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
Stratotypes:
Type Section  Ritchie Crag, 1.7 km SSE of the Haweswater Hotel, Haweswater, Cumbria. 
Reference(s):
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