初论铌、钽和钨的成矿作用：实验研究

A PRELIMINARY EXPERIMENTAL STUDY ON MINERALIZATION OF Nb,Ta AND W

针对目前没有关于Ｗ和Ｎｂ、Ｔａ的成矿作用与富氟钠长花岗岩成因关系的统一认识和实验证据的缺乏，我们完成了Ｗ、Ｎｂ、Ｔａ在流体和熔体中分配的一些实验。本研究旨在借助实验结果解释Ｗ、Ｎｂ、Ｔａ矿床的成因联系及它们成矿的可能机制。实验结果表明：在钠长石花岗岩熔体结晶过程中发生了Ｎｂ、Ｔａ和Ｗ的明显分离；钨倾向于在流体中分布，而Ｎｂ、Ｔａ则具有向硅酸盐熔体分配的趋势，在岩浆结晶晚期以独立矿物形式存在。这些实验结果与野外地质观察到的结果一致。

To counter the lack of consensus of opinion for connection between mineralization of Ta,Nb and W and fluorine-rich albite granite and the want of experimental evidence at present, some experiments of partitioning of W and Nb and Ta between residual silicate melts and fluids have been carried out.The purpose of this paper is to explain genetic connection of Ta,Nb and W ore deposits and possible mechanism of their mineralization with the aid of the experimental results. The results show that obvious separation of Ta and Nb from W took place in the processes of crystallization of albite granitic melt. Tungsten tends to distribute in the fluids while the Nb and Ta have a tendency to partition into silicate melts and to exist in the form of independent minerals in the late period of crystallization of magma. These results are in agreement with those observed geologically in the field.