【作者】 骆地伟；

【导师】 周宗桂；

【作者基本信息】 中国地质大学 ， 矿物学、岩石学、矿床学， 2008， 硕士

【摘要】 程潮铁矿位于鄂城岩体南缘,产出于燕山期花岗岩与三叠系大冶群(Tldy)的碳酸盐岩接触带上及附近,是鄂东地区重要的大型富铁矿床。矿区地层出露极少,仅于矿区南部出露部份三叠系和侏罗系地层,其中三叠系大冶群(Tldy)和蒲圻群(T2+3pq)与程潮铁矿有密切的空间关系。矿区的断裂构造比较复杂,规模较大的呈NWW向和NNE向,这些断裂在成岩成矿前或成岩成矿期间已相当发育,对岩体、岩脉、蚀变和矿化的空间分布及产状起到了不同程度的控制作用。矿区及其附近的岩浆岩有黑云母辉石闪长岩、闪长岩、石英二长岩、花岗岩、正长斑岩和闪长玢岩等。矿床主要由Ⅰ-Ⅶ号7个矿体组成,其中又以Ⅱ、Ⅲ和Ⅵ号铁矿体规模最大,累计储量占矿床储量的94.8%。矿体成群展布,平面投影呈北西西向似平行带状分布,剖面上呈首尾错叠的雁行状排列。矿体形态多呈透镜状,倾向南或南南西,倾角0°～57°,向北西西向侧伏,侧伏4°～18°,赋存标高从Ⅰ号到Ⅶ号矿体依次加深。矿石的矿物成分较复杂,主要的金属矿物有磁铁矿、赤铁矿、黄铁矿、黄铜矿、磁黄铁矿、穆磁铁矿、镜铁矿、斑铜矿等。矿石具中粒-细粒的白形-半自形结构、交代残余结构、破碎结构和填隙结构等。构造以块状构造、浸染状构造、条带构造和角砾状构造为主。此外,矿区广泛发育有矽卡岩化、绿泥石化和硬石膏化等围岩蚀变。程潮铁矿床为矽卡岩型铁矿床,该矿床主要矿体的形成与分布受侵入-接触构造体系的控制。因此,加强对矿区接触带构造体系控矿规律的研究,是程潮铁矿深部找矿工作的关键科学问题。本次研究将矿床学、矿田构造学与计算机技术相结合,运用趋势面分析对与成矿有密切关系的花岗岩体接触带构造进行研究,查明其产状特征、岩体侵位方向和垂向上变化的异常区域。在此基础上,运用GeoMine 3D系统对花岗岩接触带构造与矿体进行三维可视化建模,分别构建矿体三维可视化模型、岩体接触带可视化模型及岩体接触带控矿三维可视化模型(前二者的叠合),从直观、科学地角度分析花岗岩体接触带产状要素与铁矿体形态、产状、空间分布特征之间的联系,总结接触带构造控矿规律。进行程潮铁矿深部成矿预测。主要认识和结论:1.研究了铁矿床的控矿因素:①三叠系下统大冶群(Tldy)的白云质大理岩、三叠系下统大冶群(Tldy)上岩性段和三叠系中上统蒲圻群(T2+3pq)下岩性段中的含石膏盐碳酸盐岩以及三叠系中上统蒲圻群(T2+3pq)的泥质角岩与铁矿成矿关系密切;②矿液是沿着花岗岩接触面的继承性构造断裂运移,然后充填和交代围岩成矿。矿体分布系受接触带构造及北西西向挤压带中所属的各种断裂的控制;③花岗岩和程朝铁矿床成因、矿体空间分布有极为密切的联系。2.根据花岗岩体接触带纵投影趋势面分析:①花岗岩体接触带构造产状总体走向NWW向,向SSW倾斜,倾角平均约50°左右,并明显向SWW(W)侧伏。②花岗岩沿SWW向NEE上侵;③花岗岩体接触带构造在垂向上变化的异常区域和主要矿体的分布密切对应。即负高异常区和各矿体的主体位置吻合;正、负异常的中心连线呈直线性且交替出现,在其之间的位置是铁矿体产出的主要部位。3.运用地质体三维可视化技术构建了矿体三维可视化模型、岩体接触带可视化模型及岩体接触带控矿三维可视化模型,并总结了花岗岩体接触带构造的控矿规律:①主要铁矿体产出于花岗岩外接触面,且向W(SWW)缓缓侧列展布成群。②矿体群的侧列方向为W(SWW),和岩体的侧伏方向SWW(W)基本一致。③花岗岩体顶面凹凸不平,铁矿体赋存在接触面由陡变缓的凹陷或平台的地段。4.深部找矿预测,根据上述研究,提出程潮铁矿深部还有找矿前景,具体的深部找矿有利位置有:①Ⅵ矿体11线SEE方向延伸到20线,相应标高范围(-600～-800m);②Ⅶ矿体27线SEE方向延伸到11线,相应标高范围(-800～-1000m);③Ⅶ矿体43-55线之间下部,相应标高(-900～-1150m)。更多还原

【Abstract】 Chengchao iron deposit in Hubei province is in the south of lithosome in E town,located in the connecting zones between Yanshanian granite and late Triassic Daye formation(T1dy) carbonatite.The deposit is the important iron deposit in Edong area.The area rarely exposed stratum,only exposed partial Triassic and Jurassic stratum in the southern,and in which Triassic Daye(T1dy)and Puxi(T2+3pq)formation had important space relationship with Chengchao iron deposit.The fracture structure was in NWW and NNE direction,which properly developed before diagenesia and metallogenesis or during diagenesia and metallogenesis,and which controlled spatial distribution and location of lithosome,vein,alteration and mineralization.The magmatic rock in and near this area was biotite-augite-diorite,diorite,quartz monzonite,granite,orthoclase-porphyry,diorite-porphyrite,and so on.The deposit makes up of seven orebodies.Ⅱ、ⅢandⅥorebodies are the largest scale of them,and their storge is 94.8 percentage of the whole ores.The plane projection of ores is like parallel banding distribution of NWW direction.The ores form overlapped echelon shape from head to end in profile chart.The ores are commonly lentoid shape,with dipping south or south-south-west direction and rake angle is 0-57 degrees,with siding NWW direction in 4-18 degrees.The height mark is gradually deepened fromⅠtoⅦ.In the area,main metal mineral is magnetite,hematite,pyrite,chalcopyrite,pyrrhotite,specularite,bornite,and so on.The texture of ores is medium-grained to fine-grained automorphic-hypidiomorphic texture,metasomatic relict texture,brocken texture,intersertal texture,and so on.The structure of ores are mainly blocklike structure,impregnation structure,streaky structure and brecciated structure.The wall-rock alteration in the area is skarnization,chloritization and anhydrization.Chengchao iron deposit in Hubei province is a typical skarn iron ore deposit in Edong area,and the formation and distribution of the main orebody controlled by the intrusion-contact tectonic system.Therefore,strengthening the research on the ore-controlling regularity of contact zone tectonic system is the key scientific problem about deep exploration in Chengchao iron deposit.Combining mineral deposit geology and orefield structure geology with computer technology,we use trend surface analysis for contact zone tectonic of granite lithosome which is closely related to mitallization,so we find its occurrence characteristics,the direction of lithosome invasion and changed abnormal region in vertical direction.In its basis,China University of Geosciences GeoMine 3D system is used to construct three-dimensional visualization models of orebody,contact zone of lithosome and ore-controlled by contact zone of lithosome(the former two superimposed),for contact zone tectonic of granite lithosome and ore body.From the intuitionistic and scientific view,the research analyses contact zone of granite lithosome and the relationship with shape,production and spatial distribution of iron orebody, and summaries ore-controlling regularity of contact zone tectonic for deep metallogenic prognosis.I get the following view points:1.The research studies ore-controlling factors of the iron ore deposit:①Triassic Daye formation dolomitic marble(T1dy),Daye formation(T1dy)and Puxi formation(T2+3pq) carbonate rocks with gypsum and Puxi formation(T2+3pq)pelitic hornstone have close relation with metallization;②The ore fluid move along the succession tectonics fracture of granite surface,and then fill and alternate wall rock for mineralization.The distribution of ore body has been controlled by contact zone tectonic and different fracture in NWW squeezing belt;③The granite and ore deposit genesis,the spatial distribution of ore bodies in the Chengchao iron deposit are extremely close ties.2.According to trend surface analysis with granite contact zone projection in longitudinal direction,we get conclusions as follows:①The granite lithosome contact zone tectonic with NWW to the overall direction,lean to SSW,with rake angle at an average of about 50 degrees, and obviously side to SWW(or west).②The granite invade along the SWW to NEE;③The changing abnormal areas of granite contact zone tectonic in vertical direction and the the distribution of main ore body are closely corresponding.That is,negative altitude abnormal areas correspond with the main location of ore bodies;the line of centres with positive and negative abnormal area is a straight line and alternating appear,and between them is the main site of the orebody.3.GeoMine 3D system is used to construct three-dimensional visualization models of orebody,contact zone of lithosome and ore-controlled by contact zone of lithosome.We summary ore-controlling regularity of the granite lithosome contact zone tectonic:①The major iron orebody locates in external contact surface of the granite,and sides slowly to the W(SWW)in distribution groups.②The side array direction W(SWW)of the orebody groups and the side direction SWW(W)of the lithosome tend to unification.③The top surface of the granite lithosome is sags and crests.The orebodies usually lie in platform or sag of the contact surface.4.On these bases,some preferable sections with potential prospecting are forecast:①FromⅥOrebody 11-exploration section in SEE direction extended to 20-exploration section,the corresponding height mark range is -600～-800m;②FromⅦOrebody 27--exploration section in SEE direction extended to 11-exploration section,the corresponding height mark range is -800～-1000m);③On the bottom betweenⅦorebody 43--exploration section and 55-exploration section,the corresponding height mark range is -900～-1150 m,which is the favorable space of mineralization.更多还原