Late Wisconsin Ice Lobe Dynamics: Assessment Through G.I.S. Supported Three Dimensional Mapping and Surface Physiography

Abstract

<p>the study are is approximately 4,500 km^2 including [arts of Hastings, Prince-Edward and Northumberland countries. The area was glaciated during the Late Wisconsin (20-11,800 y.b.p) by the Simcoe Lobe and the Lake Ontario Lobe of the Laurentide ice sheet. Ice activity created subsurface characteristics and surface physiography that can, therefore, be used to suggest patterns of ice flow during the Late Wisconsin.</p> <p>A computer generated recreation of the bedrock topography within the area revealed two bedrock channels and other characteristics that aid in determination of ice flow patterns. Computer generated drift thickness maps exposed several packages of sediment that were also important in the creation of an ice flow model. Surface features such as drumlins, moraines and eskers provided the final link in suggesting that ice flow was actually contained by bedrock topography.</p> <p>Evidence suggests, both subsurface and surface, that the Lake Ontario Lobe moved in a southwest direction following bedrock channels. for this reason it is believed that the profile of the ice in this region was thin. At one time the Simcoe Lobes and the Lake Ontario Lobe approached one-another and created the Oak Ridges Moraine. The profile of the Oak Ridges Moraine at this point extended much further than suggested by Chapman and Putnam (1984). There was then a surge of one of the Simcoe Lobes towards the south which ultimately, after ice recession, created the physiography of today.</p>