【摘要】 对采自浙江景宁望东样亚高山湿地自然保护区的沼泽泥炭柱样（WDY-2）,进行了磁学、粒度参数和腐殖化度分析,结合AMS¹⁴C测年数据,探讨了中国东部亚高山沼泽泥炭磁性特征的环境指示意义。结果表明:1)WDY-2柱样沉积物总体以粘土质粉砂为优势组分,磁性特征由亚铁磁性矿物主导,同时存在不完整反铁磁性矿物的贡献,磁性矿物主要富集在粘土粒级中。2)磁学参数SIRM能间接反映研究区域流水搬运能力强弱。气候暖湿时,沉积物以粉砂为主,SIRM较低;气候相对冷干时,沉积物粘土含量高,SIRM较高。3)综合沉积物粒度、腐殖化度以及SIRM的垂向变化特征,重建了WDY-2泥炭剖面记录的7.6cal.kaB.P.以来的环境变化历史:7.6-3.6cal.kaB.P.,季风降水增加,对应全新世大暖期,期间存在明显气候波动;3.6～1.2cal.kaB.P.,气候转向冷干;1.2～0.9cal.kaB.P.,气候暖湿,对应中世纪暖期（MWP）,尤其在1.1cal.kaB.P.左右达到了暖湿组合的鼎盛期;0.9～0.4cal.kaB.P.,季风降水减弱,以冷干气候为主,但也存在暖湿阶段,对应小冰期（LIA）;0.4cal.kaB.P.以来,气候回暖,降水增加,趋近现代气候环境。更多还原

【Abstract】 Environmental magnetism is widely used to study environmental change by characterizing magnetic minerals including magnetic mineral assemblage and grain size. Peat deposition contains valuable paleoclimatic history information, yet environmental magnetic study of peat deposition is quite limited. A peat core WDY-2（ 122 cm in length） was obtained from Wangdongyang Subalpine Peatland（27°40’58 "N, 119°38’15" E; altitude in1300 m a.s.l.）,Zhejiang Province, China, which is surrounded by low hills with water supplied by atmospheric precipitation. Analyses of magnetic properties, granularity, humification and chronology were conducted on core WDY-2 to explore the environmental meaning of magnetic indexes of subalpine peatland in Eastern China. The results are as follows :（1） Particle-size analysis shows that the sediment of core WDY-2 is mainly composed of clayey silt, consisting on average of 58. 3% silt, 25. 1% clay, 16.6% sand. Magnetic analysis shows that magnetic properties of core WDY-2 are dominated by ferrimagnetic minerals, together with the contribution of antiferromagnetic minerals. Correlation analysis between magnetic parameters and particle-size shows that SIRM and HIRM are significantly correlated with clay, and S_{-100 mT} and S_{-300 mT} are negatively correlated with clay. It can be concluded that ferrimagnetic minerals and antiferromagnetic minerals are mainly associated with clay fraction.（2） The index SIRM of WDY-2 can indirectly indicate the strength of hydrodynamic forces. In dry-cold climate condition, there is higher clay content in the sediment that results in higher SIRM value. In contrast, more silt is transported to the peatland in a warm and moist climate that results in lower SIRM value.（3） Climatic changes since 7. 6 cal.ka B.P. were reconstructed based on the vertical variations of particle size, humification and SIRM values of WDY-2, that is: 7. 6～3. 6 cal.ka B.P., SIRM is low on the whole which indicates humid-warm climate of Holocene Megathermal, but there are some fluctuations in some phases; 3. 6～1. 2 cal.ka B.P., SIRM is higher than the first phase, showing that the climate being cold and dry; 1. 2～0. 9 cal.ka B.P., a lower SIRM indicates that monsoon rainfall increased dramatically and climate changed dry-cold to humid-warm. The chronology and the climatic characteristics corresponds to the Medieval Warm Period（ MWP）; 0. 9 ～0.4 cal.ka B.P.,SIRM presents high level on the whole, but there are some fluctuations. It is suggested that the general trend of climate is dry-cold with some humid-warm stages. The climatic characteristics are roughly corresponding to the Little Ice Age（ LIA）.0. 4 cal.ka B.P. to present, SIRM presents declining trend which shows that climate becomes warm and humid in this stage.更多还原