The BGS Lexicon of Named Rock Units — Result Details

Ehen Valley Silt Member

Computer Code: EVSI Preferred Map Code: notEntered
Status Code: Full
Age range: Devensian Stage (QD) — Devensian Stage (QD)
Lithological Description: Very fine-grained sand, silt and clay, greyish brown to dark grey, typically fines downwards and contains much finely disseminated coal debris; generally thickly laminated. Thin diamictons present in thick silt sequences recorded in boreholes. It forms part of the infill of the buried valleys of the Ehen Calder and Lower Uldale and was laid down principally in a glaciolacustrine environment, probably during the deglaciation of the main Late Devensian ice sheet.
Definition of Lower Boundary: At its type site conformable on the Catgill Wood Sand and Gravel Member of the Seascale Glacigenic Formation, elsewhere conformable with diamictons of the Low Wath Till Member of the Seascale Glacigenic Formation.
Definition of Upper Boundary: At its type site a gradational contact into the Ehen Valley Sand and Gravel Member of the Seascale Glacigenic Formation. Elsewhere it is conformably overlain by diamictons of the Rothersyke Till Member of the Gosforth Glacigenic Formation.
Thickness: 8.7m exposed at its type section; 21.25m thick in reference section (Nirex borehole QBH 21; BGS registered borehole NY01SW 602).
Geographical Limits: On 50k Sheets 28 (Whitehaven) and 37 (Gosforth).
Parent Unit: Seascale Glacigenic Formation (SEAG)
Previous Name(s): Middle Sands And Gravels (-122)
Alternative Name(s): none recorded or not applicable
Type Section  "Rothersyke Scar" river cliff section [Logs NY00NW ME6a-c Nirex Science Report 768 (1995), western side of River Ehen between Rothersyle House and Low Mill, c.300m west of Thornhill village, west Cumbria. Nirex Science Report SA/97/045 (Issue 2.0) 
Reference Section  Between 5 and 26.25m depth in Nirex borehole QBH 212 (BGS Registered borehole NY01SW 602).c.200m southsouthwest of Moss Dalts, c.1km eastnortheast of Egremont, west Cumbria. Nirex Science Report SA/97/045 (Issue 2.0) 
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.] 
Auton, C A, Alexander, S A, Eaton, G P, McMillan, A A, Skinner, A C and Wealthall, G P. 1997. Logging and interpretation of Quaternary boreholes (QBH) drilled in the Sellafield area during 1966. Nirex Science Report SA/97/043 (Issue 2.0). 
Trotter, F M, Hollingworth, S E, Eastwood T and Rose, W C C. 1937. Gosforth District. Geological Survey Memoir, England and Wales, Sheet 37. 
Eastwood T, and others. 1968. Geology of the country around Whitehaven. Memoir of the Geological Survey of Great Britain, Sheet 28 (England and Wales). 
1:50K maps on which the lithostratigraphical unit is found, and map code used:
none recorded or not applicable