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通过现代季风边缘区的吉兰泰盐湖钻孔JLT11-A孔沉积岩芯的矿物分析,结合地层盘星藻的含量探讨末次冰盛期(LGM)时湖泊的状态和古气候特征。结果显示:在LGM时吉兰泰湖泊沉积矿物主要是石英、长石为主的碎屑岩沉积,含量在85%左右,显示出陆源碎屑矿物的高输入状态,可能指示区域寒冷干旱的环境;其次是以方解石为主的碳酸盐的沉积,含量约为10%;氯化物为主的石盐类矿物一般不足5%,但持续存在,指示湖泊仍然有较高的盐度,因此地层中的淡水藻类盘星藻可能是由河流输入。由于陆源碎屑矿物输入强烈,矿物组合可能难以直接指示吉兰泰盐湖湖水状态。区域的干冷的气候与大多数的古气候记录一致,而与新疆西部的冷湿的环境不同。对比邻近区域的古气候研究结果发现,本区域在LGM时段夏季降水相对于冰消期偏多,而相对于MIS3阶段晚期偏少,整体夏季风减弱。吉兰泰盐湖末次冰盛期到末次冰消期以来矿物组合的变化表明,湖泊环境可能受到夏季太阳辐射、全球与区域温度变化以及夏季风强弱变化的影响。
Through the mineral analysis of JLT11-A hole sedimentary core in the Jiyangtai salt lake drilling in the edge of the modern monsoon region, the lake status and palaeoclimate characteristics during the last ice age (LGM) are discussed according to the contents of the strata. The results show that at LGM, the sedimentary minerals in the Jiyantai Lake are mainly quartz and feldspar-based clastic sediments with a content of about 85%, indicating a high input state of terrigenous detrital minerals and may indicate a cold and arid environment in the region Followed by calcite-based carbonate deposits of about 10%. Chloride-based rock salt minerals are generally less than 5% but persist, indicating that the lake still has a high salinity, so the strata The freshwater algae in Chlamydomonas may be imported from rivers. Due to the strong input of terrigenous clastic minerals, the mineral assemblage may not be able to directly indicate the state of the Jilantai Salt Lake water. The dry and cold climate in the region is consistent with most of the paleoclimatic records, unlike the cold and wet environment in western Xinjiang. Comparing the paleoclimate research results in the adjacent areas, it is found that the summer precipitation in the LGM period is slightly higher than that in the ice depletion period, while the overall summer monsoon weakened compared with the late MIS3 period. Changes in mineral assemblages since the last ice age of the Jilanthi Salt Lake to the last ice depletion suggest that the lake environment may be affected by summer solar radiation, global and regional temperature changes, and changes in the intensity of the summer monsoon.