| Computer Code: |
LSD |
Preferred Map Code: |
Lsd |
| Status Code: |
Full |
| Age range: |
Cautleyan Stage (OU)
— Cautleyan Stage (OU) |
| Lithological Description: |
Interbedded, thick sequence of conglomerate, sandstone and siltstone composed essentially of detritus derived locally from the Borrowdale Volcanic Group. The conglomerate beds are poorly sorted in fining upwards cycles. The red and green coloured siltstone beds are sporadic but well laminated. Details of these beds in the Ambleside district are given by Millward et al. (2000, p. 119-123). |
| Definition of Lower Boundary: |
Taken at the base of conglomerate beds, unconformably overlying volcanic rocks of the Borrowdale Volcanic Group. |
| Definition of Upper Boundary: |
Abruptly gradational into the overlying part of the Stile End Formation; in places overlain unconformably by carbonate rocks of the Kirkley Bank Limestone Formation. |
| Thickness: |
0 - 65 m. |
| Geographical Limits: |
The main outcrop of the Longsleddale Conglomerate Member is from west of Kentmere to just east of Longsleddale. Sporadic occurrences of conglomerate are present at the base of the Dent Group along its outcrop from Furness to Shap, but these have not always been assigned to the member, as most are thin and their ages not clearly established. |
| Parent Unit: |
Stile End Formation (SEN)
|
| Previous Name(s): |
none recorded or not applicable
|
| Alternative Name(s): |
none recorded or not applicable
|
| Stratotypes: |
| Type Section |
The type section [NY 4888 0670 to 4883 0583] is 450 m north-north-west of Stockdale Farm,
Longsleddale (Lawrence et al., 1986). |
| Reference(s): |
| Millward, D, and Stone, P. 2012. Stratigraphical framework for the Ordovician and Silurian sedimentary strata of northern England and the Isle of Man. British Geological Survey Research Report, RR/12/04. 119pp. |
| Kneller, B C, Scott R W, Soper N J, Johnson E W and Allen P M, 1994. Lithostratigraphy of the Windermere Supergroup, Northern England. Geological Journal, Vol. 29, 219-240. |
| Lawrence, D J D, Webb, B C, Young, B and White, D E. 1986. The geology of the Late Ordovician and Silurian rocks (Windermere Group) in the area around Kentmere and Crook. Includes map, 1:25,000 series, Parts of Sheets NY40 and SD49 Kentmere and Crook, Solid and Drift Geology. Report of the British Geological Survey, 18/5. |
| Moseley F. 1984. Lower Palaeozoic lithostratigraphical classification in the English Lake District. Geological Journal, Vol. 19, p. 239-247. |
| Millward, D, Johnson, E W, Beddoe-Stephens, B, Young, B, Kneller, B C, Lee, M K, Fortey, N J, Allen, P M, Branney, M J, Cooper, D C, Hirons, S, Kokelaar, B P, Marks, R J, McConnell, B J, Merritt, J W, Molyneux, S G, Petterson, M G, Roberts, B, Rundle, C C, Rushton, A W A, Scott, R W, Soper, N J, and Stone, P. 2000. Geology of the Ambleside district. Memoir of the British Geological Survey, England and Wales, Sheet 38. |
| McNamara, K J. 1979. The age, stratigraphy and genesis of the Coniston Limestone Group in the southern Lake District. Geological Journal, 14, 41-69. |
| 1:50K maps on which the lithostratigraphical unit is found, and map code used: |
|
E039
|
