Study On Mineralogy And The Migration Of Elements In Skarn Of Katebaasu Au-Cu Deposit

Katebaasu is a super large gold and copper deposit,founded in "Asian Gold Belt" in resent years. The unique geographical environment and good prospecting potential have made it a hot topic of geological scholars.This paper is based on field geological survey and predecessors’ work,through the deposit geological characteristics, ore body and wall rock alteration characteristics and the characteristics of the ore,focus on skarn mineral as the research object,by using electron probe and geochemical analysis to study the mineralogical characteristics. Combined with the knowledge of Genetic mineralogy,we study the relationship between different alteration types and mineralization,analysis skarn element migration patterns and summarize the typomorphic mineral combination of different wall rock alteration types.The author analysis the change of the physical and chemical conditions influence on the gold the concentration mechanism,in order to provide theoretical guidance for further prospecting in mining area.At last,we obtained main understandings as below:1.Skarn is given priority to Calcium skarn,has the feature of double metasomatism skarn. in this area.Skarn minerals are mainly garnet, pyroxene, tremolite, actinolite, epidote, etc.From the contact zone of monzonitic granite and marble center to both sides,we can see garnet skarn,diopside skarn,tremolite and actinolite skarn,epidote skarn,etc,in turn.Skarn mineral electron probe analysis results show that garnet minerals are mainly Grossular;pyroxene minerals are mainly Diopside.2.The paper, based on the geochemical analysis,discusses the migration of elements in the skarn formation process,and shows that in the metasomatism process of forming the skarn,main elements,trace elements and REE elements happened different level bring in and bring out.Al,Si,Fe element and LREE in monzonitic granite migrate in marble;Ca,Mg element, Ni、Zn、Co、V、Cr chalcophile,siderophile element and HREE in the marble migrate in monzonitic granite.With silicon card lithification degree enhancement,Rb, Sr, Ba, K and other large ion lithophile losses increased3.The paper through to studing the change of physical and chemical conditions in the process of mineralization,find that gold element mainly exists in the form of the HS- complex base class in fluid,precipitation in the lithology unconformity interface related to a large number of K-feldspar crystal,PH falling fast;precipitation in the calcium silicon lithologic interface maybe related to high temperature and alkaline environment translate to middle and high temperature,alkaline environment.