The use of a cultural overlay in defining Landscape Character Areas (LCAs) means that they frequently subdivide natural physiographic units. It is common therefore for significant geomorphological features to run across more than one LCA. It is also possible in turn, to group physiographic units into a smaller number of natural regions. These regions invariably reflect underlying geological, topographic and, often, visual continuities between their component physiographic units, and have generally formed the basis for defining landscape areas such as AONBs. It is essential therefore, that in considering the 'Geodiversity' of an individual LCA, regard should be given to adjacent LCAs and to the larger regions within which they sit. In the original Land Utilisation Survey of Northern Ireland, Symons (1962) identified twelve such natural regions.
This LCA is an extension of the region described as the Uplands and Drift Covered Lowlands of Down and Armagh. The generally subdued relief associated with the underlying basement complex of highly folded Palaeozoic strata provides the unity of this region. Most of the region lies to the north of the Mournes Massif, where relative relief is provided in the north by the Silurian hills that overlook the lower Lagan Valley, The Newtownhamilton Plateau in south Armagh, the Caledonian igneous complex of Slieve Croob and the structural depression that underlies and defines Strangford Lough. North of the Mournes, and below ca 350m, there is an almost complete mantle of drumlins forming an internationally acknowledged type example of a 'drumlin swarm'. However, in the limited area south of the Mournes, the landscape is dominated by glaciofluvial features, particularly extensive moraines and post-glacial raised beaches.
The Kingdom of Mourne comprises the rolling footslopes of the Mourne Mountains, including the outlying mountain of Knockchree. The land falls to the coastal fringe to the south and is dissected by numerous parallel streams and rivers running broadly northwest to southeast towards the coast. There are long views to the coast and to the Mourne Mountains, the latter providing a backcloth to the intricate pattern of blocky stone walls and fields. This rural 'stone wall landscape', is known locally as the 'Kingdom of Mourne'. The national importance of this scenic landscape is reflected by its AONB status. Its open character and highly distinctive landscape pattern is crucial as a setting to the Mournes. Any disruption to the stone wall pattern would be highly damaging to landscape character.
Geomorphologically, the landscape is dominated by suites of glaciofluvial deposits, especially moraine ridges. The south of the LCA contains the Mourne Plain complex, and from an aesthetic point of view, the complex adds considerable topographic diversity within a small altitudinal range, accentuated by the drainage pattern which exploits inter-ridge depressions and dissects some of the ridges. The pockmarked landscape resulting from pit abandonment detracts from the aesthetic appeal of the area. In the north and east of the LCA, the Northeast Mournes complex has created a topographic variability through moraine ridges that have been little scarred by quarrying. The few pits in the area are no longer worked, are mostly overgrown, and are well hidden. In the foothills of the Mournes, the south draining river valleys are associated with arcuate moraine ridges that mark the retreat of late-glacial valley glaciers.
Orford (in Whalley et al. 1985) has described the coast of the Kilkeel plain as typically characterised by coastal cliffs cut into till exposing a wave cut platform. Sub-aerial erosion of the cliffs supplies sediment to fringing sand and gravel beaches of no great extent as much of the sediment is too fine to remain in the beach system. Shoreline retreat rates are the highest for Northern Ireland and have a mean of ca 0.3m/y. Where a moraine axis crops out in the longshore cliff section, lag boulder beaches occur, though boulder armouring of the wave cut platform is common. Variations in the planform of the cliffs appear to be related to refraction controls imposed by variability in the composition of the glacigenic material. For example, boulder lags can leave remnant shoals that influence longshore beach development. Between Dunmore Hill and Ballymartin Hill the coastal plain has a stepped profile, produced by notches trending subparallel to the coast. Between Dunmore Hill and Annalong coastal moraine ridges are truncated or notched at ca 30m a.s.l. Between Mullartown and Annalong the gentle slopes are also notched at ca 20m a.s.l. This notch is continuous south to 1km north of Ballymartin Hill, where it pinches out. A notch (10m a.s.l) cuts into lateglacial beach deposits between Glasdrumman and Annalong and forms a discontinuous cliff (<8m high). These are late-glacial marine notches and are analogous to similar notches on the Mourne Plain. They are the result of the interplay of glacioisostatic and glacioeustatic forces, and record coastal erosion of moraines following retreat northward of Late Midlandian ice along the coast.
Pre-Quaternary (Solid) GeologyThe stratigraphy of this area is made up of the mapped formations in the table, the youngest of which usually overlie the oldest. The older formations can be upside down (tectonically inverted).
Stratigraphic Table (youngest rocks at the top of the table)| Tertiary - various late intrusives, about 50 million years old |
| Tertiary - early intrusives (Mourne Granites) about 55 to 50 million years old |
| Tertiary - various late intrusives, about 50 million years old |
| Lower Palaeozoic - Hawick Group, about 450 million years old |
This LCA comprises the southern slopes of the Mourne Mountains and has 65% Lower Palaeozoic Hawick Group (intruded by felsites and dolerites) in a southern strip, with Tertiary Mournes Granites (G2 to G5) through the northern part of the LCA (ASSI 095). Tertiary intrusives are observable at Glassdrumman Port (ESCR Site 95).
The Mourne Granites were emplaced in successive injections at two centres: LCA74 covers the boundary between the eastern and western centre. The G2 granite contains the unusual dark quartz crystals known from other areas of the Mournes. In the western Mournes intrusive centre pink outer granites (G4) enclose a later, fine-grained microgranite or granophyre (G5): the metamorphosed (Silurian) roof of these granites can be seen at Eagle Mountain (ESCR Site 104). The spectacular granite exposures comprise ASSI 95, designated because the G2 to G5 succession shows evidence of pulsed granite intrusion.
A felsitic (acid - composite) cone-sheet extends in an arc through the Hawick Group exposure on the western edge of LCA75, where it is best observed along the coast. This was a late intrusion, forming as the granite solidified, cooled and the overlying ground collapsed and cracked in a crater-like manner, allowing late molten rock to inject in a thin sheet.
Quaternary (Drift) GeologyNorthern Ireland has experienced repeated glaciations during the Pleistocene period that produced vast amounts of debris to form the glacigenic deposits that cover >90% of the landscape. Their present morphology was shaped principally during the last glacial cycle (the Midlandian), with subsequent modification throughout the post-glacial Holocene period. The Late Midlandian, the last main phases of ice sheet flow, occurred between 23 and 13ka B.P. from dispersion centres in the Lough Neagh Basin, the Omagh Basin and Lower Lough Erne/Donegal. The clearest imprint of these ice flows are flow transverse rogen moraines and flow parallel drumlin swarms which developed across thick covers of till, mostly below 150m O.D. during a period that referred to as the Drumlin Readvance. At the very end of the Midlandian, Scottish ice moved southwards and overrode parts of the north coast. Evidence for deglaciation of the landscape is found in features formed between the glacial maximum to the onset of the present warm stage from 17 and 13ka B.P. - a period of gradual climatic improvement. Most commonly these are of glaciofluvial and glaciolacustrine origin and include: eskers, outwash mounds and spreads, proglacial lacustrine deposits, kame terraces, kettle holes and meltwater channels (McCarron et al. 2002). During the Holocene, marine, fluvial, aeolian and mass movement processes, combined with human activities and climate and sea-level fluctuations, have modified the appearance of the landscape. The landforms and associated deposits derived from all of these processes are essentially fossil. Once damaged or destroyed they cannot be replaced since the processes or process combinations that created them no longer exist. They therefore represent a finite scientific and economic resource and are a notable determinant of landscape character.
This area arguably contains one of the most varied and complex suite of glacigenic and glaciofluvial features in Northern Ireland, and records the interface between ice originating in the valleys that now drain the south side of the Mournes, ice moving across the coastal plan and Irish Sea ice impinging on the coastal zone. Because of this it has been possible to identify a range of glaciofluvial complexes associated with the Late Midlandian as well as numerous individual features. The principal lowland complexes are summarised below, together with their areal extent in the LCA.
The Mourne Plain Complex (13.9km2 in this LCA) is located on the coastal belt between Killowen, Ballymartin and Cranfield Point, south of the Mourne massif. The relatively flat-lying, undulating plain extends for 16 km along the coastal lowlands, with a maximum width of 5.5 km. The entire area is overlain by thick glacigenic deposits of Late Midlandian age. Coastal cliff exposures reveal a minimum drift thickness of 15m. Deposits include elongate, arcuate morainic ridges which record ice margins during the last deglacial cycle ca15kyr B.P.. A large proportion of this Complex lies to the south in LCA 73.
The Cranfield Moraine (2.6km2 in this LCA) is a conspicuous, round-crested ridge or nested set of ridges which forms a shallow, eastward curving arc between Cranfield Point and the lower slopes of the Western Mourne Mountains. Its arcuate form means that it is visible for a considerable distance and from many directions. In the northern part of the moraine the ridge flank slopes precipitously from the ridge crest, which lies 70m above the local topography immediately to the west. Most of the moraine lies to the south in LCA 73, with a very minor element in LCA 75.
The Northeast Mournes Moraine and Raised Beach Complex (14.2km2 in this LCA) comprises two zones. This LCA is restricted to the southern zone that is roughly triangular in shape and extends from Ballymartin north to Newcastle and west to Ballyveagh Beg Upper. The complex consists of two main morphological elements. Recessional moraines that were linked to ice that initially advanced southwards around the eastern flank of the Mournes as far as Ballymartin. Deposition followed the lowering of the ice sheet and its retreat northwards and eastwards during the Late Midlandian. Shoreline notches cut into moraine ridges on the coastal lowlands and in the Newcastle area during late- and postglacial marine highstand are associated with spreads of beach sand and gravel. The northern part of the southern zone lies in LCA 75.
As well as the above lowland complexes there are three moraine/outwash complexes along the southwards trending Whitewater/Attical Valley (5.6km2 in this LCA), Silent Valley (1.1km2 in this LCA) and Annalong Valley (2.8km2 in this LCA). These reflect patterns of ice advance and retreat across the boundary between the coastal plain (LCA 74) and the Mournes Massif (LCA 75). Although individually variable, the complexes all characteristically comprise well-preserved, cross-valley, arcuate recessional moraines. These are associated with a Late Midlandian advance through the mountains, and subsequent retreat of ice up the valleys. Those in the Annalong Valley are seen to postdate moraines of an earlier Late Midlandian phase which records the retreat of ice northward across the Mourne Plain. In the Attical region, the moraines are related to proglacial outwash in inter-moraine areas.
Key Elements ASSI/ASIs095 eastern mournes ASSI
Geologically significant in the development of the theory of pulsed granitic emplacement; the largest outcrop of Tertiary granites in the British Isles.
MOURNES COAST ASI
Deglacial ComplexesMOURNE PLAIN COMPLEX
The Mourne Plain complex is regarded as highly important in understanding the recent glacial history of Northern Ireland. The nature, pattern and size of the curvilinear, subparallel moraine ridges between the Mournes and the lateglacial shorelines, are visually striking and record the phased retreat of the main Late Midlandian ice westwards into Carlingford Lough. Withdrawal of ice from the Plain was followed by an extensive readvance of ice from Carlingford as far east as the moraine ridge at Cranfield Point. Numerous exposures record highly variable sediment inputs and facies sequences that are critical for modelling changes in late Midlandian relative sea levels.
CRANFIELD MORAINE
The area is of high scientific importance because it provides dated evidence for a major readvance towards the end of the Late Midlandian that stabilized at the entrance of Carlingford Lough. Coastal exposures show that it was deposited partly into a marine environment and are of international importance as they probably record a significant ice sheet oscillation synchronous with the main drumlin forming event in Northern Ireland.
The Northeast Mournes Moraine and Raised Beach Complex
The complex is important scientifically as the moraines record the retreat of the main Late Midlandian ice sheet, with frequent stillstands. Moraines in the northern section that record a readvance of ice in the area, synchronous with ice which entered Carlingford Lough from the north at around 15ka B.P.. Beach notches record the relationship between high late glacial sea levels and the retreating ice front.
Attical valley moraine and outwash complex
The complex is of importance because the ice-contact cross-valley moraines cut across and thus postdate the preserved moraines associated with the main late Midlandian retreat phase. The pattern and distribution of moraine ridges records the pattern of ice-front retreat through the mountains of readvance ice which crossed the mountains and also occupied Carlingford Lough, at the southwestern foot of the mountains;
ANNALONG RIVER MORAINE COMPLEX
The moraine complex indicates that the valley was influenced by at least two principal glacial events, of different magnitudes. The earlier, larger glaciation filled the valley and reached its mouth ca 22ka B.P.. The smaller readvance occurred during the period of climatic deterioration at the end of the Midlandian.
DUNMORE HILL MORAINE (The Northeast Mournes Moraine and Raised Beach Complex)
Dunmore Hill is a conspicuous moraine remnant that records a stillstand position of an ice lobe during the overall retreat of ice northwards towards its Lough Neagh Basin source area. The feature is part of a series of cross-plain moraines between the lower slopes of Slieve Donard in the north and Carlingford Lough in the south. It is important in understanding the development of theories concerning the extent of glaciation during the Last (Midlandian) Glacial Maximum.
BALLYMARTIN MORAINE (The Northeast Mournes Moraine and Raised Beach Complex)
The area immediately to the north of Ballymartin contains a major morainic ridge that extends northwards towards the lower slopes of the Mourne Mountains from Ballymartin Hill. It is bounded along much of its length by well-marked meltwater channels and was deposited, partly into a marine environment, as ice on the Mourne Plain separated into northward- and westward-retreating lobes. The northern section of the ridge is marked by ridge-parallel, interconnecting meltwater channels and kettleholes.
Other sites/units identified in the Earth Science Conservation Review92 Dunmore Head and Green Harbour
Tertiary.
93 Samuel's Port
Tertiary.
95 Glasdrumman Port
Tertiary.
104 Eagle Mountain
Tertiary. Mountain summits show roof of Silurian hornfels above intrusive granites of Western Mournes. Dykes intersecting the hornfels but truncated by granite can be seen.
AONBAll of the LCA lies within the Mourne AONB (1986). This designation is indicative of the scenic quality of the landscape.