Typomorphic Characteristics And Significance Of Sphalerite In The Sichuan Pb-Zn Deposit

The Pb-Zn deposit of Tianbao mountain in Sichuan province is a large lead-zinc deposit in southern Sichuan Province,which belongs to the main Pb-Zn metallogenic belt of China,which is located at the junction of Sichuan,Yunnan and guizhou.In this paper,it is based on the previous studies,through the field geological work and indoor work,study the typomorphic characteristics of sphalerite of the Pb-Zn deposit in Tianbao mountain.Sphalerite of the Pb-Zn deposit in Tianbao mountain is divided into three stages.From the first stage to the third stage,the color of sphalerite is from dark brown,brown black,to brown,at last become light brown,light yellow;crystal shape degree decreased by euhedral-anhedral crystal,crystal morphology from the diamond twelve face body to can not see crystalline;Vickers hardness decreased;the content of Fe gradually decreased;mineral assemblages consist of pyrite sphalerite quartz into sphalerite galena stage,and finally changed to sphalerite quartz calcite.The chemical composition of sphalerite,Zn,S content in the whole heaven sphalerite of the Pb-Zn deposit in Tianbao mountain showed weak losses,dispersed elements are enriched in Cd and Ga,the characteristics of poor in Ge and In,Se and Te content were lower,the total REE is relatively low,light REE enriched and distinct,hree,rare earth element chondrite distribution curve is right type,the overall negative anomaly and Eu positive anomaly characteristics of weak Ce.From the first stage to the second stage of sphalerite,and to the third stages of sphalerite,loss of Zn and S decreased,the sulfur fugacity environment is weak and with the mineralization weakened;the overall content of Cd,Ga,Ge increased,In content decreased significantly,Cd,Ga and Ge are enriched in light and color in sphalerite,In,Ag,and Mn are enriched in the dark sphalerite;rare earth elements REE,(La/Yb)N value decreased gradually,LREE/HREE,?Eu??Ce,(Gd/Yb)N and the value increased gradually,the distribution patterns of Ce by negative anomaly type,Ce weak negative anomaly and weak negative Ce anomaly.Abnormal Eu from weak negative anomaly changes in positive anomaly,reflecting the ore-forming fluid from late stage oxidation reduction conditions of the early stage of transformation,and shows the later stage of sphalerite LREE differentiation is relatively strong,HREE differentiation level is relatively weak.The inter element correlation analysis and cluster analysis,Fe and Zn existed in class relations with the form of replacement like,Se,Mn and Sn may be a form of isomorphism to replace the Zn into the zincblende lattice,Fe was negatively correlated with Cd,Ga,Ge,Cd,Ga,Ge in sphalerite which may be in the form of isomorphism to replace Fe to form Cd-S,Ga-S,Ge-S,Cd,exist in sphalerite ore deposit is mainly Fe Ga,Ge Fu,and Te may mainly occur in galena and pyrite.The source of the metal material in the Pb-Zn deposit in Tianbao mountain is a multi source,upper crust of orogenic belt,various sedimentary rocks and mantle rocks may have volcano provided some ore-forming materials;the ore-forming materials were derived from the strata.The ore-forming fluid of sphalerite is medium low temperature hydrothermal fluid,The homogenization temperature range of the first stage of sphalerite is 186-200?,the average is 194?;homogenization temperature range of second stages of sphalerite is 153-197?,the average is 165?;homogenization temperature range of third stages of sphalerite is 89-135?,the average is 122?.Synthesize various opinions,the results show that the Pb-Zn deposit in Sichuan Tianbao mountain belongs to the MVT type Pb-Zn deposit.