CONSTRUCTING A CHRONOLOGY OF LONG ISLAND SOUND SEDIMENTS USING PALYNOLOGICAL DATA

Palynological analysis of three sediment cores, each representing the last several hundred years of Long Island Sound history, demonstrates clear signals of vegetation change. In cores of sufficient age, both the rise in Ambrosia artemisiifolia (ragweed), associated with human settlement, and the blight-induced decline in Castanea dentata (chestnut) are evident and in conjunction with Clostridium perfringens, ²¹⁰Pb, and heavy metals analyses provide a multi-proxy methodology for dating recent Long Island Sound sediments. Within each core, combined results of the multiple marker horizons provide a consistent chronological profile, yet also indicate an increased sedimentation rate in the estuary since 1850. Our new results in conjunction with prior data, which demonstrated a well-mixed spatially-uniform palynological assemblage throughout Long Island Sound, suggest that use of regionally-coherent vegetation signals preserved in the Long Island Sound pollen record should provide an accurate and robust means of dating the late-Glacial and Holocene record of Long Island Sound history.