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Earth Science Conservation Review
| Kearney Point - Caledonide Igneous Complex | Down |
| Site number: | 578 | ||
| ESCC: | EF | ||
| Locality Type: | Coastal exposure | Status: | ASSI |
| Grid Reference: | J36463512 Centroid | ||
| Google maps: | 54.24705,-5.90746 | ||
| County: | Down | Council area: | Newry, Mourne & Down District Council |
| Period: | Devonian, Silurian | ||
| Stages: | Lower Devonian | ||
| Lithostrat: | Newry Igneous Complex | ||
| Site Description | |
|---|---|
| Highlights: | |
In coastal exposures it is possible to demonstrate the relationships between Silurian country rocks and foliated lamprophyre dykes of the older series (Reynolds, 1931). These dykes are believed to have been emplaced syn-tectonically during the Caledonian Orogeny and are generally associated with the nearby Newry Igneous Complex. | |
| Introduction: | |
This coastal exposure is located at Kearney Point on the Ards Peninsula. The site is located approximately 700m southwest of Kearney in an area owned by the National Trust. The exposure can be approached on foot using the coastal path. Viewing of the exposure is tide dependent and should be done at least two hours before high tide on a rising tide, and one hour after high tide on a falling tide. Care is needed when traversing slippery rock surfaces. The first edition of the Downpatrick (Sheet 49) one-inch to the mile geological map (Geological Survey of Ireland, 1869) shows a number of lamprophyre dykes of hornblende and mica type, intruded into folded Upper Silurian country rocks. The country rocks are sedimentary and are described on the map as grey grits and slates. In the accompanying explanatory memoir, Trail and Egan (1871) described the country rocks and lamprophyre dykes in detail classifying them as intrusive felstones, minettes and diorites of Silurian age. Reynolds (1931) made important advances in the study of these intrusions. On the basis of field observation and petrology, Reynolds separated the dykes of the Ards Peninsula into an older and younger series on the basis of the amount of deformation. Reynolds described the older series dykes as "crushed" and indicated that these were restricted geographically below a line joining Ringburr Point on the west of the Ards Peninsula to Ringboy Point on the east. The dykes at Kearney Point fall within the older crushed series. The older crushed series of dykes are classified as minettes and rare vogesites (Reynolds, 1931). | |
| Description: | |
Silurian country rock is sedimentary and consists of interbedded greywacke sandstones and shales of turbiditic origin. Bedding is steeply inclined to the northwest and strikes northeast- southwest. A number of the lamprophyre dykes have dip and strike almost parallel to bedding and can be difficult to distinguish visually from the country rock. Trail and Egan (1871) showed a dyke dipping gently to the southeast cutting across steeply inclined bedding; examination of the exposure clearly demonstrates this early field sketch. Freshly broken surfaces show a schistose, deformed rock with a green matrix and pink feldspars. It can be seen that the orientation of the dyke switches from steeply inclined to shallowly dipping reflecting the active fracture pattern during emplacement. Examination of the rock in thin section reveals a fine-grained dyke rock composed mainly of K-feldspar (35%), plagioclase (25%) and biotite (7%), with secondary chlorite and carbonate (Merriman and Hards, 2000). Although the primary minerals have all been altered, their nature and proportions indicate that this rock is a variety of lamprophyre known as minette. | |
| Importance: | |
Kearney Point is the best site to view a deformed lamprophyre dyke of the older or crushed series of Reynolds (1931). The dykes were emplaced syn-tectonically during the Caledonian Orogeny and are believed to be associated with the nearby Newry Igneous Complex. The dykes form an important part of the geological history of the mountain building event. | |
| Interpretation: | |
The association with the nearby Newry Igneous Complex and relationship between folded Silurian country rocks and foliated lamprophyre dykes leads to the interpretation that the dykes were emplaced syn-tectonically during the Caledonian Orogeny. | |
| Conclusions: | |
Kearney Point is the best site to view a deformed lamprophyre dyke interpreted as being emplaced syn-tectonically during the Caledonian Orogeny. The dykes form an important part of the geological history of the mountain building event. | |
| Notes: | |
For information and references on other sites within the Newry Igneous Complex see the following sites: Key Site 568 - Ardglass, Co Down Key Site 569 - Slieve Croob Key Site 570 - Shannaghan Hill Key Site 571 - Ballymagreehan Quarry Key Site 572 - Rathfriland Key Site 573 - Gransha Key Site 574 - Aughnagon Quarry Key Site 575 - Goraghwood Quarry Key Site 576 - Newry By-pass Key Site 577 - Cam Lough Quarry Key Site 579 - Ballyhalbert Pier For general information and references on the Caledonian Igneous Complexes of N. Ireland, and for directions to other regional sites, see the following site: Key Site 595 - Introduction to the Caledonian Igneous Complexes of N. Ireland | |
| Keywords | |
|---|---|
| Rocks: | Greywacke, Shale, Turbidite, Lamprophyre, Minette, Vogesite |
| Structures: | Caledonian, dyke |
| Relations: | Intrusion |
| Access | |
|---|---|
| Approach: | The exposure can be approached on foot using the coastal path. |
| Management: | |
Given the limited exposure of this particularly useful example of a deformed lamprophyre dyke, hammering or sampling should as far as possible be restricted. | |
| Threats: | Hammering and sampling should be restricted. |
| Map(s): | GEOLOGICAL SURVEY OF IRELAND, 1869. 1:63,360 Geological Sheet 49 (Downpatrick). Dublin, Ordnance Survey for Geological Survey of Ireland. GEOLOGICAL SURVEY OF NORTHERN IRELAND, 1997. Northern Ireland. Solid Geology (2nd edition). 1:250,000. (Keyworth, Nottingham: British Geological Survey). | ||
| Record type: | ESCR report | ||
| Entered by: | E M Porter | ||
| Last updated: | 03 MAR 2001 | ||
| Enlander, I., Dempster, M. & Doughty, P., 2026. Kearney Point - Caledonide Igneous Complex, County Down, site details. [In] Earth Science Conservation Review. https://www.habitas.org.uk/escr/site.php?item=578. Accessed on 2026-11-06. |
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