贵阳地区碳酸盐岩岩系成土方式及其特征

碳酸盐岩上覆红土的成因主要有溶蚀-残积说、溶蚀-交代说和外来沉积说。通过对贵阳地区碳酸盐岩岩系上覆红土剖面的调查研究,发现碳酸盐岩岩系成土作用有岩性变化的层间界面上成土、岩-土界面上成土、岩层整体块状层内风化成土等方式。其中岩-土界面成土方式是最常见的一种,而岩层整体块状层内风化成土也有一定比例,岩性变化的层间界面上成土方式相对较少。三种成土类型说明碳酸盐岩岩系成土是复杂的,是多层面、多方式的,并非是单一的成因形成,碳酸盐岩岩系成土速率应比原来认为的高。

PEDOGENIC MECHANISM OF CARBONATE LATERITE AND ITS CHARACTERISTICS IN GUIYANG, GUIZHOU PROVINCE, CHINA

The hypotheses of dissolution-residuum,dissolution-metasomatism and exogeneous sedimentation were considered as the forming mechanisms of laterite overlying carbonate rocks.On the basis of research and investigation of laterite sections overlying carbonate rocks in the Guiyang area,the authors suggested that the laterite patterns of carbonate rocks can be divided into three types,i.e.,the forming laterite pattern on rock-laterite surface,the forming laterite pattern at intervals(including carbonate-bearing mud,mudstone) in carbonates(dolestone and milestone),and the forming laterite pattern of rock body(including carbonate,carbonate-bearing mud,mudstone interval in carbonate) weathering synchronously.The forming laterite pattern on rock-laterite surface is distributed extensively;the forming laterite pattern at intervals of carbonates and the forming laterite pattern of rock body weathering are commonly seen in the Guiyang area.The three forming laterite patterns show that the laterite of carbonate is complete,and the laterite process is of mutli-surface,multi-pattern in the carbonate,other than the forming laterite pattern on rock-laterite surface only.Finally,the authors considered that the forming rate of carbonate laterite is much higher than that considered in previous research.