The BGS Lexicon of Named Rock Units — Result Details

Stainmore Forest Till Formation

Computer Code: SFTI Preferred Map Code: notEntered
Status Code: Full
Age range: Devensian Stage (QD) — Devensian Stage (QD)
Lithological Description: Dark bluish grey,brown or reddish brown,extremely compact,stony sandy silty clay diamicton with clasts dominated by local Carboniferous lithologies (sandstone, granule-conglomerate, limestone, mudstone, gannister, coal), including Whin Sill dolerite and far-travelled clasts from Scotland and the Lake District (greywacke sandstone and siltstone, welded tuffs and rhyolites, Shap Granite, granodiorite), and the Vale of Eden (red sandstone, Brockram). In Teesdale this till grades up into, or is overlain unconformably by yellowish brown, rubbly diamicton with clasts mainly of sandstone.
Definition of Lower Boundary: Generally a sharp uneven contact on bedrock, but locally a complex gradational glaciotectonic contact with fractured or decomposed bedrock. Overlies dolerite of the Whin Sill at the Partial Type Section
Definition of Upper Boundary: Generally the ground surface or overlain unconformably by glaciofluvial sand and gravel or younger superficial deposits. Overlain unconformably by a thin bed of cross-laminated silt and sand capped by loose, yellowish brown stony diamicton at the Partial Type Section.
Thickness: Up to 50m, thicker in some buried valleys
Geographical Limits: Stainmore Gap to the west of Darlington, and Teesdale upstream of Barnard Castle, extending towards the Vale of York.
Parent Unit: North Pennine Glacigenic Subgroup (NPEG)
Previous Name(s): none recorded or not applicable
Alternative Name(s): none recorded or not applicable
Stratotypes:
Type Area  The Stainmore Gap west of Barnard Castle and Tessdale Mills and Hull (1976) 
Partial Type Section  River cliff section in a drumlin on the northern bank of the River Tees immediately downstream of the confluence with the Harwood Beck Burgess and Holliday (1979) 
Reference(s):
Mills, D A C. and Hull, J H. 1976. Geology of the country around Barnard Castle. Memoir of the Geological Survey of Great Britain. HMSO. 385pp. 
Burgess, I C and Holliday, D W. 1979. Geology of the country around Brough-under-Stainmore. Memoir for 1:50 000 geological sheet 31 and parts of sheets 25 and 30. Geological Survey of Great Britain (England and Wales). [London: HMSO.] 131pp. 
Mitchell, W A. 2007. Reconstructions of the Late Devensian (Dimlington Stadial) British-Irish Ice Sheet: the role of the upper Tees drumlin field, north Pennines, England. Proceedings of the Yorkshire Geological Society, 56, 221-234. 
1:50K maps on which the lithostratigraphical unit is found, and map code used:
none recorded or not applicable