The BGS Lexicon of Named Rock Units — Result Details

Whelter Knotts Tuff Formation

Computer Code: WLT Preferred Map Code: Wlt
Status Code: Full
Age range: Caradoc Series (O4) — Caradoc Series (O4)
Lithological Description: A pale, yellowish grey, to grey-weathered, garnetiferous, massive silicic tuff and eutaxitic lapilli tuff, with subordinate foliated vitrophyric tuff, and bedded units of lithic-rich tuff and lapilli-tuff. Lithologically distinctive units have member status.
Definition of Lower Boundary: Taken at the abrupt change to silicic pyroclastic rocks from andesite of the Birker Formation or the volcaniclastic rocks of the Scalehow Formation.
Definition of Upper Boundary: Defined by the base of the Mardale Formation.
Thickness: Up to 300 m thick.
Geographical Limits: North-eastern Lake District, south and east of Ullswater to the Haweswater area.
Parent Unit: Borrowdale Volcanic Group (BVG)
Previous Name(s): Atkinson & Fordingdale Ignimbrite Group (-3137)
Hugh's Laithes Pike Ignimbrite Group (-3138)
Haweswater Ignimbrite Group (-615)
Place Fell Group (-1279)
Alternative Name(s): none recorded or not applicable
Stratotypes:
Type Area  Kidsty Pike to Whelter Knotts, west of the Haweswater Reservoir. Beddoe-Stephens, B. 2000; Woodhall, D. 2000. 
Reference(s):
Nutt, M J C, 1970. The Borrowdale Volcanic Series and associated rocks around Haweswater, Westmorland. Unpublished PhD thesis, University of London (Queen Mary College). 
Millward, D, 2002. Geology of the area between Haweswater and Shap. British Geological Survey Research Report RR/02/02 
Beddoe-Stephens, B, 2000. The Borrowdale Volcanic Group between Haweswater and eastern Ullswater. British Geological Survey Technical Report WG/00/04. 
Woodhall, D G. 2000. The geology of the Haweswater and Martindale areas of the north-eastern Lake District. British Geological Survey Technical Report WA/00/55. 
Moseley, F, 1960. The succession and structure of the Borrodale Volcanic rocks south-east of Ullswater. Quarterly Journal of the Geological Society of London, Vol.116, 55-84. 
1:50K maps on which the lithostratigraphical unit is found, and map code used:
E030 E039 E029