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 Tardree Upland Pastures are found on the broad, rounded summits of upper basalt to the southwest of the Larne Basalt Moorland. This is a transitional landscape, with characteristics of both upland moorland and lowland farmland; the pronounced open valley of the Glenwhirry River is an important local landscape feature. The area includes the southern fringes of the Antrim uplands on the northern slopes of the Six Mile Water Valley. The summits and south facing slopes of Tobernaveen Hill, Donegore Hill and Drumdarragh Hill are prominent in views from the town of Antrim and the valley. The topography of the area is undulating, rising to 353m at Big Collin. There are a number of quarries close to the foot of the hills that are prominent in some valley views.
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 | Upper Basalt Formation, about 55 million years old |
| Tertiary | Interbasaltic Formation & Tardree Rhyolite, about 55 million years old |
| Tertiary | Lower Basalt Formation, about 55 million years old |
The geology comprises a mix of Tertiary igneous formations overlying one another. The three formations cover roughly equal areas. The basalts are extensively quarried for construction materials, especially roadstone.
The two Tertiary-aged basalt formations comprise a crudely-bedded succession of lava flows, columnar jointed lava flows, ash-falls and red-weathered horizons (or boles). Throughout LCA125, these two formations are separated by red beds and ashfalls of the Interbasaltic Formation. Within the Interbasaltic Formation, lava flows dominate Tardree Mountain in the southwestern part of this LCA. The best exposure of the Tardree volcanic succession is seen at Sandy Braes (ESCR Site 74).
The northernmost tip of LCA125 cuts the Carnlough Fault - a NE-SW oriented normal fault that juxtaposes upper and lower basalt formations.
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 complex upland landscape of this area is reflected in a drift cover that is interspersed with numerous ridges of drift free bedrock. This is particularly the case in the east of the LCA, where the ridges are defined by a series of valleys that run down to the Six Mile Water. In between these outcrops are expanses of Late Midlandian till associated with the large ice mass that was centred on the Lough Neagh Basin. 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 upland areas such as the Antrim Plateau ice free and surrounded by encircling ice. Under these conditions it would appear that a number of ice marginal lakes were created in the valleys that drained the uplands. This has left a legacy of glaciolacustrine deposits that formed when deltaic sediments infilled these lakes. These deposits can be found in LCA 115 to the south and west of the Tardree Uplands, together with glaciofluvial deposits that represent deposition by meltwater as Lough Neagh ice retreated from the upland areas at the end of The Midlandian..
Key Elements ASI(ESCR site 74) Sandy Braes
Tertiary. Exposures of Tardree Rhyolite Complex. Major vent complex consisting of a range of obsidian and rhyolite tuffs and agglomerates bounded by Lower Basalts, rhyolite lava flows and acid tuffs and agglomerates.
AONBThe northeastern fringe of this LCA overlaps the Antrim Coast and Glens AONB (1988). This designation is indicative of the scenic quality of the landscape.