Accessory Minerals Characteristics Of Bashilazi Alkali Granite In Yongji, Jilin Province

Baishilazi alkaline granite is located in Yongji Country, Jilin Province,which is at the northern end of the Tanlu fault zone on the geotectonic west Yilan- Yitong fault zone near, slitting Xingmeng-Jihei orogenic belt. Based on alkaline granite in the study area as the research object, through field geological survey and indoor method of combining the modern testing technology, from the angle of mineralogy, dialogue through the characteristics of accessory minerals in the alkaline granite has carried on the comprehensive analysis and research, have the following knowledge and results:1. The pale red Baishilazi alkaline granite is the coarse grain texture, block structure, the structure visible geode.The main rock-forming minerals are alkaline kfeldspar(60%±),quartz(20%±),arfvedsonite(15%±),aegirine(5%±).The accessory minerals are astrophyllite, loparite-(Ce), fergusonite-(Y), monazite, ilmenite, thorite, niobite, allanite, sphene, thorianite, apatite, rutile, fluorite and zircon.2. Accessory minerals containing rare, rare earth and radioactive elements are often in the form of different association in alkaline granite.In this area, Nb, Ta, rare elements mainly occurs in the fergusonite-(Y), rutile, loparite-(Ce) and niobite;rare earth elements mainly occurs in the monazite, allanite,loparite-(Ce),fergusonite-(Y) and apatite;radioactive elements mainly occurs in the thorite,thorianite,zircon,monazite,fergusonite-(Y),loparite-(Ce) and allanite.3. The substitution of accessory mineral chemical elements is very common:Ca is repaced by Na,Sr,Ce and Ti is replaced by Nb in loparite-(Ce).In fergusonite-(Y), elements of a large number of REE instead of Y, Ta instead of Nb. The genesis of some U and a small amount of Ca replaces Th. In apatite, elements of lots of Sr and a small amount of Ce instead of Ca. The high concentration of niobium oxide to replace is in rutile.4. The astrophyllite of the study area which we examined the chemical composition test, infrared spectra and differential thermal test, thermogravimetric analysis, further enrich the mineralogy of astrophyllite family information. As we examined the research laid the foundation of the study area.5. The loparite-(Ce) and fergusonite-(Y) in the studied area has carried on the preliminary mineralogy research. Both the findings of the study area of niobium minerals and rare earth mineralization and geochemical aspects, the research is of important geological significance and academic value, the work added mineralogical information for them.