投稿时间：2012-07-31
修订日期：2013-05-28
网络发布日期：2014-10-23
中文摘要:广西巴马料屯金矿床是较为典型的卡林型金矿床，金矿体与燕山晚期石英斑岩脉空间上相关。矿床勘查成果和野外露头观察均表明石英斑岩脉切割金矿体，说明岩浆岩形成于矿体之后。成矿元素地球化学测量结果表明，Au、As元素沿石英斑岩脉走向出现明显的分异，表现为在导矿和容矿断层区段Au、As质量分数高，局部形成矿（化）体；远离矿体的砂泥岩和灰岩围岩地段，则逐渐降低至正常背景值，说明石英斑岩侵位过程中切割早期的矿体或含矿断层，萃取了矿（化）体中成矿元素Au、As，从而在这些断层之间形成一定宽度的高值带。成矿元素地球化学测量支持岩浆岩形成于矿体之后的结论。石英斑岩脉白云母斑晶的40Ar/39Ar坪年龄为（95.5±0.7） Ma，代表了岩浆侵位年龄，由于岩脉形成于矿体之后，此年龄可以作为成矿年代的上限年龄。本矿床及滇黔桂"金三角"其他卡林型金矿的确切成矿年代，尚需更多高精度直接成矿年龄数据的约束。
Abstract:The Liaotun gold deposit, whose gold ore bodies are spatially related to late Yanshanian quartz porphyry veins, is one of Carlin-type gold deposits in Yunnan-Guizhou-Guangxi triangle area of southwestern China. Both the prospecting of the ore deposit and the observation of outcrops show that quartz porphyry veins cut gold ore bodies, suggesting that quartz porphyry was formed later than gold ore bodies. Geochemical survey of ore-forming elements shows that an obvious differentiation between Au and As occurs along the strike of the quartz porphyry vein, i.e., the content of Au and As increases between the ore-conduit faults and the ore-containing faults, locally forming mineralized bodies. Au and As gradually decrease to the normal background level in the wall rock of detrital rock and limestone which are far away from gold ore bodies. This differentiation indicates that quartz porphyry extracted Au and As from the mineralized body and then formed a high value belt of a certain width between faults when quartz porphyry cut early ore bodies or ore-containing faults during magmatic emplacing. Geochemical survey of ore-forming elements supports the conclusion that quartz porphyry was formed after gold ore bodies. The 40Ar/39Ar dating of muscovite phenocryst from quartz porphyry veins yielded a plateau age of (95.5±0.7) Ma which is interpreted as the emplacement age of quartz porphyry veins. Because quartz porphyry was formed later than gold ore bodies, the age is interpreted as the upper limit of the metallogenic epoch. The definite metallogenic epoch of this deposit and other Carlin-type gold deposits in the Yunnan-Guizhou-Guangxi triangle area needs to be constrained by more high precision data of direct metallogenic ages.
keywords:geology quartz porphyry upper limit of the metallogenic epoch Carlin-type gold deposits Liaotun gold deposit Guangxi
文章编号：
中图分类号：P618.51
文献标志码：
基金项目:本文得到“国家重点基础研究发展计划973课题（编号：2014CB440902）”；“国土资源部公益性行业科研专项经费项目（编号：200911007-28）”和“广西自然科学基金项目（编号：2012GXNSFAA053184）”联合资助
引用文本：
陈懋弘,张延,蒙有言,陆刚,刘苏桥.2014.桂西巴马料屯金矿床成矿年代上限的确定——对滇黔桂“金三角”卡林型金矿年代学研究的启示[J].矿床地质,33(1):1~13CHEN MaoHong,ZHANG Yan,MENG YouYan,LU Gang,LIU SuQiao.2014.Determination of upper limit of metallogenic epoch of Liaotun gold deposit in western Guangxi and its implications for chronology of Carlin-type gold deposits in Yunnan-Guizhou-Guangxi “golden triangle” area[J].Mineral Deposits33(1):1~13
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