The Identification Of Feldspar Group Minerals To The Mineralization

The feldspars are K,Na,Ca aluminosilicate with a framework structure.They are the most abundant constituents of igneous rocks,arenaceous sediments,schists and gneisses.They constitute 50%of the earth's crust.And they are one of the most common rock-forming minerals.In this paper,I have collected and determined 1141 major elements data of feldspars(involve 26 intrusive rocks and six kinds of mineralization),103 minor elements data of plagioclases(involve 11 intrusive rocks five kinds of mineralization),and 38 X-ray data of K-feldspars(involve 9 intrusive rocks and five kinds of mineralization).These feldspars occur in the intrusive rocks or shallow intrusive rocks.And these rocks may relate with the Gold deposits,Copper deposits,Iron deposits,Molybdenum deposits,Tin deposits and Tungsten deposits.So I consider these feldspars also relate with each deposits.For this paper,I use the electron microprobe analysis(EPMA),laser ablation inductively coupled plasma mass spectrometry(LA-ICP-MS)and X-ray powder diffraction.For this study,I want to find the typomorphic features of feldspars which occur in the intrusive rocks in different mineralization.After this study,I find there is a gradual change of feldspars occurrence in different types minerals.The feldspars may occur as crystal phase and matrix phase in the Copper deposits.And the matrix phase may reduce in the Gold deposits.There is not the matrix phase in the Tin deposits and Tungsten deposits.The major constituents of feldspars,i.e.KAlSi3O8,NaAlSi3O8 and CaAl2Si2O8,suggest the feldspars which related with the Gold,Copper and Iron deposits vary in a wide range.And the feldspar related with the Tin and Tungsten deposits may change in a small range.They may occur as Or-rich and Ab rich feldspars.With the analysises of plagioclases major elements,I find the plagioclases related with the Tin and Tungsten deposits may have high concentrations of Si and Na and low concentrations of Al,K and Ca relative to other feldspars.In the minor elements,the plagioclases related with Tin and Tungsten deposits have high Ba,Sr,and Eu,and low concentrations of Rb and Th.The REE of plagioclases suggest that the plagioclases related with the Gold and Copper deposits have a positive anomaly of Eu.The Eu anomaly of plagioclases may negative and positive in the Tin and Tungsten deposits.In this paper,I also use the two feldspar thermometer to calculate the equilibrium temperature and there are minor differences with equilibrium temperature in the rocks of different deposits.The results show the equilibrium temperature always vary between 500 and 600?.The structural parameters of K-feldspars also show a low differs.They varies in the intermediate feldspar and orthoclase.The structural temperature of K-feldspar is also vary between 500 and 600?.