Are late-glacial climate oscillations recorded in varves of the upper Connecticut Valley, northeastern United States?

Abstract

Ernst Antevs' original varve chronology for the upper Connecticut Valley in New England (USA), published in 1922 and 1928, has been extended and a 14C calibration has been established based on 1736+3 −20 5 varves containing terrestrial plant macrofossils at Newbury, Vermont. Varve deposition at Newbury began in a glacial lake (12.1 14C kyr BP) and persisted in a non-glacial lake (to at least 10.4 14C kyr BP). The calibrated Newbury varve stratigraphy and associated glacial events may be compared to climatic events recognized in cores from modern lakes in eastern North America and Europe and in Greenland ice cores. Thickness of glacial varves at Newbury is difficult to correlate to climate because of the thinning of varves in response to ice recession, flood events, and lake level changes that obscure thickness changes resulting from climate change. The Littleton-Bethlehem Read-vance (11.9–11.8 14C kyr BP), that is tied to the varves, may correspond to Older Dryas (GI-1d) cooling. Non-glacial (after 11.6 14C kyr BP) varve thickness cannot be unequivocally tied to climate but may represent a proxy record of temperature with thin varves representing warm intervals and cold events represented by thicker varves displaying a pronounced 25-yr oscillation. The Intra-Allerød Cold Period (GI-1b), recognized in eastern North America as the Killarney Oscillation, and the Younger Dryas (GS-1) may be recorded by thicker varves at 11.1–10.8 14C kyr BP and beginning at 10.65 14C kyr BP.