with subordinate thin beds of fine-grained dolomite. Breccias also present.
Definition of Lower Boundary: Drawn at diachronous base of dolostone of the Roker (Dolomite) Formation where it rests conformably on and interdigitates with the Concretionary Limestone Formation. Gradational contact with the underlying Hartlepool Anhydrite Formation offshore and with the equivalent dissolution residue that overlies the Ford Formation onshore.
Definition of Upper Boundary: Above and to the west of the Ford Formation reef; by incoming of reddish brown mudstone and siltstone at the base of the overlying Edlington Formation. East of the Ford Formation reef-edge it is overlain by the Seaham Residue, (dissolution residue of Fordon Evaporite Formation) overlain offshore by the Fordon Evaporite Formation.
Thickness: Up to approx. 80m (offshore); [Smith, et al. 1986].
Geographical Limits: Durham Province, onshore and offshore, of the English Zechstein Group: County Durham, Tyne and Wear, Cleveland and northernmost North Yorkshire.
Parent Unit: Zechstein Group (ZG)
Previous Name(s): Upper Magnesian Limestone (-2105)
Roker Dolomite Formation (-1793)
Hartlepool And Roker Dolomite [Obsolete Name And Code: Use ROD] (HPRD)
Upper Magnesian Limestone (Durham) [Obsolete Name And Code: See SHE, CNCL, ROD] (UML)
Concretionary Limestone (-498)
Alternative Name(s): Kirkham Abbey Formation
Stratotypes:
Partial Type Section  Sea cliffs at Roker, Sunderland, Tyne and Wear. (From mouth of Roker Park to Cannonball Rocks). 
Reference Section  About 16 m. the uppermost 5 - 6 m. comprising of dolomite ooid grainstone. Coastal cliff section near Cross Gill, Blackhall Rocks, County Durham. 
Reference(s):
none recorded or not applicable
1:50K maps on which the lithostratigraphical unit is found, and map code used:
E021 E027 E033 E015