Drumlin Landscapes

Abstract

In Ireland, evidence of two main glacial periods exists, the Munsterian (c 300,000–132,000 years ago) and the more recent Midlandian (c 79,000–13,000 years ago). Today, Ireland has a very rich legacy of glacial deposits and landforms which can be widely found across the Irish landscape. Drumlins, one of the most commonly found glacial landform features, are smooth, oval shaped hills consisting mostly of deposited boulder clay or till. In Ireland, as the glacier retreated, the melting ice left large areas across the country, particularly the central plain, covered in boulder clay deposits. Two different types of drumlins occur, rock and till. Till or drift drumlins are comprised of compact, unstratified glacial till or drift. In contrast, rock drumlins are mostly made up of rock core with a concentric covering of drift. Rock drumlins tend to have a slightly better drainage status than till drumlins. In Ireland, around 25,000 drumlins have been recorded by the Geological Survey of Ireland. Drumlins generally occur in swarms and Ireland is home to one of the most extensive drumlin belts in Europe stretching across parts of Northern Ireland from Co. Down into the Republic of Ireland. Drumlins also occur in the Castlebar—Newport—Clew Bay region of West Mayo, in Co. Clare, and in the Bantry Bay area of West Cork. Of the seven major soil associations across the drumlin landscape, four have a gley lead series meaning that these are predominantly water-affected soils. Peats are also prevalent across the drumlin belt, particularly in counties Donegal and Leitrim. Poor natural drainage represents a major limitation to utilisation and while certain soils might benefit from artificial drainage, drumlin slopes present a major limitation in the use of agricultural equipment to carry out such operations.