【摘要】 角闪石的种类、化学组成、微量元素特征显示所研究的碱性花岗岩分为两类 :达拉布特型和恰库尔特型。前者结晶温度为 6 6 5～ 750℃、定位深度为 4 .95～ 8.2 5km,形成于相对封闭的环境中 ,岩浆演化晚期水 -岩作用不强烈 ;角闪石主要为钙质角闪石 ,富 Fe、Co、Cr、Rb、Sc、Cs、Hf,贫 Ta、Zn;其球粒陨石标准化稀土模式曲线呈左高右低的台阶式“V”型。后者结晶温度相对较高、定位较浅 ,形成于开放环境中 ,岩浆演化晚期水 -岩作用强烈 ;角闪石为钠 -钙质角闪石和碱性角闪石 ,富 Ta、Zn,中组稀土亏损 ,球粒陨石标准化稀土模式曲线呈山谷状“V”型更多还原

【Abstract】 Based on the characteristics of hornblendes, we classified the alkali granitoids as two types. The Dalabut type alkali granitoids were emplaced in the crust at the depth of about 4.95 —8.25km and their solidification temperatures are between 665—750℃. The amphiboles are rich in Co, Cr, Rb, Sc, Hf, REE; their chondrite normalized REE patterns are characterized by negative Eu anomaly. It is suggested that the Dalabut type alkali granitoids were formed in a closed environment and water rock interaction was not obvious at the late stage of rock formation. The Qiarkurt type alkali granitoids were emplaced in the shallow crust and the crystallization temperatures are higher than those of the Dalabut type alkali granitoids. These rocks contain sodic calc amphiboles and alkali amphiboles. The hornblendes are rich in Ta, Zn and REE, with the normalized REE patterns having negative Eu anomaly and MREE depletion and the curves being valley shaped. It is indicated that the Qiarkurt type alkali granitoids were formed in an open system and water rock interactions had happened in the late period of rock formation.更多还原