本文選題：密云縣 + BIF型鐵礦床　； 參考：《中國地質(zhì)大學(xué)(北京)》2015年碩士論文

【摘要】：桑園鐵礦床屬于華北地臺重要的鐵礦集區(qū)之一—冀東—密懷礦集區(qū),礦床成因類型為火山—沉積變質(zhì)型(BIF)礦床。本文通過野外地質(zhì)調(diào)查、鉆探施工和室內(nèi)巖相學(xué)、礦相學(xué)研究,深入闡述了桑園鐵礦的地質(zhì)特征,在此基礎(chǔ)上,結(jié)合前人的相關(guān)研究成果,總結(jié)了礦床的成礦規(guī)律,建立了礦床成礦模式,并結(jié)合地面磁測及井中物探的資料,對礦區(qū)深部及周邊進(jìn)行成礦預(yù)測。主要取得了以下認(rèn)識:1、桑園鐵礦賦存于太古宇密云群大漕組,礦區(qū)出露的巖性主要為黑云斜長片麻巖、黑云輝石斜長片麻巖、石榴輝石斜長片麻巖、黑云二長片麻巖及磁鐵石英巖。礦區(qū)構(gòu)造發(fā)育較弱,多為一些局部小褶皺和小斷層,它們對礦體的形態(tài)和分布具有一定的影響。礦體呈似層狀、透鏡狀,北東向展布,變化較穩(wěn)定。礦石主要為磁鐵石英巖,具粒狀變晶結(jié)構(gòu),條帶狀構(gòu)造或片麻狀構(gòu)造。礦床整體上位于高嶺-西恒河大型復(fù)式向斜的東南翼,其空間分布受該復(fù)式向斜控制。2、礦層產(chǎn)狀與圍巖一致,其空間分布受地層層位控制。礦床形成時代為中太古代,成礦年齡大于2800Ma,礦床經(jīng)歷了角閃巖相—麻粒巖相的區(qū)域變質(zhì)作用的改造。礦層頂、底板圍巖普遍發(fā)育石榴石化,深紅色的石榴子石富集成明顯的條帶狀,可作為鉆探工程預(yù)見礦或過礦的參考標(biāo)志。3、桑園鐵礦的成因類型為火山—沉積變質(zhì)型,成礦環(huán)境為遠(yuǎn)離火山活動中心的相對穩(wěn)定的海盆環(huán)境,成礦物質(zhì)來源于海底火山活動。礦床的成礦模式為:海底火山活動噴出的富含鐵質(zhì)和硅質(zhì)的熱液,在上升性洋流作用下運移到淺部,Fe2+被氧化沉淀形成鐵質(zhì)層,而海水化學(xué)平衡的改變導(dǎo)致硅質(zhì)的沉淀形成硅質(zhì)層。礦石條帶狀構(gòu)造的形成可能與周期性的上升流有關(guān),而海底火山活動的多旋回性造成礦體具有多層性。4、地面磁測的成果顯示,桑園鐵礦區(qū)東南側(cè)磁異常明顯,預(yù)測該區(qū)具有較大的找礦潛力。井中磁測的結(jié)果,以ZK170-1鉆孔為例,△Z曲線負(fù)張口,△T'曲線正張口,△H⊥與△H//矢量向線簇較短,反映礦區(qū)深部的找礦潛力不大。
[Abstract]:The Sangyuan iron deposit belongs to one of the important iron ore accumulation areas of the North China platform Jidong Mihuai ore accumulation area. The genetic type of the deposit is the volcanic sedimentary metamorphic type BIF-deposit. Based on field geological investigation, drilling construction, laboratory petrography and mineralogy, the geological characteristics of Sangyuan Iron Mine are expounded in depth. On the basis of this, the metallogenic regularity of the deposit is summarized in combination with the related research results of predecessors. The metallogenic model of the ore deposit is established, and the metallogenic prediction is carried out on the deep and periphery of the ore area with the data of surface magnetic survey and geophysical exploration in the well. We have obtained the following understanding: Sangyuan Iron Mine is located in the Dacao formation of Miyun Group, Taigu. The lithology of the ore area is mainly composed of black cloud plagioclase gneiss, black cloud pyroxene obliquity gneiss, pomegranate plagioclase gneiss, and garnet gabbro plagioclase gneiss. Black cloud gneiss and magnetite quartzite. The structure of the mining area is relatively weak, most of them are local small folds and small faults, which have certain influence on the shape and distribution of orebody. The orebody is layered, lenticular, and distributes from north to east, and its variation is stable. The ore is mainly magnetite quartzite, with granular metamorphic structure, stripe-like structure or sheet-like structure. As a whole, the deposit is located in the southeast wing of the large complex syncline of Kaoling-Xihang River. The spatial distribution of the deposit is controlled by the complex syncline. The occurrence of ore bed is consistent with that of surrounding rock, and its spatial distribution is controlled by the stratigraphic position. The ore deposit was formed in the Middle Archean with a metallogenic age of more than 2800Ma.The deposit underwent the transformation of regional metamorphism of amphibolite facies and granulite facies. Pomegranate fossilization is widely developed in the surrounding rock of the top and bottom of the ore bed, and the Shi Fu of the crimson pomegranate has obvious strip shape, which can be used as the reference mark of the drilling engineering to foresee the ore or go through the ore. The origin type of the Sangyuan iron deposit is volcanic-sedimentary metamorphic type. The ore-forming environment is a relatively stable oceanic environment far from the center of volcanic activity, and the ore-forming material originates from submarine volcanic activity. The ore-forming model of the deposit is as follows: hydrothermal fluid, rich in iron and siliceous, spewed from undersea volcanic activity, transported to the shallow part of Fe _ 2 to be oxidized and precipitated to form an iron layer under the action of rising ocean currents. The change of the chemical equilibrium of seawater results in the formation of siliceous layer. The formation of ore stripe structure may be related to the periodic upwelling, and the polycycle of submarine volcanic activity causes the orebody to have multilayer. 4. The results of surface magnetic survey show that the southeast side of Sangyuan Iron Mine is obviously abnormal. It is predicted that this area has great prospecting potential. Taking ZK170-1 borehole as an example, the results of magnetic logging in wells show that Z curve is negative, T 'curve is positive, H ~ (-) and H _ (-) / vector linear cluster is short, which shows that the prospecting potential in deep mining area is not great.
【學(xué)位授予單位】：中國地質(zhì)大學(xué)(北京)
【學(xué)位級別】：碩士
【學(xué)位授予年份】：2015
【分類號】：P618.31

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本文編號：1974402