Research On Formation Mechanism And Vulnerability Of Granite Geoheritage In The Area Of Huashan Mountains

The doctoral dissertation is supported by the Geological Survey Project ?Research on Classification and formation of Granite Geoheritages in Shaanxi province?. The author mainly focused on the granite geoheritages in the area of Huashan Mountains, and systematically investigated its distributions and types. Moreover, the formation mechanism, evolution process and genetic classification have been discussed in detail on the basis of field investigations. Finally, by means of field works and indoor study, the classification and assessment for vulnerability of granite geoheritages have been fulfilled according to three different assessment index systems. This dissertation achieves the following innovative results:(1) On the basis of previous study of regional geological surveys in the area of Huashan Mountain, the mapping of geological-tectonic sketch was finished. The new geological-tectonic map divided the Huashan Mountain scenery into three structural regions of Taihua Group, Archaean TTG gneisses and Yanshanian granites. The mapping method is very significant not only for identifying granite structural types but also for promoting the research level of basic geology in the study area.(2) Base on field investigations, the spatial distribution pattern of the geoheritages in Huashan Mountains has been identified. Moreover, the geological characters for those geoheritages have been disclosed. Furthermore, the author also has proposed classifying the granite geoheritage into four levels and types which includes mountain scenery, peak scenery, valley scenery and individual geoheritage. According to the four levels and types, a series of sub-types have been classified. The development characteristics and distribution regularities for the Huashan granite geoheritages also have been analyzed, and the viewpoints of four levels for granite geoheritage have been first proposed.(3) The granite geoheritages have been first proposed the new ideas of four-level dynamical drive, which can be described as the Huashan mountain-pregnant stage of magmatic dynamic, the geoheritage-creative stage of structural dynamic, the geoheritage-carved stage of geologic forces, and geoheritage-polished stage of human activity. In fact, the granite geoheritages are the results of the endogenic and exogenic geological processes. The processes can be depicted as four-stage evolution process of a) magmatic intrusion, b) tectonic uplift, c) weathering & erosion, and d) human modification. Furthermore, the genetic classification of granite geoheritage in the Huashan Mountains area has been obtained.(4) According to the granite geoheritage environment, development characteristics, genetic mechanism and evolution process, the different modes of vulnerability of granite geoheritage have been clarified. By means of three different index systems, the assessment for vulnerability of granite geoheritage has been fulfilled, and the main results will provide an example for future study of granite vulnerability of granite geoheritage in future.