青藏高原扎布耶盐湖SZK01孔粘土矿物X射线粉晶衍射分析

X-Ray Powder Diffraction of Clay Minerals of SZK01 Core of Zabuye Lake,Tibetan Plateau

青藏高原具有独特的地质地理区位优势,并且是我国最大的盐湖分布区,在其晚第四纪湖相沉积中保存着丰富多彩的古环境信息,可为研究青藏高原对全球变化的响应提供崭新而翔实的科学依据。扎布耶盐湖位于青藏高原腹地北部,对于高精度研究青藏高原更新世晚期以来古气候、古环境变化具有重要意义。选择扎布耶盐湖SZK01孔岩芯粘土矿物为主要研究对象,通过X射线粉晶衍射对其进行定性、定量分析。结果显示粘土矿物种类主要是伊利石(I)、伊利石/蒙皂石混层矿物(I/S)以及少量高岭石(K)和绿泥石(C)。按照粘土矿物种类和含量变化,并综合沉积物矿物组合特征以及δ18 O同位素结果,重建扎布耶盐湖115ka(千年)以来的古气候演化。将结果与扎布耶SZK02孔、格陵兰冰芯、古里雅冰芯δ18 O同位素结果对比,将扎布耶盐湖115ka以来划分为5个阶段:末次间冰期(115~75.5ka)、末次冰期早阶(75.5~60ka)、末次冰期间冰阶(60~30.1ka)、末次盛冰期(30.1~16.7ka)、冰消期和全新世(16.7ka以来),识别出H6-H16个Heinrich事件和71ka左右的暖事件,说明青藏高原在该时期气候变化具有全球性。特别的是在52~53ka左右,高岭石含量较低,δ18 O值急剧偏负,SZK02孔δ18 O也相应偏负,古里雅冰芯δ18 O也偏负,说明青藏高原该时段存在冷事件,命名为H5-1。通过该研究综合说明青藏高原在末次冰期早冰阶以来气候变化具有全球性,但也有一定的地域性。

The present article chooses the core from the borehole SZK01 in Zabuye Lake as the main research object .According to the results of X-ray powder diffraction of clay minerals ,the major components are illite ,illite and smectite mixed layer mineral (I/S) ,kaolinite and chlorite .According to the different species and contents of clay ,integration of the characteristics of mineral and the results of δ18 O ,we reestablished the evolution process of paleoclimate in Zabuye Lake .In compaison with SZK02 core in Zabuye ,Greenland GISP2 and GRIP and Guliya ice core ,it contains 5 stages since 115 ka in Zabuye:the last interglacial(115~75.5 ka) ,the earlier last glacial(75.5~60 ka) ,the interstage of the last glacial(60~30.1 ka) ,the last glacial maximum(30.1~16.7 ka) and deglacial-holocene(since 16.7 ka) .We also recognized 6 Heinrich events (H1-H6) and warm event in 71 ka .In particular ,the content of kaolinite is low ,with the negative-skewed value of δ18 O in 52~53 ka ,while the value of δ18 O in SZK02 and Guliya ice core is negative-skewed too ,indicating the cold event in Tibet plateau ,named H5-1 .All the above demon-strated that the climate in Tibet plateau is global since the earlier last glacial ,and it also has regional characteristics .