A unique 800-yr-long record of annual temperatures and precipitation over the south of western Siberia has been reconstructed from the bottomsediments of Teletskoye Lake, Altai Mountains using an X-ray fluorescence scanner (XRF) providing 0.1-mm resolution timeseries of elementalcomposition and X-ray density (XRD). Br content appears to be broadly correlative with mean annual temperature variations because of changesin catchment vegetation productivity. Sr/Rb ratio reflects the proportion of the unweathered terrestrial fraction. XRD appears to reflect water yieldregime and sediment flux. Sedimentation is rather continuous because annual clastic supply and deposited mass are the same. The artificial neuralnetworks method was applied to convert annual sedimentary time-series of XRD, Br content, and Sr/Rb ratio to annual records of temperature andprecipitation using a transfer function. Comparison of these reconstructed Siberian records with the annual record of air temperature for theNorthern Hemisphere shows similar trends in climatic variability over the past 800 yr. Estimated harmonic oscillations of temperature andprecipitation values for both historical and reconstructed periods reveal subdecadal cyclicity.
Helmholtz Research Programs > MARCOPOLI (2004-2008) > POL6-Earth climate variability since the Pliocene