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1.
黄典豪 《矿床地质》1999,18(3):244-252
通过对热液脉型的铅－锌－银矿床（３个）和银矿床（１个）和闪锌矿中硫化物包囊体的特征研究表明,石英－硫化物阶段富铁闪锌矿（主矿物）的硫化物包裹体十分发育：沿生长带产出的乳滴状黄铜矿与主矿物为共同沉淀成因;沿穿切主矿物的黄铜矿或石英细脉两侧,和受粗粒黄铜矿溶蚀的富铁闪锌矿近接触部位发育的乳滴状黄铜矿为渗透－交代产物;沿解理（裂隙）或粒间、粒内产出的各种形态磁黄铁矿是充填－交代的结果;沿解理分布的脉状毒  相似文献   

2.
The Laloki and Federal Flag deposits are two of the many (over 45) polymetallic massive sulfide deposits that occur in the Astrolabe Mineral Field, Papua New Guinea. New data of the mineralogical compositions, mineral textures, and fluid inclusion studies on sphalerite from Laloki and Federal Flag deposits were investigated to clarify physiochemical conditions of the mineralization at both deposits. The two deposits are located about 2 km apart and they are stratigraphically hosted by siliceous to carbonaceous claystone and rare gray chert of Paleocene–Eocene age. Massive sulfide ore and host rock samples were collected from each deposit for mineralogical, geochemical, and fluid inclusion studies. Mineralization at the Laloki deposit consists of early‐stage massive sulfide mineralization (sphalerite‐barite, chalcopyrite, and pyrite–marcasite) and late‐stage brecciation and remobilization of early‐stage massive sulfides that was accompanied by late‐stage sphalerite mineralization. Occurrence of native gold blebs in early‐stage massive pyrite–marcasite‐chalcopyrite ore with the association of pyrrhotite‐hematite and abundant planktonic foraminifera remnants was due to reduction of hydrothermal fluids by the reaction with organic‐rich sediments and seawater mixing. Precipitation of fine‐grained gold blebs in late‐stage Fe‐rich sphalerite resulted from low temperature and higher salinity ore fluids in sulfur reducing conditions. In contrast, the massive sulfide ores from the Federal Flag deposit contain Fe‐rich sphalerite and subordinate sulfarsenides. Native gold blebs occur as inclusions in Fe‐rich sphalerite, along sphalerite grain boundaries, and in the siliceous‐hematitic matrix. Such occurrences of native gold suggest that gold was initially precipitated from high‐temperature, moderate to highly reduced, low‐sulfur ore fluids. Concentrations of Au and Ag from both Laloki and Federal Flag deposits were within the range (<10 ppm Au and <100 ppm Ag) of massive sulfides at a mid‐ocean ridge setting rather than typical arc‐type massive sulfides. The complex relationship between FeS contents in sphalerite and gold grades of both deposits is probably due to the initial deposition of gold on the seafloor that may have been controlled by factors such as Au complexes, pH, and fO2 in combination with temperature and sulfur fugacity.  相似文献   

3.
The southwestern Sabzevar basin is the north of Central Iranian Microcontinent hosts abundant mineral deposits, including exhalative Mn mineralization and Cu-Zn volcanogenic massive sulfide (VMS) deposits. Amongst them, the Nudeh Besshi-type Cu–Zn volcanogenic massive sulfide (VMS) deposit is hosted within the lower part of a Late Cretaceous volcano-sedimentary sequence composed of alkali olivine basalt flows and tuffaceous silty sandstone. Based on investigations into the ore geometry, mineralogy, and texture, we recognized three different ore facies: (1) a stockwork of sulfide-bearing quartz veins cutting across the footwall volcano-sedimentary rocks and representing the stringer zone; (2) a massive ore type, displaying replacement texture with pyrite, chalcopyrite, sphalerite, friedrichite, and minor magnetite; and (3) a bedded ore type, with laminated to disseminated pyrite and chalcopyrite. EPMA studies indicate a distinctive minor element distribution between the different ore types of the Nudeh deposit. The Fe content in the sphalerite ranges from 0.65–1.80?wt.%, indicating the Fe-poor nature of the sphalerite. However, the Cd content in sphalerite ranged between 0.164–0.278?wt.%. According to the mineral compositions, Zn, Se, and Ag are found in bornite as minor elements. In the bedded ore facies, the pyrite contains higher levels of Se (up to 0.35?wt.%). The Zn content in the friedrichite in all of the ore samples is low. The Co/Ni ratios in pyrite from the Nudeh ore are lower than those of most magmatic deposits, but are similar to those from volcanogenic deposits, and hence support the proposed hydrothermal origin of the deposit. Two generations of quartz, Q1 and Q2 in the stockwork veins, contain primary fluid inclusions and these contain two phases (liquid and vapor). The lack of vapor-rich inclusions or variable liquid/vapor ratios indicate that the fluids did not boil at the site of trapping. Salinity for both Q1 and Q2 fluid inclusions ranges between 2.2–6.8?wt.% eq. NaCl. Homogenization temperatures for inclusions in the Q1 and Q2 veins average at about 296?°C and are similar to the temperatures of hydrothermal fluids discharged through vents in many modern seafloor VMS deposit. The Nudeh Besshi-type VMS deposit appears to have formed on the seafloor and based on the salinity and temperature constraints from the underlying stockwork, a buoyancy plume model is proposed as a mechanism for precipitation.  相似文献   

4.
长江中、下游地区块状硫化物矿床普遍受到燕山期岩浆及其热液的改造与叠加.本文以铜陵冬瓜山矿床为例,探讨这类矿床的成矿机制.该矿床主要由层状硫化物矿体组成,伴有矽卡岩型和斑岩型矿体.野外地质观察及室内矿相学的研究表明,冬瓜山层状矿体中矿石遭受了强烈的热变质作用及热液交代作用.进变质过程中形成的结构主要为黄铁矿受燕山期岩浆侵...  相似文献   

5.
MVT型铅锌矿床中矿物组成一般较简单,铜矿物非常少见。云南富乐铅锌矿床是川滇黔MVT型铅锌成矿域中代表性 大型铅锌矿床,其赋矿层位为该区最新地层-中二叠统阳新组白云岩,矿体距上覆峨眉山玄武岩不到160 m。通过矿相、 扫描电镜及能谱等分析测试,本研究在该矿床中发现了大量铜矿物,主要包括以下四类,即黄铜矿、锌砷黝铜矿、黝铜矿 和孔雀石,这些铜的独立矿物常交代闪锌矿和黄铁矿等矿物,形状多为环带状、脉状及不规则状等,部分黄铜矿呈乳滴状 分布于闪锌矿颗粒内部或呈他形交代闪锌矿,可能与闪锌矿同时形成,锌砷黝铜矿和黝铜矿呈他形细脉状穿插于闪锌矿或 分布于闪锌矿边缘及孔洞中,暗示这些铜矿物形成略晚于铅锌成矿。上述铜矿物常见于中低温热液铅锌矿床,其中锌砷黝 铜矿是硫盐矿物中较罕见的矿物,黝铜矿和锌砷黝铜矿的出现指示相对氧化的成矿环境,而孔雀石是在铜矿物的氧化过程 中形成的次生矿物。研究表明,本矿床矿石矿物的生成顺序为：黄铁矿→闪锌矿（乳滴状黄铜矿） →方铅矿→黄铜矿→锌 砷黝铜矿→黝铜矿→孔雀石,结合矿床产出的地质地球化学特征,云南富乐铅锌矿床中铜可能有两个来源：早期的乳滴状 黄铜矿与铅锌矿同期且均来自基底地层--昆阳群;后生铜矿物（黄铜矿、黝铜矿和锌砷黝铜） 主要来源于上覆峨眉山玄 武岩,这与铅锌主要来源于昆阳群等基底地层有所差异,研究成果为认识川滇黔地区铅锌成矿作用与峨眉山玄武岩关系提 供了新的地球化学依据。  相似文献   

6.
To determine the bulk chemical compositions of chalcopyrite containing starlike sphalerite and sphalerite including dotlike chalcopyrite, specimens from various types of ore deposits in Japan were used for modal and electron microprobe analyses. According to the analytical results, most of the measured zinc contents in chalcopyrite containing starlike sphalerite are less than 0.8 at%, corresponding to the maximum solubility of zinc in chalcopyrite as determined experimentally at 400°C. However, specimens from the Maruyama deposit in the Tsumo mine contain 1.2–1.4 at% Zn, which are within the solubility limit of an intermediate solid solution (ISS) above 400°C. It is therefore concluded that starlike sphalerite in chalcopyrite are exsolution products derived from primary chalcopyrite solid solution and/or zincic ISS. Measured copper contents in sphalerite including dotlike chalcopyrite yield considerably higher values, i.e., 1.5–6.0 at%, which exceed the solubility limits of copper in sphalerite solid solution as determined experimentally. This result suggests that not all the chalcopyrite dots were exsolved from sphalerite, but that most of them are the product of some other mechanisms.  相似文献   

7.
The Ohori deposit, one of the base metal deposits in the Green-Tuff region, NE Japan, is composed of two types of mineralization; a skarn-type (Kaninomata orebody) made by the replacement of the Miocene calcareous layer, and a vein-type (Nakanomata orebody). While the ore mineral assemblage of the deposit (chalcopyrite, pyrite, sphalerite and galena) has been known for being rather simple, some Pb-Bi-S minerals have been discovered for the first time in the present study. The minerals mainly occur in the chalcopyrite-rich ores of both orebodies. They essentially belong to the Pb-Bi-S system and contain Cu and Ag in minor amounts, which correspond to the lillianite–gustavite solid solution series (phases Z and X), cosalite, neyite, felbertalite, krupkaite and Bi-bearing galena. The chalcopyrite-rich (Bi-bearing) ores from both orebodies are richer in chalcopyrite, pyrite and chlorite, and have higher homogenization temperatures (>300°C) of fluid inclusions, and higher FeS contents in sphalerite compared to the Bi-free ores. In the Green-Tuff region, Bi-minerals have been reported from many base metal deposits. Most of these Bi-bearing ore deposits are referred to as xenothermal-type deposits, and are characterized by the following common features; composite mineralization of high- and low-temperatures in the shallower environments, and close relationships with the Tertiary granitic rocks. The whole mineralization at the Ohori deposit also has a similar xenothermal character because of the coexistence of high-temperature chalcopyrite-rich ores with Pb-Bi-S minerals, which were formed by the influence of the Tertiary granitic rocks at a shallow depth.  相似文献   

8.
The sequence of orebody formation at the Talgan massive sulfide deposit; morphology of sulfide orebodies; mineralogy, texture, and structure of ore; chemical composition of minerals; and fluid inclusions and relationships between stable isotopes (S, C, O) in sulfides from ores and carbonate rocks are discussed. The deposit is localized in the Uzel’ga ore field of the northern Magnitogorsk Megazone. The sulfide ore is hosted in the upper felsic sequence of the Middle Devonian Karamalytash Formation, composed of basalt, basaltic andesite, and rhyodacite. Orebodies are irregular lenses lying conformably with host rocks. Pyrite, chalcopyrite, sphalerite, and fahlore are the major ore minerals; galena, bornite, and hematite are of subordinate abundance. Sulfide mineralization bears attributes of deposition under subseafloor conditions. The carbonate and rhyolite interlayers at the roofs of orebodies and the supraore limestone sequence served as screens. Zoning typical of massive sulfide deposits was not established. The study of fluid inclusions has shown that the temperature of the hydrothermal solution varied from 375 to 110°C. δ34S‰ ranges from ?2.4 to +3.2‰ in pyrite, from ?1.2 to +2.8‰ in chalcopyrite, and from ?3.5 to +3.0‰ in sphalerite (CDT). These parameters correspond to an isotopic composition of magmatic sulfur without a notable percentage of sulfate sulfur. δ13C and δ18O of carbonates vary from ?18.1 to +5.9‰ (PDB) and from +13.7 to +27.8‰ (SMOW), respectively. The carbon and oxygen isotopic compositions of carbonates from ores and host rocks markedly deviate from the field of marine carbonates; a deep source of carbon is suggested. The results obtained show that the main mass of polysulfide ore at the Talgan deposit was formed beneath the floor of a paleoocean. The ore-forming system was short-lived and its functioning did not give rise to the formation of zonal orebodies. Magmatic fluid played the leading role in mineral formation.  相似文献   

9.
大横路式钴(铜)矿床地质特征及成因探讨   总被引：6，自引：1，他引：5  
大横路式钴(铜)矿床产于辽吉古元古代裂谷增生地体内,是国内新近发现的新类型钴矿床,其矿化特征独特、埋藏浅、规模大,具有较高潜在经济价值.矿床赋存于老岭群富硼、碳粘土岩夹硅质岩建造之中,矿体呈层状、似层状、鞍状产出,产状与围岩一致;矿石中金属矿物以硫化物、砷化物形式存在,钴以硫钴镍矿、辉砷钴矿、方钴矿和含钴黄铁矿等形式与黄铜矿、闪锌矿、方铅矿等共生.通过对矿床地质、地球化学特征和流体特征研究,证明该矿床既具有明显的热水沉积成因特征,又受后期变质热液的强烈叠加,属海底热水沉积-变质热液叠加改造型矿床.  相似文献   

10.
新疆小热泉子铜(锌)矿床位于大南湖晚古生代岛弧带内,矿体主要赋存于一套凝灰质火山碎屑沉积岩中,矿石类型主要为块状黄铜矿矿石、闪锌矿矿石和脉状硫化物矿石。硫化物的显微结构研究表明,黄铁矿主要发生脆型变形,形成碎裂结构、细粒化结构、充填交代结构、"布丁"结构以及变斑晶结构,黄铜矿和闪锌矿发生塑性变形,黄铜矿表现为"S型"面理结构以及在闪锌矿中呈团斑状结构,电子探针结果表明黄铜矿发生明显的活化迁移富集作用。硫化物的稀土微量元素研究表明,闪锌矿中Mn、Ga、As等元素含量很低,Ga/In<<1,Ge/In多数小于1,174相似文献   

11.
The Dongshengmiao Pb-Zn deposit located in the Mesoproterozoic aulacogen in a passive continental margin in the north- west margin of the North-China Craton is widely considered to be a untypical SEDEX deposit.Recently,new types of mineralization such as chalcopyrite veins and re-crystallized sphalerite ores with visible hydrothermal alteration have been found in the deposit at depth.In this paper we report the decrepitation temperatures of fluid inclusions in chalcopyrite,sphalerite and quartz from these new types of ores.The decrepitation temperatures of fluid inclusions in chalcopyrite(4 samples),sphalerite(2 samples)and quartz(5 samples)are 303～456℃,97～497℃,146～350℃and 350～556℃,respectively.The decrepitation temperatures of fluid inclusions in the vein-type chalcopyrite are similar to the decrepitation temperatures of fluid inclusions in chalcopyrite from the Hercynian Oubulage porphyry Cu-Au deposit(313～514℃)and the Chehugou porphyry Cu-Mo deposit(277～485℃),supporting our interpretation that the Dongshengmiao deposit was overprinted by magmatic hydrothermal mineralization.The decrepitation temperatures of fluid inclusions in re-crystallized sphalerite from the Dongshengmiao deposit are characterized by two peaks,97～358℃and 358～497℃.The decrepitation temperatures of fluid inclusions in quartz in ehalcopyrite veins from the Dongshengmiao deposit are also characterized by two peaks,146～350℃and 350～556℃.The lower and higher temperature peaks in both cases are considered to represent two separate mineralization events,original SEDEX mineralization and magmatic hydrothermal overprinting,respectively.The higher decrepitation temperatures of fluid inclusions in quartz and sphalerite from the Dongshengmiao deposit are similar to the decrepitation temperatures(340～526℃)of fluid inclusions in sphalerite from the Baiyinnuoer skarn-type Pb-Zn deposit in the region. Replacement of pyrite by sphalerite and overgrowth of chalcopyrite on pyrite in the Dongshengmiao support our interpretation that the original SEDEX mineralization was overprinted by magmatic hydrothermal activity in the deposit.Our results suggest that there may be separate porphyry and skarn-type deposits related to Hercynian magmatism and associated hydrothermal activities in the Langshan area, which are potential exploration targets in the future.  相似文献   

12.
哈密天湖铁矿是新疆东天山地区的一个大型铁矿床。天湖铁矿床产出在新元古界天湖群第三组变质岩系中,铁矿体赋存于白云质大理岩内并呈层状、似层状产出;碳酸盐岩蚀变部位的部分铁矿石变富,且有黄铜矿、闪锌矿等硫化物生成。矿石组构方面,具有细-中细粒状结构、网格状结构、残余结构,层状、条带状构造。矿床成因类型属于沉积变质-区域混合岩化热液叠加改造型。  相似文献   

13.
广西拉么铜锌矿床矿物学特征及其地质意义   总被引：3，自引：0，他引：3  
广西拉么铜锌矿床矿物学特征及其地质意义李明琴税哲夫聂爱国张杰（贵州工业大学资源工程系，贵阳５５０００３）关键词黄铜矿闪锌矿矿物学特征铜锌矿床广西拉么广西拉么铜锌矿床位于黔桂边界广西南丹县境内，在大地构造上位于江南地轴西南缘、南丹河池轴缘凹陷带中。矿床...  相似文献   

14.
Ore textures and electron microprobe analyses show that in addition to highly scattered blebs in sphalerite grains,intergrown chalcopyrite also occurs as rods,myrmekites and lamellae aligned along cleavages and twin boundaries of the host sphalerite.The majority of the intergrowths could have been formed by replacement of sphalerite by chalcopyrite,albeit part of them may have resulted from exsolution,Not only copper,but also iron were introduced into the sphalerite by replacive fluids.While the front of the replacing fluid was moving forward through a sulphide orebody,Zn and Pb were dissolved and Cu was precipitated,resulting in zonal refining of the sulphide ores,The remobilized zinc and lead were precipitated at favourable sites with changed physico-chemical conditions .This is a possible mechanism for the formation of copper-poor zinc and lead ores above or lateral to the copper orebodies in some of the massive sulphide deposits reworked and overprinted by late-stage granites and their hydrothermal fluids.  相似文献   

15.
The Emarat deposit, with a total proved reserve of 10 Mt ore grading 6% Zn and 2.26% Pb, is one of the largest Zn–Pb deposits in the Malayer–Esfahan belt. The mineralization is stratabound and restricted to Early Cretaceous limestones and dolomites. The ore consists mainly of sphalerite and galena with small amounts of pyrite, chalcopyrite, calcite, quartz, and dolomite. Textural evidence shows that the ore has replaced the host rocks and thus is epigenetic.Sulfur isotopes indicate that the sulfur in sphalerite and galena has been derived from Cretaceous seawater through thermochemical sulfate reduction. Sulfur isotope compositions of four apparently coprecipitated sphalerite–galena pairs suggest their precipitation was under equilibrium conditions. The sulfur isotopic fractionation observed for the sphalerite–galena pairs corresponds to formation temperatures between 77 °C and 168 °C, which agree with homogenization temperatures of fluid inclusions.Lead-isotope studies indicate that the lead in galena has been derived from heterogeneous sources including orogenic and crustal reservoirs with high 238U/204Pb and 232Th/204Pb ratios. Ages derived from the Pb-isotope model give meaningless ages, ranging from Early Carboniferous to future. It is probable that the Pb-isotope model ages that point to an earlier origin than the Early Cretaceous host rocks are derived from older reservoirs in the underlying Carboniferous or Jurassic units, either from the host rocks or from earlier-formed ore deposits within these units.This research and other available data show that the Emarat Zn–Pb deposit has many important features of Mississippi Valley-type (MVT) lead–zinc deposits and thus we argue that it is an MVT-type ore deposit.  相似文献   

16.
《International Geology Review》2012,54(14):1635-1648
The Koushk zinc–lead deposit in the central part of the Zarigan–Chahmir basin, central Iran, is the largest of several sedimentary–exhalative (SEDEX) deposits in this basin, including the Chahmir, Zarigan, and Darreh-Dehu deposits. The host-rock sequence consists of carbonaceous, fine-grained black siltstone with interlayered rhyolitic tuffs. It corresponds to the upper part of the Lower Cambrian volcano-sedimentary sequence that was deposited on the Posht-e-Badam Block due to back-arc rifting of the continental margin of the Central Iranian Microcontinent. This block includes the late Neoproterozoic metamorphic basement of the Iran plate, overlain by rocks dating from the Early Cambrian to the Mesozoic. Based on ore body structure, mineralogy, and ore fabric, we recognize four different ore facies in the Koushk deposit: (1) a stockwork/feeder zone, consisting of a discordant mineralization of sulphides forming a stockwork of sulphide-bearing dolomite (quartz) veins cutting the footwall sedimentary rocks; (2) a massive ore/vent complex, consisting of massive replacement pyrite, galena, and sphalerite with minor arsenopyrite and chalcopyrite; (3) bedded ore, with laminated to disseminated pyrite, sphalerite, and galena; and (4) a distal facies, with minor disseminated and laminated pyrite, banded cherts, and disseminated barite. Carbonatization and sericitization are the main wall-rock alterations; alteration intensity increases towards the feeder zone. The δ34S composition of pyrite, sphalerite, and galena ranges from?+6.5 to?+36.7‰. The highest δ34S values correspond to bedded ore (+23.8 to?+36.7‰) and the lowest to massive ore (+6.5 to?+?17.8‰). The overall range of δ34S is remarkably higher than typical magmatic values, suggesting that sulphides formed from the reduction of seawater sulphate by bacteriogenic sulphate reduction in a closed or semi-closed system in the bedded ore, whereas thermochemical sulphate reduction likely played an important role in the feeder zone. Sulphur isotopes, along with sedimentological, textural, mineralogical, and geochemical evidences, suggest that this deposit should be classified as a vent-proximal SEDEX ore deposit.  相似文献   

17.
Abstract: The Anle Sn‐Cu and Huanggangliang Fe‐Sn deposits have been exploited in the Linxi district, which is located 165 km northwest of Chifeng City in northern China. In this study the formation mechanisms of the tin deposits in the Anle and Huanggangliang mining area were investigated to understand the mechanisms of tin mineralization in northern China. The veins of the Anle deposit are divided into cassiterite–quartz–chlorite veins, chalcopyrite‐bearing quartz veins, cassi–terite–chalcopyrite–bearing quartz veins and sphalerite‐quartz veins. The sequence of mineralization is tin mineralization (stage I), copper mineralization (stage II), and lead‐zinc mineralization (stage III). The Huanggangliang tin deposit consists of magnetite skarn orebodies and many cassiterite‐bearing feldspar–fluorite veins and veinlets cutting the magnetite orebodies. The fluid inclusions in quartz and fluorite in ores from the Anle and Huanggangliang tin deposits are divided into two‐phase fluid inclusions, vapor‐rich fluid inclusions and poly‐phase fluid inclusions. The final homogenization temperatures of fluid inclusions of quartz in the ores of the Anle deposit and fluorite of tin‐bearing feldspar veins in the Huanggangliang tin deposit range from 195 to 425C and from 215 to 450C, respectively. The fluids responsible for the Anle and Huanggangliang tin deposits were of very high temperature and NaCl‐rich ones containing K, Ca, Al, Si, Ti, Fe and Cl in addition to ore metals such as Sn and Cu. The temperature and chemical composition of fluid in fluid inclusions of igneous rocks in the mining area are very similar to those of fluid in fluid inclusions in the ores of these deposits. The fluid for these ore deposits had a close relation with the fluid coexisting with melt of Late Jurassic granitic rocks in this mining area. Salinities of fluid inclusions from these ore deposits and granitic rocks in the mining area were estimated to range from 35 to 50 wt % NaCl equivalent. Based on arsenopy‐rite geothermometry and fluid inclusion studies, a fluid containing 40 wt% NaCl (eq.) could be formed by phase separation of fluid having 6 wt% NaCl (eq.) at a temperature of 420 to 500C and a pressure of 0.3 to 0.4 kb. The temperatures and pressures presented above indicate an NaCl‐rich magmatic fluid derived from granitic melt that had intruded into a shallow level of crust caused the Sn–Fe–Cu mineralization of the mining area. The geological relationship between these ore deposits and granitic bodies around the ore deposits, and the similarity of fluids forming these ore deposits and coexisting with granitic melt, suggest that these ore deposits were formed by the activity of fluid derived from granitic melt in Late Jurassic age.  相似文献   

18.
江西省广昌县竹坑铜银矿床位于华南板块南华造山带武夷隆起区中段,江西省广昌县和福建省建宁县交界处。本次研究从矿床地质特征入手,对矿床不同类型矿石的黄铜矿、黄铁矿、闪锌矿所含元素含量用电子探针进行测定,分析不同类型矿石的黄铜矿、黄铁矿、闪锌矿的地球化学特征,从而推断竹坑矿床成因。研究表明矿体赋矿围岩主要有震旦系下统上施组混合花岗岩;矿体赋存于北东向F4断裂构造内,均受北北东向、北西向断裂构造共同制约;铜银矿体形态较简单,呈脉状、似层状、船状产出;竹坑铜银矿化与碳酸盐化、硅化、黄铁矿化蚀变紧密相关。矿石中黄铁矿Fe/S平均值0.82~0.83,小于0.875,Co/Ni比值1.26~53;显示出热液成因特点。矿石中黄铜矿平均成分的矿物化学式为Cu 0.933 Fe 0.971 S 2,显示竹坑矿床中黄铜矿普遍富硫的特点;矿石中闪锌矿呈红褐色,闪锌矿中Fe含量为8.466%~10.748%,平均值为9.334%,含量明显偏高;从而表明了矿床黄铜矿形成于中低温环境。综上现象推断广昌县竹坑铜银矿床属中低温热液型矿床。  相似文献   

19.
The Shurab Sb-polymetallic mineralization is a subvolcanic rock-hosted epithermal deposit and located in north Lut Block, eastern Iran. It is one of the most important deposits of the Iranian East Magmatic Assemblage (IEMA) in which numerous Middle-Cenozoic precious and base metals deposits occur. The main lithological units in the area are Paleogene subvolcanic intrusions and minor Jurassic sedimentary rocks. Mineralization occurs as veins in a series of NW-SE and E-W trending faults and fractures in the Eocene-Oligocene dacite and andesite subvolcanic rocks. Mineralization at the Shurab deposit can be subdivided into four stages: pre-ore stage, Cu-Zn-Pb ore stage, Sb-Ag ± As ore stage and post-ore stage. The total sulfide content of the veins in the area is variable, ranging from 1 to 50%, and is dominated by stibnite, chalcopyrite, galena, Fe-poor sphalerite and pyrite with minor chalcostibite, Ag-tetrahedrite and bournonite; gangue minerals are mainly quartz and calcite. Silicic, argillic, propylitic, and sericitic, are the most obvious wall rock alterations. Microthermometric measurements of primary liquid-rich fluid inclusions in quartz and sphalerite indicate that the veins were formed at temperatures between 115 and 290 °C from fluids with salinities between 0.7 and 16.2 wt% NaCl eq., suggesting an epithermal origin. The δ34S values of pyrite, chalcopyrite and galena vary between -2.5 and 0.8‰, and δ18O values of quartz range between 12.5 and 14.8‰. It is inferred that the Shurab mineralization is of epithermal origin, related to an Eocene-Oligocene magmatic geothermal system involving fluids of magmatic and meteoric origin.  相似文献   

20.
英城子金矿床位于兴蒙造山带东缘,矿床产于近东西向韧性脆性剪切带（靡棱岩带）内,矿体主要呈透镜状、似层状和脉状产出.矿石矿物主要为黄铁矿、闪锌矿和黄铜矿,主要结构为交代结构、乳滴状结构、半自形-他形结构,主要构造为浸染状构造、脉状构造、条带状构造.成矿作用先后经历了4个阶段：石英-毒砂-黄铁矿阶段、石英-黄铁矿阶段、石英-多金属硫化物阶段和石英-方解石阶段.成矿流体总体属于中温、低盐度、低密度的CO2-CH4-H2O体系.英城子金矿床与国内外典型的造山型金矿相比具有诸多相似之处,其成因类型属于造山型金矿.  相似文献   

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