碳酸盐岩岩层与石漠化关系分析——以桂西北喀斯特石山区为例

On relations between carbonate rock formation and rocky desertification——A case study of Western-Guangxi karst area

以桂西北碳酸盐岩石山区为例,采用野外地质特征调查和岩石化学分析等技术手段,从碳酸盐岩岩层的厚度、倾角和岩性等方面来分析喀斯特地区石漠化的成因,并结合反映石漠化程度的土壤和植被的盖度等相关数据,对岩层与喀斯特地区石漠化程度进行相关分析,得出喀斯特地区石漠化与碳酸盐岩岩层的厚度、倾角和岩性等具有相关关系的结论,即岩层厚度大的地区石漠化程度更高,岩层厚度小的地区石漠化程度较低;中等岩层倾角岩层分布区有利于雨水的流动和成土,石漠化程度较低;岩石性质的差异对石漠化程度也有相关性,石灰岩类的酸不溶物含量较低,对成土不利,其植被的盖度相对也较低,相应的石漠化程度更高。相反,白云岩类岩层区的石漠化程度较低。

Taking Western-Guangxi karst area as an example, on the basis of field survey in geology and analysis of chemical composition of carbonate rocks, origins of rocky desertification in the karst formation area are discussed from aspects including thickness, obliquity and lithology of carbonate rock formations. Relations between carbonate rock formation and extent of rocky desertification are discussed considering the overlay rate of soil and plant, which would reflect the extent of rocky desertification in the karst formation area. It is concluded that carbonate rock formations with different thickness, obliquity and nature are correlated with the extent of rocky desertification. That is, the thicker the thickness of carbonate formation is, the stronger the extent of rocky desertification is. The distribution of carbonate rock formations with middle obliquity is an area with weak extent rocky desertification,owhere it is favorable for water flowing and soil formation. Lower content of acid indiscerptible matter is disadvantageous for soil formation in the limestone formation area, where there is lower overlay rate of plant and more extent of rocky desertification as well. Contrarily, dolomite formation area correspondingly shows less extent of rocky desertification.