孢粉记录的晚全新世以来大兴安岭北部多年冻土泥炭地演化及其影响因素OA北大核心CHSSCDCSTPCD

At present,extensive research has already been conducted on regional ancient vegetation,paleoclimate and environmental changes revealed by peat.However,evolution of peatland itself is rarely involved,and especially the evolution process of permafrost peatland and its influencing factors are still unclear in the northern Greater Khingan Mountains(GKM),which hinders our understanding of the historical dynamics and future development trends of this special type of peatland.To address this,based on palynology evidence from permafrost peat cores in the northern GKM and using AMS14 C dating technique,the vegetation and climate history of the region since 3500 cal a BP have been reconstructed.This history was then compared with other paleoclimate indicators to reveal the evolutionary process of the regional peatland and its influencing factors.The results indicated that:From 3500-2900 cal a BP,the vegetation mainly consisted of Pinus,thermophilic broad-leaved forest,and Polypodiaceae,warm and wet climate was the peat incubation period.From 2900-2250 cal a BP,the vegetation mainly consisted of Pinus,thermophilic broad-leaved forest,and Artemisia,warmer and humid climates led to an initiation of peat developmental initiation period.From 2250-1650 cal a BP,the vegetation mainly consisted of Pinus,Betula and polypodiaceae,cold and wet climates led to an initiation of peat prosperity period.From 1650-1150 cal a BP,the vegetation mainly consisted of Pinus,and Artemisia,cold and dry climate led to a slowdown or stagnation of peat development period.From 1150-750 cal a BP,broad-leaved forests and wetland vegetation expansion,warm and wet climate caused peat to development period again,completed the transition from low swamp to medium swamp.Since 750 cal a BP,the vegetation mainly consisted of Pinus,Alnus and Cyperaceae,cold and wet climate as a period of peat prosperity period again,medium swamp began to transit to high swamp.The analysis reveals that the dominant factors causing the evolution of permafrost peatland are not geological landform and human activities,but rather the changes in the permafrost environment driven by climate change.Therefore,climate change is the primary force determining the evolution of permafrost peatland,and future changes in these peatlands will depend on the development of the global climate.