东秦岭宽坪花岗岩体及其附近含铷伟晶岩的成矿机理

Metallogenic Mechanism of Kuanping Granite and Its Nearby Pegmatites Containing Rubidium in Eastern Qinling Mountains

东秦岭宽坪岩体是华北板块与杨子板块碰撞后形成的钙碱性花岗岩体,岩体内部及附近地层中发育有花岗伟晶岩脉。通过地球化学分析,利用A/CNK-A/NK图解及微量元素R1-R2构造环境判别方法,分析认为伟晶岩脉的形成与岩体具有一定的继承性,是宽坪岩体晚期热液岩浆结晶的产物。通过岩体及伟晶岩脉稀有元素含量对比分析、矿石多元素及光谱半定量分析,认为伟晶岩中铷的富集与钾含量关系密切,为东秦岭商丹地区寻找伟晶岩型铷矿提供了方向。

Kuanping Granite in Eastern Qinling Mountains is a calc alkaline granite formed after the collision of the Northern China Plate and Yangzi Plate.There are granitic pegmatite dikes occure in the granite or the strata near it.Through geochemical analysis,by using A/CNK-A/NK diagram and R 1-R 2 tectonic environment identification method of rare elements,the results show that the formation of granitic pegmatite dikes in the area has a certain inheritance with Kuanping Granite,and the granitic pegmatite dikes is the products of the late hydrothermal magmatic crystallization.Through the comparative anlysis of rare elements in rock mass and pegmatite dikes,ore polyelement analysis and semiquantitative spectrometric analysis,it is concluded that the enrichment of rubidium is closely related to the content of potassium in pegmatite,whitch can also provide the prospecting directions of pegmatite type rubidium deposit in Shandan Region in Eastern Qinling Mountains.