云南兰坪罗善铅锌矿控矿因素及成因     

徐兴业  黄发梅  张桂银  苏泰民  黄联飞 《云南地质》2013,(4):421-423,416

铅锌矿赋存于上三叠统三合洞组下段（T3s1）灰岩容矿岩层中及近南北向、北北东向、北西向断裂破碎带内,少数赋存在近东西向节理裂隙中,成因具多成矿阶段、多成矿物质来源特征,层位＋构造控制的中低温热液型铅锌多金属矿床.  相似文献   

北京市铁矿资源特征及开发利用建议     

许海涛  马海全 《城市地质》2013,(3):10-13

从北京市铁矿资源的地质矿产特征,矿床类型及其分布情况,矿石类型及其利用情况以及资源储量特征出发,重点分析了北京市铁矿资源的基本情况,从而把北京市铁矿划分为3个矿集区：库西北、库东北、库南铁矿矿集区,并对目前北京市铁矿的开发利用情况进行了分析,指出库西北,库东北铁矿矿集区在确保区内矿山企业适度发展的前提下,宜限制开采,作为战略储备,库南铁矿矿集区可以适度发展。  相似文献   

Chemical fluid transport (CFT): A window into Earth and its development     

Werner Schrön 《Chemie der Erde / Geochemistry》2013

Gas phase transport according to chemical fluid transport (CFT) in Earth's crust as well as in the solar nebula is characterized by very high transport efficiency. Systematic investigations of mobilization, transport and deposition of gaseous MeX (Me = metal, X = F or Cl) compounds by solid gas equilibrium reactions are suitable to explain numerous extensive accumulations of minerals and ores. More than 40 of the considered chemical elements form volatile MeX compounds. Some elements tend to form MeF compounds, whereas others are more likely to form MeCl compounds. Silicon reacts with HF to form SiF₄ and replaces other elements to form MeF compounds at low temperature ranges. Accumulations caused by SiF₄ transport explain the formation of numerous quartz varieties and silicate minerals in Earth's crust. Iron most likely reacts with HCl to form FeCl₂ as well as FeCl₃ and explain the formation of iron or iron compounds. Thermodynamically directed transport from cool to hot areas in connection with cyclic processes increases the transport efficiency of MeX-species. Such species are SiF₄, Al₂F₆, POF₃, Cu₃Cl₃, SnCl₄, BF₃, GeF₄, GeCl₄, Ga₂Cl₆, ZrF₄, NbF₅ and TiF₄. The transport gases SiF₄ and POF₃ often react with environmental compounds forming pneumatolytic and metasomatical mineral accumulations. CFT is the “motor” of pneumatolytic and metasomatical processes.  相似文献   

Major and trace element geochemistry of Lake Bogoria and Lake Nakuru,Kenya, during extreme draught     

Franz Jirsa  Martin Gruber  Anja Stojanovic  Steve Odour Omondi  Dieter Mader  Wilfried Körner  Michael Schagerl 《Chemie der Erde / Geochemistry》2013

The physico-chemical properties of water samples from the two athalassic endorheic lakes Bogoria and Nakuru in Kenya were analysed. Surface water samples were taken between July 2008 and October 2009 in weekly intervals from each lake. The following parameters were determined: pH, salinity, electric conductivity, dissolved organic carbon (DOC), the major cations (FAAS and ICP-OES) and the major anions (IC), as well as certain trace elements (ICP-OES). Samples of superficial sediments were taken in October 2009 and examined using Instrumental Neutron Activation Analysis (INAA) for their major and trace element content including rare earth elements (REE). Both lakes are highly alkaline with a dominance of Na > K > Si > Ca in cations and HCO₃ > CO₃ > Cl > F > SO₄ in anions. Both lakes also exhibited high concentrations of Mo, As and fluoride. Due to an extreme draught from March to October 2009, the water level of Lake Nakuru dropped significantly. This created drastic evapoconcentration, with the total salinity rising from about 20‰ up to 63‰. Most parameters (DOC, Na, K, Ca, F, Mo and As) increased with falling water levels. A clear change in the quality of DOC was observed, followed by an almost complete depletion of dissolved Fe from the water phase. In Lake Bogoria the evapoconcentration effects were less pronounced (total salinity changed from about 40‰ to 48‰). The distributions of REE in the superficial sediments of Lake Nakuru and Lake Bogoria are presented here for the first time. The results show a high abundance of the REE and a very distinct Eu depletion of Eu/Eu* = 0.33–0.45.  相似文献   

辽吉裂谷区铅锌金矿床S、Pb同位素组成特征及其地质意义   总被引：1，自引：0，他引：1  

马玉波  邢树文  张增杰 《地质学报》2013,87(9):1399-1410

辽吉裂谷区发育有众多大中型铅锌、金等多金属矿床,本文选择该地区的青城子榛子沟铅锌矿、白云金矿、五龙金矿、荒沟山铅锌矿和临江金矿作为研究对象,开展其矿石S、Pb同位素分析及其地质意义研究.数据显示榛子沟脉状铅锌矿δ34SCDT值介于-10.3‰～6.8‰之间,白云金矿δ34SCDT值介于-7.7‰～1.9‰之间,五龙金矿δ34 SCDT值介于0.8‰～3.6‰之间,荒沟山铅锌矿δ34 SCDT值介于6.7‰～17.8‰之间,临江金矿δ34 SCDT值介于0.7‰～1.5‰之间.研究区铅锌金矿床的矿石硫同位素主要有两种来源,其一来自于早期火山喷流沉积而成的地层硫,如青城子榛子沟层状铅矿矿体和荒沟山层状铅锌矿;另一类为后期岩浆硫,如青城子榛子沟脉状铅锌矿、白云金矿、五龙金矿以及临江金矿,此类岩浆硫形成过程中,对早期地层硫进行了混染.辽吉裂谷区典型多金属矿床矿石铅同位素值变化较大,206 pb/204 Pb值介于15.72～24.02,207pb/204 Pb值介于15.32～16.43,208pb/204 Pb值介于34.96～39.79,不同的矿床其比值具有不同特点.研究区铅同位素μ值相对集中且较大,显示铅源具有上地壳物质特征,但均受到了不同铅源的混合.榛子沟铅锌矿脉状矿体矿石铅和岩体铅均为混合铅源,矿石铅为上地壳与地幔的混合源铅,而岩体铅则是造山带铅与上地壳的混合源铅;白云金矿床矿石铅为造山带铅,而其岩体铅为上地壳与地幔的混合源铅;五龙金矿的铅同位素主要来源于元古宙造山带铅,同时又有幔源铅的混合;荒沟山铅锌矿矿石铅一组为正常铅,微偏钍铅,来源于统一矿源层,另外一组铅为放射成因铅,即铀铅,而临江金矿矿石铅属于放射成因铅.  相似文献   

华北克拉通沉积变质型铁矿床的特征与预测评价模型   总被引：1，自引：0，他引：1  

史蕊  陈建平  王刚 《岩石学报》2013,29(7):2606-2616

华北克拉通是我国面积最大、时代最古老的陆块,地质构造演化历史复杂,也是我国重要的铁矿资源分布区.本文在系统总结该区域成矿规律的基础上,利用GIS平台提取了多元成矿有利信息(变质建造、控矿构造、矿致磁异常、氧化铁异常、自然重砂信息).在此基础上,建立了沉积变质型铁矿床的找矿预测模型,并采用MRAS系统中的证据权模块进行矿产资源定量预测.按照后验概率的大小划分了两级区域有利成矿远景区,分别是冀东、辽东、五台-吕梁三个A级成矿远景区和大青山-色尔能腾山、鲁山-舞阳、鲁西三个B级成矿远景区.这些远景区与已知矿床(点)重叠或比邻,显示远景区具有较好的成矿条件和较大的成矿潜力,应在今后的找矿勘查工作中予以充分重视.  相似文献   

Domainal fabrics of hematite in schistose,shear zone-hosted high-grade Fe ores: The product of the interplay between deformation and mineralization     

《Journal of Structural Geology》2013

Schistose high-grade hematite orebodies (>64 wt % Fe) in the Iron Quadrangle, Minas Gerais, were formed in shear zones by hydrothermal alteration of the Paleoproterozoic Cauê BIF during the Transamazonian orogenesis. The ore is comprised of platy hematite (specularite) grains that define the foliation and overprint a relict banded martite-hematite fabric resembling, at first sight, a mylonite. The EBSD analyses of a m-scale schistose orebody from the Pau Branco mine show that specularite grew as elongated plates with the (00.1) plane parallel to the foliation. The population of the measured grain aspect ratio (GAR) is homogenous in different scales, and the longest axes of the crystals align with the stretching lineation (L//X) building continuous domains, or anastomose around stretched iron oxide aggregates and rootless fold hinges. The pole figure of the (00.1) plane shows usually a maximum centered on the pole of the foliation Z often elongated on a girdle perpendicular to the lineation L. The {10.4} pole figure has the configuration of a symmetric cleft girdle and the corresponding {11.0} and {10.0} pole figures present well developed girdles parallel to the foliation with an elongated maximum centered on X. Microstructures associated with crystal-plastic behavior and dynamic recrystallization are missing and the fabric of the orebody probably results from precipitation of strain-controlled oriented hematite plates and anisotropic syntaxial growth of favorably oriented grains with the intervention of hydrothermal fluids during Fe enrichment. The shear zone provided pathways for the percolation of mineralizing fluids under temperatures that varied from 140 to 350 °C or higher, under ductile or ductile–brittle conditions. The orthorhombic fabric and CPO (crystallographic preferred orientation) of the ore nevertheless contrast with the asymmetry of simple shear as observed in the torsion experiments by Siemes et al., 2010, Siemes et al., 2011, probably due to volume loss and possibly a flattening component of deformation in the ore zone.  相似文献   

滇东北渔户村组内的富铅锌矿床成矿地质特征及成因   总被引：4，自引：0，他引：4  

陈启良 《云南地质》2001,20(2):186-194

渔户村组为滇东北富铅锌矿床的重要产出层位。通过茂粗、金沙厂、五星、乐红、大海等矿床，总结了滇东北渔户村组内的富铅锌矿床的地质特征及成因，认为其与喷流沉积成矿作用和后期改造作用有关，为海底火山喷流沉积－改造成因。  相似文献   

Manganese ore deposits in Koira-Noamundi province of Iron Ore Group, north Orissa, India: In the light of geochemical signature   总被引：1，自引：0，他引：1  

B.K. Mohapatra  P.P. Mishra  P.P. Singh  Rajeev 《Chemie der Erde / Geochemistry》2009,69(4):377-394

Several small Mn–Fe oxide and Mn-oxide ore bodies associated with Precambrian Iron Ore Group of rocks are located within Koira-Noamundi province of north Orissa, India. These deposits are classified into in situ (stratiform), remobilized (stratabound) and reworked categories based on their field disposition. Volcaniclastic/terrigenous shale in large geographic extension is associated with these ore bodies.The in situ ore bodies are characterised by cryptomelane-, romanechite- and hematite-dominating minerals, low Mn/Fe ratio (1.1) and relatively lower abundance of trace (1500–2500 ppm) constituents. In such type of deposits the stratigraphic conformity of oxides with the tuffaceous shale suggests precipitation of Mn and Fe at a time of decreased volcaniclastic/terrigenous contribution. The minor and trace elements were removed from solution by adsorption rather than by precipitation. Both Mn and Fe oxides when precipitated adsorb trace elements strongly but the partitioning of elements takes place during diagenesis. The inter-elemental relationship reveals that Cu, Co, Ni, Pb and Zn were adsorbed on precipitating hydrous Mn oxides and form manganates. Some of these elements probably get desorbed from Fe oxide because of their inability to substitute for Fe³⁺ in the lattice of its oxide. However, P, V, As and Mo were less partitioned and retained in Fe-oxide phase. Positive correlation between Al₂O₃ and SiO₂, MgO, Na₂O, TiO₂ and some traces like Li, Nb, Sc, Y, Zr, Th and U points to their contribution through volcaniclastic/terrigenous detritus of both mafic and acidic composition.The remobilized ore bodies are developed in a later stage through dissolution, remobilization and reprecipitation of Mn oxides in favorable structural weak planes under supergene environment. Increase in average Mn/Fe ratio (8) and trace content (5000–8500 ppm) by 5–2.5 orders of magnitude, respectively, or more above its abundance in adjoining/underlying protore is characteristic of these deposits. The newly formed Mn ores constituting lithiophorite, cryptomelane/romanechite and goethite get quantitatively enriched in traces like Cu, Co, Ni, Pb and Zn. Positive correlation between Mn, Li, Co and Zn is due to the formation of mineral of lithiophorite–chalcophanite group during redistribution and reconcentration of Mn oxide. P and V, which were present in Fe oxide, also get dissolved and reprecipitate with Fe oxyhydroxide in these ores. Some other elements like Y, Th and U show positive relation with Fe. This is probably due to leaching of these elements during chemical weathering of associated shale and getting re-adsorbed in Fe-oxyhydroxide phase.However, under oxidizing environment selective cations like Ba, K, etc. resorb from Mn-structure, resulting in the development of pyrolusite (Mn/Fe>20). In such transformation, trace metals from pyrolusitic structure expels out, resulting thereby in a considerable reduction in total trace value (<3000 ppm).The reworked ore bodies are allochthonous in nature and developed through a number of stages during terrain evolution and lateritisation. Secondary processes such as reworking of pre-existing crust; solution and remobilization; precipitation and cementation and transport, etc. are responsible for their development. Such deposits are usually very low in Mn/Fe ratio (3) and trace content (<2000 ppm).  相似文献   

新疆玉泉山石墨矿床地质特征及成因探讨   总被引：1，自引：0，他引：1  

陈刚  李凤鸣  彭湘萍 《新疆地质》2009,27(4)

新疆玉泉山石墨矿床赋存于塔里木古陆库鲁克塔格地块中下元古界兴地塔格群辛格尔组云母石英片岩中,经历了沉积-聚炭和区域变质-结晶2个主要成矿期.区域变质-结晶成矿期又分为与低角闪岩相、高绿片岩相和低绿片岩相对应的3个成矿阶段.地层岩石条件、区域变质条件、构造条件是最重要的控矿因素,矿床成因属区域变质型晶质石墨矿床.  相似文献