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 lies within 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. 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. Below ca 350m, there is an almost complete mantle of drumlins forming an internationally acknowledged type example of a 'drumlin swarm'.
The Ballyquintin and Lecale Coast landscape character area is underlain by sedimentary rocks with numerous Dolerite dykes aligned in a NE direction. It occupies the southern tip of the Ards Peninsula below Cloghy and the eastern section of Down District. This is a predominantly coastal landscape and its character is influenced by its extremely windswept position. The flat coastal topography becomes gently undulating towards Downpatrick where it meets the North Lecale Hills. Throughout the area, there are low drumlins with wide open inter-drumlin hollows, often with fen and wetland. Much of the area is within the Strangford Lough and Lecale Coast AONBs. Geomorphologically, the most important element in the landscape is the Killard Moraine. This is a discontinuous belt of flat lying to undulating topography that runs for 10 km approximately parallel to the coast of east Co. Down southwestwards from Tara Fort, on the Ards Peninsula, to Killard Point and Ardglass. The ice-contact, glaciomarine apron occurs 1km to the southeast (seaward) of the Co. Down drumlin swarm that dominates the regional topography. The landscape is largely undisturbed by excavation or construction, and is located in a largely rural area. The morainic belt and raised beach complex which truncates the gravel deposits occurs along the coastal zone. The subdued, undulating topography contrasts with the strong lineation of the drumlin swarm to the northwest and forms a stark topographic contrast with the rock outcrops that form an irregular framework along the coast.
The extension of the Outer Ards coastline in the north of the LCA has been described by Orford (in Whalley et al. 1985) as a series of crenellate bays hinging on eroding drumlins or Tertiary dykes that normally open to the north. A number of sediment cells can be recognised along the coast defined by littoral drift reversals related to shifts in wave energy. Good examples of swash ridge welding under fair weather conditions can be seen in the bays. The Silurian basement crops out along the nearshore and acts as a 'reef' type barrier to wave attack. A number of sites, such as the raised beaches on the headland at Ballyquintin Point, have been used to understand post-glacial sea level fluctuations. In tharea to the south of The Narrows, Orford (1985) has described glacial sediment along the length of the coastline as the only barrier to the marine extension of Dundrum Bay into Strangford Lough. There are few drumlins along the coast and the numerous low cliffs are cut into glaciomarine till. The cliff sections often show basal exposures of an ice-moulded abrasion platform cut into the underlying Palaeozoic strata.
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 |
| Lower Palaeozoic Silurian (Hawick Group) Ordovician (predominant) - Moffat Shale and Gala Sandstone, between 470 and 420 million years old |
Predominantly Lower Palaeozoic greywackes and shales with numerous minor igneous intrusions. 99% of the LCA comprises Lower Palaeozoic (Silurian) Hawick Group with Moffat Shale inliers: the northern 10% of the LCA comprises Gala Group, the remainder being Tertiary intrusives.
Tieveshilly ASSI (099) comprises a graptolite-bearing succession of shales that span the late Ordovician to early Silurian. The Tara Sandstone Formation and Kearney Siltstone Formation occur above. Exposures of siltstone and deformed lamprophyre occur at Kearney Point (ESCR Site 423).
The greywackes vary from a few centimetres to a few metres in thickness with a large proportion of rock fragments and a fine-grained matrix. They are interbedded with thinner beds of siltstone or mudstone, commonly arranged as fining-up cycles. The Hawick Group also have numerous NE-SW faults. In the central fault zone there occur slivers of the predominantly Ordovician (and thus older) Moffat Shale Group. The NE -SW strike of the beds at outcrop is produced by faulting and belies the fact that minor folds occur within each fault tract. The greywackes are of sandstone grade and vary from a few centimetres to a few metres in thickness with a large proportion of rock fragments and a fine-grained matrix. The greywackes are commonly quarried as a source of aggregate.
A Tertiary age (55 million years) basaltic dyke swarm is exposed at St. John's Point (ESCR Site 86).
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 map for this LCA shows it to be predominantly underlain by Late Midlandian till associated with the large ice mass that was centred on the Lough Neagh Basin. This ice flowed southeastwards from an ice divide that lay approximately SW-NE along the line of the north Belfast Hills. Evidence for this flow direction is found in the orientation of the numerous drumlins that make up much of the landscape in the west of the LCA. However, within the LCA there are also significant outcrops of drift free bedrock that were scoured by the overriding ice. McCabe and Knight (in Knight 2002) have suggested that this area, and much of central Co. Down, was the site of an ice stream during the Drumlin Readvance that delivered a high sediment flux to the ice margin at areas such as the Lecale Coast to the southeast. This may go some way to explain the partial drift cover in the region and the widespread occurrence of rock cored drumlins. Within Northern Ireland drumlins take a variety of forms; some are rounded in plan, although the majority are elongated in the direction of ice flow. Some have sharp crests, whereas others are more whaleback in profile. Although most drumlins are composed of glacial till or tills, a small number are 'drumlinoid features' are rock-cored and some are composed of sand and gravel. Where drumlins are rock cored there may have been significant frost shattering prior to their shaping by ice flow. It is possible therefore to see tails of shattered debris within till leading away from the feature in the direction of flow (Davies and Stephens 1978). It is generally accepted that the drumlins of Northern Ireland were formed by deposition beneath fast flowing ice. In the majority of cases this has resulted in a thick layer of Upper (younger) Till overlying a core of Lower (older) Till. This pattern has been observed across Northern Ireland, apart from a limited area in the north of County Down, where Hill (1971) observed drumlins composed only of Lower Till. The precise temporal relationship between the two tills has not been definitively resolved, but Davies and Stephens (1978) refer to an organic layer between the tills in County Fermanagh that has been dated at 30 500 ± 1170/1030 years B.P. and shelly material between the tills on the Ards Peninsula dated at 24 050 ± 650 years B.P.. However, these deposits only indicate that the Lower Till is older than the dates obtained.
It can be argued that an equally important component of any 'drumlin landscape' are the similarly numerous inter-drumlin hollows. The majority of these hollows would have held open water from local runoff at the end of the Pleistocene. Whilst some continue to exist as isolated small loughs, many have now been infilled by sediment washing off the surrounding drumlins. This has created typically flat-bottomed, marshy areas between the drumlins that are subject to seasonal inundation. Much of the infilling probably occurred early in the Holocene, as the landscape adjusted to increasingly temperate conditions. However, erosion may also have been accelerated in historical times, when rural population densities were considerably higher and much of the lowland landscape of Northern Ireland was more intensively cultivated. Whatever the stimulus for erosion and deposition, the sediments within these hollows typically contain an important record of local environmental change.
The drift geology map highlights the presence along the coastal margin of the LCA, of a major deglacial complex either side of the entrance to Strangford Lough that is important scientifically and for its sand and gravel resources. The Killard point Moraine (13.5km2) illustrates the internal geometry of a coarse-grained, glaciomarine apron which fronts the drumlin swarms of east Co. Down. The deposits indicate a high subglacial sediment flux associated with drumlinisation and variability in the processes that operated at a grounded, tidewater ice front. It demonstrates that deglaciation of the Irish Sea basin was influenced by fast ice flow, marine downdraw of the lowland ice sheet over north-central Ireland during the last glacial cycle and tidewater processes. High relative sea level at this time is associated with deep isostatic deflection in the northern part of the Irish Sea basin. Dating of red marine muds interbedded in the outwash sequence indicates that these events occurred around 15 kyr B.P..
Key Elements ASSIs099 TIEVESHILLY
Historically important exposures of graptolite-rich shales are evidence of continuous deep-water sedimentation from the Upper Ordovician to the Lower Silurian. The overlying succession of Tara Sandstones and Kearney Siltstones is apparently unique. The site is of international importance in the debate over the timing and processes involved in the closure of the Iapetus Ocean. The most important rock outcrop is in a series of old shale pits but limited exposure occurs in the banks of the Carrstown Burn and also as scattered rocky knolls elsewhere within the site.
087 BALLYQUINTIN POINT
Ballyquintin exhibits an exceptionally well developed raised cobble beach of the cuspate foreland type, with associated ridges and bars, together with a range of contemporary coastal landforms. The site displays an intact transtition from maritime through to inland vegetation communities.
086 KILLARD
The type locality for a prograded glaciomarine apron. The site is unique in the Irish sea Basin.
Deglacial ComplexesKILLARD POINT MORAINE
The scientific attributes of the Killard Point moraine are of international importance as they date a deglacial sequence which enables correlations to be made between other sequences in a circum-North Atlantic context. It therefore provides input into global scale studies of ice-sheet activity, the driving forces responsible for climatic change and ice-sheet variability during the last deglacial cycle. The constraining date on drumlinisation allows correlations to be made between deglacial events in the Irish Sea basin and those in the wider, circum-North Atlantic basin.
Other sites/units identified in the Earth Science Conservation Review86 St. John's Point
Tertiary. Exposure of a basaltic dyke swarm intruded into Lower Palaeozoic sandstones and shales.
423 Kearney Point
Caledonide-Igneous. Best site to view deformed lampophyre dyke. Exposure shows relationship between these foliated dykes and folded Silurian country rocks. The dykes are important in geological history of mountain building during Caledonian Orogeny.
AONBsThe southern and eastern part of this LCA lies within the Strangford Lough AONB (1972), whilst a very limited area in the south overlaps with the Lecale Coast AONB (1967). These designations are indicative of the scenic quality of the landscape.