萨拉乌苏河地区地层中CaCO_3和易溶盐含量变化与气候环境

本文结合萨拉乌苏河地区的自然地理特征,重点分析讨论了该区晚更新世以来地层中CaCO_3和易溶盐含量变化与气候变迁的关系。并提出关于晚更新以来干湿周期变化及其幅度的看法。

THE CONTENT CHANGES OF CaCO_3 AND SOLUBLE SALT IN THE STRATA AND THE CLIMATIC ENVIRONMENTS IN ARID AND SEMI-ARID REGIONS——As examplified by Salawusu River

The regularity of content changes of CaCO_3 and solvable salt in thestrata and the relationship between it and climatic changes, combined withthe characteristics of physical geography, in Salawusu River region sinceEpipleistocene have been analyzed and discussed in this paper. Therefore,three preliminary conolusion have been drawn as follows: 1.The property of CaCO_3 content changes in the strata of Salawusu-River region is contrary to that in the section of deep-sea deposition and thatof loess strata in China because of the influence of climatic fluctuations ininterglacial age and glacial age.Thus it can be inferred that if the formingtype of sedimentary facies in strata is the same or similar to SalawusuRiver region in other arid and semi-arid zones of China, the property ofcontent changes of CaCO_3 in the strata will also be the same or similar. 2.The climate in the study area experienced three different periods ofthe alternation of dry spell and wet spell since Epipleistocene: The first periodwas the formation of 1 -- 5 strata; the second one was that of 6 -- 8 strata;the third one was that of 9 -- 12 strata. 3.The magnitude of climatic fluctuation was always between draught andsemi-humidity since Epipleistocene. There were several warm and moist flu-ctuations during the period in which the stratum of Chengchuan Formationbegan to deposit and the climate became dry and cold,but its range was smalland its duration was short, and it never got up to such warm and moist de-gree as stratum deposition of Salawusu Frmation.It is suggested that SalawusuFormation and Chengchuan Formation belonged to the products of Riss-WurmInter-glacial Age and wurm Glacial Age respectively. Therefore, it is provedthat the climate in this region has never picked up to the warm and moistdegree of Riss-Wurm Inter-glacial Age since Wurm Glacial Age.