| Computer Code: |
TRF |
Preferred Map Code: |
Trf |
| Status Code: |
Full |
| Age range: |
Ediacaran Period (AD)
— Comley Series (EC) |
| Lithological Description: |
Felsic pyroclastic and extrusive rocks interbedded with shallow water sediments. Lithologies comprise volcanastic breccias, crystal tuffs, porphyritic rhyolitic lavas and thinly interbedded quartzose sandstones, tuffs, lapillistone and mudstone. |
| Definition of Lower Boundary: |
Not defined - contacts mostly faulted. |
| Definition of Upper Boundary: |
Unknown - unconformably overlain by mudstones and sandstones of the Solva Group (Cambrian) |
| Thickness: |
Unknown - at least 15m proved in boreholes around Llandeloy. |
| Geographical Limits: |
Pembrokeshire. |
| Parent Unit: |
Pebidian Supergroup (PN)
|
| Previous Name(s): |
none recorded or not applicable
|
| Alternative Name(s): |
none recorded or not applicable
|
| Stratotypes: |
| Type Area |
Around Treffynnon, near St. David's, Pembrokeshire, South Wales. |
| Reference Section |
Quarries in village of Treffynnon. Williams, T G. 1934. |
| Reference(s): |
| Williams, T G. 1934. The Precambrian and Lower Palaeozoic rocks of the eastern end of St David's Precambrian area Pembrokeshire. Quarterly Journal of the Geological Society, London, Vol.90, 32-75. |
| George, T N. 1970. British Regional Geology, South Wales, Third Edition. British Geological Survey. |
| Allen, P M and others. 1985. Exploration for porphyry-style copper mineralisation near Llandeloy, southwest Dyfed. Mineral Reconnaissance Programme Report No 78, British Geological Survey, Keyworth, Nottingham, 99pp. |
| 1:50K maps on which the lithostratigraphical unit is found, and map code used: |
|
E209
|
