The BGS Lexicon of Named Rock Units — Result Details

Applethwaite Member

Computer Code: AP Preferred Map Code: AP
Status Code: Full
Age range: Cautleyan Stage (OU) — Cautleyan Stage (OU)
Lithological Description: Mainly a calcareous siltstone, although it occurs in graded units that range from a fine-grained sandstone with shelly lag accumulations at the base, to a bioturbated and fine-grained top. Cross-bedding is widespread, and there are rare interbeds of concretionary limestone. The unit is interpreted as a series of storm surge deposits.
Definition of Lower Boundary: Rests with a marked lithological change either on the rhyolitic ignimbrite of the Yarlside Volcanic Formation, or on the concretionary limestone of the Kentmere Member (Kirkley Bank Formation).
Definition of Upper Boundary: Overlain by uniform, bioturbated calcareous siltstone of the Torver Member. The top of the Applethwaite Member is taken as the top of the highest graded unit, which is transitional into the overlying and more homogeneous siltstone.
Thickness: To about 60m
Geographical Limits: Southeastern part of the English Lake District, Cumbria, between Coniston [SD 300 980] and the Birkbeck Fells [NY 560 070].
Parent Unit: Kirkley Bank Formation (KKB)
Previous Name(s): Applethwaite Group (*240)
Applethwaite Series (*241)
Applethwaite Beds [Obsolete Name And Code: Partially Replaced By AP] (APB)
Applethwaite Formation (-1309)
Applethwaite Beds (-1951)
Alternative Name(s): none recorded or not applicable
Stratotypes:
Type Section  Series of exposures to the east of the Garbourn Road on Moor Head, Applethwaite Common. Sheet 39, Kendal. 
Reference(s):
McNamara, K J. 1979. The age, stratigraphy and genesis of the Coniston Limestone Group in the southern Lake District. Geological Journal, 14, 41-69. 
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. 
1:50K maps on which the lithostratigraphical unit is found, and map code used:
E039