Earth Science Conservation Review
| Beaghbeg | Tyrone |
| Site Type: | Crags |
| Site Status: | ESCR |
| Grid Reference: | H674828 |
| Google maps: | 54.68921,-6.95483 |
| Rocks | |
|---|---|
| Rock Age: | Ordovician |
| Rock Name: | Tyrone Volcanic Group |
| Rock Type: | Breccia, Volcanic, Chert, Lapilli Tuff, Volcaniclastic sediment |
| Interest | |
| Other interest: | Caledonian, Extrusion |
Introduction:
Beaghbeg is located in unfenced, rough pasture in the Townland of Beaghbeg about 1.7km north-northwest of Dunnamore. The site is approached via farm lanes which run southwards from Beaghmore Road or northwards from Beaghbeg Road.
On one of the earliest geological maps of the area, (Portlock, 1843) the combined extent of the Tyrone Volcanic and the Tyrone Plutonic Groups were accurately mapped and clearly distinguished from the mica schists of the nearby Sperrin Mountains and Tyrone Central Inlier. The rocks at Beaghbeg and throughout the surrounding area were described collectively as "metamorphic rocks of hornblendic type" and Portlock noted a variety of hornblendic schistose rocks present at Beaghbeg.
On the first edition of the one-inch to the mile geological map (Sheet 26, Draperstown, Geological Survey of Ireland, 1882) the rocks at Beaghbeg were represented as "pyroxenic rocks" loosely classified as "probably of Pre-Cambrian or Upper Laurentian age". The coarse lapillae tuff at Beaghbeg appears to be an along strike equivalent of rocks noted as "remarkable breccias" at Meenascallagh, Cole (1897).
Hartley (1933) produced the first detailed lithological map and descriptions of the rocks of the central Tyrone Ordovician volcanic plutonic terrane and incorporated the rocks at Beaghbeg within the division referred to as the Tyrone Igneous Series.
On the 1:50,000 scale second edition of Sheet 26 (Draperstown, Geological Survey of Northern Ireland, 1995) Hartley's Tyrone Igneous Series was subdivided into two distinct stratigraphic components, the Tyrone Plutonic Group and the Tyrone Volcanic Group and included the rocks at Beaghbeg within the Tyrone Volcanic Group.
In a regional tectono-stratigraphic context, the Tyrone Volcanic Group forms part of an arc-volcanic type geological sequence in the Tyrone-Girvan Sub-Terrane of the Midland Valley Terrane as defined by Bluck et al. (1992). The Tyrone Volcanic Group formed along the Laurentian foreland at the northern margin of the Iapetus Ocean during closure of the Iapetus Ocean during Ordovician times.
On one of the earliest geological maps of the area, (Portlock, 1843) the combined extent of the Tyrone Volcanic and the Tyrone Plutonic Groups were accurately mapped and clearly distinguished from the mica schists of the nearby Sperrin Mountains and Tyrone Central Inlier. The rocks at Beaghbeg and throughout the surrounding area were described collectively as "metamorphic rocks of hornblendic type" and Portlock noted a variety of hornblendic schistose rocks present at Beaghbeg.
On the first edition of the one-inch to the mile geological map (Sheet 26, Draperstown, Geological Survey of Ireland, 1882) the rocks at Beaghbeg were represented as "pyroxenic rocks" loosely classified as "probably of Pre-Cambrian or Upper Laurentian age". The coarse lapillae tuff at Beaghbeg appears to be an along strike equivalent of rocks noted as "remarkable breccias" at Meenascallagh, Cole (1897).
Hartley (1933) produced the first detailed lithological map and descriptions of the rocks of the central Tyrone Ordovician volcanic plutonic terrane and incorporated the rocks at Beaghbeg within the division referred to as the Tyrone Igneous Series.
On the 1:50,000 scale second edition of Sheet 26 (Draperstown, Geological Survey of Northern Ireland, 1995) Hartley's Tyrone Igneous Series was subdivided into two distinct stratigraphic components, the Tyrone Plutonic Group and the Tyrone Volcanic Group and included the rocks at Beaghbeg within the Tyrone Volcanic Group.
In a regional tectono-stratigraphic context, the Tyrone Volcanic Group forms part of an arc-volcanic type geological sequence in the Tyrone-Girvan Sub-Terrane of the Midland Valley Terrane as defined by Bluck et al. (1992). The Tyrone Volcanic Group formed along the Laurentian foreland at the northern margin of the Iapetus Ocean during closure of the Iapetus Ocean during Ordovician times.
| Enlander, I., Dempster, M. & Doughty, P., 2024. Beaghbeg, County Tyrone, site summary. [In] Earth Science Conservation Review. https://www.habitas.org.uk/escr/summary.php?item=585. Accessed on 2024-12-26 |
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