The BGS Lexicon of Named Rock Units — Result Details

Holmrook Till Member

Computer Code: HRTI Preferred Map Code: HR
Status Code: Full
Age range: Devensian Stage (QD) — Devensian Stage (QD)
Lithological Description: Very dense, pale reddish grey to red (Munsell Soil), very gravelly sandy clay diamicton with many cobbles and boulders, with clasts of Borrowdale Volcanic Group rocks (rhyolite, welded tuff, slate), granite and granophyre. Generally matrix supported and massive, but with some interbeds of cobble and boulder gravel, and of pebbly clay.
Definition of Lower Boundary: Variable, but mainly a sharp, irregular, unconformable contact with bedrock, or an undulating to planar, unconformable contact with laminated silt and clay of the Stubble Green Silt or Carleton Hall Clay members of the Glannoventia Formation.
Definition of Upper Boundary: Variable, mainly a sharp, undulating, draped unconformable contact with overlying dark brown laminated clay of the Whinneyhill Coppice Clay Member of the Aikbank Farm Glacigenic Formation or a sharp, planar, unconformable contact with reddish brown, gravelly sandy clay diamicton of the Ravenglass Till Member of the Seascale Glacigenic Formation.
Thickness: To 11m
Geographical Limits: Western side of Lake District inland of the limit of the "Gosforth Oscillation".
Parent Unit: Blengdale Glacigenic Formation (BLGL)
Previous Name(s): Lower Boulder Clay Of The Main Glaciation (-1603)
Alternative Name(s): none recorded or not applicable
Stratotypes:
Reference Section  BGS registered borehole SD19NW11 (Aikbank Farm Borehole 1), from 49.2 to 55.1m depth. Nirex 1997. 
Type Section  BGS registered borehole SD09NE21 (Nirex QBH 2A) from 38.5 to 49.5m depth. Nirex 1997. 
Reference(s):
Akhurst, M C, Chadwick, R A, Holliday, D W, McCormac, M, McMillan, A A, Millward, D, Young, B, Ambrose, K, Auton, C A, Barclay, W J, Barnes, R P, Beddoe-Stephens, B, James, J C W, Johnson, H, Jones, N S, Glover, B W, Hawkins, M P, Kimbell, G S, MacPherson, K A T, Merritt, J W, Milodowski, A E, Riley, N J, Robins, N S, Stone, P and Wingfield, R T R. 1997. The geology of the west Cumbria district. Memoir of the British Geological Survey, Sheets 28, 37 and 47 (England and Wales). 138pp. 
Merrit, J W and Auton, C A. 2000. An outline of the lithostratigraphy and depositional history of Quaternary deposits in the Sellafield district, west Cumbria. Proceedings of the Yorkshire Geological Society, Vol.53, 129-154 
Merritt, J W and Auton, C A. 1997. Quaternary lithostratigraphy of the Sellafield district. Nirex Science Report SA/97/045 (Issue 2.0). [Report prepared for UK Nirex Ltd. 69pp, 5 tables, 20 figures, 14 enclosures and one appendix.] 
Trotter, F M, Hollingworth, S E, Eastwood T and Rose, W C C. 1937. Gosforth District. Geological Survey Memoir, England and Wales, Sheet 37. 
1:50K maps on which the lithostratigraphical unit is found, and map code used:
none recorded or not applicable