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Earth Science Conservation Review
| Northeast Mournes Complex - Northeast Mournes Moraines | Down |
| Site number: | 459 | ||
| ESCC: | IS | ||
| Locality Type: | Inland exposure | Status: | TBC |
| Grid Reference: | J345170,J370305,J330215 Corners of site, Not Entered | ||
| Google maps: | 54.08505,-5.94466 | ||
| County: | Down | Council area: | Newry, Mourne & Down District Council |
| Period: | Quaternary | ||
| Stages: | Late Midlandian | ||
| Site Description | |
|---|---|
| Description: | |
1. Southern Section The Ballymartin ridge widens from ca. 550m near the coast to ca. 1km on the lower mountain slopes (J330215), where the western ice proximal slope begins to trend westward and the eastern ice proximal slope begins to trend eastward. Ridge morphology becomes less well defined as the ridge widens, and the ridge surface becomes more undulating, with frequent enclosed depressions. The ridge is dissected longitudinally by a conspicuous channel (<150m wide) at Ballyveagh Beg. The channel eventually forms the western boundary of the ridge, and is occupied by the underfit Mullagh River. Between the Ballymartin ridge and the next major ridge to the northeast, the Longstone Ridge (J353200), the terrain is extremely undulating with numerous interconnected enclosed depressions and channels which are dry or contain underfit streams. Depressions are kettleholes which tend to increase in size tends towards the coast. The largest kettlehole (J350180) is500m long and 200m wide. Cross-plain ridges become more strongly arcuate from the Longstone ridge eastward as they adopt a lateral form against the mountain slopes. To the east of the Annalong River readvance moraine system, the coastal lowlands narrow rapidly, as the mountain slopes approach the coast. Between Annalong and Glasdrumman, ridges are dissected and separated by well marked channels. The lateral element of the ridges becomes more important as their frontal sections were truncated, and eventually, at Dunmore Hill, totally removed, by late glacial marine erosion. North of Dunmore Hill, moraines frequently show lateral transitions from ridge to bench morphology, and intersect the coast at an increasingly acute angle. Ridges traverse the boundary between cultivated fields from which boulders have been removed, and boulder strewn mountain slopes. Ridges north of Glasdrumman are closely nested, to give a corrugated rather than an undulating landscape. Ridge height tends to increase downslope. The proximal side of ridges rarely exceeds 5m in height. The major exception is Dunmore Hill, which has the form of a rounded double hump, the higher of which stands ca. 15m above the intermoraine low to the north. The humps record two ice front positions, and their preservation is probably due to their site on a subdued bedrock high. Ridges finally pinch out as the lower slopes of Millstone Mountain intersect the coast. An exposure (J379238) records deposition in the ice-distal side of a moraine ridge. Facies present are interbedded sand and gravel, and massive diamict. Facies description Interbedded sand and gravel (<4m thick) consists of massive to crudely stratified pebble to boulder gravel in channels, and lenticular sand and crudely-sorted gravel. Massive channel infills consist of mainly clast-supported cobbles and boulders. Stratified channel infills mostly consist of beds (<30cm) of matrix to clast supported pebble to cobble gravel. Overlapping channels contain stratified silt and sand, with drapes over small pebbles. Channel bottoms are frequently lined with cobbles. A sand lens (<40cm thick) contains rippled sand beds (<20mm thick) with occasional granule streaks. There is a non-erosional planar contact with overlying massive matrix-supported diamict (<1m thick). The facies contains numerous isolated and clustered cobbles and boulders. Facies interpretation Deposits record highly variable flow and sediment supply at an ice front. Deposition is mainly the result of high density cohesionless gravity flow. Massive channel infills are the result of freezing of a plug (Postma, 1986). Poor sorting and lack of bed continuity are characteristic of debris flows (Middleton & Hampton, 1976). Stratified sand and silt with draped pebbles record deposition from suspension in low flow conditions. Granule streaks in current rippled sand record low energy bottom currents. Diamict, characterised by matrix support, dispersed cobbles and boulders, and incorporation of underlying unconsolidated sediments, is typical of deposition of subaerial sediment flow (Lawson, 1982). 2. Northern Section Moraine ridges immediately to the west of Newcastle are massive and round-crested, trending westward in a gentle arc along the course of the Shimna River as far west as Tollymore Park (J340320). The best developed of these ridges extends from a postglacial cliffline at Tollymore (J368327) and through Bryansford (J350333). The ridge is up to 300m wide and the crest is up to 10m higher than the proximal intermorainal low. Ridges trend upslope against the lower slopes of Slievenabrock (J345308), Luke's Mountain (J330310) Spellack (J305295) and Slieve Meelbeg (J300395), with upslope transitions to bench morphology. They cross valley entrances, as at Tullybrannigan (J358310) to produce stepped profiles. To the north of Bryansford, ice retreat was controlled by the bedrock high of McLeans' Hill (161m a.s.l.). Ridges on the northeastern shoulder of McLeans' Hill trend southeast - northwest from the Burren River valley upslope to the northern shoulder of the hill, and intersect a westward trending ridge (J366330). From the northern shoulder, moraines trend downslope into the gap between McLeans' Hill and the neighbouring bedrock high of Moneyscalp Hill (247m a.s.l. at J321329). The gap is crossed by ca. 12 benches and narrow (<100m wide) ridges in ca. 2.3km as nested arcs, concave northwards. Moraines again trend upslope towards the north along the eastern slope of Moneyscalp Hill. Nested arcuate moraine ridges also fill the gaps between Moneyscalp Hill and Tullyree Hill (214m a.s.l., J314323), Tullyree Hill and Slievenaman (323m a.s.l., J297312) and Slievenaman and the northern spur of Butter Mountain (J280295). Arcuate moraines in the Shimna River valley record retreat of ice which entered the valley via the Slievenaman - Butter Mountain gap. Moraines show a clear cross-cutting relationship with moraines which record an earlier retreat towards the south west across the Slievenamuck - Ott Mountain col (J278274). Ice entering the valley adopted a lobate shape, extending ca. 2km south and 1km north from the centre line of the gap. Moraines adopt the form of low (<3m high in the valley bottom), narrow (mostly <80m, but up to 150m wide) round crested ridges which trend steeply upslope (ca. 50°) against the valley sides. At least seven arcuate moraine ridges in the Shimna valley and six within the Slievenaman - Butter Mountain gap are succeeded by more massive linear ridges across the northern entrance to the gap. These ridges show upslope transitions into benches towards the southwest on the northern flank of the bedrock high of Kinnahalla (296m a.s.l., J257292), and along the northern slopes of Craigdoo and Spelga Mountain. Benches trend downslope towards the south at the entrance to Spelga Pass. Arcuate ridges on the lower slopes of Kinnahall record retreat northeastward through the gap between Stang Tops (212m a.s.l., J255307) and Goward Hill (207m a.s.l., J238299). | |
| Notes: | |
For site specific information on other sites within the Northeast Mournes Complex see the following site: Key Site 460 - Northeast Mournes Raised Beaches For overview information and references on the Northeast Mournes Complex see the following site: Key Site 449 - Northeast Mournes Complex - Overview For overview and site specific information on other sand and gravel sites within the Mourne Mountains area see the following sites: Key Site 440 - Mourne Plain Complex - Overview Key Site 447 - Attical Complex, Mourne Mountains - Overview Key Site 448 - Bloody Bridge River Valley Complex, Mourne Mountains - Overview Key Site 450 - Western Mournes Complex - Overview Key Site 451 - Annalong Valley For general information and references on the sand and gravel landscapes of N. Ireland, and directions to sites other than those within the Mourne Mountains area, see the following site: Key Site 439 - Introduction to the Sand and Gravel Landscapes of N. Ireland | |
| Keywords | |
|---|---|
| Geomorph: | recessional moraine |
| Record type: | ESCR report | ||
| Entered by: | E M Porter | ||
| Enlander, I., Dempster, M. & Doughty, P., 2026. Northeast Mournes Complex - Northeast Mournes Moraines, County Down, site details. [In] Earth Science Conservation Review. https://www.habitas.org.uk/escr/site.php?item=459. Accessed on 2026-11-08. |
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