The BGS Lexicon of Named Rock Units — Result Details
Treffgarne Volcanic Formation
| Computer Code: | TREV | Preferred Map Code: | notEntered |
|---|---|---|---|
| Status Code: | Pending Upgrade | ||
| Age range: | Tremadoc Series (O1) — Tremadoc Series (O1) | ||
| Lithological Description: | Blue-green keratophyric or andesitic lavas, basaltic andesite, purple, red and green andesitic tuffs and volcanic agglomerate. | ||
| Definition of Lower Boundary: | Drawn at base of Treffgarne Volcanic Group where it rests unconformably on green/grey micaceous shales, sandy mudstones and grits of the Treffgarne Bridge Beds. | ||
| Definition of Upper Boundary: | Drawn at conformable upward passage from tuffs and volcanic agglomerate of Treffgarne Volcanic Formation to shales, tuff, ashy sandstone and rhyolitic tuff of the Brunel Beds. | ||
| Thickness: | c.150m | ||
| Geographical Limits: | Cleddau Valley, south-west Dyfed. | ||
| Parent Unit: | Not Applicable (-) | ||
| Previous Name(s): | Treffgarne Andesite Group [Obsolete Name and Code: Use TREV]
(-3092)
Treffgarne Andesitic Series [Obsolete Name and Code: Use TREV] (-3093) Treffgarne Volcanic Series [Obsolete Name and Code: Use TREV] (-3094) Treffgarne Volcanic Group [Obsolete Name and Code: Use TREV] (-4375) |
||
| Alternative Name(s): | none recorded or not applicable | ||
| Stratotypes: | |||
| Type Area | Cleddau Valley, near Treffgarne, southwest Dyfed, Wales. | ||
| Reference Section | Within quarry near Wolfsdale, southwest Dyfed, Wales. | ||
| Partial Type Section | South end of main quarry by A40 trunk road north of Treffgarne, southwest Dyfed, Wales. | ||
| Reference(s): | |||
| Thomas, H H, "In" Strahan, A and others, 1914. South Wales Coalfield, part XI, Haverfordwest. Memoir of the Geological Survey of Great Britain. | |||
| Brown, M J, Allen, P M, Cooper, D C, Cameron, D G, Pease, S F, Evans, A D, and Beddoe-Stephens, B W. 1987. Volcanogenic mineralisation in the Treffgarne area, south-west Dyfed, Wales. Mineral Reconnaisance Programme, Report No. 86. British Geological Survey. | |||
| 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. | |||
| Cantrill, T C and others, 1916. South Wales Coalfield, part XII, Milford. Memoir of the Geological Survey of Great Britain. | |||
| 1:50K maps on which the lithostratigraphical unit is found, and map code used: | |||
| E210 | |||