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新疆阿尔泰山南缘卡拉先格尔斑岩铜矿带成因再认识——来自哈腊苏铜矿硫-铅-氢-氧同位素和40Ar-<sup>39Ar年龄的约束
New understanding on origin of Kalaxiangeer copper deposit on southern margin of Altay mountain, Xinjiang: Constraints from S-Pb-H-O isotope geochemistry and 40Ar-39Ar age of Halasu copper deposit
【摘要】 通过对卡拉先格尔铜矿带中的哈腊苏斑岩铜矿床详细的野外地质调查和系统的同位素地球化学示踪和测年研究,探讨了阿尔泰南缘铜矿的成矿时代及矿床成因。研究表明,卡拉先格尔铜矿带的铜矿化主要呈不均匀团块、细脉或细脉浸染状产于受断裂控制的钾长石石英脉、绿帘石脉以及石英方解石脉中,线型分布明显,空间分布极不均匀,缺乏典型斑岩铜矿的面型蚀变矿化分带。含矿钾长石脉40Ar39Ar年龄为(230±5)Ma,大大晚于容矿斑岩脉的形成时代〔锆石SHRIMPUPb年龄(380.8±5.7)Ma〕。硫铅同位素指示成矿物质主要源于火山岩地层和花岗闪长斑岩脉。氢氧同位素显示成矿流体为岩浆水和大气降水的混合物。据此认为,卡拉先格尔铜矿带主成矿时代为印支期,成矿作用与后造山阶段沿NNW向老山口断裂发育的偏碱性岩浆活动有关,但不排除存在同造山期的斑岩型矿化。
【Abstract】 Based on detailed field geological survey and systematic isotope geochemical studies, the authors have discussed the metallogenic epoch and origin of the Kalaxiangeer copper deposit on the southern margin of the Altay Mountain, Xinjiang. The copper_bearing minerals mainly occur in the form of heterogeneous gobbets and veinlets disseminated in various veins such as K_feldspar_quartz veins, epidote veins and quartz_calcite veins, which are obviously controlled by NNW_striking faults. The mineralization distribution in the ore district is highly uneven and shows lack of pervasive alteration_mineralization zonation typical of representative porphyry copper deposits. The (230±5) Ma age for the formation of copper_bearing K_feldspar was obtained by 40Ar_ 39Ar method, which is remarkably younger than the age of the ore_hosted porphyry〔(380.8±5.7) Ma,zircon SHRIMP U_Pb age〕. The sulfur and lead isotope compositions indicate that the ore_forming materials were mainly derived from the volcanic rocks and granodioritic porphyries. The hydrogen and oxygen compositions suggest that the ore fluid is a mixture of magmatic water and meteoric water. According to the above results, the authors have reached the conclusions that the main metallogenic epoch in the Kalaxiangeer copper deposit is Indosinian, and that most of the mineralization might have been related to the post_orogenic meta_alkaline granitic magmatism developed along the NNW_striking Laoshankou fault. Nevertheless, it is also probable that there might have existed non_significant syn_orogenic porphyry_style mineralization.
【Key words】 geochemistry; 40Ar-39Ar age; porphyry copper deposit; Halasu copper deposit; Kalaxiangeer copper belt; Altay;
- 【文献出处】 矿床地质 ,Mineral Deposits , 编辑部邮箱 ,2006年03期
- 【分类号】P618.41
- 【被引频次】62
- 【下载频次】682