Presented By:
Dr. Gil Hanson
Distinguished Service Professor Emeritus
Department of Geosciences
Stony Brook University
Abstract:
When most local geologists think of the moraines on Long Island their view is of a line of hills rising high above the outwash plain. However, a significant part of the moraines where the glaciers rested and then retreated are not at much higher elevations than the outwash plains. The areas of the moraines with highest elevations are push moraines, whereas the lower areas along the moraines are hummocky terrains consisting of ridges, valleys, and kettle holes formed under stagnant ice left behind as the glacier retreated to the north. The Ronkonkoma moraine is made up of a significant area of hummocky terrain. In the Bridgehampton to Amagansett area are three places where hummocky terrain extends south of the Ronkonkoma moraine suggesting that small lobes of ice briefly moved south and covered the area. Hummocky terrain on the north side of the Ronkonkoma moraine is not covered by outwash. Whereas further north, hummocky terrain either does not exist everywhere or is covered by outwash from the Harbor Hill moraine suggesting that as the front of the Ronkonkoma moraine retreated it left areas of stagnant ice.
Other names for hummocky terrain, include knob and kettle terrain, ablation moraine, ground moraine, and hummocky glacial topography.
This Course Has Been Approved for New York State 1 PDH Credit
*Bio: Dr. Gilbert N. Hanson is a Distinguished Service Professor Emeritus (Stony Brook University). Professor Hanson is a member of the Long Island Groundwater Research Institute and focuses his research on Long Island’s geology and aquifer system to help address the region’s groundwater problems. In this endeavor, he is currently pursuing studies on the area’s soil, plant, and groundwater chemistry. Professor Hanson is the coordinator for the annual Long Island Geologists events. These include the annual Conference on the Geology of Long Island and Metropolitan New York in April, and occasional field trips.
E-mail: gilbert.hanson@stonybrook.edu
HOPE TO SEE YOU THERE!!!