Typomorphic Characteristics Of Apatite In Wanghuizhuang Ree Deposit,Shanxi Province And Its Metallogenic Significance

Based on the typomorphic characteristics of apatite,a rare earth rich mineral in wanghuizhuang rare earth deposit,Shanxi Province,the genesis of the deposit is discussed.On the basis of field investigation and previous literature summary,the geological characteristics of the structure,magmatic rock and several rare earth mineralized veins in the mining area are mainly studied.By means of optical microscope and electron probe / laser ablation plasma mass spectrometry(LA-ICP-MS),the composition typomorphic study of apatite,the main rare earth rich mineral in the deposit,was carried out,and then the source of diagenetic and ore-forming materials was inferred,and the ore-forming environment and ore-forming fluid properties were discussed.Combined with the previous scientific research results of the alkaline complex and the exploration results of the rare earth mining area,the prospecting prediction of the wanghuizhuang rare earth deposit and its surrounding area is carried out.The main results are as follows:1.The ore body of wanghuizhuang rare earth deposit in Shanxi Province is mainly controlled by NW trending faults,and there are three main veins in the deposit.According to the characteristics of mineralization,the veins can be divided into two types:(1)carbonatite type REE veins(2)Alkaline syenite type rare earth veins are closely related in temporal and spatial distribution.The ore minerals are mainly apatite,epidote and fluorite,which are associated with plagioclase,quartz and biotite.Chloritization and carbonation are widely developed in the veins.The rare earth apatites show bright yellow fluorescence under the cathodoluminescence microscope,some of them have light and dark changes,and a few of them have ring characteristics,which indicates that the environmental changes during the crystallization process of apatite are complex.2.The major element characteristics of apatite show that all apatites in the mining area belong to fluorapatite.Trace element analysis shows that the mineral is characterized by LREE enrichment and hree depletion,and LREE fractionation is serious.According to the graphical results of(La/Sm)N,(La/Yb)N,(Sm/Yb)N and Sr contents,it is inferred that the ore-forming materials are mainly derived from the mantle.The results of REE content analysis show that the apatite crystal of No.3 ore vein is behind the feldspar crystal,and has more metallogenic stages,suggesting that the ore-forming fluid activity is strong.3.Combined with the research results of the alkaline complex in Tianzhen Yangyuan area,it is considered that the wanghuizhuang REE deposit may have been affected by two stages of tectonic activity,and the multi-stage hydrothermal fluid activity promoted the enrichment of REE in apatite,forming a hydrothermal REE deposit related to carbonatite alkaline complex.The content of rare earth in apatite crystallized in late stage is higher.Purplish red flesh red apatite,strong wall rock alteration and significant radioactive anomaly are the prospecting indicators for this type of rare earth deposits in this area.