皖南伏岭岩体稀有金属含量特征及其对稀有金属花岗岩成矿作用的指示
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摘要
伏岭岩体为一燕山晚期侵入体,其Rb-Sr等时线年龄为121Ma。伏岭岩体可分为荆墈岭、鱼龙川、小昌溪、饭蒸尖四个侵入单元,岩体中的Li、Be、Rb、Nb、Cs、Ta、Hf元素含量自早期的荆勘岭单元至晚期的饭蒸尖单元逐渐升高,符合不相容元素的富集规律;Zr自早期的荆勘岭单元至晚期的饭蒸尖单元含量逐渐下降。伏岭岩体源岩为西村岩组或休宁组,岩浆在结晶过程中由于熔融围岩导致稀有元素含量降低。伏岭岩体岩浆在上侵过程中与围岩交代稀有金属元素的作用较弱,岩体外接触带稀有金属元素含量较低。随着岩浆的分离结晶,稀有元素在残余岩浆中逐渐富集,饭蒸尖单元Rb含量可到边界品位,表明稀有金属成矿作用的主要成因为岩浆自分异。
The Fuling rock mass is a late Yanshan intrusion, its Rb-Sr isochron age is 121 Ma. The Fuling rock mass can be divided into four intrusion units: Jingkanling, Yulongchuan, Xiaochangxi and Fanzhengjian. The contents of Li, Be, Rb, Nb,Cs, Ta and Hf in the Fuling rock mass increased gradually from the early Jingkanling unit to the late rice steaming tip unit,which accorded with the enrichment of incompatible elements; The content of Zr gradually decreased from the Jingkanling unit to the late Fanzhengjian unit. The source rocks of the Fuling rock are the Xicun Formation or the Xiuning Formation,and the magma is reduced in the crystallization process due to the melting of the surrounding rock. With the separation and crystallization of magma, the rare elements are gradually enriched in the residual magma, and the Rb content of the rice steaming tip unit can reach the boundary grade, indicating that the rare metal mineralization is mainly due to the magma selfdivision.
The Fuling rock mass is a late Yanshan intrusion, its Rb-Sr isochron age is 121 Ma. The Fuling rock mass can be divided into four intrusion units: Jingkanling, Yulongchuan, Xiaochangxi and Fanzhengjian. The contents of Li, Be, Rb, Nb,Cs, Ta and Hf in the Fuling rock mass increased gradually from the early Jingkanling unit to the late rice steaming tip unit,which accorded with the enrichment of incompatible elements; The content of Zr gradually decreased from the Jingkanling unit to the late Fanzhengjian unit. The source rocks of the Fuling rock are the Xicun Formation or the Xiuning Formation,and the magma is reduced in the crystallization process due to the melting of the surrounding rock. With the separation and crystallization of magma, the rare elements are gradually enriched in the residual magma, and the Rb content of the rice steaming tip unit can reach the boundary grade, indicating that the rare metal mineralization is mainly due to the magma selfdivision.
引文
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