Mineralization Evaluation And Geostatistical Analysis Of Granite Body In The Luanchuan Ore District

The Luanchuan ore district is located in the middle of the eastern Qinling molybdenum metallogenic belt.Various magmatic rocks are developed in this area because of many stages of magmatism.The most frequent magmatism period is Yanshanian,which forming many granite bodies.Based on the Luanchuan fault,this ore district is divided into two parts.One is the north part,where there are many small ore-forming granite bodies,the other is the Laojunshan granite base,located in the south of this area with sporadic mineralization.These various granite bodies have obvious differences.Through geostatistical analysis,we can get the quantification and visualization of these differences,which has great significance for the development of the deep prospecting work.Based on previous studies,we carried out some experiments in the Luanchuan ore district,including the whole rock geochemical test and biomimetic analysis.Through these experiments we can comprehensively evaluate mineralization differences of various granite bodies and explore the relationship between magma evolution and mineralization.Combined with the chronological data,the erosion rates of granite bodies in this area was calculated.By Selecting appropriate interpolation methods,we realized the geostatistical analysis of various data and achieved the quantification and visualization of the differences among these granite bodies.What we have got are as follows:(1)The granite bodies in the Luanchuan ore district are all characterized by high silicon,alkali and potassium,and they all belong to the series of potassium basalt and high calcium alkaline granite.Mixed crust and mantle is the major source of magma,and the ore-bearing hydrothermal fluid shows extremely strong oxidizing properties which has favorable conditions for forming molybdenum polymetallic deposits.(2)The reasons for the differences in ore-bearing properties of granite bodies are as follows.Mineralization is subject to the rock genesis,material sources and tectonic environment.The ore-forming scale is affected by the oxidation or reduction state of the ore-bearing hydrothermal fluid and the temperature and pressure conditions of thearea,what's more,when the deposit is formed,it is restricted by the structural uplift and erosion of the area.The minerals types involved by deposits are related to the surrounding rocks.(3)The Laojunshan granite body was formed in 120-110 Ma,during which time the granite body was in a stretched environment.The ore-bearing granite bodies in the north of this area were formed in 160-130 Ma,and it reached peak during 150-145 Ma.This period belonged to the late stage of continental collision,and the tectonic regime was transforming into the intraplate environment.(4)The southwest area is higher than the northeast area in the Luanchuan ore district.Combined with the emplacement depth and chronological data,we calculated out the average erosion rate of this area,which is 0.0172mm/a.The Laojunshan granite body in the southwest showed a higher erosion rate than the granite bodies in the north of the Luanchuan fault,which is consistent with the conclusion that the erosion rate is positively correlated with the regional height.(5)The Huangbeiling granite body is located at the intersection of multiple faults and the Huangbeiling-Shibaogou.In addition,the temperature and heat production rate are higher than other granite bodies.Therefore,we speculated that the location of the Huangbeiling granite body is the center of heat source.Located in the north wing of the anticline,the Nannihu and Shangfang granite body have great metallogenic conditions.