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): Haweswater Ignimbrite Group (-615)
Place Fell Group (-1279)
Atkinson & Fordingdale Ignimbrite Group (-3137)
Hugh's Laithes Pike Ignimbrite Group (-3138)
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):
Beddoe-Stephens, B, 2000. The Borrowdale Volcanic Group between Haweswater and eastern Ullswater. British Geological Survey Technical Report WG/00/04. 
Millward, D, 2002. Geology of the area between Haweswater and Shap. British Geological Survey Research Report RR/02/02 
Nutt, M J C, 1970. The Borrowdale Volcanic Series and associated rocks around Haweswater, Westmorland. Unpublished PhD thesis, University of London (Queen Mary College). 
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:
E039 E029 E030