Varve, paleomagnetic, and 14C chronologies for late pleistocene events in New Hampshire and Vermont (USA)

A deglacial chronology for northern New England has been formulated using an atmospheric C-14 calibration of the New England Varve Chronology and paleomagnetic records. This C-14 chronology is based on C-14 ages from macrofossils of non-aquatic plants and is about 1500 yr younger than existing chronologies that are based primarily on C-14 ages of bulk organic samples. The lower and upper Connecticut Valley varve sequences of Ernst Antevs (NE varves 2701-6352 and 6601-8500) overlap (lower 6012 = upper6601) based on their crudely matching varve records and their similar paleomagnetic records. Th ree 14C ages at Canoe Brook, Vermont (NE varve 6150 = 12.3 C-14 ka) calibrate the lower Connecticut Valley sequence. New AMS and conventional C-14 ages on woody twigs from Newbury, Vermont calibrate the upper sequence from 11.6-10.4 C-14 ka (NE varves 7440-8660) and are consistent with the overlapping varve and paleomagnetic records, and the Canoe Brook C-14 ages. Deglaciation of the Connecticut Valley in southern Vermont began at 12.6 C-14 ka (15.2 cal ka) and the Littleton-Bethlehem Readvance in northern New Hampshire and Vermont reached its maximum at 11.9-11.8 C-14 ka(14.0-13.9 cal ka) followed by recession of ice into Quebec at about 11.5 C-14 ka(13.4 calka). A lake persisted in the upper Connecticut Valley until at least 10.4(14)C ka (12.3 cat ka) and may have been seen by the first humans in the area.