Mullaghcarn ASSI

The area is of special scientific interest because of its earth science features, and its upland habitat mosaic of peatland, lakes and woodland together with associated flora and fauna. Mullaghcarn ASSI displays important examples of glacial landforms. The landform within the Gortin delta complex is one of the largest and best examples of a proglacial delta landform assemblage in Northern Ireland. The main landform dates from the end of the last glacial period when the Owenkillew Valley was part of an extensive lake formed between the high ground of the Sperrins and an ice sheet blocking the Foyle valley. The lake was fed by water from the melting ice sheets which also fed huge quantities of gravel, sands and clays into the lake.

An area of oakwood, known as Boorin Wood, covers a steep, north-facing slope towards the most northerly perimeter of Mullaghcarn ASSI.

The earth science interest at Mullaghcarn occurs as features formed by the interaction of ice, rock and water towards the end of the last Ice Age, some 17,000 to 13,000 years ago. At this time, the climate was beginning to warm after the prolonged cold period that had allowed the ice to accumulate.