Climatic change in the Russian Altai, southern Siberia, based on palynological and geomorphological results, with implications for climatic teleconnections and human history since the middle Holocene.

摘要

Two pollen diagrams from near the Chuya Basin, Russian Altai, are presented together with results from geomorphological archives. The Kuray Range profile (2330 m asl) is situated just above the forest line and starts with the weak cooling of the middle Atlantic period (~ 6500-5900 B.P.) that bisects the Holocene optimum, as in other parts of Siberia. Taiga (boreal coniferous forest) with Picea obovata established afterwards but was displaced at ~5300 B.P. by the pronounced cooling of the early Sub-boreal. A gradual recovery of taiga stopped and it disappeared around 3400 B.P. at the end of the middle Sub-boreal. Since then the climatic and vegetational conditions much resemble those of the Sub-atlantic. In the last two millennia, three climatic declines are documented in the second diagram from the Tarkhata Valley (2210 m asl) from the dry limit of Larix sibirica: a cold and wet one around the 5th century A.D., a cold and dry one around A.D. 1200 and the Little Ice Age which started around A.D. 1600. In addition, several of the climatic periods and especially local human influence can be proved by the geomorphological findings. Most of the climatic changes seem to be connected with socioecological changes in Asia and even Europe, with movements of the Huns and Mongols, which show the possible dimensions of global climatic change. Hints of teleconnections between Siberia, the Mediterranean and the Himalayas via the North Atlantic and the Arctic Oscillation are discussed.