本文選題：鋯石U-Pb年齡 + Hf同位素��； 參考：《新疆大學》2015年碩士論文

【摘要】：東天山是中亞成礦域的重要組成部分,具有極為復雜的地質演化歷史,也是我國最重要的鐵礦、有色金屬和銅鎳礦床成礦帶之一。東天山地區(qū)廣泛分布著石炭紀巖漿巖,并且在石炭紀火山巖中發(fā)育多個鐵(銅)多金屬礦床,因此石炭紀巖漿巖是重建東天山造山帶構造格局的重要研究對象,也是研究火山巖型鐵礦床成礦過程的關鍵。沙泉子鐵(銅)礦床是東天山地區(qū)賦存于火山巖中的礦床之一,礦體產于底坎爾組玄武巖與英安巖接觸部位,在閃長玢巖與圍巖接觸帶上也可見不規(guī)則鐵礦化,并且礦區(qū)出露有同時代的侵入巖。本論文對沙泉子鐵(銅)礦區(qū)的火山巖及侵入巖開展了詳細的年代學、巖石學和巖石地球化學研究。為東天山地區(qū)火山巖型鐵礦床成因及該區(qū)的構造地質背景研究提供重要信息。目前取得的主要認識有:(1)沙泉子鐵(銅)礦床賦存于東天山阿奇山-雅滿蘇成礦帶底坎爾組火山-沉積地層中,火山巖為基性-中性-酸性連續(xù)序列,以中基性巖為主。其中底坎爾組流紋巖的鋯石LA-ICP-MS U-Pb年齡為(321.7±1.7)Ma,與成礦有關的閃長玢巖形成于(322.2±1.7)Ma,是早石炭世末巖漿活動的產物,磁鐵礦化不早于322Ma。(2)礦區(qū)早二疊世巖漿活動強烈,出露的閃長巖鋯石LA-ICP-MS U-Pb年齡為282.5~276.3Ma。(3)底坎爾組火山巖屬鈣堿性系列,富集輕稀土元素(LREE)和大離子親石元素(LILE),虧損高場強元素(Nb、Ta、Ti),具有島弧火山巖地球化學特征。(4)早石炭世巖漿巖是陸緣弧環(huán)境的產物,基性、中性和酸性巖來自不同的源區(qū),基性巖來源于受俯沖板片流體交代的虧損地幔,中性巖為基性巖分離結晶的產物,流紋巖是新生地殼物質部分熔融形成。幔源巖漿為鐵礦化提供了重要的物質來源。(5)早二疊世侵入巖是后碰撞環(huán)境的產物,天山古生代洋盆在早二疊世已經閉合。
[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 鹵1.7 Ma.The ore-forming diorite porphyrite was formed at 322.2 鹵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.
【學位授予單位】：新疆大學
【學位級別】：碩士
【學位授予年份】：2015
【分類號】：P618.41;P618.31;P588.1

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本文編號：2031081