新疆巴音布鲁克乔霍特铜矿区钾长花岗岩中钾长石的^(40)Ar-^(39)Ar年龄及其地质意义  

^(40)Ar-^(39)Ar isotope dating of K-feldspar from moyite in the Qiaohuote copper deposit, Xinjiang, and its geological implication

作　　者：王志良[1] 毛景文[1] 杨建民[1] 韩春明[2] 陈文[3] 张作衡[1] 

机构地区：[1]中国地质科学院矿产资源研究所 [2]中国科学院高能物理研究所,北京100039 [3]中国地质科学院地质研究所,北京100037

出　　处：《岩石矿物学杂志》2004年第1期12-18,共7页Acta Petrologica et Mineralogica

基　　金：国土资源大调查资助项目 (2 0 0 3 10 2 0 0 0 0 1_3 ;DKD2 0 0 10 2 7_2 ) ;国家重点基础研究资助项目 (G19990 43 2 16)

摘　　要：采用单矿物40 Ar_3 9Ar同位素年代学方法 ,对乔霍特铜矿区钾长花岗岩中钾长石进行精确的年龄测定 ,获得坪年龄为 2 74 .78± 0 .4 4Ma,等时线年龄为 2 72 .7± 3.0Ma。鉴于该钾长花岗岩体形成之后未见构造变形和热液蚀变现象 ,因此40 Ar_3 9Ar同位素年龄代表钾长花岗岩中钾长石结晶年龄 ,即钾长花岗岩体的结晶晚期年龄。根据钾长花岗岩体和乔霍特铜矿体的空间关系、铜矿石的品位变化、钾长花岗岩和铜矿石的稀土元素特征及铜矿石流体包裹体氢氧同位素组成等 ,认为乔霍特铜矿床的成矿作用直接与钾长花岗岩的侵入活动有关 ,钾长花岗岩中钾长石结晶年龄基本上代表乔霍特铜矿床成矿时代的下限。Using the ^(40)Ar-^(39)Ar isotopic chronological method to analyze K-feldspar from moyite in the Qiaohuote copper deposit, the authors obtained a plateau age of 274.78±0.44 Ma and an isochron age of 272.7±3.0 Ma. As there existed no tectonic deformation and hydrothermal alteration in the moyite intrusive body after its rock-forming stage, the ^(40)Ar-^(39)Ar isotopic age should represent the crystallization age of the K-feldspar in moyite, i.e. the late crystallization age of the moyite intrusive body. Based on such factors as the spatial relationship between the moyite intrusive and the Qiaohuote copper orebodies, the variations of copper ore grade, the REE characteristics of the moyite and the copper orebody, and the H and O isotopic composition of fluid inclusions in the copper ores, it is held that the ore-forming process of the Qiaohuote copper deposit was related directly to the intrusive activity of the moyite, and therefore the crystallization age of the K-feldspar in moyite should approximately represent the lower limit of the metallogenic epoch of the Qiaohuote copper deposit.

关 键 词：^40AR-^39AR年龄 地质意义 钾长花岗岩 乔霍特铜矿 巴音布鲁克 新疆 

分 类 号：P578.968[天文地球—矿物学]