The BGS Lexicon of Named Rock Units — Result Details

Sabden Shales

Computer Code: SDSH Preferred Map Code: SdSh
Status Code: Index Level
Age range: Arnsbergian Substage (CG) — Kinderscoutian Substage (CK)
Lithological Description: A fossiliferous mudstone with subordinate beds of locally pebbly sandstone and thin argillaceous limestone and ironstone.
Definition of Lower Boundary: The lower boundary is taken at the base of fissile black mudstones of the Reticuloceras reticulum Marine Band, or where this is absent, at the base of the mudstone-dominated succession overlying the sandstones of the Warley Wise [Wilpshire] Grit
Definition of Upper Boundary: The upper boundary is taken at the base of a sandstone-dominated succession of the Todmorden (Parsonage) Grit, overlying the mudstone-dominated Sabden Shales
Thickness: About 400m
Geographical Limits: Longridge [SD 60 35] to Bailey Hall [SD 68 37] on the Ribchester Syncline, eastwards to approximately Foulridge [SD 88 42].
Parent Unit: Millstone Grit Group [See Also MIGR] (MG)
Previous Name(s): Sabden Shales Formation (-1810)
Alternative Name(s): Part Of The Formally Defined Silsden, Samlesbury And Hebden Formations
Stratotypes:
Partial Type Section  Immediately north of Samlesbury Bottoms, on the east bank of the River Darwen in Blackburn, Lancashire, where approximately 130m of the upper part of the unit is exposed [E2, H and R1] in a river section. Price et al. 1963. 
Reference Section  Stream section along Duddel Brook, Ribchester Lancashire, which exposes 208 m from the mid part of the unit. Aitkinhead et al. 1992. 
Reference(s):
Aitkenhead, N, Bridge, D M, Riley, N J and Kimbell, S F. 1992. Geology of the country around Garstang. Memoir of the British Geological Survey, Sheet 67 (England and Wales) 
Price, D, Wright, W B, Jones, R C B, Tonks, L H and Whitehead, T H. 1963. Geology of the country around Preston. Memoir of the Geological Survey of Great Britain, Sheet 75 (England and Wales). 
1:50K maps on which the lithostratigraphical unit is found, and map code used:
E067 E076 E075 E068