Changes of vegetation and environment at the Laptev-Sea coast in Northern Siberia during the Late Quaternary reconstructed by means of plant macroremains
The Arctic was exposed to dramatic environmental changes during the Quaternary. It is possible to detect the biological effects of these changes in terrestrial arctic ecosystems using bioindication by vascular plants. The results of studies about changes of structure and dynamic of plant communities...
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| Format: | Conference Object |
| Language: | unknown |
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2003
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| Online Access: | https://epic.awi.de/id/eprint/12161/ https://hdl.handle.net/10013/epic.22594 |
| Summary: | The Arctic was exposed to dramatic environmental changes during the Quaternary. It is possible to detect the biological effects of these changes in terrestrial arctic ecosystems using bioindication by vascular plants. The results of studies about changes of structure and dynamic of plant communities in arctic Siberia during the Late Quaternary are introduced. We reconstructed the composition of plant communities in different time slots from botanical macrofossil assemblages preserved in permafrost sequences in Northern Siberia.The studies have been carried out at the Bykovsky Peninsula southeast of the Lena-Delta. The study area is situated directly at the Laptev-Sea coast today. But the location was far inland during the last glaciation of the northern hemisphere due to the marine regression. The Laptev-Sea level fell down to 120-135 m beneath its present-day level. Its coast shifted consequently northward several hundred km.The permafrost sequence investigated is outcroped along a cliff line, which is up to 40 m high. It was made accessible for sampling by thermal erosion and wave action. The outcrop consists of several subprofils. These so called thermokarst mounds represent the sediments, which were accumulated in the former polygonal depressions after the thawing of the ice wedges walling them. The sediment-blocks are very rich in fossil seeds. Due to the freezing of the plant remains simultaneous with their accumulation they are normally very well preserved. The Thermokarst mounds were sampled for several studies, which were carried out within the multidisciplinary project, named Palaeoclimatic signals from ice rich Permafrost. A detailed age model was constituted based on radiocarbon data both conventional and AMS. According to this the investigated permafrost sequence was deposited continuously since about 60 000 years bp and is hence an excellent archive of the Late Quaternary history of vegetation and climate. 18 samples from different thermokarst mounds were sieved. Plant remains were picked and ... |
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