IMAGE-BASED ANALYSIS OF DRUMLIN MORPHOMETRY, WESTERN ERIE COUNTY, PENNSYLVANIA

It is widely accepted that drumlins exhibit certain morphometric characteristics, such as asymmetric shape and preferred orientation that can be used to infer the direction of glacial flow. This study used a Digital Elevation Model (DEM) to characterize the planimetry of the Laurentide drumlin field in western Erie County, Pennsylvania. The landforms (n=210) generally occupied higher topographic elevations, with the entire field stretching along Lake Erie shoreline in a general NE-SW orientation within a 40x20 km polygon. The 3-m DEMs published by the Pennsylvania Spatial Data Access were used for morphometric analysis via ArcGIS and MATLAB platforms. Drumlin long axes ranged from 237-2680 m in length, with the bulk of long/short axis ratios of 2-3 (highly elongated landforms skewed the mean ratio to 4.2). The plan-view area values ranged from very small (0.02-0.03 km²) to large (up to 0.75 km²) landforms, with more than half of the hill areas yielding values of 0.10-0.15 km². The tight NW-SE orientation of the drumlins (mean azimuth: 334°) is consistent with the Ontario-Erie Lobe ice flow and their presence and distribution place constraints on the ice thickness as it expanded out of the Lake Erie trough.