用GIS方法研究我国南方花岗岩地区新构造——以广东花县芙蓉嶂地区为例

本文基于构造地貌地理信息系统(GIS)分析的基本原理,以广东花县芙蓉嶂地区新构造研究为例,探讨将GIS方法与遥感及传统地质方法相结合,综合研究我国南方花岗岩地区新构造的新途径,阐述机助宏观定量地貌分析对基岩山区,特别是岩性较单一的花岗岩地区新构造研究的作用和意义。

USING GIS ANALYSIS METHODS TO STUDY NEOTECTONICS IN THE GRANITIC AREA-A CASE STUDY IN FURONGZHANG AREA, HUAXIAN, GUANGDONG, CHINA

Based on the basic principles of morphotectonics and using the geographical information system (GIS), the morphotectonic information system is a specialized sub-system of GIS, which has provided a useful means for the three-dimensional quantitative geomorphological analysis and the study on neotectonics. The system uses topographic maps and geologic maps as its hasic input data source and is capable of quick processing, comprehensive analysis of these data and generation of maps and plots from them. The present study has applied the above system to the study of neotectonics of Furongzhang area, Huaxian County, Guangdong Province, China. The software used is SPACEMAN (a micro-GIS tools). The input data include topographic and geologic maps of this area both having the scale of 1:10 000. After processing, 4 types of maps were obtained including: 1) graded elevation; 2) slope; 3) slope aspect and simulated landscape image; and 4) threedimensional display of landforms and geological maps. An example is a neotectonic fracture zone in the study area. It was recognized not by the field geological mapping for quite a few times, but from the interpreted statellite images. GIS analysis provided essential new evidences on the geometry and dynamics of it. A typical "split mountain range" was identified on the graded elevation map, indicating that the fracture is a neotectonic fracture, from which we could measure the amount of horizontal and vertical neotectonic movement; the dip of the fracture surface was derived from the map of graded slope. By incorporating this information with that by other methods, we have found that this fracture is a compressive-shear neotectonic one, the displacement between the two blocks is greaterthan 400 m. The study shows that this method of quantitative geomorphological analysis enhances and incorporates such information like the topography and geology on the three-dimensional basis and thus makes it more tangible, more direct and easily recognized, therefore, it is a useful new approach of neotectonic studies in the granitic areas.