福建漳平洛阳铁矿“三位一体”特征及成矿机制研究

发布时间：2018-03-05 00:13

本文选题：洛阳铁矿　切入点：三位一体　出处：《中国地质大学(北京)》2017年硕士论文　论文类型：学位论文

【摘要】：福建漳平洛阳铁多金属矿床位于闽西南坳陷的东缘,政和大埔断裂的南东侧。该区在前泥盆纪时期形成地区古老基底,在晚古生代时期形成盆地,以沉积一套晚古生代地层为特色,而在中生代时期则发生了强烈的构造变形,并伴随有大规模的岩浆活动,并在各时期形成不同规模的矿床。洛阳铁矿作为“马坑式”铁矿的代表性矿床,其研究意义重大。本文从“三位一体” 成矿地质体,成矿构造和成矿结构面,成矿作用标志等成矿要素方面进行了研究,探讨了矿床成因和成岩成矿时代,建立了成矿机制和找矿模型。洛阳铁矿花岗岩体主要为由中细粒斑状花岗岩和花岗斑岩组成的复式岩体,侵入时期为153±1Ma和129±1Ma两个阶段。地球化学成分上岩体具有高硅,富碱,高钾钙碱性,弱过铝质特征,富集大离子亲石元素,亏损高场强元素,具有I型花岗岩特征,为下地壳重熔型花岗岩,混入少量幔源物质,显示为后碰撞环境,体现出晚侏罗世晚期早白垩世期间从挤压到伸展转换的构造背景。洛阳铁矿中辉钼矿床的主要形成时代为133.0±1.9Ma~134.0±4.2Ma。推出洛阳铁矿成矿时代为早白垩世。结合地球化学特征,推出早白垩世(130Ma±)花岗岩体与成矿密切相关,为成矿地质体。洛阳铁矿受构造和岩性及构造差异性界面硅钙面控制。背斜褶皱构造、推覆构造和滑脱构造为成岩成矿提供了良好的运移通道和成矿空间。洛阳铁矿主矿体赋矿层位为林地组(C1l)碎屑岩与船山组-栖霞组(C3c-P1q)灰岩之间的层间破碎带,以及花岗斑岩与碳酸盐岩的接触带附近,为层控矽卡岩型矿床。在矿床成因方面,本文对洛阳矿床中石英开展了氢-氧同位素和对黄铁矿、辉钼矿开展了硫同位素研究。其中氢-氧同位素结果为δD投点基本落入岩浆水范围内,说明洛阳铁矿床具有岩浆源的特点。洛阳矿区硫同位素分布特征属于深部岩浆硫值的范围,说明硫化物来源于深部岩浆热液。通过Re同位素测定,岩浆具有壳幔混源特点。所以,洛阳铁矿成矿物质来源于壳幔混源的深部岩浆热液。通过对洛阳铁矿成矿要素的研究,表明了洛阳铁矿是严格受地层,构造和花岗岩联合控制的层控矽卡岩型矿床,同时建立了成矿模式与找矿勘查模型,对“马坑式”矿床成因和成矿机制的研究具有重大意义。
[Abstract]:The Luoyang iron polymetallic deposit in Zhangping, Fujian Province, is located in the eastern margin of southwestern Fujian depression and the south east side of Zhenghe Tai Po fault. The ancient basement of the area was formed during the pre-Devonian period and the basin was formed during the late Paleozoic. It is characterized by a set of late Paleozoic strata, and a strong tectonic deformation occurred during the Mesozoic period, accompanied by large-scale magmatic activity. The study of Luoyang Iron Mine, as a representative deposit of "Maqing-type" iron ore, is of great significance. In this paper, the ore-forming geological bodies, ore-forming structures and ore-forming structure planes of "trinity" are studied. In this paper, the metallogenic factors, such as metallogenic markers, are studied, and the genesis of the deposits and the diagenetic and metallogenic epoch are discussed. The ore-forming mechanism and prospecting model have been established. The Luoyang iron ore granitic body is mainly composed of medium-fine-grained porphyry granite and granitic porphyry, and the intrusive period is 153 卤1Ma and 129 卤1Ma. The ore-body is rich in silicon and alkali-rich in geochemical composition. High potassium calcium alkalinity, weak peraluminous characteristics, enrichment of large ion lithophile elements, depletion of high field strength elements, I type granite features, is a lower crust remelting type granite, mixed with a small amount of mantle material, showing a post-collision environment, The main forming age of molybdenum deposit in Luoyang iron deposit is 133.0 卤1.9 Ma-134.0 卤4.2 Ma.The metallogenic age of Luoyang iron deposit is early Cretaceous, which is combined with geochemical characteristics, and the ore-forming age of Luoyang iron deposit is early Cretaceous. The early Cretaceous (130Ma 卤) granite body is closely related to metallogenesis and is a ore-forming geological body. Luoyang Iron Mine is controlled by structure, lithology and the interface of structural difference, calcium silicate surface, anticline fold structure, etc. The nappe structure and slip structure provide a good migration channel and ore-forming space for diagenesis and mineralization. The ore-bearing horizon of the main orebody of Luoyang Iron Mine is the interlayer fracture zone between the detrital rock of woodland formation and the C3c-P1qlimestone of Chuanshan formation-Qixia formation. And near the contact zone between granitic porphyry and carbonate rock, it is a stratabound skarn type deposit. In terms of genesis of the deposit, hydrogen oxygen isotope and pyrite have been developed for quartz in Luoyang deposit. Sulfur isotopic studies have been carried out in molybdenum ores, in which the hydrogen and oxygen isotopic results show that 未 D point basically falls into the magmatic water range. It shows that the Luoyang iron deposit has the characteristics of magmatic source. The sulfur isotopic distribution of Luoyang ore area belongs to the range of sulfur value of deep magma, indicating that sulfide originates from deep magmatic hydrothermal solution. Therefore, the ore-forming material of Luoyang iron ore is derived from the deep magmatic hydrothermal fluid from the crust-mantle mixing source. Through the study of the ore-forming elements of Luoyang Iron Mine, it is shown that Luoyang Iron Mine is strictly subject to strata. The stratabound skarn type deposit controlled jointly by tectonics and granite is of great significance to the study of genesis and metallogenic mechanism of the "Maqing-type" deposit, and the metallogenic model and prospecting model have been established at the same time.
【学位授予单位】：中国地质大学(北京)
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：P618.31

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