Deglaciation chronology and paleoclimate of the Pieciu Stawow Polskich/Roztoki Valley, high Tatra Mountains, Western Carpathians, since the Last Glacial Maximum, inferred from ~(36)C1 exposure dating and glacier-climate modelling

摘要

Exposure dating of abraded bedrock surfaces below glacial trimlines in the Pieciu Stawow Polskich/ Roztoki Valley, using cosmogenic ~(36)C1, has been applied to determine the deglaciation chronology in the study area. Nineteen rock samples yielded ages between 21.5 and 9.5 ka. The spatial distribution of ages provides evidence of progressive downwasting of glaciers within the study area. Dates of exposure indicate that the onset of ice volume decrease occurred no later than 21.5 ka. This provides evidence that the local maximum glaciation occurred in accordance with the global Last Glacial Maximum (LGM). The first period of deglaciation in the study area was completed around 18 ka. Further significant loss of ice volume is confirmed between 15 and 13 ka. The spatial distribution of chronological data within the Pieciu Stawow Polskich Valley indicates post-LGM readvances of glaciers around 17 ka and 12 ka. Using the glacier modelling and paleoclimate proxies from the study area, the early Late Glacial glacier had been stable with a 9—10 ℃ decrease in temperature and 30—50% lower precipitation in relation to modern conditions. The subsequent advance took place with temperatures 6-7 ℃ lower and 10-30% less precipitation. The timing of the readvances is nearly synchronous with Late Glacial advances in the European Alps, Southern Carpathians and Anatolian peninsula. This suggests synchronicity of major climatic fluctuations across Central Europe and the northern margin of the Mediterranean Basin.