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. Recession of the plateaux margins has exposed underlying Mesozoic strata and, in some areas, the Palaeozoic basement. The plateaux margins are typically characterised slope failures that range from large rotational landslides to individual blockfalls.
The Moyle Glens, which include the famous Glenariff, are a series of steep sided valleys carved out of the schists and basalt of the Antrim Plateau by glacial activity. The northern glens (within the Moyle Moorlands and Forests) have a v-shaped form with undulating sides, whereas the glens further south, including Glenariff, have sweeping u-shaped profiles with dramatic basalt cliffs. The valleys fall towards the sea, with the rocky mountain streams and waterfalls becoming meandering streams as they reach the flat floodplains near the coast. Distinctive peaks and hills such as Tieverah, Tievebulliagh, and Lurigethan are dominant in this landscape. The steep upper slopes have a wild, remote character and any form of landscape change would be prominent against the backdrop of the high, open moorlands. The steep slopes of the upper glens are particularly prone to mass movements triggered by intense and/or prolonged rainfall. These include rockfalls, debris flows and slides and on rare occasions, bog bursts as saturated peats on the plateau surface suddenly release very large quantities of stored water. At lower elevations, the landscape structure provided by existing vegetation is more robust, although the long open seaward views would result in any significant change being highly visible.
The coastline of east Antrim has been described by Orford (in Whalley et al. 1985) as comprising high, stepped coastal slopes formed on the ice-trimmed eastern margin of the Antrim Plateau. Post-ice cambering and Pleistocene neotectonic movement along Tertiary faults has produced a highly unstable cliff line with numerous rotational landslides often masked on their seaward side by slumped drift deposits. Shoreline sediments are predominantly basalt and chalk boulders with a matrix of sand and clay from debris flows that are moved longshore and offshore. The SW-NE trending Antrim Glens define offset re-entrant bays in which sand and gravel have been deposited as prograding beach ridges. On the north of Red Bay at Waterfoot, the Glenariff River enters the sea through a series of low dunes fronted by a sandy beach. The beach extends along the entire foreshore of Red Bay but removal of sand and gravel over time for agricultural purposes has destroyed a dune system that used to lie at the centre of the bay. Although no long-term trend has been identified, photographic records have been used to indicate that the whole shoreline is showing signs of erosion. The cliffs along the northern shore from Waterfoot show evidence of a time when sea level was higher than at present in the form of caves and raised beaches.
The entire landscape of the Glens is extremely sensitive to change and their scenic quality is recognised in their designation as an Area of Outstanding Natural Beauty.
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 | Intrusives (Fair Head Sill - about 55 million years old) |
| Cretaceous | Hibernian Greensand & Ulster White Limestone - about 100 million years old |
| Carboniferous | limestones and coal measures - about 350 million years old |
| Neoproterozoic (Dalradian) | Murlough Bay, Torr HeadLimestone, Owencam metamorphic formations - about 550 million years old |
This LCA extends from Ballycastle to Fair Head, Murlough Bay, Torr Head and Runabay Head. The geology comprises a mix of Neoproterozoic metamorphic, Carboniferous and Mesozoic sedimentary and Tertiary igneous rocks in faulted and unconformable contact.
The NE Antrim Neoproterozoic Dalradian was originally layers of sediments and volcanic beds that have been buried and metamorphosed. Exposed on the crags at Benvan (ESCR Site 339). Limestones in the succession have been converted to marbles such as the Torr Head Limestone exposed at Escort Port (ESCR Site 340) and Torr Head (ESCR Site 341).
The succession is also exposed at Carnaneigh Point (ESCR Site 344 and Loughan Bay (ESCR Site 345). The Leckpatrick Green Beds type location (Leckpatrick Point) is also in this LCA - ESCR Site 343. Altmore Formation type section ESCR Site 342.
The Carboniferous succession comprises laterally lavas, pillow lavas and limestones at the base, passing up into laterally more continuous sandstones and coals (with one correlatable limestone succession). The basal pillow lavas are exposed at the northwestern edge of LCA120. ASSI 147.
The Cretaceous succession is found below the Fair Head Sill on its eastern outcrop. Murlough Bay (ESCR Site 296) also encroaches into this LCA.
The main Tertiary rock type of the area is the Fair Head Sill (ESCR Site 90), at the centre of the LCA.
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 complex area has been described in detail by Prior (1970). Through analysis of drift deposits in the area he concluded that much of the Late Midlandian till that underlies the coastal lowlands was deposited by ice that had moved northwards along the present-day coastline. This swung westwards up the Glens, but did not loin up with Antrim Plateau ice that was coming down the Glendun and Glenann Valleys. He proposed that this left an ice free area within the glens that is marked by the accumulation of large quantities of slope debris (head deposits) derived from the periglacial weathering and erosion of the valley sides. The lower valley floors of the glens are marked by the accumulation of alluvial material behind raised beach deposits that may be masked by coastal dune complexes. The raised beach deposits are the result of post-glacial flooding by a rising sea level, of a landscape that was still isostatically depressed following the disappearance of Midlandian ice (see key element below).
Key Elements ASSIs025 GLENARIFF
Largest area of undisturbed semi-natural woodland on basalt escarpment, Co. Antrim. Also streams, waterfalls, scree slopes and cliffs.
Other sites/units identified in the Earth Science Conservation Review
347 Knocknacarry
Precambrian. Southern Highland Group. Exposures of lithologies of Glendun formation. Exposures of thermal metamorphic effects of Cushendall granite on Dalradian country rock.
348 Cushendun Bay
Precambrian. Lithology of Glendun Formation. Late Caledonian granite porphry intrusions.
46 Cushendun Caves
Upper Palaeozoic - Devonian. Spectacular exposures of the red-beds of the Cross Slieve Group.
47 Cave House
Upper Palaeozoic - Devonian. Good exposures of interbedded quartzite conglomerates and sandstones of transition between lower and upper units of Cushendun Formation.
48 Port Obe
Upper Palaeozoic. Exposures of coarse pink sandstones of Ballyagan Formation. Some exposures of basal beds of Cushendall Formation.
49 Lifeboat House
Upper Palaeozoic. Excellent wave-cut platform exposures of conglomerates of Red Arch Formation.
51 Red Arch
Upper Palaeozoic. Exposures of pink sandstones and conglomerates of Red Arch Formation, especially overlying Unconformity B.
440 Cushendun
Caledonide-Igneous. Exposure of granitoid intrusion within Dalradian strata.
279 Garron Point - Cloghastucan
Mesozoic. Excellent exposures of Galboly Chalk and Garron Chalk Members of Ulster White Limestone Formation. Effects of Dalradian ridge on chalk sedimentation can be seen.
AONBAll of this LCA lies within the Antrim Coast and Glens AONB (1988).
Others
Cushendun
Cushendun is sited at the foot of a glacially oversteepened valley. As far as can be ascertained, the lower valley floor has been infilled with alluvium, possibly overlying and interdigitating with marine deposits. Former exposures in gravels behind the beach have been interpreted as raised marine sediments , pointing to a higher sea level of about 5 - 6m. The gravels overly possible estuarine and limnic sediments that have been dated to 7 500 years B.P.. Unfortunately, height constraints on the samples are unreliable and there are doubts concerning the depositional environment of the gravels and these factors make the interpretation tentative. Taken from: Whalley, et al, (1985).