米仓山区碱性花岗岩的物质组分

On the Composition of Alkali-granite in Micangshan Area

古老的碱性花岗岩在地壳中较为罕见。分布在米仓山区的碱性花岗岩属晋宁期同源岩浆演化后期的产物，其岩石化学成分以富碱（Ｋ＿２Ｏ＋Ｎａ＿２Ｏ＞８．０％）为特征，且Ｎａ＿２Ｏ＞Ｋ＿２Ｏ；含多种稀土、稀有分散元素。副矿物种类繁多，人工重砂中重矿物达３２种之多。稀土、稀有分散元素赋存状态多样。详细研究其物质组成及其特征对深入探索区内岩浆演化规律、元素地球化学特征及其成矿作用具有重要的理论和实际意义。

Ancient aliali granite is a uncommon kind of rock in the crust.The alkli granite, distributing in Northern Tie-chuanshan of Meicangshan Area , was crystallized by Comagmatic evolution inthe later Phase ar Jingling Orogeny. The chemical Composition is charcterized by enriching alka-line and Na_2O K_2O,Containingrare earth and rare dispersed elements,having many Kinds of min-rals , the artificial heavy placer minerals are about thirty two. Rare earth and rare dispersed ele-ments appear in different forms. The study on Composition and its characteristics in details willhave important theoretical and practical significance for search on reguiation of magmatic evolu-tion , element geochemistry and mineralizations.