贵州岩溶地区红土的地球化学特征及其意义

GEOCHEMICAL FEATURES AND EVOLUTION OF LATERITE IN KARST AREAS OF GUIZHOU

选择贵州岩溶地区具有典型亚热带岩溶地貌和生态环境特征、发育完整的白云岩和灰岩红土剖面，依据１２个剖面７２件样品的常量和微量元素化学分析资料，研究了岩溶地区红土的地球化学特征。提出了碳酸盐岩红土成土地球化学的三个主要过程：富硅铝脱钙镁过程、富铁锰过程和富铝脱硅过程。在碳酸盐红土的形成和演化过程中，Ｃｕ、Ｐｂ、Ｚｎ、Ｎｉ、Ｃｏ、Ｃｒ、Ｒｂ、Ｆ、Ｃｌ和Ａｓ等微量元素也发生了明显的富集和分异。

In this paper,seventy-two laterite samples are taken from twelve laterite sections evolved completely from dolostones and limestones in the karst areas of Guizhou,which typify subtropical karst geomorphological and ecological environmental features.The major,and trace data for the samples show the geochemical characteristics and evolutionary rule of laterite formation.There have been involved three pedogenetic geochemical processes:(1) enrichment of silicon and aluminum and depletion of calcium and magnesium;(2) enrichment of iron and manganese;and (3) enrichment of aluminum and depletion of silicon.During the formation and evolution of laterite,obvious enrichment and differentiation of trace elements such as Cu,Pb,Zn,Ni,Co,Cr,Rb,F,Cl,and As can be obrved.