巴基斯坦吉尼奥德矿区新元古代火山岩年代学及地质意义

发布时间：2018-04-20 22:12

本文选题：巴基斯坦 + 安山岩　；参考：《地球科学》2017年12期

【摘要】：罗迪尼亚超大陆的裂解及与之相关的吉尼奥德玢岩型铁矿的形成是目前研究的热点,对安山岩锆石进行了U-Pb年龄、Hf同位素和微量元素分析.所有锆石都属岩浆成因,具有一致的稀土配分型式以及明显的Ce正异常、Eu负异常和重稀土元素富集特征.锆石年龄主要分为两组,分别为947.8±4.0Ma和883.0±5.1Ma,代表两期安山岩的成岩年龄,指示安山岩为两期岩浆活动的混合产物;此外,捕获的基底锆石年龄为1 523.0±66 Ma,属于中元古代.εHf(t)值变化范围较大(-4.67~+13.10),指示其为壳幔物质混合的产物.安山岩产生于罗迪尼亚超大陆时期,是由高温幔源岩浆通过底侵作用,使得中元古代花岗质岩石组成的下地壳发生熔融,壳幔熔体混合形成的,与伸展裂谷有关的构造热事件及地幔柱的活动有着密切关系.吉尼奥德铁矿与凯特里铜矿在成矿地质背景方面具有诸多相似性,暗示其有大型IOCG型矿床的成矿潜力.在960~880 Ma期间,印度板块西北部与华北-刚果-圣弗朗西斯科板块可能连接在一起.
[Abstract]:The pyrolysis of the Rodenia supercontinent and the formation of the associated Jinyod-porphyrite type iron ore have been the focus of research at present. The zircons of the andesite have been analyzed by U-Pb age, HF isotopes and trace elements. All zircons belong to magmatic origin, and have the same REE distribution pattern, obvious ce positive anomalies, negative EU anomalies and enrichment characteristics of heavy rare earth elements. The zircon ages are mainly divided into two groups, 947.8 卤4.0Ma and 883.0 卤5.1 Ma, representing the diagenetic ages of the andesite, indicating that the andesite is a mixture of magmatic activity in the two periods. The zircon age of the captured basement is 1 523.0 卤66 Ma, which belongs to the Mesoproterozoic. The range of 蔚 Hfcht values varies from -4.67 to 13.10, indicating that it is the product of the mixing of crust-mantle material. The andesite originated in the Lodinia supercontinent period and was formed by the melting of the lower crust composed of the Mesoproterozoic granitic rocks and the mixing of the crust and mantle melts by the high temperature mantle magma through the underplating process. The tectonic thermal events associated with the extensional rift and the activity of mantle plumes are closely related. There are many similarities in metallogenic geological background between the Gini Ore and the Kaili copper deposit, which implies the metallogenic potential of the large IOCG type deposit. During 960- 880 Ma, the northwestern Indian plate may be connected with the North China-Congo-San Francisco plate.
【作者单位】：中国地质大学地球科学学院地质过程与矿产资源国家重点实验室;中冶集团武汉勘察研究院有限公司;
【基金】：国家自然科学基金项目(No.41272079) “中巴经济走廊”成矿背景综合研究引智计划(No.T2017005)
【分类号】：P588.14

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