The BGS Lexicon of Named Rock Units — Result Details

Roddlesworth Formation

Computer Code: RODD Preferred Map Code: notEntered
Status Code: Full
Age range: Tournaisian Stage (CT) — Chadian Substage (CI)
Lithological Description: At the stratotype, the formation comprises in ascending order: a pale green, grey and red conglomerate with quartz pebbles in a medium-grained chloritic sandstone matrix; medium to dark grey dolomitic siltstone, with beds of white to buff fine-grained dolostone, anhydrite and red siltstone; pale grey, medium-grained sandstone with siliceous and dolomitic cement, interbedded with medium to dark grey, fine-grained sandstone with an argillacous and dolomitic matrix.
Definition of Lower Boundary: Conglomerate or sandstone overlying an angular unconformity above Lower Palaeozoic purple slates, or conformably upon white, pink to red and green, fine- to medium-grained sandstone of the Old Red Sandstone Group.
Definition of Upper Boundary: The pale to dark grey, green or red, fine- to medium-grained sandstone with siliceous and dolomitic cement of the Roddlesworth Formation is overlain unconformably by dolostone or limestone of the Trawden Limestone Group. The top of the formation is taken at the base of the lowermost limestone or dolostone of the predominantly carbonate succession of the Trawden Limestone Group.
Thickness: 140m in the Roddlesworth borehole, and 28m in the Holme Chapel borehole.
Geographical Limits: Not proved at outcrop. Proved in the subsurface over the Central Lancashire High, a SW-NE structure extending from Chorley [SD 60 20] to Bradford [SE 10 30], bounded to the northwest by the Pendle Fault and the Bowland Basin, and to the southeast by the Rossendale Basin.
Parent Unit: Not Applicable (-)
Previous Name(s): none recorded or not applicable
Alternative Name(s): none recorded or not applicable
Stratotypes:
Type Section  Roddlesworth No.1 borehole (SD62SE274), from a depth of 2470.6 m to 2331.0 m, which comprises the entire thickness of the formation. Evans & Kirby, 1999. 
Reference Section  Holme Chapel No.1 borehole (SD82NE68), from a depth of 1968.0 m to 1940.0 m, which comprises the entire thickness of the formation. Evans & Kirby, 1999. 
Reference(s):
Waters, C N, Barclay, W J, Davies, J R and Waters, R A. In press. Stratigraphical framework for Carboniferous successions of Southern Great Britain (Onshore). British Geological Survey Research Report, RR/05/06. 
Evans, D J, and Kirby, G A. 1999. The architecture of concealed Dinantian carbonate sequences over the Central Lancashire and Holme highs, northern England. Proceedings of the Yorkshire Geological Society, Vol. 52, 297-312. 
1:50K maps on which the lithostratigraphical unit is found, and map code used:
E075 E076