摘要
治岭头矿床上部(火山岩盖层)以铅锌矿床、硫矿床为主,中间(变质岩基底)以金银矿、铅锌矿为主,深部(侵入岩体)以斑岩型钼矿床为主的"三层楼"模式。本文在前人研究的基础上,通过辉钼矿Re-Os同位素定年技术对治岭头矿床进行了成矿时代的厘定。6件辉钼矿样品的模式年龄为113.7~114.6 Ma,加权平均年龄为114.03±1.78 Ma,表明治岭头钼多金属矿床成矿作用发生于早白垩世晚期。该矿床辉钼矿样品的Re含量变化于16.05×10-6~66.29×10-6,表明其成矿物质具有壳幔混源的特征。矿石硫同位素组成变化范围较窄(-2.1‰~2.6‰),具有相对均一的来源,可能主要来自上地幔或下地壳的深源岩浆,但也可能受到陆壳沉积物的混染。治岭头钼铅锌金多金属矿床矿石铅同位素组成变化范围比较小,208Pb/204Pb、207Pb/204Pb、206Pb/204Pb的范围分别为38.765~39.137、15.523~15.751、18.450~18.667,具有明显的壳幔混合特征。治岭头钼多金属矿床成矿年龄的厘定为下一步在区内开展同时期的斑岩成矿系统找矿勘探提供了重要的线索,同时为进一步深入研究中国东南沿海大陆边缘成矿带成岩成矿作用提供了新的资料和证据。
The Zhilingtou deposit has a "three-story" mode: the upper part(volcanic rock caprock) is dominated by lead-zinc deposits and sulfur deposits, the middle section(metamorphic rock basement) by gold-silver and lead-zinc deposits, and the deep part(intrusive rock) by porphyry molybdenum deposits. Based on the previous studies, this paper determined the ore-forming age of the Zhilingtou deposit by molybdenite Re-Os isotope dating. The model age of the six molybdenite samples was 113.7~114.6 Ma, with a weighted average age of 114.03±1.78 Ma, indicating that the mineralization of the Zhilingtou Mo polymetallic deposit occurred in the late stages of the Early Cretaceous. The Re content of the molybdenum sample in this deposit changed from 16.05×10-6 to 66.29×10-6, indicating that its ore-forming material has the characteristics of crust-mantle mixed source. The sulfur composition of sulphide has a narrow range of changes(-2.1‰~2.6‰), which reaches the equilibrium of isotope fractionation and may be derived mainly from the deep magma of the upper mantle or the lower crust. It has a relatively uniform source of sulfur, but may also be affected by the continental crust. The range of lead isotope composition of the ore minerals from the Zhilingtou Mo-Pb-Zn-Au polymetallic deposit is relatively small. The values of 208Pb/204Pb, 207Pb/204Pb, and 206Pb/204Pb are 38.765~39.137, 15.523~15.751, 18.450~18.667, respectively, indicate crust-mantle mixing characteristics. The determination of the ore-forming age of the Zhilingtou Mo polymetallic deposit provides an important clue for the prospecting of contemporary porphyry ore-forming systems in the region, and provides new information for further studying the petrogensis and metallogeny of the southeast coastal metallogenic belt.
作者
楚克磊
陈小荣
齐刚
高翔
胡博
李胜进
CHU Kelei;CHEN Xiaorong;QI Gang;GAO Xiang;HU Bo;LI Shengjin(Chinese Academy of Geological Sciences,Beijing,100037;State Key Laboratory for Mineral Deposits Research,Nanjing University,Nanjing,210093;No.7 Geological Party of Zhejiang Province,Lishui,Zhejiang,323000)
出处
《地质学报》
EI
CAS
CSCD
北大核心
2020年第8期2325-2340,共16页
Acta Geologica Sinica
基金
南京大学内生金属矿床成矿机制研究国家重点实验室开放基金项目(2018-LAMD-K10)
中国地质科学院基本科研业务费课题(编号JYYWF20180601)共同资助成果。
关键词
治岭头钼铅锌金多金属矿床
辉钼矿RE-OS定年
成矿物质来源
东南沿海成矿带
Zhilingtou Mo-Pb-Zn-Au polymetallic deposit
molybdenite Re-Os dating
sources of ore-forming materials
southeast coastal metallogenic belt
