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以米浪沟湾地层剖面作为萨拉乌苏河流域的典型剖面,探讨了150 ka B.P.以来的CaCO3含量分布与气候变化的关系。1)该剖面CaCO3含量及其低-高变化同古风成沙与上覆河湖相或古土壤构成的沉积旋回呈现出明显的对应关系。与米浪沟湾剖面的沉积旋回一样,CaCO3在分布上相应地构成了27个含量高低变化旋回。2)CaCO3在风成沙中含量的分布比较稀散,0.8％～7.18％,平均值2.50％;在河湖相和古土壤中相对富集,2.20％～14.90％。平均值5.74％。从而揭示出其时两者的气候背景是不同的,前者是干旱寒冷气候作用下的风力的侵蚀、搬运与堆积的产物;而后者则与暖湿气候环境下萨拉乌苏河流域地处鄂尔多斯高原和黄土高原之间特殊的低洼地貌位置有关。气候暖湿,河湖沼泽发育、成土成壤作用增强,低洼的集水条件有利于CaCO3的聚集。3)导致米浪沟湾剖面CaCO3的多旋回相对稀散与聚集的根本原因可能是150 ka B.P.以来北半球冰期-间冰期气候波动影响下毛乌素沙漠冬夏季风的多次更迭所致。
Based on the Mi Langgou Bay strata profile as a typical section of the Salawusu basin, the relationship between the distribution of CaCO3 content and climate change since 150 ka BP was discussed. 1) The CaCO3 content in the profile and its low-high change show a clear correspondence with sedimentary cycles formed by palaeofacies and overlying river lacustrine facies or paleosol. Similar to the sedimentary cycles of the Mielonggouwan profile, the distribution of CaCO3 constitutes a corresponding variation of 27 levels. 2) The distribution of CaCO3 in the aeolian sand is relatively scattered, ranging from 0.8% to 7.18% with an average of 2.50%. It is relatively enriched in the lacustrine facies and the paleosol, ranging from 2.20% to 14.90%. Average 5.74%. Which reveals that the climatic background is different between the two at that time. The former is the product of erosion, transport and accumulation of wind under arid cold climates. The latter, on the other hand, is located in the Ordos Basin under warm and humid climatic conditions Plateau and the Loess Plateau between the special low-lying landform related. Warm and humid climate, the development of rivers and lakes swamp, soil forming soil enhancement, low-lying water conditions conducive to the accumulation of CaCO3. 3) The fundamental reason for the relative thinning-up and accumulation of multi-cycles of CaCO3 in the Meiguanggouwan profile may be due to the frequent alternations of the winter monsoon and the monsoon in the Mu Us Desert under the influence of the climatic fluctuations in the Northern Hemisphere glacial-interglacial period since 150 ka B.P.