地学前缘 ›› 2015, Vol. 22 ›› Issue (3): 357-367.DOI: 10.13745/j.esf.2015.03.031

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浙江金华银坑斑岩型钼矿床的成岩成矿作用:来自岩石学、岩石地球化学、同位素与锆石SHRIMP U-Pb年代学的证据

王科强, 张德会, 王晨昇, 印贤波, 朱玉娣, 付芬   

  1. 中国地质大学(北京) 地球科学与资源学院, 北京 100083; 中国地质大学 地质过程与矿产资源国家重点实验室, 北京 100083; 北京东方燕京矿山工程设计有限责任公司, 北京 100070; 中国有色金属矿产地质调查中心, 北京 100012; 西藏金龙矿业股份有限公司, 西藏 拉萨 850000; 西南石油大学 地球科学与技术学院, 四川 成都 610500
  • 收稿日期:2014-05-20 修回日期:2014-09-20 出版日期:2015-05-15 发布日期:2015-05-15
  • 作者简介:王科强(1967—)，男，博士研究生，高级工程师，主要从事矿床学、成矿区规划与地球化学研究。E-mail：wkq32639832@sina.com
  • 基金资助:

    国土资源部公益性行业科研专项“成矿地质体找矿预测理论研究与应用示范”(201411024)；国家自然科学基金项目(41373048)；浙江省地质勘查局项目“江绍拼合带中西段铜多金属矿床成矿与成矿规律研究”

Petrogenesis and metallogeny of Yinkeng porphyry Mo deposit in Jinhua, Zhejiang: The evidence from the petrology, petrogeochemistry, isotopes and SHRIMP zircon UPb dating.

 WANG  Ke-Jiang, ZHANG  De-Hui, WANG  Chen-Sheng, YI  Xian-Bei, SHU  Yu-Di, FU  Fen   

  • Received:2014-05-20 Revised:2014-09-20 Online:2015-05-15 Published:2015-05-15

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摘要：

银坑斑岩型钼矿床细脉浸染型钼矿化分布于花岗斑岩体内部并受其控制。含矿花岗斑岩为高硅、富碱、高分异、准铝—弱过铝质A型花岗岩；稀土分布型式整体右倾，呈“V”型，具明显负Eu异常；岩石富集Rb、Th、U、LREE等大离子亲石元素，亏损Nb、Ta、Zr、Hf等高场强元素；硫主要源自岩浆，成矿流体具有以岩浆水为主，混和少量大气降水的特点。流体包裹体成分以H2O为主，另含有一定量的CO2、CH4及CO2-3等成分；(87Sr/86Sr)i值平均为0.712 38。εNd(t)值为-7.2～-1.8，平均-5.796；锆石SHRIMP UPb年龄为(110.1±1.5) Ma。研究表明：与成矿有关的岩浆作用形成于伸展构造背景下，源区主要为下地壳古老基底物质，兼有部分地幔物质的混染，岩浆侵入事件发生在中国东南部由古特提斯构造域向太平洋构造域转换作用完成之后，处于中国东南大陆岩石圈扩张伸展阶段。

关键词: 斑岩型钼矿, 岩石地球化学, SrNd同位素, 锆石SHRIMP UPb年龄, 浙江银坑

Abstract:

Yinkeng porphyry Mo deposit is located in the east of JiangshanShaoxing suture zone. The veinletdisseminated type of Mo mineralization occurred in the interior of porphyry granite. The orebearing granite was classified as Atype granite with high silica and alkaili content, strong fractionation and medium to weak peraluminous. The REE model appears “V” shape, and the enrichment of LREE is obvious with an obvious negative Eu anomalies. The granite is richer in Rb, Th, K, U, La, Ce, Pb and poorer in Ti, P, Nb, Ta, Zr, Hf. The sulfur originated mainly from magma. The metallogenic fluids comprised water and a small amount of CO2, CH4 and CO2-3, which seemed to be mixed with aqueous magma vapour and meteoric water. Orebearing porphyry has relatively high ISr(0.710910.71477) and low εNd(t)(-7.2-1.8)value, which suggests that the source rock of porphyry possibly originated from EarlyProterozoic bed rock. The mean age of Yinkeng deposit is 110.1±1.5 Ma. Research shows that the magma closely related to mineralization occurred in extensional setting. The source region of magma is the lower crust and may have been contaminated by mantle materials. The magma intrusion happened after the transition of Ancient Tethys to Pacific tectonic domain of South China, in the period of lithospheric territorial expansion.

Key words: porphyry Mo deposit, petrogeochemistry, SrNd isotopes, SHRIMP zircon UPb age, Yinkeng, Zhejiang

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