昌都盆地碱性岩的稀土元素地球化学特征——以高吉岩体为例

REE geochemistry of alkaline rocks:an example from the Gaoji rock body in the Qamdo Basin,Xizang

一、前言目前，在三江地区发现的少数碱性岩体之中，高吉岩体发育较好，且与金矿成矿关系十分密切。在近１０年来，地质工作者在高吉地区对该碱性岩地质特征进行了较详细的研究，并发现了自然金①。二、地质概况昌都盆地是三江地区一个较大的盆地，面积约６８０万ｋｍ２（...

Abstract The REE abundance patterns tend to differ in various rocks. The geochemical rehaviours of the REE from alkaline rocks are approached in this paper on the basis of the REE amounts, REE parameter variations and relevant tables and diagrams for the Gaoji alkaline rock body in the Qamdo Basin, Xizang in the intraplate extensional settings. The comparative studies of the Gaoji and other rock bodies in the south central part of the basin show that:(1)the Gaoji, Kenzuo and Mamupu rock bodies are all situated on the margins of the Qamdo block and emplaced in the post collisional extensional environments. Generally speaking, the Kenzuo alkaline rock body has higher REE contents because of the influence of abundant volatile components from the volcanic island arc zones;(2)the REE are more enriched in the alkaline rock bodies than in the granite bodies in the same zone;(3)the above mentioned alkaline rock bodies in this region are characterized by enriched LREE and depleted HREE, and(4) the REE abundance patterns similar to those for the other places indiacte a mantle source of these alkaline rock bodies.