Earth Science Conservation Review
| Craigballyharky and Craigbardahessiagh - Caledonide Igneous Complex | Tyrone |
| Site Type: | Inland exposure |
| Site Status: | ESCR |
| Grid Reference: | H73337573,H72187433 |
| Google maps: | 54.62462,-6.86514 |
| Rocks | |
|---|---|
| Rock Age: | Silurian, Ordovician (Arenig, Llandovery, Llanvirn) |
| Rock Name: | Little River Group, Tyrone Volcanic Group, Desertcreat Group, Tyrone Plutonic Group |
| Rock Type: | Granodiorite, Quartz-diorite, Tonalite |
| Interest | |
| Other interest: | Caledonian, Intrusion |
Introduction:
The Craigballyharky and Craigbardahessiagh sites occur ~3-5km northeast of Pomeroy, County Tyrone. Craigballyharky Hill is located within an extensive but patchy area of natural exposure. It is approached via a single track used for farm and reservoir access. Craigbardahessiagh is an area of extensive but patchy exposure that is best approached via a farm from the junction of Bardahessiagh Road and Bardahessiagh Lane.
The first edition of the Ballygawley (Sheet 34) one-inch to the mile geological map (Geological Survey of Ireland, 1913) and accompanying explanatory memoir (Nolan, 1878) shows and describes an intrusive body of syenite and syenitic granite. The map shows a single body intruded into hornblendic and pyroxenic country rocks, while the southern margin of the body is shown in contact with sedimentary rocks of Silurian age.
On the second edition of Sheet 34 (renamed Pomeroy) two parts to the complex were recognized (Geological Survey of Northern Ireland, 1979). One was centered on Craigballyharky and the other around Craigbardahessiagh. Both were emplaced in the Tyrone Basic Plutonic Complex and include large roof pendants of the Tyrone Basic Plutonic Complex and Ordovician Tyrone Volcanic Group. Graptolitic shales and turbidites of the Ordovician Desertcreat Group (Caradoc-Ashgill) and Silurian (Llandovery) Little River Group overly the intrusive complexes at the southern contact.
The first edition of the Ballygawley (Sheet 34) one-inch to the mile geological map (Geological Survey of Ireland, 1913) and accompanying explanatory memoir (Nolan, 1878) shows and describes an intrusive body of syenite and syenitic granite. The map shows a single body intruded into hornblendic and pyroxenic country rocks, while the southern margin of the body is shown in contact with sedimentary rocks of Silurian age.
On the second edition of Sheet 34 (renamed Pomeroy) two parts to the complex were recognized (Geological Survey of Northern Ireland, 1979). One was centered on Craigballyharky and the other around Craigbardahessiagh. Both were emplaced in the Tyrone Basic Plutonic Complex and include large roof pendants of the Tyrone Basic Plutonic Complex and Ordovician Tyrone Volcanic Group. Graptolitic shales and turbidites of the Ordovician Desertcreat Group (Caradoc-Ashgill) and Silurian (Llandovery) Little River Group overly the intrusive complexes at the southern contact.
| Enlander, I., Dempster, M. & Doughty, P., 2024. Craigballyharky and Craigbardahessiagh - Caledonide Igneous Complex, County Tyrone, site summary. [In] Earth Science Conservation Review. https://www.habitas.org.uk/escr/summary.php?item=590. Accessed on 2024-12-26 |
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