| This paper mainly study on scheelite of Dingjiashan mine of Youxi,Fujian province,combining with the characteristics of scheelite of Xingluokeng mine of Ninghua and Shangfang mine of Jianou,Fujian province,to research mineralogical characteristics of scheelite with different molybdenum content.Through mine geological survey,hand specimens observation,polished thin section microscopic identification,electron microprobe analysis,X-ray powder diffraction analysis as well as steady-state fluorescence spectral analysis,mineralogical characteristics of composition,unit cell parameters and fluorescence spectra of scheelite with different molybdenum content,are investigated.Through the above research,the author preliminarily probes into the space distribution state of Dingjiashan's scheelite and make clear mineralogical characteristics of scheelite of Dingjiashan,Xingluokeng and Shangfang mine.Through the discussion and research about the experimental results,some knowledge is listed as follows:(1)Results of electron microprobe analysis show that,overall variation range of MoO3 within scheelite is 0-6.07%,variation range of MoO3 within scheelite of Dingjiashan is 0.02?4.09%and Xingluokeng's can be up to 6.07%.When molybdenum content increase gradually,fluorescent color of scheelite change from blue to yellow.Range of molybdenum content corresponding to different fluorescent colors of scheelite are divided as follows:blue(MoO3%<0.1%),bluish white-yellowish white(0.1%?MoO3%<0.5%),yellow(MoO3%?0.5%).Under the backscattered electron image of scheelite,composition zone of scheelite are found both in Dingjiashan and Xingluokeng mine,the results of point analysis for different brightness areas show that the zone is caused by the different content of molybdenum.The relational graph of mole number of Mo-W using point analysis results and surface,line scan analysis are used to further study the relationship between Mo and W.The results show that,Mo is negatively related with W,and uniformly distributes in the scheelite,it indicates that Mo substitutes W in the form of isomorphism in scheelite.Composition zone of scheelite reflects that molybdenum content in the ore-forming solution and physico-chemical conditions fluctuated when scheelite formed in Dingjiashan and Xingluokeng;(2)Results of steady-state fluorescence spectra(including the excitation spectrum and emission spectrum)analysis show that,with the increase of the molybdenum content within scheelite,peak positions shift and intensity decline both in excitation spectrum and emission spectrum of scheelite,excitation and emission wavelength present the smaller and larger trend,respectively.Comparing with the correlation between excitation wavelength and molybdenum content,the correlation between emission wavelength and molybdenum content is better.Emission wavelength increases with the increase of molybdenum content.Besides,intensity ratio of emission wavelength 410nm and 490nm(I410nm/I490nm)also has certain correlation with molybdenum content.I410nm/1490nm decreases with the increase of molybdenum content.Thus,through the emission spectral analysis,the above two spectral data can be used to estimate molybdenum content in scheelite;(3)Results of X-ray powder diffraction analysis show that,Mo content in the three mines' scheelite has a certain variation range,but the unit cell parameters of scheelite overall change little comparing with the data of ICSD standard card 41-1431.Therefore,the influence of Mo to the unit cell parameters can be neglected in natural scheelite;(4)Results of mine geological investigation preliminarily indicate that,scheelite mainly distribute in the the contact position between green-schist type lead-zinc ore and marble,which Ca came from marble,while W.Mo came from ore-forming fluid.In combination with characteristics of scheelite with variation range of molybdenum content and skarn minerals(garnet,pyroxene,etc.),genetic type of Dingjiashan scheelite shall be the skarn type. |
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