The BGS Lexicon of Named Rock Units — Result Details

Windermere Clay And Silt Formation

Computer Code: WMCS Preferred Map Code: notEntered
Status Code: Full
Age range: Devensian Stage (QD) — Devensian Stage (QD)
Lithological Description: Lacustrine and organic sediments infilling Lake Windermere, comprising upper (Upper Laminated Clay), and lower (Lower Laminated Clay) units of laminated clay separated by a sequence of silt or organic silt (Non-organic and organic silt unit). Sporadic rock fragments are present in the organic silt.
Definition of Lower Boundary: Overlies gravel and till of the Central Cumbria Glacigenic Subgroup (Caledonia Glacigenic Group).
Definition of Upper Boundary: The Upper Laminated Clay passes conformably upwards into organic muds of the Cumbria-Lancashire Catchments Subgroup (Britannia Catchments Group) of Flandrian age.
Thickness: Cores of up to 6m have been sampled on the lake floor in water depths of 30m. Echo sounding in deeper water indicates 21 to 40m of sediment (Howell, 1971).
Geographical Limits: Cumbria.
Parent Unit: Britannia Catchments Group (BCAT)
Previous Name(s): none recorded or not applicable
Alternative Name(s): none recorded or not applicable
Stratotypes:
Type Section  Cored borehole (5 inch diameter) taken in Low Wray Bay, Lake Windermere, Cumbria. The core represents the type site for the Windermere interstadial of the Late Devensian Stage. Coope and Pennington, 1977; Pennington, 1977, 1978. 
Reference(s):
Coope, G R and Pennington, W. 1977. The Windermere Interstadial of the Late Devensian. Philosophical Transactions of the Royal Society of London, Vol.280, Series B, 337-339. 
Pennington, W. 1978. Quaternary Geology. 207-225 in Moseley, F (Editor), The Geology of the Lake District. Yorkshire Geological Society Occasional Publication, No.3. 
Thomas, G S P. 1999. Northern England. 91-98 in Bowen, D Q (Editor), A revised correlation of Quaternary and Neogene deposits in the British Isles. Geological Society Special Report No.23. 
Howell, F T. 1971. A continuous seismic profile survey of Windermere. Geological Journal, Vol.,7, 329-334. 
Pennington, W. 1977. The late-glacial flora and vegetation of Britain. Philosophical Transactions of the Royal Society of London, Vol.280, Series B, 247-271. 
1:50K maps on which the lithostratigraphical unit is found, and map code used:
none recorded or not applicable