Tanderagee ASSI

The Tanderagee area is of importance in understanding the recent glacial history of Northern Ireland. The landscape has been defined by events that occurred towards the end of the last Ice Age, between 18,000 and 12,000 years ago, a period of gradual climatic warming. The ice-sheet which covered this area and the highland areas further north, split into two lobes during the final stages of deglaciation, which retreated into the original glacier source areas of the Lough Neagh lowlands and the Omagh basin.

The eastward retreating ice lobe deposited the proglacial Pomeroy moraines. Ice marginal deposition resulted in the formation of a classic example of hummock and ridge topography, best seen in the area of Killey Bridge, where a valley-parallel ridge extends for a total of 3 - 4 km.

The classic hummocky morainic topography displayed by the Pomeroy moraine comprises low-relief mounds and discontinuous ridges which formed when sediment accumulated on and around stagnant or inactive ice in the ice marginal zone. The melting of ice blocks, buried under the sediments, resulted in the distinctive belt of chaotic topography characterised by mounds, undulations and enclosed hollows. This is the finest example of this type of glacial topography in Northern Ireland.

Melting ice associated with the collapse of the ice sheet generated large volumes of melt-water resulting in erosion of a notable melt-water channel through the moraine. Transported sediment infilled the lower ground, producing the contrasting flat and featureless lands to the south.