The Internal Composition and Structure of Drumlins in North down and South Antrim, Northern Ireland

Abstract

The drumlins in north Down and south Antrim have a variety of internal compositions, ranging from features composed of a single till to those containing two tills. A few drumlins containing significant cores of rock or consisting of sand and gravel were also encountered. Till fabric analysis at various depths within the drumlins indicates that the majority of fabrics have mean orientations which correspond approximately with the drumlin trend. Occasional fabrics were also found which deviate considerably from the drumlin orientation. The internal composition and structure of the drumlins, together with the evidence of fabric orientation, suggest that the till drumlins were formed mainly by depositional processes. There is some evidence in north Down and south Antrim that the plunge of pebbles in drumlin till fabrics, as well as the orientation strength of these fabrics differs significantly from fabrics in ground moraine. Such differences in fabric characteristics may be relevant to a detailed understanding of the mechanism of drumlin formation.