川西热香铜矿含矿花岗岩地球化学特征及成因初探

PRELIMINARY STUDY ON GEOCHEMICAL FEATURES AND GENESIS OF HOST GRANITES OF REXIANG COPPER DEPOSIT IN WEST SICHUAN PROVINCE

热香铜矿位于乡城大断裂上盘娘拥复向斜次级旺央向斜核部,是川西地区新发现铜矿床,成因上与二长花岗岩密切相关.热香含矿岩体地球化学特征表现为富集Rb,Th,U和Ta,而Ba,Sr,Ti强烈亏损.稀土元素总量较高,轻稀土相对富集,分馏程度较重,负Eu异常显著(δEu=0.08～0.21).而通过微量元素构造环境投图、成岩年龄及区域构造环境演化历史分析,初步认为热香含矿二长花岗岩是在喜马拉雅期陆内造山阶段(65～15 Ma)由于陆内走滑作用,岩浆在板内裂陷环境中引发地壳浅部岩石大规模熔融侵位而成.

Rexiang copper deposit locates in secondary syncline core of Niang Yongfu syncline in hangding walls of Xiangcheng fault.It is a newly found copper deposit in ChuanXi areas,and the genesis is closely related to the Monzonitic Granites. Geochemistry of host granites in Rexiang copper enriched Rb, Th, U and Ta, strong depletion in Ba, Sr, Ti.The gross of REE content is high, LREE is relatively rich and the fractionation of LREE is higher than HREE. Eu is Strong depletion （δEu=0.08-0.21）.Aecording to the trace element discrimination diagrams for tectonic classification,diagenesis age,regional tectonic setting evolution, the Preliminary genesis of Rexiang host Monzonitic Granites is that magma in intraplate fracture caused largely-scale melting and intrusion of the rock in hypabyssal crust because of intracontinental strike-slip in Himalayan intracontinental oeogenic stage.