南秦岭志留系铅锌矿床中硅质岩岩石学及地球化学   总被引：12，自引：1，他引：12       下载免费PDF全文

刘淑文  薛春纪  曾荣  李强  朱经祥  王涛  赵国斌 《矿床地质》2005,24(5):490-500

南秦岭泥盆系内产出的众多矿床中含有层纹条带状硅质岩-硅质板岩,对其成因的研究有助于查明矿床成因和确定区域找矿方向.研究表明,硅质岩化学成分纯净,SiO2含量多在90%以上.硅质岩中大部分微量元素含量低于地壳克拉克值,但富集Zn、Pb、As、Sb、Ag;硅质岩的Fe-Mn-(Cu+Ni+Co)×10图解表明硅质岩具热水沉积性质.硅质岩与矿石两者的稀土元素特点相似,具有ΣREE低(44.52×10-6)、轻重稀土分异较明显(LREE/HREE=6.51)、北美页岩标准化配分曲线呈平缓趋势、铈负异常不明显(δCe值为0.97)和铕正异常明显(δEu值为1.42)的特点;硅质岩的δ30Si为-0.5‰～0.0‰,δ18O为17.8‰～19.9‰,硅、氧同位素组成及形成温度(84～101℃)也暗示它为海底热水沉积成因.  相似文献   

地质流体及成矿作用研究综述     

谭文娟  魏俊浩  郭大招  谭俊  伍静华 《矿产与地质》2005,19(3):227-232

地质流体是一定地质作用的产物，而矿床的形成过程与特定地质构造背景下地质流体的产生、运移和聚集有着密切联系。不同成矿流体的成矿机制各有差异。岩浆热液因温度降低、压力减小等因素使热液中成矿物质达到过饱和，从而产生矿质沉淀；沉积盆地含矿热卤水流体在热对流、沉积压实等作用下运移、充填、聚集；与海底基性火山活动有关的现代大洋海底热液形成硫化物矿床；地幔流体的碱交代作用形成大型一超大型中高温热液矿床。在具体的成矿过程中，各种构造环境又对流体中的成矿元素的分配、集中起到至关重要的控制作用。  相似文献   

湖南城步县金水铜矿地质特征及成因探讨     

谢新泉  张衡龙 《华南地质与矿产》2005,(1):37-40

金水铜矿床受构造控制,热液成矿标志明显。依据成矿地质背景及矿床地质特征、硫同位素和流体包裹体特征等研究认为,成矿物质来源深部,成矿作用具多阶段,成矿流体具热卤水性质;矿床初步确定为岩浆期后热液脉型铜矿床。  相似文献   

龙门地下热水的开发与利用前景分析     

李宏伟  罗锐 《中国煤田地质》2005,17(6):26-28

通过多年的地质勘探、研究与开发,对龙门地热资源的发育特征有了较深入的了解.龙门地热田热储层为富含温热水的∈2＋3碳酸盐岩,属水热型地热田中的温热水型热储,温热水的补给来自大气降水,在径流的过程中、受本区构造的控制,经深循环加热而成.经检测,龙门温热水中锶及偏硅酸含量都达到了天然饮用矿泉水标准,具有较高的开发价值于利用前景.  相似文献   

Solubility of gold in the SiO2-NaCl-H2O system at 300°C and50 MPa     

Yishan Zeng  Fengzhen Wang  Ruiying Ai 《中国科学D辑(英文版)》1997,40(5):485-490

The solubility of gold and quartz in 0.01, 0.10 and 1. 00 mol/kg NaCl solutions with various pH was determined in the presence of the NNO oxygen buffer at 300°C and 50 MPa using a flexible gold cell hydrothermal apparatus. The Au speciation in the SiO₂-NaCI-H₂O system was inferred and the equilibrium constants for the following dissolution reactions were obtained: Au+H₂O = AuOH⁰+1/2H₂, logK(AuOH⁰) = -7.92 ± 0.25; Au+Cl^-+H₂O = AuOHCl^-+1/2H₂, logK(AuOHCl^-) = - 7. 56 ± 0.65. The present study suggests that Au as AUOH⁰ and AuOHCl^- is basically transported in ore-forming solutions under geologically realistic conditions of acidity, chloride molality and oxygen fugacity. The reason for the common association of Au with SiO₂ in hydrothermal gold deposits is discussed. Project supported hy the National Natural Science Foundation of China.  相似文献   

浙西石炭纪层状硅质岩地球化学特征及其意义   总被引：7，自引：0，他引：7  

徐跃通  胡文Xuan 《地层学杂志》1997,21(1):47-54

在浙西石炭纪地层中存在与地层整合产出的层状硅质岩。硅质岩中ＦｅＯ、ＭｎＯ、ＴｉＯ２、Ａｌ２Ｏ３、ＭｇＯ、ＣａＯ、Ｎａ２Ｏ、Ｋ２Ｏ等含量相对较高，富集Ａｓ、Ｓｂ、Ｂｉ、Ａｕ、Ａｇ、Ｇａ，Ｆｅ２Ｏ３／ＦｅＯ、ＳｉＯ２／Ａｌ２Ｏ３、ＳｉＯ２／（Ｎａ２Ｏ＋Ｋ２Ｏ）、ＳｉＯ２／ＭｇＯ比值较小，稀土元素总量低，Ｃｅ弱负异常，重稀土相对富集，包裹体富含气相组份ＣＨ４、ＣＯ２、Ｎ２、ＣＯ、Ｈ２，具热水沉积硅质岩的地球化学特征。在Ｆｅ—Ｍｎ—（Ｎｉ＋Ｃｏ＋Ｃｕ）三角图及ＳｉＯ２—Ａｌ２Ｏ３、ＳｉＯ２—Ｆｅ２Ｏ３图上均属于热水沉积硅质岩。硅质岩中硅、氧同位素也显示其热水成因之特点。硅质岩的硅同位素和稀土元素Ｃｅ／Ｃｅ※值表明本区层状硅质岩主要是在浅海环境下沉积的。硅质岩的形成温度较高，为９８℃～１５２℃  相似文献   

新疆预须开普台铁铜矿床成因探讨   总被引：1，自引：1，他引：1  

莫江平  黄明扬 《地质与勘探》1997,33(4):7-12

根据矿床地质地球化学等方面的研究，认为该矿床成矿物质来源于深部地壳或上地幔；通过海底火山同流作用，在酸性相对还原的热学沉积盆地中沉积成矿。成矿流体来源岩浆水，并有海水混入。红碧玉、重晶石等具有喷流岩的特征。矿床成因属于海底火山喷流一热水沉积矿床。  相似文献   

The geochemistry of wall rock alteration in turbidite-hosted gold vein deposits, central Victoria, Australia   总被引：3，自引：0，他引：3  

Z.L. Gao  T.A.P. Kwak 《Journal of Geochemical Exploration》1997,59(3):259-274

Gold deposits hosted in Ordovician to Devonian turbidites in central Victoria, Australia, consist of steeply dipping quartz vein systems hosted mainly by reverse faults. Wall rock alteration of the host metasandstones, metasiltstones and shales (or slates) extends at least 20 m from the veins in the Bendigo-Ballarat zone (BBZ) and 10 m in the Melbourne zone (MZ) deposits. Alteration minerals include carbonates (ankerite, siderite and dolomite) chlorite, seriate, arsenopyrite, pyrite, chalcopyrite and sphalerite, with less common barite, albite and biotite in the BBZ and carbonates (siderite, ankerite, dolomite and ferromagnesite), sericite, chlorite, arsenopyrite, pyrite, and stibnite with less common chalcostibite in the MZ. SiO₂, Na₂O, MgO and Sr with P₂O₅ commonly decreasing during alteration while CO₂, S, As, Sb, Au, V, Al₂O₃, Ga, K₂O and Rb with Ni and Cr commonly increase. TiO₂, FeO, Fe₂O₃, MnO, Th, U, Nb, La, Ce, and Sc showed little change. Concentrations of Zn, Cu, Pb, and Ca are variable.The relatively large decrease of SiO₂ could account for most, if not all, quartz present in the ore veins. The Na₂O and MgO could have crystallized in the veins in the very minor albite and chlorite present. The addition of V in all and Ni and Cr in most deposits probably reflects a source enriched in these elements such as underlying greenstones. The source of both the volatile (S, As, Sb) and lithophile (K₂O and Rb) elements as well as Au is unknown, but they could have been derived from a magmatic source or from the metamorphism of Cambrian greenstones. CO₂, present as carbonate, was derived mainly by the reaction of graphite, originally present in the sediments, with the ore solutions. Al₂O₃, the only other major element after SiO₂, probably increased mainly due to the decrease of the latter.  相似文献   

华南某大型铀矿床成因新识   总被引：1，自引：0，他引：1  

闵茂中  沈保培 《大地构造与成矿学》1995,19(2):155-160

华南某大型铀矿床具典型的岩溶特征。研究发现矿石中铀主要以微脉浸染状沥青铀矿形式存在，沥青铀矿的晶胞参数ａ０＝５．４１６～５．４２８，含氧系数为２．３１～２．３４，属低、中温热液成因。矿床中出现一套低、中温热液矿物组合。测得成矿温度为１５０～１８１℃（均一法）。矿床中热水叠加改造特征明显，故建议称之为岩溶热造铀矿床，是一种特殊的新成矿类型。  相似文献   

成矿物质来源的定量判别方法的探讨     

李长江  徐有浪  蒋叙良 《矿床地质》1995,14(4):369-375

热液矿床的成矿物质往往具有多来源性。因此，定量判别不同来源矿质的量比关系，从而正确地识别矿床的主要成矿物质来源和成因机制，是现代矿床学研究的关键性问题之一。本文给出了三元混合模式的同位素－成矿元素的比值型判别方法，并给出了金银和萤石矿床成矿物原来源的定量判别应用实例。  相似文献