澜沧老厂多金属矿床叠加成矿系统稳定同位素对比研究  

A comparative study of stable isotopes of superimposed metallogenic systems in the Laochang polymetallic deposit,Yunnan Province

作　　者：刀艳[1] 杨帆 李峰[1] 赵晓勇[1] 

机构地区：[1]昆明理工大学国土资源工程学院,云南昆明650093 [2]中国有色金属工业昆明勘查设计研究院,云南昆明650051

出　　处：《岩石矿物学杂志》2014年第4期693-706,共14页Acta Petrologica et Mineralogica

基　　金：国家危机矿山接替资源勘查项目(20089943);云南省自然科学基金资助项目(2011FZ035)

摘　　要：云南澜沧老厂多金属矿床是"三江"成矿带南段重要的多金属矿床之一,属于多种构造环境演变过程中形成的火山喷流沉积+隐伏斑岩热液成因为主的矿床,多因复成矿特征典型。本文在对不同成矿系统典型矿物/岩石开展S、Pb、H、O、Sm-Nd、Rb-Sr同位素分析研究的基础上,对比了不同成矿系统在矿床地球化学特征上的异同。研究表明,两个成矿系统的成矿物质来源既有继承性,又有新生性,多源特征明显。其中,火山喷流沉积成矿系统的S主要来源于火山热液,Pb主要来源于古陆壳基底和火山岩,成矿流体主要为海水与岩浆水的混合。斑岩型矿石矿物的S、Pb同位素组成也具壳幔混合源的特征,金属成矿物质来源主要与岩浆有关,成矿流体主要来源于岩浆水及大气降水,晚期成矿流体向大气降水漂移的特征相对明显。斑岩热液成矿系统中花岗斑岩的^(87)Sr/^(86)Sr比值介于地壳与地幔岩石平均值之间,Sm-Nd同位素数据接近EMⅡ地幔端员,指示岩浆源区处于壳-幔组分过渡区。The Laochang polymetallic deposit is one of the most important deposits in the south of the Sanjiang metallogenic belt and belongs to the polygenetic mineral deposit with superimposed metallogenic systems between the SEDEX oreforming system and the hydrothermal porphyry metallogenic system. Based on an analysis of the typical minerals and rocks in different mineralization systems in the aspects of S, Pb, H, O isotopes, the authors compared the differences and similarities of deposit＇s geochemical characteristics in the different metallogenic systems, and the result shows that mineral sources of the two metallogenic systems were characterized by inheri- tance, regeneration and multiple sources. In the SEDEX oreforming system S was mainly derived from volcanic hydrothermal solution, Pb mainly came from ancient continental crust basement and volcanic rocks, and oreforming fluids were mainly derived from mixed magmatic water and brine as shown by H-O characteristics. In the porphyry-hydrothermal mineralization system, S mainly came from the mantle or crustmantle magma homogenization, Pb was mainly from the crustmantle mixing, orefomaing fluids were mainly derived from mamnaticwater and meteoric water, and ore fluids of the late stage had more characteristics of meteoric water. 873r/86Sr ratios of granite porphyry are between the average of the crust and that of the mantle, whereas isotope data of Sm-Nd is close to the EMⅡ, suggesting that the magma source was in the crust-mantle transition zone.

关 键 词：火山喷流沉积成矿系统 斑岩热液成矿系统 S Pb H O Sr ND同位素 澜沧老厂 云南省 

分 类 号：P597[天文地球—地球化学] P611.22[天文地球—地质学]