| Geotectonic structure of the super large lead-zinc deposit lies in the northeastern part of Qinghai-Tibet Plateau and is located in the north part of the "Three-river" metallogenic belt.At present,ore reserves have exceeded 6 million tons.Significant breakthroughs have been made in prospecting.At the same time,the mineral deposit has been studied in detail,including the characteristics of ore-forming fluids,isotopic signature,genesis of the deposit,metallogenic model and so on.However,with the further development of prospecting work,support from other work is needed,especially the practical application of magnetism and electricity.The further study of the magnetism and electricity in this area is particularly important for the next step of deciding the target section.In this paper,the magnetic properties of specimen of rock or ore in the study area have been counted,and the magnetic strength of different types of rocks and ores has been obtained.Based on the 1:10,000 high-precision magnetic survey data of the surface in the Duocaima mining area of Tuotuo River,through various corrections and calculation of magnetic anomalies,theoriginal anomaly map was finally generated,three magnetic anomaly areas were obtained,nine fractures were conjectured,the genetic type of mineral deposit was determined,we also took the metallogenic prospect analysis meanwhile.We have made magnetic properties statistics for 422 rocks and ores in the study area,of which the main sample are breccia,crystallized limestone,galena cataclastic limestone,micritic limestone and syenite-porphyry.According to statistics,crystallized limestone and galena cataclastic limestone micritic limestone have the weak magnetism,the magnetism of rhyolite and micritic limestone is medium in this study area.The strongest magnetism is breccia and syenite porphyry.At the same time,the range of variation is the largest,which is related to the ferromagnetic minerals in rocks.According to the research area 1:10000 high precision magnetic ?T section plan,the?T number of TuotuoRiver area ranges from-30 nT to 200 nT.From north to South and from west to east,three anomalies can be distinguished as C1 and C2,C3 respectively.The anomaly is relatively regular in form,like a striped or planar waterfall.The overall trend is EW direction,The northern side is mostly positive anomalies,whereas on the contrary,the South has more negative anomalies,it is a reflection of the size of the deep magnetic body in the study area is larger.We can speculate and divide the fractures into 9 parts in total by the comprehensive reasoning explanation of the contour map of the magnetic ?T anomaly contour section.The orebody occurrence of Ducaima mining area is controlled by East-West tensional fracture,north-east compressive fracture and South-North secondary fracture.Ore minerals are mainly composed of galena and sphalerite and low temperature mineral assemblage.The ore-forming material has the characteristics of mixed source,partly from stratum and partly from magmatism.The ore-forming fluid should be derived from magmatic fluid,and there is a strong water rock reaction with the surrounding rock during the rising process.Genetic type epithermal vein type deposits.Based on the research results of Geology and high-precision magnetic survey,the prospecting criteria of strata,magmatic rocks and structures in Tuotuohe area and Duocaima mining area are finally given,and three prospecting areas are preliminarily divided.Combining geological features with high-precision magnetic methods in prospecting work in the study area is for metallogenic prognosis. |
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