The BGS Lexicon of Named Rock Units — Result Details

Mainsgate Wood Sand And Gravel Member

Computer Code: MGW Preferred Map Code: MGW
Status Code: Full
Age range: Devensian Stage (QD) — Devensian Stage (QD)
Lithological Description: Sand and gravel, coarsening upwards from pale brown fine-grained sand, with low-angle cross stratificationand ripple-drift cross lamination, to pebbly sand disposed in planar deltaic foresets (dip towards the south), and capped by gravel deltaic topsets. Clasts comprise local Lake District igneous and metamorphic rock-types together with some red and yellow sandstone, and coal. Forming flat-topped plateaux some 20m above the surrounding, poorly drained ground underlain by the Holmeside Clay Member.
Definition of Lower Boundary: Sharp, undulating, erosional boundary with underlying moderate to reddish brown thinly interbedded clay and silt of the Holmeside Clay Member of the Aikbank Farm Glacigenic Formation.
Definition of Upper Boundary: Either not overlain, or partially overlain by Flandrian peat or alluvial deposits.
Thickness: About 9m
Geographical Limits: Lower Wasdale, West Cumbria, inland of the limit of ice of the Irish Sea Ice Stream during the "Gosforth Oscillation".
Parent Unit: Aikbank Farm Glacigenic Formation (AIK)
Previous Name(s): none recorded or not applicable
Alternative Name(s): Glaciofluvial Deltaic Deposits
Stratotypes:
Reference Section  BGS registered borehole SD19NW11 (Aikbank Farm Borehole 1), from 1.06 to 9.91m depth. Nirex, 1997. 
Type Section  BGS registered borehole SD19NW12 (Aikbank Farm Borehole 2), from 1.5 to 10.06m depth. Nirex, 1997. 
Reference(s):
Huddart, D. 1991. The glacial history and glacial deposits of the north and west Cumbrian lowlands, 151-167 in Ehlers, J, Gibbard, P L and Rose, J (editors), Glacial deposits in Great Britain and Ireland. [London: Balkema.] 
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.] 
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. 
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