Analysis of Subglacial Deposits and Landforms in Southern Ontario Using Sedimentology and Geomatics

Abstract

<p>This research utilizes sedimentology and geomatics to investigate relationships between sediment types, landforms and former glacial movement in southern Ontario, Canada. The research integrates qualitative field observations of sedimentary successions with quantitative assessment of landforms, specifically drumlins, using Geographic Information Systems (GIS). A detailed sedimentological analysis of late Quaternary sediments exposed in Vineland Quarry, Ontario identifies glaciolacustrine deposits which were subsequently overridden and deformed by glacial ice. The gradual transition from undisturbed, laminated sediment to increasingly deformed sediment and structureless diamict exposed at Vineland is consistent with theoretical models of subglacial deformation and suggests that the succession records a single episode of ice advance across the Vineland region.</p> <p>The second component of this research is presented within two research papers that explore a computational methodology within GIS which allows identification of drumlins and their morphological characteristics from existing topographic digital data. The two studies examine the form and spatial distribution of drumlins within the Arran, Galt and Guelph drumlin fields and from a portion of the Peterborough drumlin field. Drumlins and their morphological characteristics, such as elongation ratio and long axis orientation, are identified and documented using a computer-based process that allows direct comparison of forms within and between individual drumlin fields. The computer-based spatial analysis shows that drumlins are not randomly distributed across the regions, but show distinct patterns of clustering. Drumlins with particular morphological characteristics also show a clustered distribution that may be related to spatial changes in sediment thickness, duration of ice cover, and the direction of ice movement. The ability to consistently identify and characterize drumlin morphology and distribution allows objective and systematic comparison of these landforms both within and between drumlin fields and will enhance understanding of the spatial controls on the development of these enigmatic landforms.</p>