The BGS Lexicon of Named Rock Units — Result Details

Oldstead Oolite Member

Computer Code: OSTD Preferred Map Code: OlO
Status Code: Full
Age range: Oxfordian Age (JO) — Oxfordian Age (JO)
Lithological Description: Ooidal limestone, yellow to grey, bioclastic, spicule-rich, sandy, grainstone to wackestone textures, cross-bedded in part.
Definition of Lower Boundary: Erosive non-sequence: ooidal limestone resting sharply on yellow sandstone of Osgodby Formation, or grey-green micaceous siltstone of Oxford Clay Formation.
Definition of Upper Boundary: Passage upward through decrease in ooid content and increase in fine-grained sand into Rievaulx Member.
Thickness: Up to 11m.
Geographical Limits: Between Roulston Scar and Shaw's Moor, southern Hambleton Hills, North Yorkshire. Passes north-east into siliceous sponge spicule-rich limestone (lower part of Rievaulx Member, Wright, 1983).
Parent Unit: Lower Calcareous Grit Formation (LCG)
Previous Name(s): Oolitic Limestone In Lower Calcareous Grit (-1746)
Alternative Name(s): none recorded or not applicable
Type Section  Crag at Raven's Gill, Oldstead, North Yorkshire, exposes 11m of ooid-limestone and slightly ooidal, sandy limestone, non-sequentially overlying the Osgodby Formation, and overlain by fine-grained sandstone of the Rievaulx Member (Lower Calcareous Grit Formation). Powell et al., 1992, p. 65; Wright, 1983, p. 261. 
Fox-Strangways, C. 1892. The Jurassic Rocks of Britain, Vol.1. Yorkshire. Memoir of the Geological Survey of the United Kingdom. 
Wright, J K, 1980. Oxfordian Correlation Chart. "In" Cope, C J W, (Editor). A correlation of Jurassic rocks in the British Isles, Part two: Middle and Upper Jurassic. Geological Society of London Special Report No.15. (p.61-76 in Correlation Chart). 
Powell, J H, Cooper, A H C and Benfield, A C. 1992. Geology of the country around Thirsk. Memoir of the British Geological Survey, Sheet 52 (England and Wales). 
Wright, J K. 1983. The Lower Oxfordian (Upper Jurassic) of North Yorkshire. Proceedings of the Yorkshire Geological Society, Vol. 44, 249-281. 
1:50K maps on which the lithostratigraphical unit is found, and map code used: