西天山吐拉苏火山盆地金矿成矿系列围岩蚀变地球化学

形成于西天山晚古生代吐拉苏火山盆地的伊尔曼得金矿、阿希金矿和塔吾尔别克金矿等3种不同类型金矿,其围岩蚀变及微量元素具有不同的特征.伊尔曼得等金矿类型的围岩蚀变为硅化、高岭石化、重晶石化和地开石化,As、Sb、Hg、Cu与Au含量呈正相关关系.塔吾尔别克金矿类型围岩蚀变为硅化、绢云母化、绿泥石化、碳酸盐化.蚀变围岩的As值增高,Au和Ag的含量明显增高.阿希金矿类型围岩蚀变主要有绢云母化、冰长石化、碳酸盐化、硅化、伊利石化,蚀变岩石的Se和As含量与Au、Ag含量基本呈正相关关系.     

河南熊耳山干树金矿成矿作用与围岩蚀变特征

干树金矿是河南熊耳山矿集区内的构造蚀变岩型金矿,矿区的金矿体主要赋存在构造蚀变岩带内,且与多阶段的热液活动密切相关。深源的含金成矿流体沿深大断裂向上运移,在温度、压力控制下,在构造的有利部位与围岩发生交代作用,形成多种围岩蚀变和金矿化。其中,硅化、绢云母化、黄铁绢英岩化、钾化与金矿化关系密切;围岩蚀变具有水平分带和垂直分带特征:从中心向两侧,蚀变依次为黄铁绢英岩化→石英绢云母化→钾化→绢云母化→绿泥石化,金品位呈逐步降低的分布规律;从地表向深部,则出现蚀变为褐铁矿化-高岭土化-硅化-碳酸盐化-绢云母化-钾化-黄铁矿化-黄铁绢云岩化,金品位呈由低转高的变化趋势。     

甘肃李坝金矿围岩蚀变与金成矿关系

西秦岭地区是目前国内造山型和卡林型金矿找矿的热点地区之一,已发现的甘肃李坝造山型金矿为超大型规模。以李坝金矿6号矿带为例,系统地研究了其蚀变矿物组合、近矿围岩蚀变分带及相应的金矿化特征,总结了矿床(带)的蚀变分带模式。该模式具典型的中心式环带结构,可分为3个蚀变带,由中心向外依次为黄铁绢英岩化带、绢云母化带和绿泥石化带。蚀变矿物组合分别为黄铁矿+绢云母+石英±毒砂±白云母±电气石±方解石、绢云母+绿泥石+石英+黄铁矿±黑云母及绿泥石+黑云母±绢云母±黄铁矿;与这3个蚀变带相对应的是金的富集带、矿化带和无矿带。蚀变岩石物质组分迁移分析表明,围岩蚀变及其分带是热水流体/岩石反应时岩石化学组分发生迁移的结果,矿化伴随着蚀变发生,且金矿化与黄铁矿化和浸染状硅化关系最为密切。     

黑龙江金厂金矿床18号矿体围岩蚀变及短波红外光谱特征

金厂金矿18号矿体围岩蚀变发育顺序从早到晚为:钾化、硅化、绿泥石化、绢云母化、碳酸盐化、高蛉土化,从内往外依次发育青磐岩化带、绢英岩化带和钾化带.矿化出现在泥化和绢英岩化叠加处,以及泥化和青磐岩化叠加处.通过短波红外光谱测试技术,识别出本矿区有26种蚀交矿物,其中白云母含量与金矿体呈正相关,说明绢云母化与金矿化关系密切;青磐岩化带蚀变矿物组合为绿泥石+绿帘石+伊利石±埃洛石±蒙脱石±石英;钾化带蚀变矿物组合为钾长石+高岭石+埃洛石±蒙脱石±石英;绢英岩化带蚀变矿物组合为绢云母+埃洛石±蒙脱石±高岭石±石英.     

河南省洛宁县三官庙金矿床构造控矿特征

三官庙金矿位于太华群与熊耳群接触带附近的似斑状花岗岩体南侧,矿床明显受断裂构造控制。矿区内拆离断裂带和层间滑脱断裂蚀变带发育,含金蚀变破碎带中的构造岩石为含矿主岩。矿体形态以较稳定的似层状为主,金矿物为银金矿等;金的载体矿物为黄铁矿、石英和方铅矿。围岩蚀变为硅化、黄铁矿化、方铅矿化、绿泥石化和绢云母化等,矿化类型属蚀变岩型金矿。在多期次强烈构造-岩浆活动、区域变质和混合岩化作用过程中,Au元素得以沿层间滑脱断裂蚀变带富集成矿。     

毕力赫金矿床围岩蚀变及其与金矿化关系

本文对毕力赫金矿床Ⅱ矿带围岩蚀变及其与金矿化关系进行了研究.矿床主要蚀变类型为硅化、钾化、黄铁矿化、绢云母化、电气石化、绿泥石化、高岭土化、碳酸盐化,其中硅化、绢云母化、黄铁矿化与金矿化关系密切;蚀变分带明显,由地表向下,依次为青磐岩化带→绢英岩化带→钾质蚀变带,绢英岩化带与金矿化关系最为密切.     

浅论津巴布韦康尼玛拉（Connemara）金矿床地质特征及其找矿意义

康尼玛拉金矿床的形成与太古宙绿岩带、前寒武系变质岩关系密切,矿体、矿化蚀变体主要受NNW向断裂构造控制,属破碎蚀变岩型金矿,围岩蚀变发育,硅化、黄铁矿化、绢云母化与矿化关系密切,该矿区具有良好的找矿前景。     

青海铜厂沟金矿床围岩蚀变特征与矿化

铜厂沟金矿床围岩蚀变强烈，并受构造脉动的控制，蚀变具不规则环形分带；蚀变作用划分为硅化－绿泥石化、硅化－碳酸盐化、黄铁矿化和硅化－黄铁矿化等四阶段，金矿化发生在黄铁矿化阶段。根据围岩蚀变特征，在已知矿体的下部，可以寻找构造－蚀变岩型金矿体。     

滇西南澜沧江带红豆山铜矿床蚀变分带及其找矿意义

红豆山铜矿床是南澜沧江带新发现的矿床之一。通过野外地质工作和系统构造—|蚀变岩相填图,发现该矿床蚀变类型主要以钾长石化、硅化、绿泥石化、绿帘石化为主,其次为碳酸盐化、绢云母化、黄铁矿化等,且在空间上呈现一定规律,各蚀变带具有明显的叠加现象。依据区内岩石蚀变矿物组合等特点,自断裂带→上盘围岩,共出现4个典型蚀变带,依次为碎裂岩化带→长英岩化—碳酸盐化—绢云母化带→硅化—绿泥石化—绿帘石化带→弱长英岩化安山岩带。矿（化）体主要分布在长英岩化、碳酸盐化、绢云母化带和硅化、绿泥石化、绿帘石化带。由斑岩脉中心至边缘发育钾化带→硅化带→青磐岩化带→绢云母化带,斑岩旁侧围岩中发育放射状石英—方解石—黄铜矿脉。     

东天山玉峰金矿热液蚀变作用与元素迁移规律

玉峰金矿位于中亚造山带东天山东缘,是近年来新发现的含银高品位金矿床。该矿床目前已探明6个金矿体,均赋存在石英斑岩中。矿区热液蚀变作用发育,与成矿关系最密切的为黄铁绢英岩化和硅化,显示明显的蚀变分带:以石英硫化物脉为中心,黄铁绢英岩化带在其两侧大致对称分布。本文选取矿体上盘和下盘的石英斑岩、黄铁绢英岩进行了全岩的主、微量元素及成矿元素测试,并对其中的长石和绢云母进行电子探针成分分析。测试结果表明,黄铁绢英岩中的Au含量较蚀变前呈指数级增长,Ag、Cu、As等成矿元素大量增加,CaO、Na_2O、P_2O_5、P_2O_5、Sr、Pb、Th、U、Sb等元素显著迁出,而SiO_2、Al_2O_3、TiO_2含量和稀土元素含量变化较小,表现稳定。热液蚀变过程中,石英斑岩中71%～76%的正长石发生绢云母化,导致K_2O大量迁出;而钠长石几乎全部蚀变为绢云母,造成Na_2O大量迁出。热液流体的贡献使得蚀变岩中MgO、Fe_2O_3~T含量成倍增加,并主要富集在绢云母和/或黄铁矿晶格中。综合分析认为,绢英岩化蚀变带,Au、Cu、As和Bi等元素的综合化探异常,低电阻率、高激化率的地球物理特征可以作为玉峰矿区深部和外围找矿的标志。研究区内的石炭纪石英斑岩带,尤其是在构造叠加部位,热液活动使其更有利于矿化富集,是找矿勘探的有利部位。     

论治岭头金银矿床的成因

治岭头金银矿床矿体为含冰长石、蔷薇辉石的玉髓状石英脉体,矿石具环带状构造,围岩蚀变具典型的浅成低温热液蚀变特征,成矿流体是一种低盐度、近中性的还原性流体.矿床硫、铅、氢、氧、碳同位素研究表明,成矿物质主要来源于地下深部（甚至上地幔）,成矿热液表现出低温热液演化特点.成矿作用与加里东晚期浅成岩浆侵入活动有内在的成因联系.治岭头金银矿床属浅成低温热液（次火山热液）型金银矿床     

Orogenic Gold Mineralization in the Qolqoleh Deposit, Northwestern Iran

The Qolqoleh gold deposit is located in the northwestern part of the Sanandai‐Sirjan Zone, northwest of Iran. Gold mineralization in the Qolqoleh deposit is almost entirely confined to a series of steeply dipping ductile–brittle shear zones generated during Late Cretaceous–Tertiary continental collision between the Afro‐Arabian and the Iranian microcontinent. The host rocks are Mesozoic volcano‐sedimentary sequences consisting of felsic to mafic metavolcanics, which are metamorphosed to greenschist facies, sericite and chlorite schists. The gold orebodies were found within strong ductile deformation to late brittle deformation. Ore‐controlling structure is NE–SW‐trending oblique thrust with vergence toward south ductile–brittle shear zone. The highly strained host rocks show a combination of mylonitic and cataclastic microstructures, including crystal–plastic deformation and grain size reduction by recrystalization of quartz and mica. The gold orebodies are composed of Au‐bearing highly deformed and altered mylonitic host rocks and cross‐cutting Au‐ and sulfide‐bearing quartz veins. Approximately half of the mineralization is in the form of dissemination in the mylonite and the remainder was clearly emplaced as a result of brittle deformation in quartz–sulfide microfractures, microveins and veins. Only low volumes of gold concentration was introduced during ductile deformation, whereas, during the evident brittle deformation phase, competence contrasts allowed fracturing to focus on the quartz–sericite domain boundaries of the mylonitic foliation, thus permitting the introduction of auriferous fluid to create disseminated and cross‐cutting Au‐quartz veins. According to mineral assemblages and alteration intensity, hydrothermal alteration could be divided into three zones: silicification and sulfidation zone (major ore body); sericite and carbonate alteration zone; and sericite–chlorite alteration zone that may be taken to imply wall‐rock interaction with near neutral fluids (pH 5–6). Silicified and sulfide alteration zone is observed in the inner parts of alteration zones. High gold grades belong to silicified highly deformed mylonitic and ultramylonitic domains and silicified sulfide‐bearing microveins. Based on paragenetic relationships, three main stages of mineralization are recognized in the Qolqoleh gold deposit. Stage I encompasses deposition of large volumes of milky quartz and pyrite. Stage II includes gray and buck quartz, pyrite and minor calcite, sphalerite, subordinate chalcopyrite and gold ores. Stage III consists of comb quartz and calcite, magnetite, sphalerite, chalcopyrite, arsenopyrite, pyrrhotite and gold ores. Studies on regional geology, ore geology and ore‐forming stages have proved that the Qolqoleh deposit was formed in the compression–extension stage during the Late Cretaceous–Tertiary continental collision in a ductile–brittle shear zone, and is characterized by orogenic gold deposits.     

Alteration and mineralization styles of the orogenic disseminated Zhenyuan gold deposit,southeastern Tibet: Contrast with carlin gold deposit

Orogenic disseminated and Carlin gold deposits share much similarity in alteration and mineralization.The disseminated orogenic Zhenyuan Au deposit along the Ailaoshan shear zone,southeastern Tibet,was selected to clarify their difference.The alteration and mineralization from the different lithologies,including meta-quartz sandstone,carbonaceous slate,meta-(ultra)mafic rock,quartz porphyry and lamprophyre were researched.According to the mineral assemblage and replacement relationship in all types of host rocks,two reactions show general control on gold deposition:(1)replacement of earlier magnetite by pyrite and carbonaceous material;(2)alteration of biotite and phlogopite phenocrysts in quartz porphyry and lamprophyre into dolomite/ankerite and sericite.Despite the lamprophyre is volumetrically minor and much less fractured than other host rocks,it contains a large portion of Au reserve,indicating that the chemically active lithology has played a more important role in gold precipitation compared to structure.LA-ICP-MS analysis shows that Au mainly occurs as invisible gold in fine-grained pyrite disseminated in the host rocks,with Au content reaching to 258.95 ppm.The diagenetic core of pyrite in meta-quartz sandstone enriched in Co,Ni,Mo,Ag and Hg is wrapped by hydrothermal pyrite enriched in Cu,As,Sb,Au,Tl,Pb and Bi.Different host rock lithology has much impact on the alteration and mineralization features.Carbonate and sericite in altered lamprophyre show they have higher Mg than those developed in other of host rocks denoting that the carbonate and sericite incorporated Mg from phlogopite phenocrysts in the primary lamprophyre during alteration.The ore fluid activated the diagenetic pyrite in meta-quartz sandstone leading the hydrothermal pyrite enriched in Cu,Mo,Ag,Sb,Te,Hg,Tl,Pb and Bi,but the hydrothermal pyrite in meta-(ultra)mafic rock is enriched in Co and Ni as the meta-(ultra)mafic rock host rock contain high content of Co and Ni.However,Au and As shear similar range in both types of host rocks indicating that these two elements most likely come from the deep source fluid rather than the host rocks.It was shown in the disseminated orogenic gold deposit that similar hydrothermal alteration with mineral assemblage of carbonate(mainly dolomite and ankerite),sericite,pyrite and arsenopyrite develops in all types of host rocks.This is different from the Nevada Carlin type,in which alteration is mainly dissolution and silicification of carbonate host rock.On the other hand,Au mainly occur as invisible gold in both disseminated orogenic and Carlin gold deposits.     

Mineralogical Zonation of Wall-Rock Alteration in Jiaodong Gold Province, North China

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北山地区金矿床金的赋存状态和金矿物特征

甘肃北山地区金矿床主要有岩浆热液型金矿床和与韧性剪切带有关的金矿床,矿化类型为石英脉型和蚀变岩型。金多呈独立金矿物形式出现,少放许呈分散状;金矿物以银金矿为主,次为自然金,平均成色７７２;金矿物以粒间金、裂隙金、连生金、连生金和包体金等形成嵌布于石英、黄铁矿、方铅矿及闪锌矿等主要载物较为发育。金矿物特征反映出本区金矿床的成矿物质主要来源于变质岩,华力西－印支期中酸性岩浆活动是主要的动力源。     

福建尤溪肖板金矿床金的赋存状态及金矿物特征

肖板金矿床属受构造控制的中低温岩浆热液矿床,矿化类型为构造蚀变岩型。金多呈独立金矿物形式出现,少许呈分散状;金矿物以自然金为主,平均成色９３０,有少量银金矿和碲金矿。金矿物以包体金、裂隙金、连生金和粒间金等形式嵌布于黄铁矿、黄铜矿、石英、方铅矿及方解石等主要载金矿物中,且石英、方解石中较金属硫化物中占优势。金矿物形态各异,粒度以中细粒为主。     

陕西省铧厂沟金矿围岩蚀变和元素迁移特征

陕西省铧厂沟金矿床位于勉略缝合带以南,矿体受控于近东西向逆冲断层和韧脆性剪切带。本文以细碧岩矿带为例,系统研究了围岩蚀变分带及蚀变矿物组合,总结了矿床的蚀变分带模式。围岩蚀变以穿切细碧岩透镜体的剪切带为中心向外依次可划分为黄铁绢英岩化带、绢云碳酸盐化带和绿泥赤铁矿化带。蚀变矿物组合分别为黄铁矿＋铁白云石＋铬云母＋绢云母＋钠长石＋石英＋方解石、铁白云石＋绢云母＋钠长石＋石英±黄铁矿、（铁）绿泥石＋钠长石＋铁白云石＋赤铁矿＋钛铁氧化物＋石英±绿帘石。蚀变岩石组分迁移分析表明,在围岩蚀变过程中, SiO2、Na2O、Fe2O3T、MgO与Y等组分发生不同程度的迁出, K2O、CaO、Ba、Rb、Sr、Cr、Cu、Pb和挥发组分等迁入,并以黄铁绢英岩化带最为显著。金在成矿流体中以Au（HS）–2络合物迁移,成矿流体与富铁细碧岩之间的反应是金沉淀重要机制。     

胶东西北部仓上金矿床上盘围岩蚀变和黄铁矿标型特征研究

上盘围岩是矿床钻探过程中首先遇到的围岩,研究其蚀变特征具有重要的找矿指导意义。对胶东西北部露天开采的仓上金矿床的详细研究表明,上盘围岩蚀变以绿泥石化为主,蚀变分带自远矿端到近矿端依次为方解石绿泥石化带、赤铁矿绿泥石化带、绿帘石化带和绢英岩化带。黄铁矿的形态、成分和热电性标型显示,成矿过程中上盘围岩提供了丰富的Ｆｅ、Ｃｏ、Ｎｉ、Ｃｕ、Ｐｂ、Ｚｎ和Ａｕ、Ｐｔ等。上盘围岩的近矿标志是绢英岩化增强,黄铁矿的｛１００｝＋｛２１０｝增多,Ｓ、Ｃｕ、Ｐｂ、Ｚｎ和Ａｕ、Ｐｔ增高,Ｓ／Ｆｅ离子比和ｗ（Ｃｏ＋Ｎｉ）／ｗ（Ａｓ＋Ｓｂ）降低,Ｐ型黄铁矿出现率增高,蚀变岩的金含量增高。