GIS BASED ANALYSIS OF THE CHAUTAUQUA DRUMLIN FIELD, NORTHWEST PENNSYLVANIA AND WESTERN NEW YORK

The Chautauqua drumlin field is an inadequately studied streamline field in the Late Pleistocene Kent ground moraine deposited by the Cary advance of the Erie Ice Lobe. The essential lack of previous work on the field is due mainly to the non-traditional morphology of the drumlins. The streamlined landforms within this field are superimposed on a highly variable pre-existing surface, and have been moderately eroded since formation. To map the drumlin, the slope and 3 m contour layers were derived from a 30 m National Elevation Dataset (NED); as a result drumlin boundaries were defined by a distinct break in slope. This method provides a more accurate drumlin outline than the traditional topographic map methods. Using the improved boundaries the morphologic properties of the drumlin and the field itself can be calculated. Initial results indicate that the field covers an area of more than 2500 km². Drumlins occur in uplands ranging in elevation from 346 to 628 m and hold a mean height of 24 m. Drumlins are oriented at 110 to 180 degrees with elongation ratios averaging 0.32. By improving methods for defining drumlins a more complete understanding of the subglacial environment within the Erie Lobe may be accomplished.