The BGS Lexicon of Named Rock Units — Result Details
Fernagh Formation
| Computer Code: | FRNA | Preferred Map Code: | FRN |
|---|---|---|---|
| Status Code: | Full | ||
| Age range: | Ordovician Period (O) — Ordovician Period (O) | ||
| Lithological Description: | Pale buff, pinkish and green aphanitic sometimes flow banded and auto-brecciated lavas and partly intrusive felsite. | ||
| Definition of Lower Boundary: | Where seen, intrusive contact with structurally underlying Tonalite intrusion. | ||
| Definition of Upper Boundary: | Not exposed but most likely to be conformable with overlying tuffs and lava of Tyrone Volcanic Group. | ||
| Thickness: | Max 300m | ||
| Geographical Limits: | Fernagh, Brackagh South and Cashel Rock, County Tyrone, Northern Ireland. | ||
| Parent Unit: | Tyrone Volcanic Group (TVG) | ||
| Previous Name(s): | Fernagh Andesite and Dacite Formation [Obsolete Name and Code: Use FRNA]
(-3408)
[Obsolete Code: Use FRNA] (*515) Fernagh Andesite And Dacite Formation [Obsolete Name And Code: Use FRNA] (FADF) |
||
| Alternative Name(s): | none recorded or not applicable | ||
| Stratotypes: | |||
| Type Area | Fernagh Townland, County Tyrone, Northern Ireland. | ||
| Reference(s): | |||
| Geological Survey of Northern Ireland 1979. Pomeroy, sheet 34, solid, 1:50 000. [Southampton, Ordnance Survey for Institute of Geological Sciences.] | |||
| 1:50K maps on which the lithostratigraphical unit is found, and map code used: | |||
| N34 | |||