The BGS Lexicon of Named Rock Units — Result Details

Pinnacle Howe Tuff Member

Computer Code: PNH Preferred Map Code: PnH
Status Code: Full
Age range: Caradoc Series (O4) — Caradoc Series (O4)
Lithological Description: A foliated, vitrophyric, rhyodacitic tuff containing a diagnostic population of angular, grey felsic clasts, in white to pink weathered exposures.
Definition of Lower Boundary: Taken at the sharp change to vitrophyric tuff from underlying units that include andesite and volcaniclastic sandstone of the Birker Felll Formastion, or bedded garnetiferous tuff and lapilli tuff of the Powley's Hill Member (Whelter Knotts Fomration).
Definition of Upper Boundary: Taken at the abrupt change to eutaxitic lapilli-tuff of the main part of the Whelter Knotts Formation.
Thickness: Up to 70 m thick.
Geographical Limits: Eastern Lake District, from Pinnacle Howe to Naddle Beck, Haweswater, Cumbria.
Parent Unit: Whelter Knotts Tuff Formation (WLT)
Previous Name(s): none recorded or not applicable
Alternative Name(s): none recorded or not applicable
Stratotypes:
Type Area  Pinnacle Howe, 2.2 km south-west of Bampton, Cumbria. Beddoe-Stephens, 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 
1:50K maps on which the lithostratigraphical unit is found, and map code used:
E030 E039