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Earth Science Conservation Review
| Barnagh Bay, Copeland Island - site of local interest | Down |
| Site number: | 715 | ||
| Locality Type: | Coastal section, Foreshore | Status: | local interest |
| Grid Reference: | J586841 Centroid | ||
| Google maps: | 54.68044,-5.54096 | ||
| County: | Down | Council area: | Ards & North Down Borough Council |
| Period: | Ordovician | ||
| Site Description | |
|---|---|
| Highlights: | |
Caledonian lamprophyre dykes are very well developed on the wave-cut platforms around the coast of the Main Copeland Island. An example of a multiple intrusion in Ordovician rocks occurs at Barnagh Bay and can be traced for 460m along the southern shore of the bay. It is offset by numerous small faults. | |
| Description: | |
Two generations of intrusive igneous rocks are known within Ards Borough Council area. Dolerite intrusions of Palaeogene age are present and well exposed at Scrabo Hill. Older, lamprophyre dykes associated with the Caledonian Newry Granodiorite occur in the Lower Palaeozoic rocks of the borough. The lamprophyre intrusions occur both as true dykes cutting across the bedding planes of the sedimentary rocks and as sills intruded conformably, or nearly so, with the bedding. Where the dykes cut across bedding they are easily recognised but recognition of the sills can be difficult as they resemble the massive greywacke units in colour and blocky aspect. In northeast County Down, no lamprophyres have been recognised in inland exposures and all those recorded occur on the wave-cut platform around the coast. The dykes are best developed on Copeland Island. At Barnagh Bay one multiple intrusion can be traced for 460m, along the south shore of the bay. It is intruded into Ordovician rocks and is off-set by numerous small faults. | |
| Importance: | |
The site is of educational significance. The well exposed multiple intrusion, off-set by numerous small faults, provides an ideal opportunity to learn about some of the basic principles of geological mapping. It would therefore make an ideal teaching locality. | |
| Notes: | |
The site falls within the Outer Ards pASSI / pSPA. | |
| Keywords | |
|---|---|
| Rocks: | Greywacke, Lamprophyre |
| Structures: | dyke, fault |
| Access | |
|---|---|
| Approach: | Shore section on northwest coast of Copeland Island. |
| Uses | |
| Educ. Level: | The site is of educational significance. It would make an ideal teaching locality. |
| Record type: | SLNCI Report | ||
| Entered by: | E M Porter | ||
| Last updated: | 09/10/03 | ||
| Enlander, I., Dempster, M. & Doughty, P., 2026. Barnagh Bay, Copeland Island - site of local interest, County Down, site details. [In] Earth Science Conservation Review. https://www.habitas.org.uk/escr/site.php?item=715. Accessed on 2026-11-05. |
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