粤西坡仔营钼矿花岗质岩石光谱学特征及意义

Spectral Characteristics and Implication of Granite from Pozaiying Molybdenite Deposits in West of Guangdong

选取粤西坡仔营钼矿的花岗质岩石,研究其XRD,FT-NIR和Raman光谱特征。与花岗斑岩及远带样品相比,近带花岗岩样品XRD衍射信号弱,FT-NIR吸收信号强,石英Raman光谱信号弱。分析表明,其石英(101)晶面的XRD衍射峰、绢云母铝羟基(Al—OH)的FT-NIR特征峰(4 529cm-1)及石英本征位移峰(464cm-1)的半高宽均大于前二者。与其他样品不同,近带样品造岩矿物含量低,低温蚀变矿物含量高;且该带内矿物结晶度、有序度及结晶温度均较低。研究认为,坡仔营钼矿发育着一个以花岗斑岩为中心的面型低温蚀变带,而控制钼成矿的石英斑岩实为该蚀变带靠近官山嶂岩体的一部分。

Some granite samples from Pozaiying molybdenite deposits in the west of Guangdong were retrieved to characterize the spectral signature of XRD,FT-NIR and Raman.The results show that compared to the Porphyry granite and granite in the far zone,the signal of XRD and Raman of granite in near zone is weaker while the signal of FT-NIR is stronger.The authors’ana-lyses indicate that the FWHM of quartz （101）peak in XRD,Sericite peak （4 529 cm-1 ）in FT-NIR and quartz peak in Raman shift from the latter are higher than those of former two.Those spectral characteristics indicate that compared with other sam-ples,the content of petrogenetic mineral in samples from near zone is lower while the content of alteration mineral is higher,and its crystallinity and crystallization temperatures are both lower.The authors’studies suggest that there may be an alteration zone,embracing the granite-porphyry,which comprised low temperature mineral.and the quartz-porphyry which related to mo-lybdenite mineralization belongs to the zone near Guanshanzhang mass.