The BGS Lexicon of Named Rock Units — Result Details
Mardale Sandstone Formation
| Computer Code: | MRL | Preferred Map Code: | Mrl |
|---|---|---|---|
| Status Code: | Full | ||
| Age range: | Caradoc Series (O4) — Caradoc Series (O4) | ||
| Lithological Description: | A mixed succession of predominantly bedded volcaniclastic rocks, comprising detritus mainly of andesitic composition with bedded volcaniclastic sandstone as the main lithofacies, and subsidiary units of volcaniclastic breccia, tuff and lapilli-tuff, of which significant units of volcaniclastic breccia and pyroclastic rocks are given member status, the whole intruded by many contemporaneous andesite sills. | ||
| Definition of Lower Boundary: | Taken at the abrupt change from silicic tuff and lapilli-tuff of the Whelter Knotts Formation, to generally well bedded volcaniclastic rocks. | ||
| Definition of Upper Boundary: | Defined by the sharp base of tte Froswick Tuff Formation. | ||
| Thickness: | Probably up to 980m, but much faulted and greatly inflated by sills. | ||
| Geographical Limits: | Between Ullswater and Haweswater, and Nan Bield Pass to Wet Sleddale, northeastern Lake District. | ||
| Parent Unit: | Borrowdale Volcanic Group (BVG) | ||
| Previous Name(s): | Keasgill Tuffs [Obsolete Name and Code: Use MRL]
(-3563)
Mardale Formation [Obsolete Name and Code: Use MRL] (-3564) Nan Bield Formation [Obsolete Name and Code: Use MRL] (-3565) Mardale Tuff Formation [Obsolete Name and Code: Use MRL] (-4204) |
||
| Alternative Name(s): | none recorded or not applicable | ||
| Stratotypes: | |||
| Type Area | The fellside on the south-east side of Swindale, near Shap, Cumbria. | ||
| 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 Unpublished PhD thesis, University of London (Queen Mary College). | |||
| Soper, N J and Numan, N M S, 1974. Structure and stratigraphy of the Borrowdale Volcanic Rocks of the Kentmere area, English Lake District. Geological Journal, Vol. 9, 147-166. | |||
| 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. | |||
| 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. | |||
| 1:50K maps on which the lithostratigraphical unit is found, and map code used: | |||
| E030 E039 | |||