Inferences on glacial flow from till clast dispersal, Coldstream Map area (N. T. S. 21 J/06), New Brunswick

Abstract

Dispersal patterns for till clasts from the Coldstream Map sheet area (N.T.S. 21 J/06), New Brunswick were compared to source outcrops and used to confirm main iceflow directions across the 1070 km2 area. The clast study was performed using till clasts collected along 2 km intervals from 274 sample sites and seven major lithologies were identified. The contour plots of percent occurrences for seven lithological groupings of till clasts demonstrate that the ice-flow direction during the last major glaciation of the area was mainly southward and southeastward. This direction is supported by the orientation of known striae in the map area. It was determined that till clasts were primarily derived from local bedrock and the dispersal patterns vary in length from 1 km to 10 km. Generally the size of the dispersal train is larger for resistant lithologies versus less resistant rock types which suggest that glaciation was probably a highly erosive and forceful event throughout much of the study area.