Geochemical Characteristics Of Sphalerite A Nd Its Genetic Indication In Jian Zhu Po Lead-Zinc-Antimony Polymetallic Deposit In North W Estern Guangxi

The Jianzhupo lead-zinc-antimony polymetallic deposit is the largest and most representative large-scale deposit in the Wuwei ore field in the southern section of the Danchi metallogenic belt in northwest Guangxi.It is composed of a series of NNW parallel vein-like orebodies and newly discovered layered orebodies in recent years,but little research work has been carried out on layered ore bodies,and there are differences in the understanding of its metallogenic characteristics.Based on the detailed field geological survey,this paper carried out the mineralogy of sphalerite and the comparison of trace elements,rare earth elements and H-O isotopes in different orebodies,and further discussed the metallogenic characteristics and metallogenic materials of the Jianzhupo deposit.and the source of ore-forming fluids and the genesis of ore deposits,the following main achievements and understandings have been obtained:（1）The mineralization characteristics,sequence relationship and controlling factors of two types of orebodies with different occurrences were further clarified.There are independent stratiform mineralization（body）in the favorable structural positions（NNW-trending faults and fold axis bends）and favorable lithological horizons（calcareous mudstone horizons in the lower part of D₁t²）in the Porcupine Po mining area,and its The distribution range is wider than previously thought;the vein-like mineralization is mainly filling,and the layer-like mineralization has both filling and metasomatism.The mineral combinations of the two are basically the same,but chalcopyrite is found in the latter,and The content of brittle pyrite and dolomite minerals is relatively small;the vein-like ore is obviously cut like layered ore,and the two may be products of different stages in the same period;Layer-by-layer sliding crushing zone control.（2）The combination characteristics of sphalerite in the vein-like orebodies and the quasi-layered orebodies in the Jianzhupo deposit are similar.Both are rich in Fe(average value 53294.4×10^-6～63961.6×10^-6),Sn(average value580.78×10^-6～1969.49×10^-6).In(average value 9.72×10^-6～53.03×10^-6),poor Ga(average value 6.05×10^-6～6.98×10^-6),Ge(average value 0.58×10^-6～2.15×10^-6)is characterized.Assemblages of trace elements in sphalerite,as well as Ga/In（0.40～0.80）and Nb/Ta ratios（2.14～3.75）are similar to those of magmatic hydrothermal lead-zinc deposits,indicating that the metallogenic materials in the area may be mainly from magma.（3）The rare earth characteristics of sphalerite in different occurrences are similar,all showing that the total amount of rare earth is low.Although there are some differences in the degree of fractionation of light and heavy rare earths and the characteristics of rare earth distribution curves,they are all characterized by negative europium anomaly（meanδEu 0.54～0.65）and high Y/Ho ratio（mean28.64 and 26.40,respectively）.The rare earth characteristics of liquid-type lead-zinc deposits are similar,indicating that the metallogenic materials in the area may be mainly from magma.（4）The vein-like sphaleriteδ_DSMOW‰=-69.2‰～-81.8‰,δ¹⁸O_H2O‰=2.1‰～5.2‰in the Porcupine Po mining area;the layered sphaleriteδ_DSMOW‰=-75.2‰～-109.4‰,δ¹⁸O_H2O‰=-4‰～4‰.The H-O isotopic characteristics show that the ore-forming fluids of both originate from the mixture of magmatic water and atmospheric water.（5）According to this research understanding of the sources of metallogenic materials and ore-forming fluids,combined with the comprehensive analysis of metallogenic geological conditions and metallogenic characteristics,as well as isotopic dating data,it is considered that the Jianzhupo deposit belongs to magmatic hydrothermal filling-metasomatism Metallogenic,the deposit type is a magmatic hydrothermal deposit.