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海南石碌铁矿床构造变形特征及其与铁多金属成矿富集的关系 总被引：1，自引：0，他引：1
海南石碌铁矿曾被誉为“亚洲最大的富铁矿”,其形成、定位与褶皱变形及伴随的剪切、塑性流动等构造密切相关。石碌矿区构造变形大致分为早期(D1)复式向斜的形成时期、晚期(D2)褶皱叠加和剪切变形时期。后者又进一步分为韧-脆性变形(D2a),脆-韧性变形、层间滑脱断层形成(D2b)和脆性变形、矿体破坏(D2c)3个阶段。石碌铁矿床受NW—SE向复式向斜及其与NE—NNE向褶皱叠加所形成的横跨或斜跨褶皱的严格控制;褶皱过程所伴随的剪切变形和高温塑性流动是富铁矿形成的重要机制。复式向斜轴部,尤其是2期向斜褶皱轴的叠加部位往往可发现厚大的富铁矿体。 相似文献
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锡铁山矿床是中国西部的超大型铅锌矿产地之一，产于柴北缘晚奥陶世滩间山群的大理岩和片岩之中，是与海相火山喷流-沉积有关的矿床。很多学者已经从地球化学、岩石学、同位素测年等对该矿床的成矿时代、成矿流体性质、矿床成因等开展了研究，但对于锡铁山矿区构造控矿特征一直存在争议，普遍认为褶皱构造对矿区的控矿作用明显。文章主要以详实的野外观测为基础，分析了矿区的褶皱和断裂构造特征，探讨了构造对矿(床)体的控制作用，为矿区找矿勘查工作部署提供依据。通过详实的野外实测和综合对比分析表明，锡铁山矿区总体上为单斜层，不发育大型的褶皱构造，但是层内褶皱发育，包括A型褶皱和B型褶皱。发育在滩间山群a段内的A型褶皱，其褶皱枢纽与拉伸线理倾向南东，与矿区矿体的总体倾伏方向一致；而在滩间山群d段内的A型褶皱，其枢纽倾向北西；矿区内发育了多条北西西走向的大型断裂，其编号为F1—F6；分析表明，F1断层发育在早期塑性变形基础之上，晚期叠加了叠瓦逆冲推覆作用，造成了矿体及赋矿围岩的局部倒转；F2断裂大规模的左行走滑-逆冲作用导致了矿区滩间山群不同岩性段地质体的拼合接触，造成了矿区部分含矿地质体的缺失；野外填图揭示出，左行走滑的F3断裂从北西往南东，走向从330°逐渐转变为290°方向，并在南东侧末端，发育了一系列分支的左行走滑-正断层，组成"马尾状"构造，截切了矿体与围岩，并发生了横向错移。以此构造控矿特征为基础，结合矿床成因分析，进一步分析了锡铁山矿区深部的找矿方向，认为矿区南东侧深部具有良好的找矿空间；并以07号勘探线为例，根据F3及其分支断层的错移情况，分析了矿体可能被错移的位置。 相似文献
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褶皱控矿,是地质找矿勘探中经常能碰到的问题,尤其是背(向)斜对内生热液、变质改造型矿床的控矿作用。 我国许多大中型矿床是以褶皱的形式赋存。这些矿区的勘探和不断开发,在一定意义上看,就是对褶皱控矿规律本身的揭示和研究。许多矿山在开发过程中,逐渐突破了找矿勘探阶段非褶皱控矿这一认识之后,才使矿床由小变大,储量大增,最终才搞清了矿床的构造形态。 沉积矿床和其褶皱之间虽也存在着翼部、鞍部矿物质流动造成鞍、翼厚度等变化,但一般地说并不改变原有沉积的基本特征。而热液和沉积改造型矿床,褶皱除了成为赋矿空间并 相似文献
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新余铁矿田含铁岩系地层物质系统沉积的地球化学环境是一个氧化相-弱氧化相-弱还原相-还原相的演变过程.矿田经历了澄江-加里东构造旋回的多期次、多方向、多型式褶皱构造改造.新余铁矿田矿层和舍铁岩系的各种成矿地质特征以及矿田东、中、西段构造特征是铁矿的沉积成岩作用以及构造演化历史的物质反映.应用系统分析方法和历史分析方法分析矿田成矿地质系统的内在规律,总结新余铁矿田矿层和舍铁岩系变化特征,矿层顶板、底板和含铁岩系标志层特征以及矿田东、中、西段构造特征.解释新余铁矿田单层矿"红绸舞式"褶皱的成因,为铁矿勘查工作提供借鉴. 相似文献
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马坑式铁矿床是永梅晚古生代坳陷次一级北东向龙漳基底断裂凹陷带内的大型铁矿床.其赋矿层位并不是很清楚, 这影响了找矿工作.在野外地质调查和认真总结前人研究成果的基础上, 探讨了马坑式铁矿的控矿因素, 认为马坑式矿区的褶皱主体为倒转背斜, 而不是背斜的一翼; 经畲组-栖霞组(C2j-P1q)及其与上覆文笔山组(P1w)之间的界面才是马坑式铁矿的赋矿层位, 而不是林西组(C1l)与上覆经畲组-栖霞组(C2j-P1q) 之间的界面; 认为逆冲推覆构造也是重要的控矿因素, 并指出了找矿方向.燕山期逆冲推覆构造是Izanagi板块自南东向北西方向向欧亚板块之下俯冲所产生的结果. 相似文献
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阿尔金喀腊大湾铁矿田褶皱构造特征及找矿意义 总被引：2，自引：0，他引：2
通过对阿尔金山喀腊大湾铁矿田内构造的系统研究,确认矿田中东段为单斜层构造,南侧为较老的下部岩层,北侧为较新的上部岩层,岩层总体倾向北,在7910铁矿床局部出现倒转倾向南。铁矿田西段为陡枢纽褶皱构造,含铁层位(卓阿布拉克组第三岩性段第一岩性层,即下部玄武岩层)与其上覆的第二岩性层(大理岩层,标志层)、第三岩性层(上部玄武岩层)以及第四岩性段沉积岩系自7914铁矿床向西逐渐转向呈半圆形状弯曲(由EW向逐渐转向至SW向?NS向?SE向?SEE向)延伸,转折端及附近发育低级别"M"型及"S"型和"Z"型褶皱,构成直立陡倾伏背斜构造,轴面近直立东西走向,枢纽约71?向西陡倾。卓阿布拉克第四岩性段组成的外层也呈现同样的褶皱构造形态。褶皱南翼大部被后期中酸性侵入岩侵位吞噬,仅残留八八铁矿床一带一小部分,形成铁矿带和含矿层位呈横卧"L"状形态;该陡枢纽褶皱形成时间介于517~482 Ma之间。铁矿田东段7910铁矿床深部的铁矿体呈向形构造,不是较大规模的褶皱,而是规模有限的局部次级褶皱构造,在自东向西观察的剖面中其形态特征为"Z"形(因为岩层产状近直立,更像"N"形)。该次级褶皱的形成与剖面上南侧较老下部岩层的相对上升、北侧较新上部岩层的相对下降的层间相对运动以及铁矿南侧花岗质杂岩体侵位和隆升有关。铁矿床和铁矿层均受火山岩特定岩性和层位以及褶皱构造控制,依据次级褶皱的形态,含铁层位将继续向深部延伸,所以深部存在很大的铁矿找矿潜力。 相似文献
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山东莱芜接触交代-热液铁矿产于中生代构造盆地周边的中奥陶统马家沟组碳酸盐岩与燕山晚期闪长岩接触带及其附近岩石中。矿山矿田的铁矿床可分为4种形态类型、6种构造类型和多种矿体型式。铁矿赋存规律研究表明,大-大中型矿床往往具有复杂和较复杂的矿体形态、单式褶皱背斜和复式褶皱背(向)斜的矿床构造类型,有利的围岩层位为马家沟组五阳山段、阁庄段和八陡段碳酸盐岩,同时矿床有比较大的埋藏深度(多为-200~-600 m),弧形隆起的南、北端和两侧的凸(凹)弯曲部位均为形成大-大中型铁矿床的有利部位。 相似文献
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内蒙古哈达门沟金矿构造演化及成矿控矿构造特征 总被引：1，自引：0，他引：1
哈达门沟金矿是内蒙古迄今最大的金矿床,具有超大型金矿床规模。金的成矿作用对岩性没有明确的选择性,而主要是受褶皱断裂构造的控制。成矿流体主要来自深源,在有利的构造扩容带中聚积成矿。研究表明,该区的构造变形从早到晚,力学性质往往从塑性到脆性,构造规模从小到大,构造类型则是褶皱与剪切带同时形成,或相间发育。该区主要经历了4个期次的强烈褶皱剪切作用,并形成了主要的成矿控矿构造。第一期构造变形时岩石的流变性较强,褶皱幅度较小,一般多表现为小规模的塑性流变褶皱,并产生了小规模韧性剪切带;第二期(主期)褶皱以乌拉山主峰为主的东西向区域规模的复式背、向斜(形),并在主期褶皱的倒转翼发育了一系列与褶皱同向延伸的脆韧性剪切带,它们构成了区域性构造薄弱带;第三期为横跨叠加褶皱,使近东西向褶皱发生了南北向蛇形弯曲,伴随该期褶皱作用形成了低绿片岩相韧脆性剪切带,为深源成矿流体的贯入与集聚成矿提供了很好的赋存空间,是主要的成矿控矿构造;第四期构造变形则以区域性隆升作用为主,使早期褶皱发生横弯褶皱的同时,还将深部形成的金矿体抬升至浅部。文中在成矿控矿构造研究的基础上,探讨了矿床成矿规律,提出了找矿远景。 相似文献
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歪头山铁矿屑鞍山式沉积变质铁矿，褶皱、韧性剪切带、断裂是矿区的主要构造形迹。通过构造解析，将矿区鞍山运动中的构造变形划分为3幕。利用共轭节理和断层擦痕反演，对矿区构造应力场进行了定向、定时研究，确定了各期构造应力场。最后，提出了歪头山铁矿“褶皱 韧性剪切带”控矿模式，新模式对矿区的采矿平面设计及寻找可能的漏矿具有指导作用。 相似文献
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以吉林省白山市板石沟铁矿区为典型实例,系统地论述了太古宙岩群中广泛发育的大型和区域性构造置换的几何特征和对BIF矿体的控制规律。本区构造置换主要表现为:在紧闭同斜褶皱发育的持续变形过程中形成S1≈S0,并伴有钩状褶皱、石香肠构造和各类型线理的生成。按照主构造面均匀性法则,划分了构造均匀区段,并对其中8个区段(Ⅰ～Ⅷ)进行了详细的SFLπ组构分析。基于构造置换规律研究,提出本区褶皱轴与包络线双向找矿的理论与方法,经工程验证,取得显著的经济效益。 相似文献
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Progressive ductile shearing in the Phulad Shear Zone of Rajasthan, India has produced a complex history of folding, with development of planar, non-planar and refolded sheath folds. There are three generations of reclined folds, F1, F2 and F3, with a striping lineation (L1) parallel to the hinge lines of F1. The planar sheath folds of F1 have long subparallel hinge lines at the flanks joining up in hairpin curves at relatively small apices. L1 swerves harmoniously with the curving of F1 hinge line. There is a strong down-dip mineral lineation parallel to the striping lineation in most places, but intersecting it at apices of first generation sheath folds. Both the striping and the mineral lineation are deformed in U-patterns over the hinges of reclined F2 and F3. Folding of axial surfaces and hinge lines of earlier reclined folds by later folds was accompanied by very large stretching and led to the development of non-planar sheaths. The reclined folds of all the three generations were deformed by a group of subhorizontal folds. Each generation of fold initially grew with the hinge line at a very low angle with the Y-axis of bulk non-coaxial strain and was subsequently rotated towards the down-dip direction of maximum stretching. The patterns of deformed lineations indicate that the stretching along the X-direction was extremely large, much in excess of 6000 percent. 相似文献
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文中根据硅铁矿层的褶皱形态、复合关系等确定迁安铁矿区在中元古代之前发生过6期褶皱变形,叙述了这6期褶皱的特征和分布,讨论了褶皱的成因。区内各期褶皱形态演化规律反映了变形过程中岩石塑性有规律递减的特点。这一演化规律对研究早前寒武纪地区褶皱变形和指导该区找矿工作有重要意义。 相似文献
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S. Bhattacharya 《Journal of Earth System Science》1997,106(3):65-75
Three major episodes of folding are evident in the Eastern Ghats terrain. The first and second generation folds are the reclined type; coaxial refolding has produced hook-shaped folds, except in massif-type charnockites in which non-coaxial refolding has produced arrow head folds. The third generation folds are upright with a stretching lineation parallel to subhorizontal fold axes. The sequence of fold stylesreclinedF 1and coaxialF 2, clearly points to an early compressional regime and attendant progressive simple shear. Significant subhorizontal extension duringF 3folding is indicated by stretching lineation parallel to subhorizontal fold axes. In the massif-type charnockites low plunges ofF 2folds indicate a flattening type of deformation partitioning in the weakly foliated rocks (magmatic ?). The juxtaposition of EGMB against the Iron Ore Craton of Singhbhum by oblique collision is indicative of a transpressional regime. 相似文献
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A. B. Roy 《Journal of Earth System Science》1995,104(3):349-371
The lead-zinc bearing Proterozoic rocks of Zawar, Rajasthan, show classic development of small-scale structures resulting
from superposed folding and ductile shearing. The most penetrative deformation structure noted in the rocks is a schistosity
(S
1) axial planar to a phase of isoclinal folding (F
1). The lineations which parallel the hinges ofF
1 folds are deformed by a set of folds (F
2) having vertical or very steep axial planes. At many places a crenulation cleavage (S
2) has developed subparallel to the axial planes ofF
2 folds, particularly in the psammopelitic rocks. The plunge and trend ofF
2 folds vary widely over the area.
Deformation ofF
2 folds into hook-shaped geometry and development of another set of axial planar crenulation cleavage are the main imprints
of the third generation folds (F
3) in the region. In addition to these, there are at least two other sets of cleavage planes with corresponding folds in small
scales. More common among these is a set of recumbent and reclined folds (F
4), developed on steeply dipping early-formed planes. Kink bands and associated sharp-hinged folds represent the other set
(F
5).
Two major refolded folds are recognizable in the map pattern of the Zawar mineralised belt. The larger of the two, the Main
Zawar Fold (MZF), shows a broad hook-shaped geometry. The other large-scale structure is the Zawarmala fold, lying south-west
of the MZF. Both the major structures show truncation of lithological units along their respective east ‘limbs’, and extreme
variation in the width of formations. The MZF is primarily the result of superimposition ofF
3 onF
2.F
1 folds are relatively smaller in scale and are recognizable in the quartzite unit which responded to deformation mainly by
buckle shortening. Large-scale pinching-and-swelling that appears in the outcrop pattern seems to be a pre-F2 feature.
The structural evolutionary model worked out to explain the chronology of the deformational features and the large-scale out-crop
pattern envisages extreme east-west shortening following formation ofF
1 structures, resulting in the formation of tight and isoclinal antiforms (F
2) with pinched-in synforms in between. These latter zones evolved into a number of ductile shear zones (DSZs). The east-west
refolding of the large-scaleF
2 isoclinal antiforms seems to be the consequence of a continuous deformation and resultant migration of folds along the DSZs.
The main shear zone which wraps the Zawar folds followed a curved path.
Because of the penetrative nature of theF
2 movement, the early lineations which were at high angles to the later ones (as is evident in the west of Zawarmala), became
subparallel to the trend ofF
2 folding over a large part of the area. Further, the virtually coaxial nature ofF
2 andF
3 folds and the refolding ofF
3 folds by a new set of N-S folds is an indication of continuous progressive deformation. 相似文献
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吉林省白山市二岔铁矿位于中朝准地台、辽东台隆、铁岭—靖宇台拱、龙岗断块中南部边缘,太古宙早期区域内发生幅度较大的拗陷,接受广泛巨厚的一套粘土质、砂质碎屑岩类沉积,其间夹有硅铁质沉积并伴有火山（基性）岩浆喷溢活动,太古宙末期强烈造山运动使这些沉积岩层发生强烈挤压,形成褶皱构造及区域性断裂。伴随强烈造山运动致使太古宙地体发生中、深度区域变质作用与混合岩化作用。区域变质作用和混合岩化作用,对本区火山沉积变质铁矿的形成具有重要意义。二岔铁矿已探明基础储量（122b）30.26万吨、资源量（333）11.44万吨 相似文献
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断裂构造中元素的迁移变化规律是构造地球化学研究的主要内容.白山市板石沟铁矿断裂构造发育,是开展断裂构造地球化学研究的有利地区.通过对板石沟铁矿17矿组和赵家沟矿组典型逆断层剖面测量,采集构造岩和周围岩石,分析常量元素和微量元素,利用构造地球化学剖面法、质量等比线法和特征元素比值来反映元素在逆断层中分布特征和迁移变化规律.通过分析认为在逆断层中常量元素SiO2、Fe2O3、CaO、Na2O亏损,Al2O3、K2O富集,微量元素中Rb、Sr等离子半径较大元素富集,离子半径较小元素Co、Cr、Ni亏损,K2O/Na2O、V/Cr、Rb/（Ni+Co）在逆断层中呈现出高值,SiO2/Al2O3、（Fe2O3+CaO+MgO）/Al2O3呈现出低值.依据这些构造地球化学特征可以用来判断断裂构造的存在,为断裂构造地球化学研究和板石沟铁矿勘查提供构造地球化学依据. 相似文献
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The Feiran–Solaf metamorphic belt consists of low-P high-T amphibolite facies, partly migmatized gneisses, schists, amphibolites and minor calc-silicate rocks of metasedimentary origin. There are also thick concordant synkinematic sheets of diorite, tonalite and granodiorite orthogneiss and foliated granite and pegmatite dykelets. The gneissosity (or schistosity) is referred to as S1, and is almost everywhere parallel to lithological layering, S0. This parallelism is not due to transposition. The gneissosity formed during an extensional tectonic event (termed D1), before folding of S0. S1 formed by coaxial pure shear flattening strain (Z normal to S0, i.e. vertical; with X and Y both extensional and lying in S1). This strain also produced chocolate tablet boudinage of some layers and S1-concordant sills and veins. S1 has a strong stretching lineation L1 with rodding characteristics. Within-plane plastic anisotropy (lower ductility along Y compared to along X) resulted in L1-parallel extensional ductile shears and melt filled cracks. Continued shortening of these veins, and back-rotation of foliations on the shears produced intrafolial F1 folds with hinges parallel to the stretching lineation. F1 fold asymmetry variations do not support previous models involving macroscopic F1 folds or syn-gneissosity compressional tectonics. The sedimentary protoliths of the Feiran–Solaf gneisses were probably deposited in a pre-800 Ma actively extending intracratonic rift characterizing an early stage of the break-up of Rodinia. 相似文献