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测定、分析毛乌素沙漠东南缘萨拉乌苏河流域米浪沟湾剖面MGS2层段的粒度与CaCO3,发现该层段不同沉积相粒度Mz和σ呈现峰谷变化,CaCO3含量在沙丘砂及其上覆的河流相和湖沼相中依次变化于0-2.94%(平均值0.39%)、0.14%-2.68%(1.43%)和0.39%-15.57%(8.82%),并与Mz呈显著相关,构成与沉积旋回波动韵律相同的5.5个峰谷交替的粒度与CaCO3旋回。研究表明,毛乌素沙漠冬季风盛行时期沙丘砂强烈堆积,CaCO3发生迁移;夏季风盛行时期河流相和湖沼相发育,粉砂和粘土含量增加,CaCO3相对聚集。这些旋回代表东亚冬夏季风千年尺度交替变化的气候旋回。
The grain size and CaCO3 of the MGS2 layer in the Mi Langgouwan section of the Salawusu River basin in the southeastern margin of the Mu Us Desert were measured and analyzed. The results showed that the grain sizes of the sedimentary facies Mz and σ varied with the peak-to-valley variation. Overlying river facies and lacustrine facies ranged from 0-2.94% (average 0.39%), 0.14% -2.68% (1.43%) and 0.39% -15.57% (8.82%), respectively, and were significantly correlated with Mz The rhythms of sedimentary swirling are the same as those of 5.5 peaks and valleys alternating with the grain size of CaCO3 cycles. The results show that dune sand strongly accumulates during the prevailing winter monsoon, and CaCO3 migrates. During the prevailing summer monsoon, the river facies and lacustrine facies develop, silt and clay contents increase, and CaCO3 accumulates relatively. These cycles represent the climatic cycles of the alternately changing thousand-year scale of the East Asian winter monsoon.