| The Xiong'ershan ore concentration area is an important gold-polymetallic metallogenic area in the East Qinling fold belt,producing large deposits such as Shanggong and Qiyugou.Over the years,previous researchers have carried out plenty of geological investigations and received great achievement in Xiong'ershan ore concentration area.However,the research focusing on ore-controlling characteristics of various types of ore deposits in the region is still relatively insufficient.Based on the summary of available previous research results,this study carries out field investigation and analyzes the ore-controlling structure patterns of the representative ore deposits,in comparison with the different fault controlling characteristics of various ore deposits,then discusses the metallogenic depth of ore-controlling fault,and the results reach the following achievements:(1)The regional stratum is dominated by the Neoarchean Taihua Group,the Mesoproterozoic Xiong'er Group and the Guandaokou Group.The Cenozoic stratum is exposed in the Songxian Basin;fault is developed and has a strong control over the distribution of the ore deposits;Mesozoic magmatic rocks are exposed in the northern and southern parts of the Xiong'ershan area.(2)According to different metallogenic mechanism,the various gold-polymetallic ore deposits can be divided into four types: altered rock type,quartz vein type,explosive breccia type and porphyry type.According to the type of mineralization and the geological characteristics of the deposit,the main ore-controlling structural patterns can be summarized as follows: fault controlled,breccia pipe controlled and intrusive contact zone controlled.(3)Different types of ore-controlling structure patterns are developed in different types of ore deposits: fault is the main ore-controlling structure pattern of altered rock type and quartz vein type deposits,the breccia pipe is the main ore-controlling structure pattern of explosive breccia type deposit,the intrusive contact zone is the main orecontrolling structure pattern of porphyry type deposit.(4)Using the microstructural estimation method,the tectonic additional hydrostatic pressures of four fault-controlled ore deposits(Hongzhuang,Yuanling,Qianhe and Shanggong)are estimated as 41.421 MPa,27.229 MPa,38.537 MPa and 76.935 MPa,respectively.In combination with available fluid inclusion data,the metallogenic depth is measured as 1.3-2.6km,1.5-2.2km,2.1-3.5km and 10.4-11.8km,respectively.(5)The results of metallogenic depth of ore-controlling fault show that the metallogenic depths of Yanshan period Hongzhuang altered rock type gold deposit,Yuanling quartz vein type gold deposit and the Qianhe altered rock type gold deposit are far lower than the Shanggong altered rock type gold deposit,which may be related to the Indosinian-Yanshanian multi period mineralization of Shanggong deposit,the measured metallogenic depth is a manifestation of the Indosinian mineralization in the early stage. |
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