17 Glacial and Postglacial Environments on the Frontier: Quaternary Studies in the New England-Canadian Border Region

Monday, 12 March 2007
1:00 PM - 4:45 PM

REVIEW AND COMPARISON OF MULTIPLE PROXY RECORDS OF HOLOCENE PALEOENVIRONMENTS AND PALEOCLIMATE, NEW YORK STATE, USA

Paper number: 17-8
Program: THEME SESSIONS
Time: 3:00 PM – 3:20 PM

Authors

Abstract

Proxy data sets for reconstructing Holocene paleoenvironments and paleoclimate in New York State, USA, are reviewed from the published literature. Pollen, plant macrofossils, oxygen (d18O) and carbon (d13C) isotopic values from cave speleothem and lacustrine sediments, cave and rockshelter lithostratigraphy and sedimentation rates, alluvial stratigraphy, and archaeofaunas are proxies for which data is currently available. Additionally, paleotemperature reconstructions derived from d18O values and pollen assemblages are compared. A rapid, first-order warming trend at the Pleistocene-Holocene boundary is the strongest signal across data sets, with mean annual temperatures rising as much as 14°C between 11,000 and 9500 14C yr B.P. Timing of the Holocene Thermal Maximum (HTM), however, is inconsistent across pollen study sites, with local maxima occurring between 9500 and 5000 14C yr B.P. d18O-derived paleotemperatures suggest a HTM centered around 6700 14C yr B.P., mean annual temperatures >5°C warmer than present, with steadily decreasing values to the present. d18O-derived paleotemperatures are uniformly higher than pollen-derived estimates.

Other proxy data sets indicate coeval, though occasionally ambiguous, responses to environmental changes. Availability of proxies varies according to physiographic province, making direct sub-regional comparisons difficult. Although general paleoclimatic trends are apparent, weak chronological control and discontinuous records impede resolution and correlation between data sets. Local versus regional signals are often difficult to ascertain, while sensitivity and thresholds appear to be system-specific. Changes in a proxy record (e.g. vegetation) may also be driven by non-climatic influences such as time-dependent pedogenic pathways. Hence, the magnitude and timing of climatic and environmental transitions may not only differ according to the proxy used, but be obscured by other factors. These proxies, taken as a whole, indicate general patterns of paleoenvironmental and paleoclimatic change, but do not individually provide a detailed and accurate reconstruction of past environments. Future research should include (1) improving chronological control and (2) refining our understanding of both climatic and non-climatic variables affecting the environmental systems from which the proxies are taken.