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1.
仑山金矿床位于宁镇矿集区东端。成矿期分为沉积成矿期和热液成矿期,后者可进一步划分为热液Ⅰ阶段和热液Ⅱ阶段。流体包裹体研究表明,热液Ⅰ阶段石英中的气液两相流体包裹体均一温度多集中在330~366℃之间,盐度w(Na Cl_(eq))变化于4.96%~6.74%之间,热液Ⅰ阶段方解石中气液两相流体包裹体均一温度多集中在150~240℃之间,w(Na Cl_(eq))变化于0.71%~9.80%之间,成矿流体为中高温低盐度流体;热液Ⅱ阶段石英、方解石和萤石的流体包裹体均一温度变化于124~260℃,盐度w(Na Cl_(eq))变化于1%~8%之间,成矿流体为中温低盐度流体。氢、氧同位素研究表明,热液Ⅰ阶段成矿流体为岩浆流体,热液Ⅱ阶段成矿流体以大气降水占主导,但仍有少量岩浆流体。硫同位素研究表明,仑山金矿床沉积成矿期硫除来源于三叠系青龙群膏盐层外,有机质也参与了沉积成矿期中金矿的形成。热液Ⅰ阶段硫来源于沉积成岩阶段黄铁矿的活化迁移和富集,岩浆硫也提供了成矿物质。萤石Sm-Nd测年分析表明,仑山金矿床热液Ⅱ阶段成矿年龄为(93.7±3.1)Ma,推断主成矿阶段形成于晚白垩世。仑山金矿床的形成代表着长江中下游成矿带最晚期的成矿作用。  相似文献   

2.
滇西南墨江金厂金镍矿床金、镍赋存状态及成矿过程探讨   总被引:5,自引:5,他引:0  
墨江金厂金镍矿床位于滇西南哀牢山造山带中段,是西南三江地区一个独特的金镍共生矿床。笔者通过野外地矿物主要为针镍矿、辉砷镍矿、锑硫镍矿、黄铁矿等。依据矿(化)脉切割关系、矿石结构构造及矿物共生组合,墨江金厂金镍矿床成岩-成矿期共发育4个世代黄铁矿。沉积变质期以草莓状黄铁矿和胶状黄铁矿为主,热液成矿期可划分为:早阶段石英-针镍矿-辉砷镍矿-锑硫镍矿-黄铁矿;主阶段石英-黄铁矿-毒砂-硫锑铜银矿-自然金;晚阶段方解石-石英-黄铁矿。对矿区赋金镍贯通性矿物黄铁矿进行详细的电子探针分析,结果显示4个世代黄铁矿微量元素有所差异。其中热液主阶段黄铁矿中含有Au、As、Sb、Pb、Zn、Cu、Co、Ni和Te,显示其流体成分复杂。不同阶段黄铁矿Ni含量不同,沉积变质期黄铁矿中Ni含量较低,为0.00%~0.82%,平均0.26%;热液早阶段黄铁矿中Ni含量最高,为0.43%~3.15%,平均1.38%;热液主阶段黄铁矿中Ni含量降低,为0.00%~0.99%,平均0.22%;热液晚阶段黄铁矿中Ni含量最低,为0.00%~0.09%,平均0.03%。研究结果表明墨江金厂金镍矿床中主要含金矿物和含镍矿物形成于热液期,含金矿物形成晚于含镍矿物。Ni在热液流体中的迁移能力与流体温度正相关,温度越高,Ni进入黄铁矿晶格的能力越强。基于上述金、镍成矿过程研究成果,并对比国内外热液镍矿床的地质-地球化学特征,推断墨江金厂金镍矿床是一个受岩浆热液改造的中-低温热液金镍矿床。  相似文献   

3.
杨金和 《世界地质》2006,25(3):264-269
黑龙江嘉荫平顶山岩金矿床的地质特征、形成条件和成因类型的研究表明:矿区内不同阶段的细晶闪长岩、闪长玢岩形成一个含金矿体的脉岩带;矿床范围内圈定5条呈脉状沿北北东向展布的矿体;矿石类型为石英脉型和蚀变岩型;金以裂隙金、晶隙金和明金为主,以银金矿的形式存在,且主要与石英、黄铁矿、毒砂和水云母共生;成矿作用分为热液期及表生期,其中热液期又分为4个成矿阶段,即纯石英阶段,黄铁矿毒砂石英阶段,黄铁矿毒砂水云母石英阶段和石英碳酸盐阶段。金矿体形成于Ⅱ、Ⅲ热液活动阶段,第Ⅲ阶段为主成矿期,成矿温度为100℃~180℃;金矿床的成因类型为岩浆中低温热液金矿床,形成于晚燕山期。  相似文献   

4.
应汉龙 《地质与资源》1994,3(3):201-207
本文主要研究了胶东金青顶和邓格庄金矿床蚀变体系的氧、硅同位素组成、硫化物矿物的硫同位素组成,方解石的碳、氧、锶、钐、钕同位素组成,结果表明金矿床早阶段成矿热液中水以非大气降水为主,晚阶段成矿热液中大气降水增加;成矿物质来源于地壳。推断金矿床由地壳物质在燕山期大规模低程度熔融出的富K、Na的流体交代改造岩石并汲取成矿元素形成的矿化热液和岩浆热液共同作用形成。  相似文献   

5.
提要:陕西双王金矿床位于西秦岭凤太矿集区东部,为一大型含金钠长角砾岩型金矿床。矿床赋存于上泥盆统星红铺组,为一套由钙质粉砂岩、粉砂质绢云板岩和灰岩组成的类复理石沉积建造。金矿体明显受角砾岩体控制,呈断续带状分布,矿石硫化物主要为黄铁矿,主要围岩蚀变类型为钠长石化。矿床稳定同位素地球化学特征研究表明:早阶段和主阶段成矿流体以岩浆热液和建造水的混合热液为主,晚阶段由岩浆热液向大气降水热液演化;碳主要来源于深部,并混有碳酸盐岩地层溶解形成的碳;硫具有地壳硫和岩浆硫混合来源的特征;铅的来源以上地壳为主,并混有少量地幔铅。结合区域地质构造背景,认为双王金矿床成矿作用与始于印支晚期的陆内碰撞造山作用有关,成矿过程经历了隐爆前的热液交代成矿期和隐爆后的热液充填成矿期,其中隐爆后的热液充填交代阶段是金矿床的主要成矿阶段,双王金矿床成因类型为隐爆角砾岩型金矿床。  相似文献   

6.
阴翠珍 《矿物学报》2003,23(2):153-157
研究了撰山子金矿床中金的主要载体矿物黄铁矿的形成世代、黄铁矿热电性的一般特征及黄铁矿的热电性与晶体形态、化学成分及金成矿作用的关系。结果表明:与岩浆作用有关的金矿床中,黄铁矿的导电类型既有n型、p型,又有n—p中间型,并以p型为主;不同成矿阶段的黄铁矿其热电性特征不同;黄铁矿热电性特征在矿体空间上具有一定的规律。  相似文献   

7.
胶东是我国最重要的金矿集中区,破碎带蚀变岩型金矿床是区内最主要的金矿床类型,该类型金矿床已探明金资源量占全区的90%以上,其巨量金的来源是引人瞩目的关键科学问题。招平断裂带是该区内规模最大的断裂-成矿带,位于招平金矿带中段的大尹格庄金矿床是该金矿带最具代表性的破碎带蚀变岩型金矿床之一,已探明金金属量约283t。大尹格庄金矿床严格受沿胶东群与玲珑花岗岩接触带发育的NNE向招平断裂带控制,矿体赋存在招平断裂下盘黄铁绢英岩化和碎裂岩化玲珑花岗岩中,主要由Ⅰ号和Ⅱ号矿体组成,其具有相似的矿物组成,矿石主要矿物是绢云母、石英、黄铁矿,次要矿物是钾长石、斜长石、黑云母、方解石、黄铜矿、方铅矿、闪锌矿、磁黄铁矿、黝铜矿和自然金、自然银、金银矿、碲银矿等;其中黄铁矿是最主要的载金矿物。根据穿插关系和矿物共生组合,大尹格庄金矿床内成矿作用可划分为4个成矿阶段,分别是黄铁矿-石英-绢云母阶段(I)、石英-黄铁矿阶段(Ⅱ)、石英-多金属硫化物阶段(Ⅲ)和石英-方解石-多金属硫化物阶段(Ⅳ)。各个成矿阶段的黄铁矿的晶体形态标型研究表明,成矿Ⅰ阶段黄铁矿以粗粒自形立方体为主,含有少量五角十二面体;成矿Ⅱ和Ⅲ阶段黄铁矿以细粒五角十二面体为主,且具有更多五角十二面体、八面体和立方体形成的聚形;成矿Ⅳ阶段主要为细粒立方体晶形。不同矿体各个成矿阶段的硫化物的δ~(34)S值集中在4.58‰~7.54‰,具有一定的塔式效应,正向偏离陨石硫,与胶东地区胶东群变质岩、围岩花岗岩类δ~(34)S比较接近,指示大尹格庄金矿床各个成矿阶段的矿石硫源总体一致,与胶东群变质岩和中生代花岗岩间具有继承演化关系。此外,从成矿Ⅰ阶段→Ⅱ阶段→Ⅲ阶段→Ⅳ阶段,大尹格庄金矿床矿石硫化物δ~(34)S呈现出逐渐降低的趋势,反映了成矿过程中物理化学条件的演化趋势:Ⅰ阶段为较高温度(330~350℃)、快速冷却、低过饱和度、低氧逸度和硫逸度的成矿环境;Ⅱ和Ⅲ阶段黄铁矿形成于中-低温(200~300℃)、成矿流体过饱和度高、高氧逸度和硫逸度、缓慢冷却同时物质供应充分的成矿环境;Ⅳ阶段处于较低温度(200℃)、热液流体过饱和度较低、低氧逸度和硫逸度、同时物质供应不足的成矿环境。  相似文献   

8.
文章在野外地质勘查、研究的基础上,系统介绍了三官庙金矿床基本地质特征.通过系统的光学显微镜、扫描电镜观察,将三官庙金矿床热液期成矿阶段划分为成矿早阶段(S1)、主阶段(S2)和晚阶段(S3),主阶段形成大量硫化物及方解石石英脉(团块),并形成金矿化;载金硫化物主要为毒砂、黄铁矿,均为同一世代,形成环境条件稳定,总体与金同时生成.利用电子探针(EPMA)对载金硫化物进行分析,结合元素面扫描成像,认为三官庙金矿石中"不可见金"普遍分布于黄铁矿、毒砂等硫化物中,在黄铁矿中主要以超显微包裹的纳米金形式存在,在毒砂中以固溶体金形式存在.三官庙金矿床热液黄铁矿电子探针(EPMA)分析具有较高的Co/Ni比值,在As-Co-Ni微量元素图解中位于岩浆热液区,这些特征指示黄铁矿为岩浆热液成因;依据金矿石、围岩、钠长角砾岩全岩稀土元素数据,认为三官庙金矿床矿石显示了对钠长角砾岩稀土元素特征的继承演化,说明二者之间具有成因联系;Au/Ag比值、热液硫化物共生组合、毒砂标型特征等表明三官庙金矿床成矿主阶段流体性质为碱性,氧逸度logf(O2)<-28.5、硫逸度logf(S2)平均-8.4,毒砂温度计计算成矿温度约350℃.综合地质、地球化学特征认为,三官庙金矿床成因类型为与钠长岩相关的受断裂构造控制的岩浆热液型金矿床.  相似文献   

9.
通过矿石中黄铁矿的ΔFe/ΔS值和Co/Ni值的分析,确定了内蒙古十八倾壕金矿床两种矿体-糜棱岩型矿体和石英脉型矿体中黄铁矿组分的不同特点:糜棱岩型矿体的黄铁矿属于贫铁贫硫型,Co/Ni值小于1;石英脉型矿体的黄铁矿属于贫铁富硫型,Co/Ni值大于1。这与该矿床两种矿石的S和Pb同位素的组成特征相呼应:前者反映同韧性剪切作用有关的变质热液成矿;后者反映岩浆热液成矿作用。这又一次在物质成分上证明了十八倾壕金矿床是两次成矿作用叠加的结果,同时也证明了前人提出的“不同层次叠加构造控矿”的观点。  相似文献   

10.
贵港龙山金矿田受近 SN向的断裂构造控制,成矿物质来源于深部,属于中低温构造蚀变热液型金矿床。以平天山岩体为中心,源于深部的含矿热液,在燕山晚期岩浆岩侵入活动过程中,伴随着的气化-热液成矿作用,构成一套成矿发展阶段的成矿系列,在不同的构造、岩性部位,形成的一套不同类型金矿床组合,具有多阶段多期次成矿富集的特征。  相似文献   

11.
甘肃阳山金矿床微量元素及稳定同位素的地球化学研究   总被引:24,自引:1,他引:24  
甘肃省阳山金矿位于川陕甘交界地带 ,为近年发现的一特大微细浸染型金矿床。该矿目前已发现 4个矿段 ,均赋存于浅变质的泥盆系地层中。矿体在平面上呈舒缓波状 ,在剖面上为脉状、似层状。矿石中金属矿物主要为黄铁矿和毒砂 ,金主要以微细粒金 (2~ 3μm)包裹于毒砂、黄铁矿及粘土矿物之中。矿床微量元素含量研究表明 ,矿石中Au、Hg、As、Bi、Sb等元素较为富集 ,并且其间呈明显的正相关关系 ,显示阳山金矿的形成与富含Au、Hg、As、Bi、Sb等低温热液元素的成矿流体活动有关 ,向深部这些元素含量趋于降低 ,表明成矿流体活动趋弱。矿石石英的δD值为 - 6 0‰~ - 72‰ ,δ18OH2 O值为 8 0‰~ 10 1‰ ,表明成矿流体主要为岩浆热液 ;矿石黄铁矿的δ3 4 S值为 - 2 2‰~ - 0 7‰ ,不同于泥盆系地层中沉积黄铁矿的δ3 4 S值 (10 9‰ ) ,表明矿石硫为岩浆硫 ,因而阳山金矿床的形成与岩浆热液活动密切相关  相似文献   

12.
The Prince Lyell copper-gold-silver deposit occurs in the late Cambrian Mt Read Volcanics, at Queenstown, Tasmania. Steeply plunging, broadly conformable lenses of disseminated and stringer pyrite-chalcopyrite mineralisation occur in quartz-sericite-chlorite rocks derived from intense alteration of predominantly felsic lavas and volcaniclastic rocks. Middle Devonian deformation has substantially modified primary sulphide textures.Although extensively fractured, pyrite grains in the ore have retained their original pre-deformation internal structure and chemistry which are revealed by etching and electron microprobe analysis. Earliest sulphide mineralisation produced oscillatory zoned, cobalt-rich pyrite (Pyrite I), coeval with chalcopyrite mineralisation. Cobalt-rich pyrite is commonly associated with Cambrian volcanic rocks in western Tasmania and suggests a volcanogenic origin for the ore fluids at Prince Lyell. Pyrite I was corroded by later hydrothermal fluids and reprecipitated as unzoned, trace element-poor pyrite (Pyrite II), commonly as overgrowths on Pyrite I cores. Minor amounts of a second cobalt-rich pyrite (Pyrite III) occurs with Pyrite II in composite pyrite overgrowths. Sulphur isotope ratios from all pyrite generations fall within a small range (3 to 11‰). In situ isotopic analyses showed no consistent δ34S variation between the various pyrite generations, suggesting recycling of sulphur derived from a single Cambrian volcanogenic source.Hematite alteration, derived from oxidised fluids possibly from the adjacent hematitic Owen Conglomerate, occurs in the structural footwall volcanics and the Great Lyell fault zone. Hematite inclusions in Pyrite II and III indicate that these pyrite generations occurred after or during deposition of the conglomerate. It is postulated that Pyrite II and III were deposited during waning volcanism, contemporaneous with Owen Conglomerate sedimentation in the late Cambrian or early Ordovician. The Great Lyell fault would have acted as a growth fault margin between a terrestrial basin, filling rapidly from the east, and the volcanic terrane to the west. The scenario raises the possibility that the concentration of mineral deposits and hematitic alteration along the Great Lyell fault resulted from the subsurface interaction of reduced volcanogenic fluids and oxidised basin waters along the growth fault contact.  相似文献   

13.
河北张家口金矿黄铁矿的标型特征及其成因意义   总被引:4,自引:1,他引:4  
黄铁矿是张家口金矿中一种十分重要的载金矿物。泰文通过对黄铁矿的形态、粒度、成分、晶胞参数及其热电性等矿物标型的详细研究,发现当细粒,立方体与五角十二面体晶形共同出现,含较高的As,Co和Ni,晶胞参数大以及具有较高热电系数值时的黄铁矿含金性好。综合黄铁矿的这些标型特征所蕴藏的成因信息,可以得出:张家口金矿为中深成中高温变质热液矿床。  相似文献   

14.
浙江省湖州黑龙洞黄铁矿矿体赋存于石炭系中统黄龙组三段燧石灰岩或硅质灰岩和二段白云质大理岩中。矿体呈扁豆状,黄铁矿体之上为含金铁帽。通过对其成矿条件的分析,认为矿床成因类型总体上属于沉积-热液改造型矿床。  相似文献   

15.
Arsenian pyrite in the Shuiyindong Carlin-type gold deposit in Guizhou, China, is the major host for gold with 300 to 4,000 ppm Au and 0.65 to 14.1 wt.% As. Electron miroprobe data show a negative correlation of As and S in arsenian pyrite, which is consistent with the substitution of As for S in the pyrite structure. The relatively homogeneous distribution of gold in arsenian pyrite and a positive correlation of As and Au, with Au/As ratios below the solubility limit of gold in arsenian pyrite, suggest that invisible gold is likely present as Au1+ in a structurally bound Au complex in arsenian pyrite. Geochemical modeling using the laser ablation-inductively coupled plasma mass spectrometry (LA-ICP-MS) analysis of fluid inclusions for the major ore forming stage shows that the dominant Au species were Au(HS)2 (77%) and AuHS(aq)0 (23%). Gold-hydroxyl and Gold-chloride complexes were negligible. The ore fluid was undersaturated with respect to native Au, with a saturation index of −3.8. The predominant As species was H3AsO30 (aq). Pyrite in the Shuiyindong deposit shows chemical zonation with rims richer in As and Au than cores, reflecting the chemical evolution of the ore-bearing fluids. The early ore fluids had relatively high activities of As and Au, to deposit unzoned and zoned arsenian pyrite that host most gold in the deposit. The ore fluids then became depleted in Au and As and formed As-poor pyrite overgrowth rims on gold-bearing arsenian pyrite. Arsenopyrite overgrowth aggregates on arsenian pyrite indicate a late fluid with relatively high activity of As. The lack of evidence of boiling and the low iron content of fluid inclusions in quartz, suggest that iron in arsenian pyrite was most likely derived from dissolution of ferroan minerals in the host rocks, with sulfidation of the dissolved iron by H2S-rich ore fluids being the most important mechanism of gold deposition in the Shuiyindong Carlin-type deposit.  相似文献   

16.
烧锅营子金矿床的黄铁矿形成于早、中、晚3期,是主要的矿石矿物和载金矿物,其中以中期黄铁矿为最主要的载金者.黄铁矿的化学成分为:TFe43.34%~45.52%,S46.58%~48.86%,与标准黄铁矿相比显示亏铁、亏硫特点.黄铁矿内含丰富的微量元素,有Au、Ag、As、Sb、Bi、Cu、Zn、Pb、Co、Ni、W、Mo、Se等.其中Au、Ag、Cu、Pb、Zn、Bi含量较高,而As、Sb低,Se极低.其Au/Ag(多大于0.5)、(Cu+Pb+Zn)/(Co+Ni+As)(4.26)、Co/Ni(>> 1)比值表明其属中温岩浆热液矿床.  相似文献   

17.
河南省罗山县金城金矿黄铁矿标型特征及其意义   总被引:1,自引:0,他引:1  
通过对河南罗山县金城金矿Ⅱ号矿体黄铁矿产出特征、金在黄铁矿中的赋存状态、化学成分、热电性等一系列标型特征的研究,认为本区含金黄铁矿主要为热液成因。黄铁矿中硫同位素具有变化范围窄(2.75‰~5.5‰)、极差值小(2.75‰)、平均值为4.195‰的特点,表明硫主要来源于深源岩浆。热电性测试显示,黄铁矿的热电系数(α)变化范围较大(-281.0~466.0μV/℃),平均为-148.9~268.2μV/℃,热电场导电类型N型、P-N型、N-P型及P型均有,总体上具有N-P混合型特征,同一世代黄铁矿热电性在空间上具有正向垂直分带的规律,表明本矿区的黄铁矿成分复杂,具有受多期次热液叠加的特征。黄铁矿热电性数据统计直方图明显出现两个峰值,表明本矿床至少具有两次金成矿作用阶段。通过经验公式计算预测该矿体的剥蚀深度为矿体中部位置,深部尚有较大的找矿潜力。这一研究反映了黄铁矿的标型特征对进一步扩大矿床规模和找矿具有重要的指示意义。  相似文献   

18.
与铀矿床伴生的黄铁矿,其热导电性、主元素Fe/S比值及杂质元素As,Sb,Hg,Co ,Ni,Mo的含量变化等都可用来判别铀矿体的剥蚀程度,在铀矿找矿过程中具有一定的判盲意义。  相似文献   

19.
The Jaduguda U (–Cu–Fe) deposit in the Singhbhum shear zone has been the most productive uranium deposit in India. Pyrite occurs as disseminated grains or in sulphide stringers and veins in the ore zone. Veins, both concordant and discordant to the pervasive foliation, are mineralogically either simple comprising pyrite ± chalcopyrite or complex comprising pyrite + chalcopyrite + pentlandite + millerite. Nickel-sulphide minerals, though fairly common in concordant veins, are very rare in the discordant veins. Pyrite in Ni-sulphide association is commonly replaced by pentlandite at the grain boundary or along micro-cracks.  相似文献   

20.
The Xiaoqinling district, the second largest gold producing district in China, is located on the southern margin of the North China Craton. It consists of three ore belts, namely, the northern ore belt, the middle ore belt and the southern ore belt. Pyrite from the Dahu gold deposit in the northern ore belt and Wenyu and Yinxin gold deposits in the southern ore belt were investigated using a combination of ore microscopy and in-situ laser-ablation inductively-coupled plasma-mass spectrometry (LA-ICP-MS). A range of trace elements was analyzed, including Au, Te, Ag, Pb, Bi, Cu, Co, Ni, Zn, Mo, Hg, As and Si. The results show that there are no systematic differences between the trace element compositions of pyrite in the three deposits from different ore belts. In general, Au concentrations in pyrite are low (from < 0.01 ppm to 2.2 ppm) but Ni concentrations are rather high (up to 8425 ppm). A four-stage mineralization process is indicated by microscopic and field observations and this can be related to the systematic trace element differences between distinct generations of pyrite. Stage I precedes the main gold mineralization stage; pyrite of this stage has the lowest Au concentrations. Stages II and III contributed most of the gold to the ore-forming system. The corresponding pyrite yielded the highest concentrations of Au and Ni. Our microscopic observations suggest that pyrite in the main gold mineralization stage precipitated simultaneously with molybdenite that has been previously dated as Indosinian (~ 218 Ma by Re–Os molybdenite dating), indicating the Indosinian as the main gold mineralization stage. The Indosinian mineralization age and the geological and geochemical features of these gold deposits (e.g., low salinity, CO2-rich ore fluids; spatial association with large-scale compressional structures of the Qinling orogen; δ18O and δD data suggestive of mixing between metamorphic and meteoric waters; δ34S and Pb-isotopic data that point to a mixed crustal-mantle source) all point to typical orogenic-type gold deposits. High Ni concentrations (up to 8425 ppm) of pyrite possibly linked to deep-seated mafic/ultramafic metamorphic rocks provide further evidence on the orogenic gold deposit affinity, but against the model of a granitic derivation of the mineralizing fluid as previously suggested by some workers. Generally low Au concentration in pyrite is also consistent with those from worldwide orogenic gold deposits. Therefore, the gold mineralization in the Xiaoqinling district is described as orogenic type, and is probably related to Indosinian collision between the North China Craton and the Yangtze Craton.  相似文献   

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