The BGS Lexicon of Named Rock Units — Result Details
Rhayader Mudstones Formation
Computer Code: | RHS | Preferred Map Code: | RhS |
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Status Code: | Full | ||
Age range: | Aeronian Age (SA) — Telychian Age (ST) | ||
Lithological Description: | Thinly interbedded green and grey turbidite mudstones and burrowed hemipelagites. Sparse thin packets of thinly interbedded turbidite mudstones and laminated hemipelagites. Scattered thin packets with turbidite sandstones. NOTE: Overlain by the Caeran Mudstones and underlain by the Derwenlas Formation. Locally underlain by the Caban Conglomerate Complex. | ||
Definition of Lower Boundary: | Taken at base of a prominent thick packet of thinly interbedded turbidite mudstones and laminated hemipelagites overlying thinly interbedded turbidite mudstones and burrowed hemipelagites of the Derwenlas Formation. | ||
Definition of Upper Boundary: | Gradational, but taken at the base of the incoming of abundant packets of thinly interbedded turbidite mudstone and laminated hemipelagites. | ||
Thickness: | c.460 metres. | ||
Geographical Limits: | Central Wales. | ||
Parent Unit: | Claerwen Group (CLAE) | ||
Previous Name(s): | Rhayader Pale Shales Formation [Obsolete Name and Code: Use RHS]
(-4861)
Cwmsymlog Formation [Obsolete Name And Code: See RHS] (CSF) Rhayader Mudstones [Obsolete Name and Code: Use RHS] (RPSL) Rhayader Shales [Obsolete Name and Code: Use RHS] (-493) |
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Alternative Name(s): | none recorded or not applicable | ||
Stratotypes: | |||
Type Section | Bed of River Wye at Rhayader. | ||
Reference(s): | |||
Lapworth, H, 1900. The Silurian sequence at Rhayader. Quarterly Journal of the Geological Society, Vol.56, p.67-137. | |||
1:50K maps on which the lithostratigraphical unit is found, and map code used: | |||
E179 |