利用岩性及地层厚度推测喀斯特地区的风化成土量——以贵阳金阳地区为例探讨二叠系以上地层的成土能力  

Using lithologic Characteristics and Strata Thicknesses in Karst Region to Estimate Laterite-forming Capacity:A Case Study for Triassic-Jurassic Sediments in Jinyang District,Guiyang City,Guizhou Province

作　　者：杨瑞东[1] 魏怀瑞[1] 

机构地区：[1]贵州大学研究生院,贵阳550025

出　　处：《高校地质学报》2008年第1期82-89,共8页Geological Journal of China Universities

基　　金：国家重点基础研究发展规划项目(2006CB403202);贵州大学学科建设基金

摘　　要：碳酸盐岩成土是喀斯特地貌发展及演化历史研究的关键问题。研究了贵阳市金阳地区碳酸盐岩风化成土剖面和红粘土层下基岩分布情况,结合该地区地层发育、厚度、岩性等特征,以及碳酸盐岩风化成土的经验数值,推算了研究区成土厚度。同时,根据理论成土厚度与实际保存红粘土厚度对比分析,确认目前保存下来的红粘土层是早更新世以来的第三个夷平期的产物,形成时间可能为4～13万年。现代碳酸盐岩上的红粘土层不仅由碳酸盐岩风化成土形成,而且很大一部分是由碳酸盐岩岩系中的碎屑岩夹层风化成土而来,同时侏罗系碎屑岩成土也占较大比例。因此,喀斯特环境中红粘土的形成及物质来源比较复杂,并非单一的碳酸盐岩风化成土。The laterite-forming capacity of carbonate rocks is an important problem in investigating development and evolution history of the karst morphology. This paper studies the carbonate rocks sections,their laterite formation by weathering, and distribution of underlain Permian-Triassic-Jurassic sediments in Jinyang District, Guiyang City, Guizhou Province. Combining with development features, thicknesses and lithologies of the strata, and the empirical values of laterite formation for carbonate rocks, the thickness of laterite in the research district is estimated. By comparison of the theoretical laterite thickness with the practical preserved laterite thickness, it is deduced that the present day preserved laterite layer is the weathering product of the third peneplanation stage since the Early Pleistocene. Its formation age is about 400-1300 ka. Our results show that the present day preserved laterite layer overlying carbonate rocks is not only weathering product of the carbonate rocks, but also of their clastic rocks interlayers which make considerable part of the laterite soil. Moreover, the Jurassic （containing no carbonates） clastic sediments were also important original rocks for laterite formation. Consequently, the sources of laterite formation in the study distrlct were multiple and complex, but not the carbonates solely.

关 键 词：风化成土 碳酸盐岩岩系 贵阳 

分 类 号：X141[环境科学与工程—环境科学]