Geomorphic Division And Zoning Comparative Study In The Central And Western Qinling Mountains

As an important geographical indication of the boundary between the north and the south,the Qinling-Huaihe line is of great significance to the division and understanding of the national landmark pattern.The Qinling Daba Mountain area,as a complete geomorphic unit and the main body of the north-south transition zone in China,has multi-dimensional zonal changes and contains extremely rich geomorphological information.In the entire Qinling region,the central and western regions are important areas for the transition from the Qinghai-Tibet Plateau to the Qinling Mountains.The geomorphological zoning of the central and western Qinling Mountains can provide a scientific basis for localization of poverty alleviation,disaster prevention and mitigation,and the development of tourism in the region.It can also deepen the geomorphology of the Daba Mountain area in the Qinling Mountains through in-depth research on the landform patterns and landform differences in the central and western Qinling Mountains Recognize the level and realize the scientific landform zoning to provide detailed information and reference significance.By consulting the relevant geological and geomorphological data and cartographic specifications of the central and western Qinling Mountains,combining the digital elevation model and remote sensing satellite imagery,and adopting a top-down zoning method,combined with GIS and spatial analysis technology,a preliminary geomorphic zoning scheme for the central and western Qinling mountains was constructed.The main conclusions are as follows:(1)After a comprehensive review of previous geomorphological zoning theories,a geomorphological zoning scheme system for the mid-western Qinling Mountains was constructed,and a four-level geomorphic zoning plan for the mid-western Qinling Mountains was initially completed.The principles of geomorphological zoning in the central and western Qinling Mountains were proposed,and the techniques and methods for geomorphological zoning and geomorphological classification of multi-source data in the central and western Qinling Mountains were established.A "three-level and sixthlevel" geomorphological classification system for the central and western Qinling mountains was formed.The four-level geomorphological zoning scheme and zoning system and naming rules and coding methods of the four major geomorphic zoning schemes and zoning systems of geomorphic regions-geomorphic regions-geomorphic regions-geomorphic subregions-geomorphic plots have established the "major areamacromorphic type combination area under the control of geomorphic structureinternal and external business Conditional sub-area-a sub-area of the microgeomorphological morphogenetic type combination zone "four-level zone index system.Considering regional differences,two landform zoning schemes have been formed.Option 1(Difference between East and West)Divides the central and western Qinling Mountains into large and medium undulating mid-alpine landforms in the western part of the Western Qinling(?),medium and small undulating mid-mountain landforms in the eastern part of the Western Qinling(?),and large-and-medium undulating areas in the western part of the Central Qinling There are 3 first-level areas,18 second-level landform areas,58 third-level landform sub-areas,and 252 fourth-level landform communities in the low mountain basin area(?).Option 2(difference between north and south)divides the central and western Qinling Mountains into a combined landform area in the middle-alpine plains of the northern Qinling Mountains(?),a combined landform area in the middle-alpine hills in the middle Qinling Mountains(?),and a combined mountain-hill area in the western parts of the South Qinling Mountains(?)3 first-level areas,25 second-level landform areas,70 third-level landform sub-areas,and 298 fourth-level landform communities.(2)Based on the geomorphological zoning results of the two schemes in the central and western regions of the Qinling Mountains,a comparison was made from four aspects:zoning method,number and scale of zoning,zoning boundaries,and zonal landform combination differences.In the first-level zoning,Option 1 mainly considers the complete river basin and basin,and uses relatively independent watersheds as the first-level zoning boundary,while Option 2 considers the integrity of the Qinba mountain area,and uses the Qinling tectonic unit boundary as the first-level zone.Boundary.The two,three,and four-level zoning schemes and zoning boundary determination methods of the two landform zoning schemes are consistent in their overall performance.The topographical characteristic abrupt lines and geological structural fault zones are used as zone boundaries.The number and scale of the secondand third-level divisions are different due to the different methods of the first-level zoning and the boundaries of the zoning.Both the number of landform divisions and the area of landform subdivisions based on the two schemes show sparse and uneven phenomena,and show the flexibility of landform classification and landform division.At the same time,the analysis of the correlation coefficient and dispersion coefficient based on landform zoning shows that the landform type combination and landform zoning of scheme 2 are better than scheme 1,and with the increase of the number of classification levels and the number of landform type combinations,the landform type combination and division The difference also increased.(3)Through fractal verification and 3D terrain scene simulation verification,combined with field investigations to verify the basic geomorphological morphological types of the central and western Qinling Mountains,the verification results obtained good results.Fractal verification uses the hydrological analysis method to obtain the fractal dimension values of the five watershed sample areas are 1.8392,1.7872,1.8039,1.7908,and 1.7857,respectively.It is concluded that the surface complexity of watershed 1 is high,and watershed 5 is the smallest.The fractal dimension value is consistent with the actual basic landform type description.The three-dimensional terrain scene model at the regional space level verified the selection of the Chenghui Basin and two types of basic landforms for comparison and observation.It was found that it conforms to the classification results and actual cognition,and it can intuitively and clearly observe the actual landforms.The thesis first constructs a hierarchical system of geomorphological zoning and a classification index system for the classification of geomorphological types in the central and western Qinling Mountains,and forms a multi-source geomorphic regionalization database for the central and western Qinling mountains.At the same time,the fractal dimension,three-dimensional terrain scene simulation combined with field surveys were used to verify the basic landform shapes in the central and western Qinling Mountains,which can provide ideas for future work.The research results provide a reference for scientific geomorphological zoning of the central and western Qinling and the entire north-south transition zone,and provide a comprehensive and indepth understanding of the geomorphological type characteristics,combinations and regional differences in their evolutionary trends in the Qinling region.The law of spatial combination,the formation and evolution mechanism of geomorphology,geomorphology and other geological elements such as hydrology and climate provide basic data,and provide necessary geomorphological information for the rational development and utilization of the local conditions in the Qinling region.