The BGS Lexicon of Named Rock Units — Result Details
Pant Y Darren Formation
| Computer Code: | PYDN | Preferred Map Code: | notEntered |
|---|---|---|---|
| Status Code: | Full | ||
| Age range: | Courceyan Substage (CF) — Courceyan Substage (CF) | ||
| Lithological Description: | Fine-grained, thinly bedded dolostones with minor mudstone layers. | ||
| Definition of Lower Boundary: | The base is a sharp, planar boundary on which the basal dolostone of the Pantydarren Formation overlie ooidal grainstone of the underlying Pwll-y-Cwm Formation. | ||
| Definition of Upper Boundary: | The top is a sharp junction where dolostones of the Pantydarren Formation are overlain by ooidal grainstones of the Blaen Onnen Oolite Formation. | ||
| Thickness: | 5m | ||
| Geographical Limits: | Northeast crop of the South Wales Coalfield, from Darren Disgwlfa [SO 217 145] southeast to around Craig-yr-Hafod [SO 2720 1001]. | ||
| Parent Unit: | Clydach Valley Subgroup (CLD) | ||
| Previous Name(s): | Bed 3 [Obsolete Name and Code: Use PYDN]
(-4280)
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| Alternative Name(s): | Pantydarren Beds Pantydarren Formation |
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| Stratotypes: | |||
| Reference Section | Roadside section on the old Brynmawr road at Blackrock, where the entire formation, lower boundary (with the Pwll-y-Cwm Oolite Formation) and upper boundary (with the Blaen Onnen Oolite Formation) are exposed. Barclay,1989. | ||
| Type Area | Disused quarries at Coed Pantydarren, 1km north of the Clydach Gorge, near Brynmawr, south Wales, which expose 5m of fine-grained, thin-bedded dolomites of the Pantydarren Formation sharply overlying massive pale grey ooildal grainstones of the Pwll-y-Cwm Oolite Formation. Barclay, 1989. | ||
| Reference(s): | |||
| George, T N. 1954. Pre-Seminulan Main Limestone of the Avonian Series in Breconshire. Quarterly Journal of the Geological Society of London, Vol.110, 282-322. | |||
| Barclay, W J, Jackson, D I, Mitchell, M, Owen, B, Riley, N J, White, D E, Strong, G E, and Monkhouse, R A. 1989. Geology of the South Wales Coalfield, Part II, the country around Abergavenny. Memoir of the British Geological Survey. | |||
| 1:50K maps on which the lithostratigraphical unit is found, and map code used: | |||
| none recorded or not applicable | |||