The BGS Lexicon of Named Rock Units — Result Details

Shanmullagh Formation

Computer Code: SHAN Preferred Map Code: SHAN
Status Code: Full
Age range: Famennian Age (DA) — Famennian Age (DA)
Lithological Description: Sandstone, purple-brown, fine- to medium-grained, thin to very thick beds; and purple-red siltstones and mudstone; ripples.
Definition of Lower Boundary: Not exposed: unconformable, in the east on Sheet 34 (Pomeroy) on Lower Palaeozoic sediments and on varied igneous/metamorphic lithologies of Tyrone Volcanic Complex (Palaeozoic).
Definition of Upper Boundary: Not exposed; overlain unconformably by Lower and Upper Carboniferous sediments.
Thickness: Not known; probably >1000m
Geographical Limits: The Irvinestown segment of the Fintona Block, Northern Ireland.
Parent Unit: Fintona Group (FIN)
Previous Name(s): Ballinamallard Mudstone Formation (BLM)
Fintona Group (FIN)
Fintona Beds (-3404)
Alternative Name(s): none recorded or not applicable
Stratotypes:
Type Area  Numerous superficial deposit-free areas and stream section in Drumharrey Townland, Drumduff Townland, 300m east and 500m east-south-east of the stratotype. 
Type Section  Disused quarry at Shanmullagh West, 2.4km north-north-east of Irvinestown. Exposes particularly arenaceous part of the sequence. 
Reference(s):
Nolan, J, 1880. On the Old Red Sandstone of the north of Ireland. Quarterly Journal of the Geological Society of London, Vol.36, 529-535. 
House, M R, Richardson, J B, Chaloner, W G, Allen, J R L, Holland, C H and Westoll, T S. 1977. A Correlation of Devonian rocks of the British Isles. Geological Society of London, Special Report No.8, Scottish Academic Press, Edinburgh. 
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. 
Mitchell, W I and Owens, B, 1990. Used on 1:50,000 geological maps of the Kesh (Sheet 32) area; to be included in Memoir of the Kesh-Omagh (Sheets 32/33) area, p.411. 
1:50K maps on which the lithostratigraphical unit is found, and map code used:
N32