新疆东天山沙泉子铁（铜）矿区岩浆岩成因

发布时间：2018-06-17 12:43

本文选题：锆石U-Pb年龄 + Hf同位素　；参考：《新疆大学》2015年硕士论文

【摘要】：东天山是中亚成矿域的重要组成部分,具有极为复杂的地质演化历史,也是我国最重要的铁矿、有色金属和铜镍矿床成矿带之一。东天山地区广泛分布着石炭纪岩浆岩,并且在石炭纪火山岩中发育多个铁(铜)多金属矿床,因此石炭纪岩浆岩是重建东天山造山带构造格局的重要研究对象,也是研究火山岩型铁矿床成矿过程的关键。沙泉子铁(铜)矿床是东天山地区赋存于火山岩中的矿床之一,矿体产于底坎尔组玄武岩与英安岩接触部位,在闪长玢岩与围岩接触带上也可见不规则铁矿化,并且矿区出露有同时代的侵入岩。本论文对沙泉子铁(铜)矿区的火山岩及侵入岩开展了详细的年代学、岩石学和岩石地球化学研究。为东天山地区火山岩型铁矿床成因及该区的构造地质背景研究提供重要信息。目前取得的主要认识有:(1)沙泉子铁(铜)矿床赋存于东天山阿奇山-雅满苏成矿带底坎尔组火山-沉积地层中,火山岩为基性-中性-酸性连续序列,以中基性岩为主。其中底坎尔组流纹岩的锆石LA-ICP-MS U-Pb年龄为(321.7±1.7)Ma,与成矿有关的闪长玢岩形成于(322.2±1.7)Ma,是早石炭世末岩浆活动的产物,磁铁矿化不早于322Ma。(2)矿区早二叠世岩浆活动强烈,出露的闪长岩锆石LA-ICP-MS U-Pb年龄为282.5~276.3Ma。(3)底坎尔组火山岩属钙碱性系列,富集轻稀土元素(LREE)和大离子亲石元素(LILE),亏损高场强元素(Nb、Ta、Ti),具有岛弧火山岩地球化学特征。(4)早石炭世岩浆岩是陆缘弧环境的产物,基性、中性和酸性岩来自不同的源区,基性岩来源于受俯冲板片流体交代的亏损地幔,中性岩为基性岩分离结晶的产物,流纹岩是新生地壳物质部分熔融形成。幔源岩浆为铁矿化提供了重要的物质来源。(5)早二叠世侵入岩是后碰撞环境的产物,天山古生代洋盆在早二叠世已经闭合。
[Abstract]:East Tianshan is an important part of the metallogenic region of Central Asia, which has a very complicated geological evolution history and is also one of the most important metallogenic belts of iron ore, non-ferrous metals and copper-nickel deposits in China. Carboniferous magmatic rocks are widely distributed in the East Tianshan area, and many iron (copper) polymetallic deposits are developed in the Carboniferous volcanic rocks. Therefore, Carboniferous magmatic rocks are important research objects for reconstructing the tectonic pattern of the East Tianshan orogenic belt. It is also the key to study the metallogenic process of volcanic iron deposit. The Shaquanzi iron (copper) deposit is one of the deposits occurring in volcanic rocks in the East Tianshan area. The orebody occurs in the contact site between basalt and dolomite of the Dikaner formation, and irregular iron mineralization can also be seen in the contact zone between diorite porphyrite and surrounding rock. And the mining area exposed a contemporaneous intrusive rock. In this paper, detailed geochronological, petrological and petrogeochemical studies of volcanic rocks and intrusive rocks in Shaquanzi iron (copper) mine are carried out. It provides important information for the origin of volcanic type iron deposit and the study of tectonic geological background in East Tianshan area. At present, the main knowledge obtained is that the Shaquanzi iron (copper) deposit occurs in the volcanic and sedimentary strata of the Decaner formation in the Aqishan Yarmansu metallogenic belt in the East Tianshan Mountains. The volcanic rock is a basic-neutral acid continuous sequence, and the middle basic rock is the main one. The zircon LA-ICP-MS U-Pb age of the rhyolite is 321.7 卤1.7 Ma.The ore-forming diorite porphyrite was formed at 322.2 卤1.7 Ma. it is the product of the late Carboniferous magmatism, and the magnetization is not earlier than the early Permian magmatism in the ore area. The zircon LA-ICP-MS U-Pb age of the exposed diorite is 282.5 (276.3Ma.Pu. 3) the volcanic rocks of the Dikaner formation belong to the calc-alkaline series. The early Carboniferous magmatic rocks are the products of the continental margin arc environment. The basic, neutral and acidic rocks come from different source areas. The basic rocks are derived from the depleted mantle which is metasomatized by subduction plate schist fluid. The neutral rocks are the product of the separation and crystallization of the basic rocks and the rhyolite is formed by the partial melting of the material in the new crust. Mantle-derived magma provides an important material source for iron ore mineralization.) the early Permian intrusive rocks were the product of post-collision environment. The Tianshan Paleozoic ocean basin was closed in the early Permian.
【学位授予单位】：新疆大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：P618.41;P618.31;P588.1

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