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 Kilkeel Coast is a gently undulating, coastal lowland dissected by narrow rocky river valleys that extends from Killowen Point to Ballymartin. It comprises gently undulating, coastal lowland between 0 m and 30 m AOD. The land falls gently and flattens out towards the shallow, sandy coastline. The lowland is dissected by numerous rocky burns and by the larger Kilkeel River, White Water and Cassy Water. The rivers flow in deep, narrow channels strewn with rocks and boulders. They are not prominent in the wider landscape but are attractive local features. The steep gullies are often clothed with trees and scrubby vegetation. Glaciofluvial deposits of the Mourne Plain and Cranfield complexes dominate the landscape. From an aesthetic point of view, the complexes 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. The extent of aggregate extraction indicates the high importance of the deposits as an economically valuable mineral resource.
The eastern coast of the LCA has been described by Orford (in Whalley et al. 1985) 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. Within Carlingford Lough, the coastal environment is described as a low energy estuary filling a structurally controlled (NW-SE fault), glacially scoured depression. The estuary mouth is shallow due to a ridge of carboniferous limestone which allows wave focusing of south westerly storms onto the northern shoreline where erosion of the glacigenic Kilkeel plain has left a number of bays dominated by gravel beaches.
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 intrusives, about 55 million years old |
| Carboniferous - Carlingford Group (limestones) - about 350 million years old |
| Lower Palaeozoic - Hawick Group - about 450 million years old |
Lower Palaeozoic greywacke sandstones and shales of the Hawick Group comprise over 90% of the area with 10% made up of Carboniferous Carlingford Group limestones and Tertiary dykes. The greywackes are commonly quarried as a sourceof aggregate; they are interbedded with thinner beds of red silty mudstone, commonly arranged as fining-up cycles, deposited in a deep marine trench. The southwestern tip of the area comprises Carboniferous Carlingford Limestone Group. These are typical Carboniferous limestones in being bedded and fossiliferous.. The Carboniferous stratigraphy is unique: ASSI 103.
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.
The drift geology of this LCA is dominated by elements of two major deglacial complexes that are important scientifically and for their sand and gravel resources.
The Mourne Plain Complex (7.5km2 in the east of the 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.. Most of the Complex lies to the north in LCA 74.
The Cranfield Moraine (8.5km2 in the centre and west of the LCA) is a conspicuous, round-crested ridge or nested set of ridges that 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. The moraine also extends northwards into LCA 74, with a very minor element in LCA 75.
The Drift Geology map for the LCA also highlights the significance of post-gacial raised beach deposits at the mouth of the Cassy Water, west of Cranfield Point and east of Kilkeel. Those west of Cranfield extend well inland and are fronted on their seaward margin by blown sand
Key Elements ASSI/ASIs103 CARLINGFORD LOUGH ASSI
The limestones of Carlingford Lough were deposited in a shallow sea basin during the Carboniferous period 339 million years ago. They contain numerous fossils, such as brachiopods and solitary corals. Moraines and deposited sediments provide evidence of the movement of ice sheets and glaciers.
MOURNES COAST ASI
SOUTH MOURNE 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.
Other sites/units identified in the Earth Science Conservation Review AONBAll of the LCA lies within the Mourne AONB (1986). This designation is indicative of the scenic quality of the landscape.