| Computer Code: |
GNNS |
Preferred Map Code: |
GNNS |
| Status Code: |
Full |
| Age range: |
Brigantian Substage (CX)
— Pendleian Substage (CE) |
| Lithological Description: |
Sandstone, purple-grey weathering distinctive orange-purple, medium- to coarse-grained, parallel and cross-laminations, thin layers of purple-red and green mudstone; basal breccia of metamorphic clasts. |
| Definition of Lower Boundary: |
Unconformable on Dalradian Supergroup metamorphic rocks |
| Definition of Upper Boundary: |
Not exposed, faulted out. |
| Thickness: |
At least 550m, probably to more than 1000m |
| Geographical Limits: |
The Milltown Segment of the Fintona Block and south side of Greenan Mountain, County Tyrone. |
| Parent Unit: |
Not Entered (?)
|
| Previous Name(s): |
Greenan Formation
(-937)
|
| Alternative Name(s): |
none recorded or not applicable
|
| Stratotypes: |
| Type Area |
Four small streams draining the south side of Greenan Mountain. Partial exposyre of the basal breccia, the lowest sandstones, and with all localities containing dateable green/blue mudstone horizons. |
| Type Section |
South flowing stream on the south side of Greenan Mountain. Exposes basal epiclastic breccia and succeeding sandstones with green mudstones clasts. |
| Reference Section |
Broad outcrop of Greenan Formation southeast of the Castle Archdale Fault, Long sections in the higher parts of the sandstone sequence are exposed in numerous northward-flowing streams. |
| Reference(s): |
| Simon, J B, 1984. Sedimentation and tectonic setting of the Lower Old Red Sandstone of the Fintona and Curlew Mountain district. Irish Journal of Earth Sciences, Vol.6, 213-228. |
| Mitchell, W I and Owens, B, 1990. The geology of the western part of the Fintona Block, Northern Ireland: Evolution of Carboniferous basins. Geological Magazine, Vol.127 (5), 407-426. |
| 1:50K maps on which the lithostratigraphical unit is found, and map code used: |
| none recorded or not applicable |
