The BGS Lexicon of Named Rock Units — Result Details

Padarn Tuff Formation

Computer Code: PDT Preferred Map Code: notEntered
Status Code: Pending Upgrade
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 Ignimbrite (-3606)
Padarn Rhyolite (-3607)
Padarn Rhyolite (Ignimbrite) [Obsolete Name And Code: See PDT] (ACPR)
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):
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. 
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. 
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. 
Greenly E. 1944. The Arvonian rocks of Arvon. Quarterly Journal of the Geological Society, London, 100, 269-287. 
1:50K maps on which the lithostratigraphical unit is found, and map code used:
E106 E118