Study On Mineralization Regularities Of The Dulong Sn Polymetallic Deposit In Southeastern Yunnan

The Dulong Sn polymetallic deposit is located in the southeastern part of Yunnan Province.The deposits of Sn,Zn and Pb lead in the deposits have reached a very large scale,and the associated raremetal element indium has also reached a very large scale.The geotectonic location of themining area belongs to the junction of the Yangtze plate,the Huaxia plate and the Indosin plate,and is the third largest tin polymetallic deposit in China.In recent years,a large number of research work has been carried out on the aspects ofmineralization chronology,metallogenicmaterial sources and ore-forming fluid evolution,and fruitful research results have been obtained.However,the genesis of the deposits has not yet formed a unified understanding.Guided by the basic theories of geochemistry and the principles of statistics,this paper explores themassivemulti-element analysis data formed during the exploration and development ofmineral deposits.By analyzing themain elements of granite,skarn and ore,the genetic types of ore-related rocks are discussed.Themulti-element symbiotic combination law and spatial enrichment law of the deposit are analyzed,which will have certain guiding significance for the analysis of the genesis of the deposit and the comprehensive development of useful components.Combining the research results of the predecessors,the followingmain points have been made:?1?The Dulongmining area is characterized by complex ore-forming geological conditions.The Yanshanian granite is closely related to the spatial location of the ore body.The skarn is themain ore-bearing surrounding rock.?2?The composition analysis of themain elements of the Yanshanian granite in themining area shows that the granite in themining area belongs to the high-calcium-calcium-alkaline series of S-type granites.The recovery of the original rock according to the composition of themain elements of the skarn of the ore deposit shows that the original rock of the skarn in the Dulongmining area is dominated by normalmarine sediments,and a small amount of terrestrial ormarine volcanic sediments are doped.?3?Cluster analysis ofmajor and trace elements shows that Ag-Cu-As is a kind ofmedium-low temperaturemetallogenic combination;Zn-Cd-S-In-Sn is a kind ofmedium-high temperature The combination of cassite polymetallic sulphide elements;the poormetals Ge and Ga have poor correlation with other elements,and the two elements have different geochemical evolution pathways with other elements.?4?The element zoning sequence from north to south as Ga>Ge>Ag>As>Cu>Zn>Sn>In>Cd>S,Ga is enrichment in the northernmost part of the deposit near the Laojunshan granite body.Low-Medium temperature elements as Ge>Ag>As>Cu are enrichment in the Northern part of the deposit.Intermediate-high temperature cassiterite polymetallic sulfide ore related elements as Zn>Sn>In>Cd>S are enrichment in the middle-south part of the deposit.It is presumed that the granite porphyry located in the middle-south part of the mining area is the key factor to cause this element zoning.?5?The element zoning sequence from top to bottom as Zn>Cd>Ag>In>S>Cu>Ge>Sn>Ga>As.Medium temperature element Zn is enriched in the upper part of the deposit.High temperature element Sn is enriched in the lower part of the deposit.Medium-low temperature elements as Cu and Ag are interpenetrated,and low temperature element.As is enriched in the lowest part.It is presumed that the mineralization of the ore area has multi-stage characteristics.?6?The results of factor analysis show that the F₁ factor high load elements are Ag,As and Cu,which are the combination of medium-low temperature frontal halo elements,the F₂ factor high load elements are Zn,Cd and S,which are the combination of upper temperature and upper halo elements,F₃ factor high load element is Sn,Ga and In,which is a combination of high temperature ore halo element,F₄ is composed of element Ge alone,Cd,Ga and In also have a certain load,F4 is a combination of rare metal elements.?7?According to the scoring results of strike factors of ore bodies,it is speculated that the key factor determining the zoning of metallogenic elements in Dulong mining area may be the late granite porphyry veins emplaced in the middle part of the mining area;the ore body vertical factor score results show that F₁ has multiple high values,indicating the superposition of multi-stage mineralization.In the space,the rare metals have the characteristics of coprecipitation and enrichment with the main metal elements Zn and Sn,which is very beneficial for the comprehensive recycling of rare metals.