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1.
祁连优地槽区块状硫化物矿床形成地质环境的初步对比研究和探讨 总被引：3，自引：0，他引：3
在成矿规律学的研究中,许多研究者常把优地槽的发展演化与矿床形成阶段相结合并力图给予模式化,认为块状硫化物矿床是优地槽发展初期的坳陷阶段,地槽基底下坳带来巨厚沉积和强烈火山作用时期,与火山和沉积作用有关的形成物(毕利宾,1950;斯米尔诺夫,1973)。 相似文献
2.
PENGRunmin ZHAIYusheng 《《地质学报》英文版》2004,78(2):534-547
Most ore-forming characteristics of the Langshan-Zha‘ertaishan hydrothermal exhalation belt, which consists of the Dongshengmiao, Huogeqi, Tanyaokou and Jiashengpan large-superlarge Zn-Pb-Cu-Fe sulfide deposits, are most similar to those of Mesoproterozoic SEDEX-type provinces of the world. The characteristics include: (1) All deposits of this type in the belt occur in third-order fault-basins in the Langshan-Zha‘ertaishan aulacogen along the northern margin of the North China Platform; (2) these deposits with all their orebodies hosted in the Mesoproterozoic impure dolomite-marble and carbonaceous phyllite (or schists) have an apparent stratabound nature; ores display laminated and banded structures, showing clear depositional features; (3) there is some evidence of syn-sedimentary faulting, which to a certain extent accounts for the temporal and spatial distribution and the size of the orebodies in all deposits and the formation of intrabed conglomerates and breccias; (4) they show lateral and vertical zonation of sulfides; (5) The Cu/(Pb Zn Cu) ratio of the large and thick Pb Zn Cu orebodies gradually decreases from bottom to top; and (6) barite is interbedded with pyrites and sometimes with sphalerite. However, some characteristics such as the Co/Ni radio of the pyrites, the volcanism, for example, of the Langshan-Zha‘ertalshan metallogenic belt, are different from those of the typical SEDEX deposits of the world. The meta-basic volcanic rock in Huogeqi, the sodic bimodal volcanic rocks in the Dongshengmiao and potassic bimodal-volcanic rocks with blastoporphyfitic and blasto-glomeroporphyritic texture as well as blasto-amygdaloidal structure in the Tanyaokou deposits have been discovered in the only ore-bearing second formation of the Langshan Group in the past 10 years. The metallogeny of some deposits hosted in the Langshan Group is closely related to syn-sedimentary volcanism based on the following facts: most of the lead isotopes in sphalerite, galena, pyrite, pyrrhotite and chalcopyrite plot on both sides of the line for the mantle or between the lines for the mantle and lower crust in the lead isotope composition diagram; cobalt content of some pyrites samples is much higher than the nickel content (Co/Ni= 11.91-12.19). Some volcanic blocks and debris have been picked out from some pyritic and pyrrhotitic ores. All Zn-Pb-Cu-Fe sulfide orebodies in these deposits occur in the strata overlying metamorphic volcanic rocks in the only ore-bearing second formation. In the Jiashengpan deposit that lacks syn-sedimentary volcanic rocks in the host succession only Pb and Zn ores occur without Cu ore, but in the Dongshengmiao, Tanyaokou and Huogeqi deposits with syn-sedimentary volcanic rocks in the host succession Cu ores occur. This indicates a relatively higher ore-forming temperature. The process of synsedimentary volcanic eruption directly supplied some ore-forming elements, and resulted in secular geothermal anomaly favorable for the circulation of a submarine convective hydrothermal system, which accounts for the precipitation of deep mineralizing fluids exhaling into anoxidic basins along the syn-sedimentary fault system in the Langshan-Zha‘ertai rift. The Dongshengmiao, Tanyaokou, and Huogeqi deposits hosted in the Langshan Group appear to be a transitional type of mineral deposit between SEDEX and VMS-types but with a bias towards SEDEX, while the Jiashengpan deposit hosted in the Zha‘ertai Group is of a characteristic SEDEX type. This evidence, together with other new discoveries of Mesoproterozoic volcanic rocks and the features of lithogeny and metallogeny of the Bayun Obo deposit in the neighborhood emphasize the diversity, complexity and uniqueness of the Mesoproterozoic Langshan-Zha‘ertal-Bayun Obo ore belt. 相似文献
3.
本文就我国中南4省区金矿分布的一般规律及金成矿地质条件进行了初步探讨,提出中南地区金矿分布5大规律:空间上集中分布具一定的统一性;赋矿层位多为古老的变质岩系;在空间分布和成因上与岩浆岩密切相关;金成矿在赋矿围岩上虽无较大的选择性,但仍偏重基性火山岩和侵入岩以及有机质、炭质高的沉积岩和变质岩;金的成矿期主要是从前寒武纪到中生代。文章并以部分典型矿床为例,论述了中南4省区金矿控矿因素除矿源层(体)、岩浆岩、构造这3个要素外,还应将深部液态矿源层及区域变质作用视为同等重要的控制因素。 相似文献
4.
Yang Changming 《地球科学》1986,(1)
本区原岩建造是-套基性—酸性火山凝灰岩（主要）+铁硅质岩+沉积岩组合。整个层序反映了一个较完整的火山喷发沉积旋回。含铁建造与沉积旋回在时空和物源上存在着密切的成因联系。铁矿的形成及分布并非受控于某一种岩石,而是受控于火山喷发沉积旋回。本文从岩浆分异、火山活动、沉积作用及构造运动等的发生、发展、演化的角度较全面地分析了火山喷发沉积旋回的控矿作用。 相似文献
5.
块状硫化物矿床(黄铁矿型矿床、黑矿型矿床)与玄武岩-流纹岩建造的相互关系是由矿石与围岩形成的近似性所决定的,更确切地说,是矿石有规律地产在火山岩一定的岩相中。近年来,火山岩系的岩相分析已成为火山岩地区区域地质调查、块状硫化物矿床普查勘探工作中最重要的方法之一。这是因为,一方面岩相分析和古火山恢复方法,可以对火山体、火山岩系的喷发沉积旋回,以及火山岩的层序进行详细的研究,从而较为客观地总结出 相似文献
6.
7.
Many metallic ore deposits of the Late Cretaceous to Early Tertiary periods are distributed in the Gyeongsang Basin. Previous and newly analyzed sulfur isotope data of 309 sulfide samples from 56 ore deposits were reviewed to discuss the genetic characteristics in relation to granitoid rocks. The metallogenic provinces of the Gyeongsang Basin are divided into the Au–Ag(–Cu–Pb–Zn) province in the western basin where the sedimentary rocks of the Shindong and Hayang groups are distributed, Pb–Zn(–Au–Ag–Cu), Cu–Pb–Zn(–Au–Ag), and Fe–W(–Mo) province in the central basin where the volcanic rocks of the Yucheon Group are dominant, and Cu(–Mo–W–Fe) province in the southeastern basin where both sedimentary rocks of the Hayang Group and Tertiary volcanic rocks are present. Average sulfur isotope compositions of the ore deposits show high tendencies ranging from 2.2 to 11.7‰ (average 5.4‰) in the Pb–Zn(–Au–Ag–Cu) province, ?0.7 to 11.5‰ (average 4.6‰) in the Cu–Pb–Zn(–Au–Ag) province, and 3.7 to 11.4‰ (average 7.5‰) in the Fe–W(–Mo) province in relation to magnetite‐series granitoids, whereas they are low in the Au–Ag(–Cu–Pb–Zn) province in relation to ilmenite‐series granitoids, ranging from ?2.9 to 5.7‰ (average 1.7‰). In the Cu(–Mo–W–Fe) province δ34S values are intermediate ranging from 0.3 to 7.7‰ (average 3.6‰) and locally high δ34S values are likely attributable to sulfur derived from the Tertiary volcanic rocks during hydrothermal alteration through faults commonly developed in this region. Magma originated by the partial melting of the 34S‐enriched oceanic plate intruded into the volcanic rocks and formed magnetite‐series granitoids in the central basin, which contributed to high δ34S values of the metallic deposits. Conversely, ilmenite‐series granitoids were formed by assimilation of sedimentary rocks rich in organic sulfur that influenced the low δ34S values of the deposits in the western and southeastern provinces. 相似文献
8.
与火山岩—斑岩有关的金银矿矿集区和大型矿床的形成是多种因素综合作用的结果,特别是火山盆地类型及结构、大地构造背景、基底断裂、火山岩岩相和岩类、基底矿源层、火山机构内部构造、流体系统等对于矿床的形成起着决定性的作用。上叠式火山盆地能否成矿,关键是基底是否具备初始矿源层,岩浆是否起源于上地幔并同熔了老基底中的矿源层。继承性火山盆地能否形成金银矿,关键在于上下两套建造中火山岩的发育程度和火山—沉积建造的连续性,一般底部构造层中发育玄武岩、科马提岩、枕状熔岩等中基性、碱性火山岩,顶部构造层以中—酸性火山岩为主时,对成矿有利。大地构造位置上为两个构造单元的接合部位,与金银矿成矿有关的火山盆地或其基底都经历过裂陷拉张环境,不管是盖层还是基底,必有其一为裂谷或岛弧环境岩石建造。许多中大型矿床和矿集区都分布在多次开合的裂谷环境中。斑岩体岩石类型、成分、形态、产状控制矿体的定位和展布,潜火山岩、斑岩体与金银矿存在空间上的不可分割性、时间上的同一性和成因上的内在联系。单一的火山熔岩很少形成矿床,形成金银矿床的火山岩常为凝灰岩、凝灰质集块岩、凝灰质火山熔岩,岩相上常为从火山岩向沉积岩过渡的地方,岩石组合为火山碎屑岩+凝灰岩+杂砂岩、粉砂岩+熔岩+泥质岩+碳酸岩。“三重结构”构造控矿,即深层次基底断裂,中深部位的盖层断裂,超浅、近地表—地表构造。以火山机构为中心从下向上形成多位容矿裂隙：侵入体(斑岩)顶部裂隙系统,隐爆角砾岩筒裂隙系统,破火山口裂隙系统。潜火山岩发生多期隐爆形成具一定延深的角砾岩筒,往往存在多个热流体系统,补给系统和排放系统完全时对成矿有利。 相似文献
9.
Central Fujian Rift is another new and important volcanogenic massive sulfide Pb-Zn polymetallic metallogenetic belt. In order to find out the material genesis and mineralization period of Meixian-type Pb-Zn-Ag deposits, S and Pb isotope analysis and isotope geochronology of ores and wall rocks for five major deposits are discussed. It is concluded that the composition of sulfur isotope from sulfide ore vary slightly in different deposits and the mean value is close to zero with the 834S ranging from -3.5‰ to ＋5.6‰ averaging at ＋2.0‰, which indicates that the sulfur might originate from magma or possibly erupted directly from volcano or was leached from ore-hosted volcanic rock. The lead from ores in most deposits displays radioactive genesis character （206pb/204pb〉18.140, 207Pb/204pb〉15.584, 208pb/204pb〉38.569） and lead isotope values of ores are higher than those of wall rocks, which indicates that the lead was likely leached from the ore-hosted volcanic rocks. Based on isotope data, two significant Pb-Zn metallogenesis are delineated, which are Mid- and Late-Proterozoic sedimentary exhalative metailogenesis （The single zircon U-Pb, Sm-Nd isochronal and Ar-Ar dating ages of ore- hosted wall rocks are calculated to be among 933-1788 Ma.） and Yanshanian magmatic hydrothermal superimposed and alternated metallogenesis （intrusive SHRIMP zircon U-Pb and Rb-Sr isochronal ages between 127-154 Ma）. 相似文献
10.
我国海相火山铁铜矿床的成因类型及其某些成矿特征的讨论 总被引：2，自引：0，他引：2
建国以来,我国在火山矿床的地质勘探和研究工作方面都积累了丰富的资料,并且有不少关于矿床成因和类型划分方面的叙述。作者近几年来有机会接触到一些这方面的工作。这里试将海底火山活动的重要产物之一——海相火山铁铜矿床作一个比较系统的成因类型的划分。限于水平,不当之处请批评指正。 相似文献
11.
The large (more than 200000 km2) Uchur-Maya Meso- and Neoproterozoic intracontinental basin is delineated for the first time in the southeastern Siberian Platform, including the territory overlapped by the Ediacaran to Cambrian plate complex. The tectonic elements of higher orders—uplifts, domes, and deeps formed during the Neoproterozoic and Late Mesozoic tectonomagmatic activity—are outlined. The tectonic nappes of Paleoproterozoic rocks from 200 to 400 m thick were established between the Calymmian and Ectasian to Stenian rocks in the southeastern portion of the basin. The thickness of sedimentary rocks increases toward the Yudoma-Maya Aulacogen. The considerable thickness of Meso- and Neoproterozoic rocks and bitumen contents in sedimentary rocks are favorable factors testifying to the petroleum resource potential of the basin. The southern part of the basin is promising for ore deposits (primarily, uranium and gold) in zones of structural and stratigraphic unconformities and within the sedimentary cover itself. This study may serve as a background for further, more detailed tectonic investigations and substantiation of strategic lines of geological exploration. 相似文献
12.
湖南前震旦系铀矿化成因探讨 总被引：1，自引：0，他引：1
湖南前震旦系冷家溪群和板溪群是一套浅变质沉积岩,主要由各种板岩、变质砂岩、凝灰质板岩组成,夹有基性、中-酸性火山熔岩、火山碎屑岩及碳酸盐岩。现已落实铀矿床3个、矿(化)点14个。铀成矿年龄为85—50Ma,最晚者16Ma。稳定同位素研究结果表明,前震旦系铀矿化属岩浆岩源及沉积(变质)岩源中-新生代大气降水热液成因;铀矿化受断裂构造控制;凝灰质板岩、砂质板岩及角岩等是矿化有利的围岩。 相似文献
13.
庐枞盆地中发育一些大中型硫铁矿床,曾长期被认为是与次火山岩有关的中低温热液成因。本文从矿床层控特点、矿体形态产状、矿石沉积组构、矿物组合及其生成顺序、矿化分带、包裹体及同位素地球化学等诸方面,证明它们具显著的火山喷气沉积成因特征,并受到后期热液叠加改造。提出了大鲍庄式陆相火山喷气沉积-热液叠加改造型硫铁矿的成矿模式。 相似文献
14.
Tobias E. Bauer Pietari Skyttä Tobias Hermansson Rodney L. Allen Pär Weihed 《Mineralium Deposita》2014,49(5):555-573
The Skellefte district in northern Sweden is host to abundant volcanogenic massive sulphide (VMS) deposits comprising pyritic, massive, semi-massive and disseminated Zn–Cu–Au ± Pb ores surrounded by disseminated pyrite and with or without stockwork mineralisation. The VMS deposits are associated with Palaeoproterozoic upper crustal extension (D1) that resulted in the development of normal faults and related transfer faults. The VMS ores formed as sub-seafloor replacement in both felsic volcaniclastic and sedimentary rocks and partly as exhalative deposits within the uppermost part of the volcanic stratigraphy. Subsequently, the district was subjected to deformation (D2) during crustal shortening. Comparing the distribution of VMS deposits with the regional fault pattern reveals a close spatial relationship of VMS deposits to the faults that formed during crustal extension (D1) utilising the syn-extensional faults as fluid conduits. Analysing the shape and orientation of VMS ore bodies shows how their deformation pattern mimics those of the hosting structures and results from the overprinting D2 deformation. Furthermore, regional structural transitions are imitated in the deformation patterns of the ore bodies. Plotting the aspect ratios of VMS ore bodies and the comparison with undeformed equivalents in the Hokuroko district, Japan allow an estimation of apparent strain and show correlation with the D2 deformation intensity of the certain structural domains. A comparison of the size of VMS deposits with their location shows that the smallest deposits are not related to known high-strain zones and the largest deposits are associated with regional-scale high-strain zones. The comparison of distribution and size with the pattern of high-strain zones provides an important tool for regional-scale mineral exploration in the Skellefte district, whereas the analysis of ore body shape and orientation can aid near-mine exploration activities. 相似文献
15.
通过对津巴布韦奇拉色卡矿区金刚石古砂矿的地质特征、矿层特征、赋矿规律等的研究,建立了该区矿床勘查模型。研究表明,该区构造上处于太古宙津巴布韦克拉通东部边缘,西部紧邻林波波造山带、莫桑比克造山带,而林波波带为重要的金刚石产地,该区处于金刚石古砂矿成矿的有利位置;矿层赋存于中元古代乌肯多群砂砾岩组沉积岩中。该区金刚石古砂矿为沉积型金刚石古砂矿类型,属滨海环境沉积建造。在中元古代,原生矿中的金刚石被风化剥蚀出来,经流水的搬运,在滨海地区沉积,固结形成金刚石古砂矿床。津巴布韦奇拉色卡矿区金刚石古砂矿的发现及研究对指导中国境内寻找金刚石古砂矿具有重要的意义。 相似文献
16.
Petrographic and sulphur isotope studies support the long‐held contention that rounded grains of pyrite in siliciclastic sequences of the Late Archaean Witwatersrand Supergroup originated as placer grains. The grains are concentrated at sites where detrital heavy minerals are abundant within quartz‐pebble conglomerates and quartzose sandstones. Depositional sites with abundant pyrite are: (1) within the matrix of bar‐type, clast‐supported conglomerates; (2) on scoured or winnowed surfaces; and (3) on stratification planes. The grains are internally compact or porous, with truncation of internal structure at outer margins indicating fragmentation and rounding of pyritic source‐rocks during erosion and sediment transport. A large range in textures reflects source‐rock lithologies, with known varieties linked to sedimentary‐hosted diagenetic pyrite, volcanic‐hosted massive sulphide deposits and hydrothermal pyrite. Laser ablation sulphur isotope analysis of pyrite reveals a broader range in δ34S values (? 5·3 to + 6·7‰) than that of previously reported conventional bulk‐grain analyses (? 1 to + 4‰). Rounded pyrite from the Steyn Reef has significant variation in δ34S values (? 4·7 to + 6·7‰) that establishes heterogeneous sulphur compositions, with even adjacent grains having diverse isotopic signatures. The heterogeneity supports a placer origin for rounded pyrite. Euhedral pyrite and pyrite overgrowths which are undoubtedly authigenic have restricted δ34S values (? 0·5 to + 2·5‰), are chemically distinct from rounded pyrite and are probably the products of metamorphism or hydrothermal alteration. The placer origin of rounded pyrite indicates that pyrite was a stable heavy mineral during erosion and transport in the early atmosphere. Its distribution in three sequences (Witwatersrand Supergroup, Ventersdorp Contact Reef and Black Reef), and in other sequences not linked to Witwatersrand‐type Au‐U ore deposits, implies deposition of redox‐sensitive detrital heavy minerals during the Late Archaean. Consequently, rounded grains of detrital pyrite are strong indicators of an oxygen‐poor atmosphere. While not confirming a placer origin for gold in Witwatersrand Au‐U ore deposits, the palaeoenvironmental significance of rounded pyrite negates its link to hydrothermal mineralization. 相似文献
17.
The uranium deposits of Bulgaria related to the Late Alpine tectonomagmatic reactivation are subdivided into two groups: exogenic–epigenetic paleovalley deposits related to the basins filled with upper Eocene–lower Oligocene volcanic–sedimentary rocks and the hydrothermal deposits hosted in the coeval depressions. The geological and lithofacies conditions of their localization, the epigenetic alteration of rocks, mineralogy and geochemistry of uranium ore are exemplified in thoroughly studied paleovalley deposits of the Maritsa ore district. Argumentation of the genetic concepts providing insights into both sedimentation–diagenetic and exogenic–epigenetic mineralization with development of stratal oxidation zones is discussed. A new exfiltration model has been proposed to explain the origin of the aforementioned deposits on the basis of additional analysis with consideration of archival factual data and possible causes of specific ningyoite uranium ore composition. 相似文献
18.
Phanerozoic volcanic-associated massive sulfide deposits (VMSD) were subdivided into the Kuroko, Besshi, Cyprus, and Ural types, which differ in their ore geochemistry and mineralogy, in their composition of volcanic ore-hosting rock associations, and in the proportions of felsic and basaltic volcanics and sedimentary rocks in the volcanic successions. The earliest deposits that can be reliably attributed to the above types originated during the Neoproterozoic during the Pangea supercontinental cycle. Archean and Paleoproterozoic VMSD can be accepted as analogues of these types, resembling them in many respects, although differing from the classic deposits of these types in some characteristics. The formation history of Cyprus-type VMSD is traceable to the Paleoproterozoic when deposits in the Outocumpu area dated at approximately 1970 Ma originated during the early stage of Pangea-I amalgamation, whereas the most ancient Besshi-type deposits 1440 million years old originated during the breakup of that supercontinent. Most of the Neoarchean and Paleoproterozoic VMSD are similar in some of their principal features to those of the Ural and Kuroko types. Deposits of both these types and their ancient analogues evolved in the process of the Earth’s evolution and demonstrated unidirectional changes in their ore composition. 相似文献
19.
新疆琼河坝位于准噶尔成矿带东段,是一个潜在的以铁、铜、金为主的矿集区。区内铁矿床(点)众多,以往的找矿和研究工作大多聚焦于矽卡岩型富铁矿,对其他类型的铁矿床缺乏足够的重视。为了拓宽琼河坝地区铁矿床勘查思路,需要对区内铁矿床的类型和成矿特征进行系统归纳。文章在野外调查和室内测试分析的基础上,依据矿床(点)的产出地质环境、矿体及矿石矿物成分特征,结合铁矿石主要矿物的主量、微量及稀土元素特征,将琼河坝地区铁矿床划分为矽卡岩型、火山岩型、岩浆分异型、火山间歇期沉积型和湖相沉积型5种类型。矽卡岩型、火山岩型、岩浆分异型和火山间歇期沉积型铁矿赋存在晚古生代泥盆纪—石炭纪火山岩中,湖相沉积型铁矿床赋存于中侏罗统湖沼相含煤碎屑沉积岩中。火山间歇期沉积型铁矿床是在琼河坝地区首次发现的新类型,矿体赋存部位、矿石颗粒磨圆度及胶结成分特征均显示了该类铁矿成矿作用的特殊性。从找矿角度分析,目前主攻方向为矽卡岩型铁矿,而火山岩型铁矿是下一步找矿研究的重点。 相似文献
20.
鞍本太古代绿岩盆地铁矿的成矿特征 总被引：5，自引：0，他引：5
辽宁省鞍山本溪地区是我国著名的铁矿产区。对于本区鞍山式铁矿的成矿特征,作者在前人工作的基础上,经过三年多的调查研究,认为本区鞍山式铁矿不是一种单一的矿床类型,而是赋存在不同时代、不同大地构造环境的两种矿床系列,即属于阿尔戈马型铁矿系列和苏必利尔型铁矿系列。并在划分成矿系列的基础上提出了本区的成矿模式。 相似文献