Академическое издательство «Гео»

Keywords: reconstruction, phytocenosis, water regime, peat accumulation, oligotrophic hollow-pool complex.


Dynamics of the hollow-pool complex of the Iksinskoe Bog (Western Siberia) as a response to climate changes in the latter half of the Holocene

Yu.I. Preis


Two peat profiles of the oligotrophic hollow-pool complex of the southern-taiga Iksinskoe bog were studied in detail. Analyses were made of the botanical composition, the degree of decay, ash content, and of the number of diatoms. Fourteen peat samples were dated. Phytocenoses and water regimes were reconstructed. The technique is suggested for improving the quality of peat accumulation chronology by taking into account its interruptions, using the peat accumulation rate of neighboring analogue layers and radiocarbon analogue dates, and synchronizing peat profiles from similar stages of water regime. System-evolutionary methodological approach and indicators of paleocryogenic processes were used to discover numerous disturbances to endogenous development caused by the combined effect of the continental climate and a considerable differentiation of the microrelief of the mineral bottom composed of calcareous loams. The study revealed the formation of complexity and heterotrophicity as early as the paludification stage; frequent (secular and intrasecular), and abrupt changes of plant communities and water regime, significant bog water level fluctuations; pseudo-inversions to the more minerotrophic stage of development; a long-lasting preservation of complexity; type and phytocenotic diversity of complexes; a predominance of mire and mire-lake complexes; the block character of peat accumulation, repeated interruptions of peat accumulation because of the formation of secondary lakes during wet warming periods, permafrost mounds during dry cooling periods, and secondary thermokarst lakes during subsequent warming periods. The analysis revealed a predominance of climate-caused stages of development, multiple effects of paleocryogenic processes, and a maximal influence of cold dry and warm wet periods on the functional state of the bogs. This confirms the existence of a regional climate-caused type, along with the endogenous type of paludification process, in the forest zone of Western Siberia. A subtle response of the type of complex under study can be used in creating high resolution reconstructions and making forecasts of the functional state of bogs as well as the climate.

Keywords: reconstruction, phytocenosis, water regime, peat accumulation, oligotrophic hollow-pool complex.