The BGS Lexicon of Named Rock Units — Result Details

Rowantreethwaite Tuff Member

Computer Code: RWT Preferred Map Code: Rwt
Status Code: Full
Age range: Caradoc Series (O4) — Caradoc Series (O4)
Lithological Description: A well-bedded dacitic tuff and lapilli-tuff, with some pyroclastic breccia and accretionary lapilli-tuff, more thinly-bedded, finer grained and better sorted upwards, with abrupt intra-bed changes in grain size common.
Definition of Lower Boundary: Taken at the abrupt change from bedded volcaniclastic sandstone to bedded pyroclastic rocks.
Definition of Upper Boundary: Intruded by andesite sills at the base of the overlying Mardale Formation.
Thickness: Up to 100 m thick.
Geographical Limits: Southeast of Haweswater Reservoir, Cumbria, between Rowantreethwaite Beck and Woof Crag.
Parent Unit: Mardale Sandstone Formation (MRL)
Previous Name(s): Rowantreethwaite Member (-3016)
Alternative Name(s): none recorded or not applicable
Type Section  Ritchie Crag, 1.7 km SSE of the Haweswater Hotel, Haweswater, Cumbria. 
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:
E039 E030