Tyrone Group

The Tyrone Group is a lithostratigraphical term coined to refer to a particular succession of rock strata which occur in Northern Ireland within the Visean Stage of the Carboniferous Period.

[1] It comprises a series of limestones, shales and sandstones which accumulated to a thickness of 2400m in the northwest Carboniferous basin of Ireland.

[2][3] The succession continues south and west across the border into the Republic of Ireland, though different names are typically applied.

This formation which was formerly referred to as the upper part of the Middle or Calp Limestone is a 100-180m thickness of grey limestone with interbedded shale and mudstone) [9] Its outcrop runs from west of Swanlinbar to Lough Macnean Lower then via Boho to the Cliffs of Magho overlooking Lower Lough Erne.

[12] Its outcrop extends from northeast of Monaghan southwest to Upper Lough Erne, though is largely covered by more recent deposits.

It also occurs in the Kesh and Ederney areas and in a broken curved outcrop towards Drumquin then northwest to Slieve Glass then west and southwest to Pettigoe and the north shore of Lower Lough Erne to Belleek.

The outcrop also extends southwest from the Tempo area to south of Lisbellaw and along the northeast edge of Enniskillen to the eastern shores of Lower Lough Erne.

[15] Though much obscured by superficial deposits, its outcrop extends from the countryside north of Donamore southwestwards towards Clogher and in the area between Fivemiletown and Fintona.