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现代地质 ›› 2019, Vol. 33 ›› Issue (06): 1275-1285.DOI: 10.19657/j.geoscience.1000-8527.2019.06.13

• 岩石学与矿床学 • 上一篇    下一篇

云南中甸地苏嘎印支期斑岩地球化学特征及其成矿标识

潘彦宁1, 董国臣2(), 李雪峰2, 王鹏2, 孙转荣2, 董朋生2, 李华伟2   

  1. 1.西安科技大学 地质与环境学院,陕西 西安 710054
    2.中国地质大学(北京) 地球科学与资源学院,北京 100083
  • 收稿日期:2019-04-15 修回日期:2019-09-28 出版日期:2019-12-26 发布日期:2019-12-27
  • 通讯作者: 董国臣
  • 作者简介:董国臣,男,教授,博士生导师,1962年出生,矿物学、岩石学、矿床学专业,主要从事岩石学及矿床学研究。Email: donggc@cugb.edu.cn
    潘彦宁,女,硕士,1992年出生,矿物学、岩石学、矿床学专业,主要从事岩石地球化学及矿床学研究。
  • 基金资助:
    国家重大基础研究“973”项目(2015CB452604);国家重点研发项目(2016YFC0600502)

Geochemistry and Their Implications for Mineralization of Disuga Indosinian Porphyry in Zhongdian, Yunnan, China

PAN Yanning1, DONG Guochen2(), LI Xuefeng2, WANG Peng2, SUN Zhuanrong2, DONG Pengsheng2, LI Huawei2   

  1. 1. College of Geology and Environment, Xi’an University of Science and Technology, Xi’an, Shaanxi 710054, China
    2. School of Earth Sciences and Resources, China University of Geosciences,Beijing 100083,China
  • Received:2019-04-15 Revised:2019-09-28 Online:2019-12-26 Published:2019-12-27
  • Contact: DONG Guochen

摘要:

地苏嘎印支期斑岩体位于中甸岛弧东斑岩带的北端,岩性为石英闪长玢岩,与普朗超大型斑岩铜矿的成矿岩体同属于甘孜—理塘洋壳俯冲作用晚期岩浆活动的产物。全岩地球化学特征显示,地苏嘎石英闪长玢岩具有中等的SiO2含量,较高的Al2O3及全碱(K2O+Na2O)含量。全岩亏损高场强元素,富集大离子亲石元素,稀土元素配分曲线呈典型的右倾状,显示出轻稀土富集、重稀土相对亏损的特点。主量元素和微量元素成矿指示方面的研究结果表明:与普朗38个与成矿有关的石英闪长玢岩的全岩数据相比,地苏嘎石英闪长玢岩具有相对较低的SiO2和Y含量、较高的∑REE和(La/Yb)N比值,但二者的Al2O3/(CaO+Na2O+K2O)比值及MnO含量差别不大。在成矿与非成矿斑岩的SiO2- Al2O3/(CaO+Na2O+K2O)和Y-MnO图解中,地苏嘎石英闪长玢岩与普朗石英闪长玢岩数据投图结果类似。此外,地苏嘎斑岩体在物探异常、化探异常及遥感影像特征上具有明显的矿化标志,同时岩体的剥蚀深度小于侵位深度,有利于矿床的保存。以上研究结果表明地苏嘎斑岩体具有成为斑岩型铜矿床的潜力。

关键词: 中甸地苏嘎, 斑岩铜矿, 普朗, 地球化学, 成矿与非成矿斑岩

Abstract:

Disuga Indosinian porphyry, proved as quartz diorite porphyry, is located at the north of the eastern-porphyry belt in Zhongdian island arc. Influenced by subduction of the Ganzi-Litang Ocean, both porphyries from Disuga and Pulang super-large porphyry copper deposit, are products of the same magmatic activity in the late subduction. Studies on major element compositions show that Disuga quartz diorite porphyries contain normal SiO2 but high Al2O3 and alkali (K2O +Na2O) contents. The porphyries are also enriched in large ion lithophile elements (LILEs) and depleted in high field strength elements (HFSEs).Light and heavy rare earth elements are highly fractionated in these porphyries,and they are enriched in LREEs but depleted in HREEs.Compared with 38 chemical data of Pulang ore-bearing quartz diorite porphyries, Disuga quartz diorite porphyries have lower SiO2 and Y, higher ∑REE and (La/Yb)N ratio, but similar MnO and Al2O3/(CaO+Na2O+K2O) ratio. In diagrams of SiO2-Al2O3/(CaO+Na2O+K2O) and Y-MnO for ore-bearing and baron porphyries, Disuga porphyries data were ploted in the same area as Pulang. In addition, Disuga porphyries have obvious anomalies of geophysical survey, geochemical prospecting and remote sensing images, which can serve as mineralized indicators. The local denudation predicted was less than the porphyry emplacement in depth, which was more favorable to the ore preservation. The above results indicate that Disuga porphyry intrusion has the potential to hold a certain large scale porphyry copper deposit.

Key words: Disuga, Zhongdian, porphyry copper deposit, Pulang, geochemistry, ore-bearing and baron porphyries

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