The BGS Lexicon of Named Rock Units — Result Details
Po House Tuff Formation
| Computer Code: | PHT | Preferred Map Code: | PHT |
|---|---|---|---|
| Status Code: | Full | ||
| Age range: | Caradoc Series (O4) — Caradoc Series (O4) | ||
| Lithological Description: | Thin and medium parallel bedded andesitic tuff and lapilli-tuff. | ||
| Definition of Lower Boundary: | Base of Dog Crag Tuff Member - a thin pyroclastic flow deposit - which rests on a non-sequence that occurs at the top of the Whinney Bank Formation (an interbedded succession of siltstone and andesitic lapilli-tuff). | ||
| Definition of Upper Boundary: | Base of Waberthwaite Formation (dacitic tuff and lapilli-tuff). | ||
| Thickness: | Up to c.400m | ||
| Geographical Limits: | Whicham Valley:- between Park Head (SD 172 834) and Lacra Bank (SD 145 815). | ||
| Parent Unit: | Borrowdale Volcanic Group (BVG) | ||
| Previous Name(s): | Mottled Shale of Dog Crag Type [Obsolete Name and Code: Use PHT]
(-4839)
Po House Tuffs [Obsolete Name and Code: Use PHT] (-2370) |
||
| Alternative Name(s): | none recorded or not applicable | ||
| Stratotypes: | |||
| Type Area | Pohouse Bank, Whicham Valley, Cumbria. | ||
| Reference(s): | |||
| Johnson, E W, Soper, N J, Burgess, I C, Ball, D F, Beddoe-Stephens, B, Carruthers, R M, Fortey, N J, Hirons, S, Merritt, J W, Millward, D, Roberts, B, Walker, A B and Young, B. 2001. Geology of the country around Ulverston. Memoir of the British Geological Survey, England and Wales, Sheet 48. | |||
| Mathieson, N A, 1986 Geology, structure and geochemistry of the Ordovician volcanic succession in south west Cumbria. Unpublished Ph.D. thesis, University of Sheffield. | |||
| British Geological Survey. 1994a. Silecroft, SD18SW solid and drift 1:10 000. (Keyworth, Nottingham, British Geological Survey.) | |||
| Green, J F N, 1913. The older Palaeozoic succession of the Dudden Estuary. London, 23pp. | |||
| British Geological Survey. 1994b. Millom Park, SD18SE, Solid and Drift, 1:10 000. (Keyworth, Nottingham: British Geological Survey.) | |||
| 1:50K maps on which the lithostratigraphical unit is found, and map code used: | |||
| E048 | |||