湘西北地质地貌特征对岩溶石漠化影响研究——以张家界市为例

Influence of geological and geomorphologic features on karst rocky desertification in northwestern Hunan Province:A case study of Zhangjiajie City

通过对张家界市DEM、地质构造、岩性特征以及地貌数据进行地理信息技术(GIS)叠加分析,探讨了地质地貌因素对张家界地区岩溶石漠化分布的影响。结果表明:该区岩溶石漠化在地貌上的发生率呈现丘陵>洼地>低山>中山>高山的特征;在坡度上以Ⅱ级坡度中石漠化发生率最大,且石漠化面积呈阳坡>半阴坡>阴坡>半阳坡分布特征,并随坡向由阴转阳,各等级岩溶石漠化面积所占比例逐渐增加;地层岩性方面以碳酸盐岩与碎屑岩互层类岩层更易发生岩溶石漠化;地质构造方面表现为石漠化空间展布与断裂构造展布方向一致,且断层对石漠化的影响在Ⅰ_(B)断裂构造主要体现在对断裂两盘的岩性、地层的差异性和对水系发育展布的影响上。

This work made an overlay analysis using geographic information technology(GIS),DEM,geological structure,lithological characteristics and geomorphological data.The objective was to examine the influence of geological and geomorphological factors on the distribution of karst rocky desertification in the Zhangjiajie area,northwestern Hunan Province.The results show that the occurrence rate of karst rocky desertification in this area exhibits the characteristics of hilly>depressions>low mountains>middle mountains>high mountains.In terms of slope,the occurrence rate of rocky desertification is the highest among the grade Ⅱ slopes,and the rocky desertification area is sunny.The distribution is featured by slope>semi-shady slope>shady slope>semi-sun slope,and with the slope direction from cloudy to sunny,the proportion of karst rocky desertification area of various grades gradually increases.In terms of stratum lithology,carbonate and clastic interbedded rock formations are more prone to karst rocky desertification.In terms of geological structure,the spatial distribution of rocky desertification is in the same direction as the fault structures,and the influence of faults on rocky desertification is mainly reflected in the impact on the two walls in the IB fault.The differences in lithology and strata pose influence on the development and distribution of water systems.