The BGS Lexicon of Named Rock Units — Result Details
Padarn Tuff Formation
| Computer Code: | PDT | Preferred Map Code: | notEntered |
|---|---|---|---|
| Status Code: | Full | ||
| Age range: | Ediacaran Period (AD) — Ediacaran Period (AD) | ||
| Lithological Description: | Strongly welded rhyolitic ash-flow tuffs with abundant phenocrysts of quartz and sodic plagioclase, subordinate air-fall tuffs and rhyolite lavas. | ||
| Definition of Lower Boundary: | Unknown. Base not seen. | ||
| Definition of Upper Boundary: | Conformably overlain by volcaniclastic sediments and rhyolitic air-fall tuffs of the Minfordd Formation. Details of the boundary are unknown. | ||
| Thickness: | 800m to 2000m | ||
| Geographical Limits: | North Wales, Snowdonia, Bangor and Caernarfon districts. | ||
| Parent Unit: | Arfon Group (ARN) | ||
| Previous Name(s): | Padarn Rhyolite (Ignimbrite) [Obsolete Name And Code: See PDT]
(ACPR)
Padarn Ignimbrite [Obsolete Name and Code: Use PDT] (-3606) Padarn Rhyolite [Obsolete Name and Code: Use PDT] (-3607) |
||
| Alternative Name(s): | none recorded or not applicable | ||
| Stratotypes: | |||
| Reference Section | Old road cutting southeast of Pont Pen y Uyn, on the southwest side of Llyn Padarn. Howells M F, et al., 1985. | ||
| Reference(s): | |||
| Morris, T O and Fearnsides, W G, 1926. The stratigraphy and structure of the Cambrian Slate Belt of Nantlle, (Caernarvonshire). Quarterly Journal of the Geological Society of London, Vol.82, p.250-303. | |||
| Reedman, A J, Leveridge, B E and Evans, R B. 1984. The Arfon Group (Arvonian?) of North Wales. Proceedings of the Geologists' Association, Vol.95, 313-321. | |||
| Pharaoh T C and Gibbons W. 1994. Precambrian rocks in England and Wales south of the Menai Strait Fault System. 85-97 in Gibbons W and Harris A L (editors), A revised correlation of Precambrian rocks in the British Isles. Geological Society of London Special Report No.22. | |||
| Greenly, E. 1944. The Arvonian rocks of Arvon. Quarterly Journal of the Geological Society, London, 100, 269-287. | |||
| Rushton, A W A and Howells, M F. 1998. Stratigraphical framework for the Ordovician of Snowdonia and the Lleyn Peninsula. British Geological Survey Research Report, RR/99/08. | |||
| Howells M F, Reedman A J and Leveridge B E. 1985. Geology of the country around Bangor: Explanation for 1:50 000 geological sheet 106 (England and Wales). British Geological Survey Sheet Explanation. [London: HMSO.] 34pp. | |||
| 1:50K maps on which the lithostratigraphical unit is found, and map code used: | |||
| E106 E118 | |||