Abstract

A new varve record from sediments of glacial Lake Hitchcock in the Connecticut River Valley along Canoe Brook in Vermont matches and provides a test of Antevs' New England varve chronology for a span of more than 530 yr. Antevs' methods of correlation and for constructing the varve chronology appear to be valid. The varve record at Canoe Brook records weather-controlled variations in meteoric (nonglacial) discharge as well as glacial runoff. Organic sediment from the Canoe Brook site, which includes twigs, leaf debris,conifer needles, and fine disseminated organic detritus, lies 460-470 couplets above the base of the section and was deposited about 500 yr after deglaciation. The organic sediment was radiocarbon dated at 12,355 ± 75 yr B.P. (GX-14231), 12,455 ± 360 yr B.P. (GX-14780), and 12,915 ± 175 yr B.P. (GX-14781). Our radiocarbon dates are the first from sediments of Lake Hitchcock, and they provide the first real calibration of the New England varve chronology. The dates place the inception of Lake Hitchcock in central Connecticut at before 15,600 yr B.P. and deglaciation of the Canoe Brook site at about 12,900 yr B.P. An abrupt change in sediment types and thickness of varves 50 yr above the radiocarbon dates (about 12,400 yr B.P.) corresponds to a basin-wide change in the New England varve chronology and records the initial breaching of the dam for Lake Hitchcock at Rocky Hill, Connecticut. Nonglacial lakes, lower than Lake Hitchcock, persisted in the northern Connecticut Valley until at least 400 yr after the incursion of marine waters into the Champlain Valley.

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