Characteristics Of Ore Controlling Structures And Prospecting Direction Of Gold Deposits In Pangjiahe-Matigou Area, Northern Fengxian County, Qinling Mountains

The gold deposits in the Pang Jiahe-Matigou area in the northern part of Fengxian are located at the core of the Qinling Mountains orogenic belt,which are located in the Shang Dan Jia-Li zone between the North China and Southern China plates,and in the Tang-Tibet-Shang Dan structural mixed zone.The Pangjiahe gold deposit has entered the deep blind area and peripheral prospecting stage,and the Matiogu gold deposit has entered the stage of detailed investigation.Based on the detailed investigation of the deep and peripheral prospecting of the Pangjiahe and the Matigou gold deposit,the prospecting direction is put forward.Through the investigation and study of field geological route,measured section,mine cavern and core,indoor test and comprehensive study,the geological features of the gold deposit in the Matigou and Pangjiahe in the northern part of Fengxian are studied in detail from the geological structure of the mine area and the related petrology and mineralogy of the deposit,exploring the characteristics of ore control structure,combined with the research data obtained in the study area and the special study on the ore control structure,the comprehensive study is carried out to summarize the characteristics of the ore control structure,the characteristics of the deposit,the metallogenic model and the prospecting direction.Through comprehensive studies,we have gained the following achievements:1.The ore bearing strata of the Matigou gold deposit are in the early Paleozoic Luohansi group?Pz₁L?.The ore bearing strata of the Pangjiahe gold deposit are the Devonian Shu Jiaba group?Dsh?.Although the two era is not consistent,the ore bearing lithology is mainly altered mylonite and altered mylonite,the main body color is gray green,and the ore structure and structure are similar,and the types of alteration are consistent.The two are preliminarily classified as the same metallogenic type.2.With the development of mylonitization,a large number of syndiagonal closed folds are characterized by a thousand rubbing and wrinkle deformation,and two strips of brittle ductile shear zone?RF1,RF2?,similar to the deformation characteristics of F9,have been made in the Matigou gold mining area,which basically control the plane distribution direction of the Matigou gold mine.The overall distribution direction is NWW direction and the attitude is unknown.The main lithology in the shear zone is the C section of the early Paleozoic Luohansi rock group.There are strong deformation structures,mylonitization,knee fracture,rotating spot,and interlayer wrinkling.3 It is generally believed that the gold bearing shear zones can be divided into three stages?according to Wu Meide et al.,1989?.The shear zones in the mining area are mainly in the Indosinian-varisi stage-the near EW toward the Luohansi-Wayaoshang?F9?brittle ductile shear zone and its derived brittle ductile shear zone.In the mineralized zone,The rocks in the mineralized zone are altered and mylonitization in varying degrees,and the mylonite is the second stage of the gold bearing shear zone.Gold bearing quartz veins were found at TC47-1 and BT24-3 of the Matigou gold deposit,which appeared to be brittle and superimposed at the later stage.All kinds of tensional fractures are formed in the tectonic strip along the near EW to brittle ductile shear movement.The metallogenic hydrothermal fluid moves along this kind of fissure to precipitate and deposit,which makes the occurrence of the ore body coincide with the formation of the formation.The Pangjiahe-Matigou gold deposit is a hydrothermal gold deposit in the superposition of brittle ductile shear zone.4.On the basis of comprehensive analysis of ore control factors,the ore prospecting model of the gold area of Pangjiahe and Matigou area is established,and the target area of the prediction and prospecting in the mining area can be basically defined as the brittle ductile shear zone which is exposed along the mining area and the alteration and development area closely related to the gold mineralization.According to the distribution law of ore body,the brittle ductile shear zone and fracture development degree,rock fragmentation strength,rock deformation strength,alteration development strength and alteration superposition,etc.,are determined in the deep and outer circle of the mining area.