RADIOCARBON AND VARVE CHRONOLOGIES OF ANNUALLY LAMINATED LAKE-SEDIMENTS OF GOSCIAZ LAKE, CENTRAL POLAND

A sequence of annually laminated sediments of the Gosciaz Lake spans ca 13,000 yr and is actually the longest known continuous sequence in the world. C-14 age measurements were performed on organic and carbonate fractions of bulk samples of laminated sediments from core G0. Accurate measurements of varve thickness performed on the lower part of cores G1 and G2 were used to establish a floating varve chronology covering ca 10,000 yr. Matching of cores G0, G1 and G2 permits comparison of C-14 dates with varve chronology. Good agreement of calibrated C-14 dates with the varve time scale suggests annual lamination of the sediment. Analysis of periodicities in varve thickness indicates solar 11-and 22-yr cycles, as well as a 200-yr cycle over a good part of the investigated sequence. Results of C-14 measurements of carbonate fractions are used to study changes in the water depth of the lake during its history.