桂西龙川—世加地区金矿的复合型控矿作用研究

<正>近年来,在桂西北陆续发现了一类与辉绿岩类岩石有关的新的微细粒浸染型金矿床(点),此类金矿床的产出在空间上与辉绿岩关系密切,金矿体赋存于岩体(层)内或岩体(层)接触带附近的断裂破碎带中,故称之为辉绿岩型金矿,但大类上仍属于微细浸染型金矿(黄立刚等,2005)。在桂西北地区虽然已探明的此类金矿(矿床或矿点)有龙川、世加、八渡、者隘等近10     

百色地区巴马辉绿岩型金矿成矿源区探讨

<正>近年来,桂西北陆续发现了一类新的辉绿岩型金矿床(点),有世加、龙川、八渡、菜家湾、者隘等近10处。该类矿床产于辉绿岩与地层的内外接触带中。这类矿床的成矿物质来源及成矿类型一直存在很大争议,一些人认为是改造型金矿,热水沉积—基性岩浆改造型金矿,其成矿物质来源于赋矿地层(黄立刚和罗寿文,2005);另一种说法认为是蚀变岩型金矿,其形成大致经     

桂西北世加金矿稀土元素特征及其成矿指示意义

世加金矿位于龙川穹窿内,区内有大量辉绿岩出露,多呈环带状、不规则状沿背斜出露.金矿体主要产于辉绿岩岩体内部的断裂破碎带以及与C1y地层的断裂接触带中,矿床成矿期石英脉、蚀变辉绿岩矿石、C1y地层硅质岩以及新鲜辉绿岩样品的稀土元素特征表明,矿床成矿流体来自于深部,形成于辉绿岩成岩后期,与区内印支-燕山期的酸性岩浆活动有关...     

广西田林县八渡金矿流体包裹体组合的物理化学特征

<正>广西田林县八渡金矿位于桂西北地区(属于滇黔桂金三角地区),是产于辉绿岩中的微细浸染型金矿。由于辉绿岩与金矿产出空间关系密切,有学者又称为辉绿岩型金矿(肖龙,1997;陈开礼,2002)。前人对辉绿岩型金矿成矿流体的研究甚少,因此对该类型金矿成矿流体的研究将有助于揭示矿床成因。本文对八渡金矿中发现的一组三相流体包裹体组合(FIA)进行了显微     

桂西北辉绿岩卡林型金矿矿化的岩石地球化学特征

<正>桂西北地区发育有一种特殊的卡林型金矿,其矿体主要产于辉绿岩与地层的断裂接触带中或者直接产于辉绿岩岩体内部,前人将其命名为辉绿岩型金矿并做了一些研究工作(潘家永,1998;罗寿文,2005;刘远栋,2011,2013;覃少耀,2012;李培荣,2013),但对该类卡林型金矿的研究程度不深。由于该类矿床未受沉积成岩作用影响,因此成矿热液活动对辉绿岩脉地球化学、矿物学、同位素影响研究可以用来约束流体组成和成矿机制,而且辉绿岩年代学可以为滇黔桂卡林型金矿成矿年代学研究提供约束(胡瑞忠,     

一种新的微细浸染型金矿──产于辉绿岩中的微细浸染型金矿

在桂西北地区新发现两个直接产于辉绿岩中,以辉绿岩为赋矿主岩的微细浸染型金矿床（点）。金矿床受断裂构造和岩性控制,含矿岩石为蚀变辉绿岩。矿区内基性岩为成矿提供了矿源和水源,并成为直接赋矿的主岩。找矿标志为：穿过辉绿岩的断裂蚀变带;发育硅化、黄铁矿化等蚀变作用;发育Au及Au、Sb、Hg、As元素综合异常。     

赣东北景德镇四村矿化蚀变带成矿地质条件及找矿潜力

四村矿化蚀变带是在塔前—赋春矿集区新发现的1处铜多金属矿化蚀变带,通过与朱溪钨铜多金属矿床进行地质、矿化蚀变、地球物理-地球化学-遥感异常等对比,认为二者的成矿地质条件相似。根据四村地区浅表闪长玢岩、煌斑岩和辉长辉绿岩脉地质特征,推测其深部可能存在花岗质岩体。结合晚古生代碳酸盐岩、断裂破碎带和层间破碎带地质特征,推测花岗质岩浆上侵并与碳酸盐岩接触交代,可形成矽卡岩型矿床或热液脉型矿床,具有较好的找矿潜力。下一步找矿重点为侵入岩与碳酸盐岩接触带、断裂带和层间破碎带。     

云南富宁县弄歪金矿地质特征及成因探讨

金矿体赋存于二叠系中统吴家坪组与辉长、辉绿岩体的接触带中,或产于辉长、辉绿岩体内的断层破碎带内,为一构造控制的热液蚀变型金矿床。     

一种新的微细浸染型金矿——产于辉绿岩中的微细浸染型金矿特征及找矿标志

在桂西北地区新发现了两个直接产于辉绿岩中、以辉绿岩为赋矿主岩的微细浸染型金矿床(点)。金矿床受断裂构造和岩性控制,含矿岩石为蚀变辉绿岩。矿区内基性岩为成矿提供了矿源和水源,并成为直接的赋矿主岩。找矿标志为:穿过辉绿岩的断裂蚀变带;发育硅化、黄铁矿化等蚀变作用;发育Au及Au、Sb、Hg、As元素综合异常。     

云南大理宝兴厂矿区乱硐山矿段成矿模式浅析

[摘要]乱硐山铜钼金矿脉总体受乱硐山向斜顺层挤压破碎带和向斜核部陡立斑岩脉(体) 与围 岩接触带附近的碎裂岩带的控制,该挤压破碎带(碎裂岩带) 为该矿段矿液的运移、矿体的赋存提供了 良好的通道和赋存空间,并严格控制了金、铜、钼矿脉(体)的空间就位。同时由于不同期次、不同性质构 造应力作用的影响,致使矿段内矿脉(体)产状呈现正反倾向交互性和东西部产状的不一致性。本文着 重研究了该矿段内构造控矿因素,初步建立起矿段的金、铜、钼矿成矿模式,用以指导该区的找矿工作     

小秦岭金矿田构造演化与金矿成矿作用

依据小秦岭金矿田的地质构造穿插关系和同位素年龄资料,建立了本区构造、岩浆、成矿事件序列。在此基础上,将小秦岭地区的构造演化划分为６个阶段：褶皱变质、韧性剪切变形、稳定升降、韧－脆性断裂转化、断裂活动、抬升剥蚀阶段。对小秦岭金矿田的成矿时代,成矿深度、矿床成因等地质问题,给出了构造地质学方面的判据。     

气态烃在铧厂沟金矿找矿中的应用

铧厂沟金矿床是一个受韧性剪切带控制的热液蚀变型金矿床。通过对矿石中石英包裹体成分分析、烃类组分在各中段不同岩石中的含量特征比较,发现在该金矿的成矿过程中,曾存在一定量有机物的参与,有机烃气是其重要的伴生气体组分,烃气异常与金矿化在空间上存在密切对应关系。因而利用有机烃气测量法在该区开展深部盲矿找矿具有重要意义。     

内蒙古新地沟金矿床中金的赋存状态研究

内蒙古新地沟金矿床为一典型绿岩型金矿。利用显微镜、扫描电子显微镜观察到自然金602粒。研究表明,金的赋存形式主要有包体金、裂隙金、粒间金和连生金。载金矿物以黄铁矿、石英为主,所占比例达到95%;其次是钾长石、绢云母、菱铁矿、褐铁矿、黝铜矿、方铅矿、闪锌矿等。自然金的粒度主要以显微极微粒金(0.2~5μm)、显微细粒金(10~20μm)、显微中粒金(20~50μm)、显微微粒金(5~10μm)为主,分别占32.23%、26.91%、20.6%、16.11%;手标本及显微镜下也能观察到显微粗粒金(50~100μm)和巨粒金(100~200μm),虽然其含量仅占4.15%,但其面积可达33.97%,对于矿石品位和储量来说十分重要。电子探针和物相分析显示,矿石中金主要以独立矿物存在,包括大量的自然金和少量的银金矿;通过计算表明金的平均成色为803,金矿物的成色和特征反映金矿形成条件为中温和中等深度。     

青海双朋西金矿床金的赋存状态及矿石可选性研究

双朋西金矿床物质组成复杂,金属矿物以金属氧化物为主,含少量硫化物.载金矿物主要有褐铁矿、碳酸盐和石英,金矿物以自然金和银金矿独立矿物形式存在,以粗粒金为主,以裂隙金为主要赋存形式.根据金的化学物相和解离分析,选矿时加强细磨可提高金的回收率,选用浮选氰化工艺金的回收率可达91.7%.     

Thio complexes of gold and the transport of gold in hydrothermal ore solutions

The solubility of gold in aqueous sulphide solutions has been determined from pH_20°C ≈ 4 to pH_20°C ≈ 9.5 in the presence of a pyrite-pyrrhotite redox buffer at temperatures from 160 to 300°C and 1000 bar pressure. Maximum solubilities were obtained in the neutral region of pH as, for example, with m_NaHS = 0.15 m, pH_20°C = 5.96, T = 309°C, P = 1000 bar where a gold solubility of 225 mg/kg was obtained. It was concluded that three thio gold complexes contributed to the solubility. The complex Au₂(HS)₂S^2? predominated in alkaline solution, the Au(HS)₂^? complex occurred in the neutral pH region, and in the acid pH region, it was concluded with less certainty that the Au(HS)° complex was present. Formation constants calculated forAu₂(HS)₂S^2? and Au (HS)₂^? emphasize their high stability. In the temperature range from 175 to 250°C, values of pβ for Au₂(HS)₂S^2? vary from ?53.0 to 47.9 (±1.6) and from ?23.1 to ?19.5 ( ± 1.5) for Au(HS)₂^?. Equilibrium constante for the dissolution reactions, $\text{Au° + H}{}_2\text{S + HS}{}^{\mathrm{?}}\text{? Au(HS)}{}_2{}^{\mathrm{?}}\text{+}\text{1}\text{2}\text{H}{}_2$ and 2Au° + H₂S + 2H8^? ? Au(HS)₂^? + H₂ vary from pK_m = +2.4 to +2.55 (±0.10) for Au₂(HS)₂S^2? and from pK_n = + 1.29 to + 1.19 (±0.10) for Au(HS)₂^? over the temperature range 175 to 250°C. Enthalpies of these dissolution reactions were calculated to be ΔH_m° = ?5.2 ±2.0 kcal/mol and ΔH_n° = +1.7 ±2.0 kcal/mol respectively. It was concluded that gold is probably transported in hydrothermal ore solutions as both thio and chloro complexes and may be deposited in response to changes in temperature, pressure, pH, oxidation potential of the system and total sulphur concentration.     

甘肃鹿儿坝金矿床金赋存状态研究

甘肃鹿儿坝金矿处在西秦岭“岷礼金矿带”上,是我国卡林型金矿“西北金三角”组成部分。该矿床赋存于洮河复向斜北东翼之中三叠统浅变质浊积岩建造中,矿体受NWW向断裂构造控制明显,矿石以中-低温热液蚀变矿物组合为特征,是一个正在开发但难选的大型金矿床。为了解金的赋存状态,文章通过中-高倍矿相显微镜、金化学物相分析及电子探针(EMPA)测试等手段,研究了金在矿石中的赋存状态。结果表明,三类矿石中金的分布型式基本一致,载金矿物主要为毒砂、石英、黄铁矿和铁白云石;金以矿物包裹金为主,总占比达96.31%,其中硫化物包裹的金占61.45%~89.01%、硅酸盐中的金占有率为7.28%~25.49%,独立存在的金矿物较少,占1.03%~9.01%;独立金矿物主要以矿物粒间单体金形式存在,金成色987.05‰,为自然金,粒度以0.0009 mm×0.0061 mm~0.0078 mm×0.0114 mm为主。这为矿床研究提供了基础信息,并为改善矿山生产提供了一定的理论依据。     

胶东金矿集中区金矿成矿年代学研究

对不同研究者采用蚀变矿物Rb Sr、K Ar和Ar Ar法 ,流体包裹体Rb Sr等时线法 ,石英Ar Ar法和矿石矿物 (黄铁矿 )Rb Sr等时线法等多种同位素定年方法获得的胶东金矿集中区金矿成矿年龄数据进行了方法适用性研究和应用选择 ,筛选后的成矿年龄集中于 15 3 8～ 80 6Ma。综合考虑与金矿床有密切时空关系的花岗岩类侵入体及脉岩的K Ar、Ar Ar及U Pb (SHRIMP)年龄 ,确认胶东金矿集中区金矿主成矿期年龄为 (115± 10 )Ma ,金 银 多金属矿成矿期年龄为 (85± 5 )Ma ,分别为中生代早白垩世晚期 (K21)和晚白垩世早期 (K12 )。     

小秦岭大湖金矿成矿流体特征及矿床成因

本文运用流体包裹体岩相学、流体包裹体温度测试、流体包裹体成分分析等方法,讨论了大湖金矿床成矿流体的特征和成矿机理。     

Magma mixing and gold mineralization in the Maevatanana gold deposit,Madagascar

The Maevatanana gold deposit in Madagascar is hosted by Archean metamorphic rocks in quartz–sulfide veins that are structurally controlled by NNW–SSE trending shear zones. Fluid inclusion data show that the trapping conditions in quartz range from 0.87 to 2.58 kbar at temperatures of 269–362 °C. Laser Raman spectroscopy confirms that these inclusions consist of CO₂, SO₂, and H₂O. The δ³⁴S values of the pyrites range from 1.7‰ to 3.6‰, with an average of 2.25‰, supporting a magmatic origin. Noble gases (He, Ne, Ar, Ke, Xe) are chemically inert, thus will not be involved in chemical reactions during geological processes. Also due to the low concentration of He in the atmosphere and the low solubility of He in aqueous fluids, the atmosphere-derived He is unlikely to significantly affect He abundances and isotopic ratios of crustal fluids, ensures that He production should have the typical crust ³He/⁴He ratios. The ³He/⁴He ratios of fluid inclusions in pyrite from the deposit range from 0.06 to 0.12 Ra, while the ⁴⁰Ar/³⁶Ar ratios range from 6631 to 11441. We infer that the ore-forming fluids could have been exsolved from a granitic magma. The oxygen and hydrogen isotope compositions of the ore-forming fluids (1.5‰ ≤ δ¹⁸O_H2O ≤ 7.8‰; –72‰ ≤ δD ≤ –117‰) indicate they were derived from a granitic magma. Four pyrite samples from the gold deposit yield a precise Re–Os isochron age of 534 ± 13 Ma. Given that the post-collisional granites in northern and central Madagascar were derived by melting of sub-continental lithospheric mantle and formed between 537 and 522 Ma, we can state that the gold metallogenesis was coeval with the crystallization age of these parental magmas. These data could be accounted for the formation of the Maevatanana gold deposit. First, the shear zones hosting the deposit formed around 2.5 Ga, when the Madagascan micro-continental blocks collided with other continental blocks, triggering large-scale tectono-magmatic activity and forming NNW–SSE trending shear zones. The gold mineralization at Maevatanana is coeval with the crystallization age of the Cambrian post-collisional A-type granitoid plutons in northern and central Madagascar, implying that this deposit is associated with extensional collapse of the East African Orogen. This extension in turn induced asthenospheric upwelling, melting of sub-continental lithospheric mantle. These magmas underplated the lower crust, generating voluminous granitic magmas by partial melting of the lower crust. The mixing magma during tectono-thermal reactivation of the East African Orogen produced large volumes of volatiles that extracted gold from the granitic magma and produced Au–S complexes (e.g., Au(HSO₃)²⁻). The shear zones, which were then placed under extensional collapse of the East African Orogen in the Cambrian, formed favorable pathways for the magmatic ore-forming fluids. These fluids then precipitated gold-sulfides that form the Maevatanana gold deposit.     

Geological Characteristics and Occurrence of Gold in the Xiling Gold Deposit,Jiaodong Peninsula北大核心CSCD

西岭金矿床是胶东金矿集区内近来新发现的超大型破碎蚀变岩型金矿床(475吨@4.56 g/t),位于著名的三山岛金矿床的东侧。本文在详实的野外地质观察的基础上,系统介绍了西岭金矿床的基础地质特征,并运用光学显微镜和扫描电镜观察,结合电子探针分析,系统研究了西岭金矿床金的赋存状态。西岭金矿床大量金矿物(银金矿和自然金)主要赋存在Ⅱ阶段石英-黄铁矿和Ⅲ阶段灰石英-多金属硫化物脉中。西岭金矿床金矿物主要有晶隙金、裂隙金和包体金三种赋存状态,以晶隙金为主。金的主要载体矿物为黄铁矿,次为石英、黄铜矿和方铅矿等。金矿物粒度大小包括粗粒金、中粒金、细粒金和微粒金,以细粒-微粒为主。金矿物形态有粒状、叶片状、线状、钩状、枝杈状和哑铃状等,以粒状为主。金矿物成分以Au和Ag为主,含微量的Cu、Cr、Fe、Ni、Te、S等元素。金成色为685~831,以银金矿为主,含少量自然金。综合地质和地球化学特征,西岭金矿床为蚀变岩型金矿床,是由早白垩世中温岩浆热液充填-交代形成。