The BGS Lexicon of Named Rock Units — Result Details
Roch Volcanic Formation
| Computer Code: | RRH | Preferred Map Code: | RRh |
|---|---|---|---|
| Status Code: | Pending Upgrade | ||
| Age range: | Arenig Series (OR) — Arenig Series (OR) | ||
| Lithological Description: | Fine-grained, highly silicified, pale greenish - blue rhyolites weathering white; thin bands of blue - green and pale mauve banded flinty tuffs with interbedded sediments. | ||
| Definition of Lower Boundary: | Not seen. | ||
| Definition of Upper Boundary: | Not seen, but generally faulted. | ||
| Thickness: | At least 180m | ||
| Geographical Limits: | Pembrokeshire. | ||
| Parent Unit: | Not Available (!) | ||
| Previous Name(s): | Roch Rhyolitic Series [Obsolete Name and Code: Use RRH, PRR]
(-3624)
Roch Rhyolitic Group [Obsolete Name And Code: Use RRH] (PRR) Trefgarn Rhyolitic Series [Obsolete Name and Code: Use RRH, PRR] (-1774) |
||
| Alternative Name(s): | none recorded or not applicable | ||
| Stratotypes: | |||
| Type Area | The area near Treffgarne, Cleddau Valley, Pembrokeshire (Dyfed). | ||
| Type Section | Cleddau Valley, Pembrokeshire, between Spittal Brook and Ford. Thomas, H H, and Cox, A H. 1924. | ||
| Reference(s): | |||
| Thomas, H H and Jones, O T, 1912. On the Pre-Cambrian and Cambrian rocks of Brawdy, Haycastle and Brimaston, (Pembrokeshire). Quarterly Journal of the Geological Society of London, Vol.68, 374-401. | |||
| Thomas, H H, and Cox, A H. 1924. The Volcanic Series of Trefgarn, Roch and Ambleston (Pembrokeshire). Quarterly Journal of the Geological Society, Vol.80, p.520-548. | |||
| Harris, A L and others, 1973. A correlation of the Pre-Cambrian rocks in the British Isles. Geological Society of London Special Report No 6. | |||
| 1:50K maps on which the lithostratigraphical unit is found, and map code used: | |||
| E210 | |||