The BGS Lexicon of Named Rock Units — Result Details
Careg Onen Formation
| Computer Code: | OCO | Preferred Map Code: | notEntered |
|---|---|---|---|
| Status Code: | Full | ||
| Age range: | Ediacaran Period (AD) — Comley Series (EC) | ||
| Lithological Description: | Fine- to coarse-grained, locally micaceous greywacke ["high-matrix"] sandstones, conglomeratic in places, with igneous and metamorphic clasts, interbedded with sandy mudstones, locally ferruginous. | ||
| Definition of Lower Boundary: | Unknown, but Greenly [1919] supposed that it overlay the Gwna Melange (now the Gwna Group)] of Anglesey. There is some doubt about this, given current uncertainties on the age of these divisions. | ||
| Definition of Upper Boundary: | Unknown, but probably overlain unconformably by Ordovician strata. | ||
| Thickness: | Unknown. | ||
| Geographical Limits: | Anglesey. The formation represents part of the Arfon Group of the mainland that extends onto Sheet 105 Caernarfon. | ||
| Parent Unit: | Arfon Group (ARN) | ||
| Previous Name(s): | Careg-Onen Beds (A) [Obsolete Name And Code: Use OCO]
(CON)
Careg-Onen Beds (B) [Obsolete Name And Code: Use OCO] (CGO) Careg-Onen-Beds [Obsolete Name and Code: Use OCO] (-1737) |
||
| Alternative Name(s): | none recorded or not applicable | ||
| Stratotypes: | |||
| Reference Section | North slope of Mynydd Llwydiarth. Greenly, 1919. | ||
| Type Section | Sea cliff at Careg-onen Cove. | ||
| Reference(s): | |||
| Greenly, E. 1946. The Monio-Cambrian interval. Geological Magazine, Vol. 83, 237-240. | |||
| Carney J N et al. 2000. Precambrian rocks of England and Wales. Geological Conservation Review Series. No 20. [Peterborough: Joint Nature Conservation Committee]. 252pp. | |||
| 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. | |||
| Greenly, E. 1919. The Geology of Anglesey, Vol 2. Memoir of the Geological Survey of Great Britain [England and Wales]. [London: H.M.S.O.]. | |||
| 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: | |||
| E093 E105 | |||