Geological Characteristics And Prospecting Direction Of Xiji Cobalt Polymetallic Ore In Xihe CountyGansu Province

As a rare and precious metal,cobalt is one of my country's important strategic minerals.The West Qinling area is an area where cobalt deposits are concentrated in my country.Cobalt is mainly used as an associated mineral,producing copper polymetallic deposits.In the process of mineral exploration in recent years,cobalt deposits with industrial value such as Xiji and Zhangping have been discovered,indicating that the study area has cobalt prospecting potential.The author took part in the research of "Comprehensive Information Prediction of Cobalt and Gold in Gansu West Qinling and Structural Analysis of Daqiao Gold-Antimony Ore Field" and "Summarization of Cobalt Mineralization Laws and Research on Typical Deposits",focusing on Xiji cobalt polymetallic ore,and summarized the results.The geological characteristics of the ore,the geological conditions of the mineralization and the signs of prospecting,the development of regional and mining area cobalt polymetallic prospecting prediction research,in order to improve the research area cobalt polymetallic mineralization theoretical research level and guide prospecting prospecting.The thesis research has made the following progress and results:Cobalt ore bodies are exposed in the second lithologic section of the Huangjiagou Formation in the West Hanshui Group of the Devonian.The light gray argillaceous slate is interbedded with layered silty limestone,dark gray thick charcoal-bearing limestone,and thick gray.Layers of fine-grained limestone;NE-trending faults are the main ore-conducting and ore-hosting structures,and the ore bodies and faults are distributed in almost the same direction;rock types can be divided into tectonic altered rock type cobalt ore and quartz vein type cobalt ore Metallic minerals mainly include pyrite,arsenopyrite and cobaltite.The ore structure mainly includes euhedral-semi-automatic granular structure,its granular structure,metasomatic residual structure and zonal structure.The ore structure mainly has dense disseminated structure.,Veins-disseminated structure;wall rock alteration mainly includes silicification,carbonation,hematite mineralization,yellow(limonite)iron mineralization,and malachite;the formation of Xiji cobalt polymetallic deposit can be divided into three phases,Respectively,are the sedimentary period,the hydrothermal transformation and the ore-forming period,and the supergene period.In-situ micro-area trace element analysis results show that the Co/Ni value of Py1 pyrite is far less than 1,which indicates that this type of pyrite is of sedimentary origin;the Co/Ni value of Py2 pyrite is between 0.93 and 2.2,indicating that Py2 Pyrite was formed during the depositional period of pyrite undergoing later hydrothermal transformation;the discrete ?34S value indicates that there are both magmatic sulfur and marine surrounding rock formation sulfur in the ore;the C-O isotope values of carbonate rock minerals in different stages and forms are at Between granite and marine carbonate rocks,it shows that carbonate minerals have experienced carbonate dissolution.Therefore,this article believes that the Xiji cobalt polymetallic deposit is a sedimentary-hydrothermal superimposed reformed deposit.The source layer formed by sedimentation is mainly derived from the marine sulfate in the surrounding rock formation.With the violent magma intrusion in the West Qinling,During the tectonic deformation activity,deep-source magma entrapped a large number of ore-forming elements and contacted with the active carbonate rock,resulting in karstification and metasomatism.Later,as the physical and chemical conditions of the system changed,the ore-forming materials were precipitated and enriched into ore deposits.Through the analysis of regional geology,geochemistry and geophysical characteristics,it is concluded that the abnormal Co element and the abnormal combination of ore-forming element factors are the direct geochemical indicators of cobalt prospecting.All ore deposits in the aeromagnetic interpretation area are distributed inside or on the edge of the ore-forming geological body(ring structure),and the output location is controlled by the change of the morphological occurrence of the ore-forming geological body;the gravity anomaly interprets the change in the occurrence of the ring structure Locations and intersections of linear structures can be used as important prospecting markers for cobalt,gold,copper,and lead-zinc deposits;remote sensing interpretation of linear structure development locations and remote sensing interpretation of alteration anomalies are important Based on the above-mentioned work,a prospecting model was established and comprehensive information prospecting prediction was carried out,and four mineralization prediction areas were delineated.The study on the distribution characteristics of the mineralization elements in the mining area shows that the high value areas of Co,Cd,Ag,As,Cu,Ni,Pb,Sb,and Zn are large in scale and have good prospecting potential;factor analysis shows that the mineralization elements It is classified into six element combinations of Cd Zn Pb-Hg,Co Cu Ni-As Sb,Au As Sb Mn-Co Hg,Ag Sn Hg-Sb,WBi Cr-Ni Ba Sn,and Mo,showing the characteristics of multi-stage mineralization.Among them,it is known that the ore bodies are present in the combined abnormalities of Ht-1 and Ht-5.The interpretation results of gravity anomalies in the Ht-3 and Ht-4 combined anomaly regions are good,and the prospecting potential is huge.According to the geological characteristics of the mining area,the symbiotic combination of ore-forming elements,the anomalous characteristics of ore-forming elements,and the geophysical characteristics,5 target areas are delineated.