Hydraulic back-flood model for the archaeological stratigraphy of the Connecticut River Alluvial Lowland, central Connecticut, USA

Abstract

State-mandated archaeological investigations associated with urban renewal in downtown Hartford led to the development of a mechanistic model for Holocene floodplain sedimentation in central Connecticut. Our model is based on: historic flood hydrometeorology and geomorphologic mapping; the lithologic, magnetic, pollen, and archaeological stratigraphy exposed in sixteen deep boreholes and 24 hydraulic push cores; the chronology provided by sixteen AMS radiocarbon ages, and diagnostic historic artifacts ranging from 10,030 cal BP to the present. We conclude that the alluvial stratigraphy in this part of the lowland resulted from bottom-up changes in hydraulic ponding at a bedrock outlet, rather than from top-down responses of the watershed to changes in climate, vegetation or human activity. Our model provides a geologically based time-space framework for the distribution of known archaeological sites, and carries implications for future research.