RIVER TERRACES, INCISION, AND POST-GLACIAL LANDSCAPE EVOLUTION IN SOUTHERN NEW ENGLAND

River terraces and bedrock knickpoints are markers of incision that are crucial to determining river reorganization and post-glacial evolution of the southern New England landscape. The formation of these features depends on sediment load, river discharge, and base level changes. As a result, these features record information about the effects of glacio-isostatic rebound in the region, rock strength, or climate and precipitation changes throughout the late Pleistocene and Holocene. River terraces can be used as geomorphic markers to interpret paleo–river levels along longitudinal profiles, determine volumes of removed material, and calculate incision rates provided that ages of abandonment can be measured. Previous studies in New England concerning fluvial terraces are limited. Here, we present an analysis of fill and cut fill terraces found adjacent to the Farmington River in west-central Connecticut and Connecticut River in central Massachusetts and Connecticut. We use high-resolution airborne LiDAR data to map the distribution and heights of terraces along these rivers, and combine this topographic analysis with fieldwork, trenching and Quaternary dating methods (e.g., carbon-14 dating) to constrain the age of formation and timing of abandonment for various river terraces levels. Preliminary studies indicate there are typically one to three terrace levels preserved above the modern channel, ranging in heights from 2 to 25 meters for the Farmington River, and 5 to 32 meters for the Connecticut River. Terrace heights display systematic variations throughout the river system and are typically higher downstream from knickpoints. Future work will be conducted within the Housatonic and Thames River watersheds in Connecticut, and Westfield River in Massachusetts.