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 Antrim Plateau and Glens. This upland area is dominated by a series of structural plateaux that dip gently in towards the Lough Neagh Basin. Detailed topography is largely controlled by a succession of Tertiary basalt lava flows that define successive, large-scale steps within the landscape. The plateaux are separated from each other and their frequently dramatic margins are fretted by often fault-guided, steep-sided glens. The plateaux margins are typically characterised slope failures that range from large rotational landslides to individual blockfalls. In the north of this LCA, the basalts have been stripped away to reveal the underlying basement complex of predominantly Palaeozoic rocks. This produces a more rugged terrain, out of which rises the prominent, steep-sided, basalt capped outlier of Knocklayd.
The Moyle Moorlands and Forests, south of Ballycastle, comprise an open exposed upland area of metamorphic schists and Lower Basalt, which reaches 550m at Trostan. It is a large scale, sweeping moorland landscape with distinctive peaks such as Knocklayd and Slieveanorra. The uplands are dominated by rough grazing of unimproved grassland and heather without field boundaries and by large areas of blanket bog, some of which has been cut for peat. The scenic quality of the landscape is reflected by its designation as part of the Antrim Coast and Glens Area of Outstanding Natural Beauty. The landscape can therefore be summarised as one of open upland reaching 550m at Trostan, comprising large scale, smooth moorland landscape dissected by small rocky burns. In the north of the LCA lie the headwaters of the Glenshesk and Carey Valleys. These contain visually prominent ridges and spreads of glaciofluvial sediments separated by deep meltwater incision. Both valleys form visually attractive landscapes to which the high plateau formed by the Antrim basalts creates a dramatic backdrop.
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.
Stratigraphic Table (youngest rocks at the top of the table)| Tertiary | Antrim Lava Group and intrusive dykes and sills, about 55 million years old |
| Cretaceous | Hibernian Greensand & Ulster White Limestone, about 100 million years old |
| Triassic | Sherwood Sandstone Group, about 240 million years old |
| Carboniferous | limestones and coal measures, about 350 million years old |
| Devonian | volcanic and sedimentary succession, about 400 million years old |
| Neoproterozoic (Dalradian) | Murlough Bay, Torr Head Limestone, Owencam, Altmore, Runabay formations, about 550 million years old |
This LCA extends from Knocklayd and the margins of Fair Head south to Slieveananeen.
The geology comprises a mix of Neoproterozoic metamorphic, Carboniferous and Mesozoic sedimentary and Tertiary igneous rocks in faulted and unconformable contact.
The NE Antrim Dalradian was originally a series of sediments and volcanic beds that have been buried and metamorphosed. The succession is equivalent to that exposed in Kintyre and is similar in being inverted (i.e. upside down), a product of tectonic events. Exposed in the crags on Benvan (ESCR Site 339) and with overlying Cretaceous Ulster White Limestone Formation around Loughareema (Vanishing Lake: ESCR Site 17).
A very small area of Devonian strata are clipped in the southeast of LCA118. They comprise Purpe conglomerates and sandstones of the Cross Slieve Group with Cushendall Porphyry at the top.
The Carboniferous succession is exposed in a small sliver at the northernmost end of LCA118 and comprises limestones and coals at the base, passing up into laterally more continuous sandstones and coals.
A small, faulted east - west trending inlier of Triassic strata are mapped south of Murlough Bay, at the top of LCA118.
The Cretaceous succession is found below the the Lower Basalt Formation on the slopes of Knocklayd and Ballypatrick Forest. 5cm to 30cm of conglomeratic greensand at the base pass up into 30m (max.) Ulster White Limestone. Greensand and limestone exposed at Murlough Bay (ESCR Site 296).
Tertiary-aged basalt formations comprise a crudely-bedded succession of lava flows, columnar jointed lava flows, ash-falls and red-weathered horizons (or boles). These two formations are separated by red, palaeoweathered beds and columnar basalts of the Interbasaltic Formation (IBF) in the south of LCA118, mined for bauxite at Salmon's Drift (ESCR Site 73).
North - south and northwest - southeast oriented dolerite and minor basaltic dykes occur throughout the area. The intrusion (an inclined plug) at Tievebulliagh (ASSI 82) contact metamorphosed the laterites to produce porcellanites and hornfels, later worked in the Neolithic for stone implements.
The main Tertiary intrusive rock type of the area is the Fair Head Sill, at the north of the LCA. Other sills occur. North - south and NW-SE trending dykes are common.
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 varied topography of this upland landscape is reflected in a drift cover that is interspersed with numerous areas of drift free bedrock, largely blanketed in a cover of peat. The drift cover is predominantly Late Midlandian till associated with the large ice mass that was centred on the Lough Neagh Basin and which moved approximately northeastwards across the region. Davies and Stephens (1978) consider that the final stages of ice-wasting in the east of Northern Ireland probably involved wide scale stagnation, downwasting and withdrawal inland towards the Lough Neagh lowlands (p.176). This would have left uplands such as the Antrim Plateau as ice free areas surrounded by encircling ice. As a consequence, meltwater, either impounded against the ice margin or flowing down the glens that cut into the plateau margin, have left a series of deglacial complexes on the edge of the Plateau. In this LCA these are characterised by deposits in the headwaters of the Glenshesk and Carey Valleys that are important scientifically and for their sand and gravel resources.
The Glenshesk Valley Complex (1.8km2 in the northwest of this LCA ) is contained in the 'rock-bounded', 10km long by 1km wide and 200 m deep Glenshesk valley to the southeast of Ballycastle at the northern margins of the Antrim Plateau. As such it overlaps LCAs 118 and 119. Glaciofluvial deposits in Glenshesk are located mainly in the middle part of the valley and consist of cross-valley moraine ridges, cross-valley glaciolacustrine ridges, outwash fans and outwash terraces associated with meltwater draining westward and northward from successive ice margin positions located across the valley. Morphological evidence suggests that these forms are associated with deposition from ice masses which decayed southeastwards from a maximum western extension along the Inver Burn valley towards higher ground to the east and southeast during the last deglacial cycle.
The Carey Valley Delta Complex (1.9km2 in the north of this LCA ) consists of variable stratified sands and gravels occur along the axis of the Carey Valley as a northward thickening wedge of sediment. Most of the complex lies in LCA 119.
Key Elements ASSI/ASIs082 TIEVEBULLIAGH ASI
Type locality for the pyrometamorphism of laterite and lithomarge producing porcellanites of varied mineralogy and hornfelses. A range of rare minerals were also generated by the reactions. Rare occurrence of doline together with other karst features, developed on Ulster White Limestone.
LOUGHAVEEMA ASI
A number of exposures along the steep sides of the Loughareema glacial overflow channel that include quartz-albite schist, psammite and biotite and hornblende 'green beds'.
CAREY VALLEY ASI
Approximately 50% of the ASI lies in this LCA, see below.
Deglacial ComplexesCarey Valley Delta Complex
The Carey Valley delta is a site of excellent scientific importance within the context of Northern Ireland and records a high relative sea level of approximately 100m O.D. This fact is of extreme value in the reconstruction of Irish Sea basin conditions upon deglaciation of the coastal shelf. It indicates significant downwarping of the Irish coast at this location.
GLENSHESK VALLEY COMPLEX
The Glenshesk valley has good scientific importance because the moraine ridge and outwash terrace associations in the valley are similar to classical models of phased retreat and decay of a valley ice lobe. The retreat pattern of the ice lobe in the Glenshesk valley also indicates continual ice pressure from the highlands to the east and southeast during the deglacial cycle. This indicates that during the deglacial cycle the Antrim plateau was glaciated by ice possibly associated with an ice dome located to the east or ice moving northwards along the coast.
Sites/units identified in the Earth Science Conservation Review339 Benvan
Precambrian. Argyll Group. Accessible outcrops of representative strata of Owencam Formation.
278 Capecastle Quarry
Mesozoic and Cretaceous. Quality exposure of Ulster White Limestone Formation. Shows history of chalk sedimentation over Dalradian ridge.
296 Murlough Bay
Palaeontological. Late Cretaceous basal conglomerates exposed beneath Ulster White Limestone cliffs. Contains macrofossil evidence for Lower Jurassic strata much younger than those preserved onshore.
73 Salmons Drift
Tertiary. Multilevel bauxite mine.
AONBApart from its far west, all of this LCA lies within the Antrim Coast and Glens AONB (1988). This designation is indicative of the scenic quality of the landscape.
OthersLOUGHAREEMA
The significance of this area depends upon the presence of a small lake in which lake level fluctuates dramatically. At times of excessive rainfall water levels rise to a maximum and are controlled by an outlet to the north. In summer months, lake level progressively falls as groundwater is depleted by seepage and a series of temporary shorelines are exposed