Research Projects

Luminescence timing of paleoenvironmental changes in Quaternary lake sediments from the Arctic Taymyr Peninsula, Siberia

PI: Glenn Berger

Project Period: June 2000 - May 2002

Funding: This material is based upon work supported by the National Science Foundation under Grant No. EAR-9909686

Right: Split sediment core (scale in cm) from one of the lakes of the Taymyr Peninsula, and the northernmost of those lakes (black triangle). Click on image for larger view.

Keywords: luminescence, dating, IRSL, Siberia, Arctic, lakes, glaciation

Project Approach

The arctic is a predicted highly sensitive region to future global climatic change, yet its harshness and remoteness have limited our knowledge of the geological record of past climatic/environmental changes in this region. Such knowledge of past changes (their timing, rates of change, nature of change) is necessary for assessing the natural context and scale of historic and predicted changes. The region of arctic Central Siberia is particularly unexplored in this regard. Sediment cores from presently existing lakes contain a record of past environmental condition (e.g., vegetation cover inferred from pollen data, glaciations inferred from sediment textures). Unexpectedly, detailed radiocarbon (14C) dating has failed to produce confident chronologies in the sediment cores, and the most recent 14C ages are controversial. In almost all of the cores concentrations of organic material are either too low or are contaminated by ancient coal.

This project builds on the PI's extensive experience with North American lake cores and other lake deposits, and applies the very sensitive infrared-stimulated- luminescence (IRSL) dating method to several samples from each core (total 34 samples). The first results from one of the Siberian lakes provides geologically self-consistent ages without the scatter and age-reversals of the 14C ages. These IRSL results also demonstrate clearly for the first time that this area remained free of Siberian ice sheets after c.45-50 ka (see Berger et.al., 2004).

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