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对居延海G36钻孔进行了系统磁性特征分析,并结合总有机碳含量和粒度等环境代用指标,在精确测年的基础上,探讨了居延海地区全新世时期以来的环境变化。结果显示,居延海岩芯磁性矿物主要存在于粗颗粒的沉积物中,载磁矿物为颗粒较粗的多畴磁铁矿;磁化率变化机制比较复杂,与干湿环境变化没有简单正(反)关系。根据G36沉积物环境代用指标的变化,大致可以将其分为4个干湿交替时期:6 700～4 600aBP干旱时期,4 600～3 100aBP湿润时期,3 100～2 500aBP干旱时期以及1 800aBP以来湖泊干涸。在这4个时期中,磁学参数记录了两次显著湿润事件和两次显著干旱事件。
The magnetic characteristics of the G36 borehole in Juyanhai were systematically analyzed. Based on the accurate dating, the environmental changes in the Juyanhai area since Holocene were discussed based on the environmental proxy indexes such as total organic carbon and grain size. The results show that the core magnetic minerals in Juyanhai mainly exist in coarse-grained sediments and the magnetic-bearing minerals are multi-domain magnetite with coarse grains. The change mechanism of magnetic susceptibility is complex and there is no simple positive ( Anti) relationship. According to the variation of sediment environmental proxy index of G36, it can be roughly divided into four periods of alternating wet and dry periods: 6 700-4 600 aBP drought period, 4 600-3 100 aB wetting period, 3 100-2 500 aBP drought period and 1800 aBP Lakes dry up. In these four periods, the magnetic parameters recorded two significant wetting events and two significant drought events.