Glarryford ASSI

The Glarryford area is of importance in understanding the recent glacial history of Northern Ireland containing a deglacial landform assemblage developed in an unusual environment. The landscape of this area has been defined by events that occurred towards the end of the last Ice Age, between 17,000 and 13,000 years ago, a period of gradual climatic warming. The area contains excellent examples of a range of deglacial landforms including the esker ridge and adjacent hummocky terrain. These landforms record subglacial deposition within a tunnel valley cut into the bedrock taking place late in the deglacial cycle. The site also records a phase of proglacial outwash deposition developed as the ice mass retreated.

The Glarryford esker is a well-marked ridge and represents the path of a subglacial stream, which drained northward during the later stages of the downwasting of the Lough Neagh ice dome. The esker is an excellent example of this type of landform, with well-preserved ice contact slopes. However its scientific importance is enhanced by its relationship with adjacent glacigenic features. The esker lies within a channel scoured in bedrock. The scale of the channel suggests that it was part of a major sub-glacial tunnel valley system. Adjoining deposits show evidence of streamlining, which, together with the presence of drumlins along both sides of the valley, is evidence of an earlier fast ice flow event. The un-deformed sediments of the Glarryford esker indicate that deposition post-dated the streamlining event. Adjacent mounds of stratified sediment are probably the eroded remnants of more extensive gravel dominated spreads formed over ice or ice-rich sediment during final ice wastage. The esker/outwash association is therefore an important element in the reconstruction of the processes which pertained during the final stages of the Lough Neagh ice mass.