Holocene climate variability as reflected by mid-European lake-level fluctuations and its probable impact on prehistoric human settlements

摘要

A data set of 180 radiocarbon, tree-ring and archaeological dates obtained from sediment sequences of 26 lakes in the Jura mountains, the northern French Pre-Alps and the Swiss Plateau was used to construct a Holocene mid-European lake-level record. The dates do not indicate a random distribution over the Holocene, but form clusters suggesting an alternation of lower and higher, climatically driven lake-level phases. They provide evidence of a rather unstable Holocene climate punctuated by 15 phases of higher lake-level: 11250-11050, 10300-10000, 9550-9150, 8300-8050, 7550-7250, 6350-5900, 5650-5200, 4850-4800, 4150-3950. 3500-3100, 2750-2350, 1800-1700, 1300-1100, 750-650 cal. BP and after 1394 AD. A comparison of this mid-European lake-level record with the GISP2-Polar Circulation Index (PCI) record, the North Atlantic ice-rafting debris (IRD) events and the ~(14)C record suggests teleconnections in a complex cryosphere-ocean-atmosphere system. Correlations between the GISP2-PCI, the mid-European lake-level, the North Atlantic IRD, and the residual ~(14)C records, suggest that changes in the solar activity played a major role in Holocene climate oscillations over the North Atlantic area.