The BGS Lexicon of Named Rock Units — Result Details

Drumchorick Siltstone Formation

Computer Code: DKSF Preferred Map Code: DKSF
Status Code: Full
Age range: Arundian Substage (CJ) — Arundian Substage (CJ)
Lithological Description: Siltstone, dark grey, calcareous, micaceous, sandy, bioturbated, fossiliferous, interbedded with mudstone and thin, commonly lenticular, calcareous sandstone and limestone, with thin beds of crinoidal calciturbidites.
Definition of Lower Boundary: Conformable abrupt change from top sandstone stratum of Mullaghmore Sandstone Formation.
Definition of Upper Boundary: Gradational upwards, conformable, with predominantly calcareous mudstones of Benbulben Shale Formation.
Thickness: 90m
Geographical Limits: Kesh-Omagh area of the northwest Carboniferous basin of Ireland.
Parent Unit: Tyrone Group (TYRO)
Previous Name(s): Included As Part Of The Clonelly Sandstone Group (-1504)
Drumkeeran Siltstone Formation (-212)
Alternative Name(s): none recorded or not applicable
Stratotypes:
Type Section  Southeast flowing river on west side of Drummacahan Townland exposes almost full sequence commencing just above base (not exposed), continuing into the overlying Benbulben Shale Formation (contact exposed). 
Reference Section  Waterfalls in Bannagh River, 960m west-south-west of Drummoney Bridge. Base of Drumchorick Siltstone Formation and lower few metres of strata rest on top sandstone (fallmaker) of Mullaghmore Formation. 
Reference(s):
Simpson, I M, 1954. The Lower Carboniferous stratigraphy of the Omagh Syncline, Northern Ireland. Quarterly Journal of the Geological Society of London, Vol.110, 391-408. 
Mitchell, W I, Johnston, T P and Legg, I C. 2004. Geology of the country around Kesh, Co. Fermanagh and Omagh, Co. Tyrone. Geological Sheets 32 and part of 31 (Kesh) and 33 (Omagh). Geological Survey of Northern Ireland. Technical Report GSNI 04/1. 
1:50K maps on which the lithostratigraphical unit is found, and map code used:
N32