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1.
Isothermal solid state experiments on the diffusion of Cu, Fe, Zn and In and related effects have been carried out in sphalerite single crystals. The driving force for the diffusion and corresponding reactions are chemical potential gradients which are established by differences in sulfur fugacity, oxygen fugacity and the chemical activity between sulfide powders as metal sources and receptor crystals.Studies in the system ZnS-CuInS2 show replacement rims in sphalerite produced by the formation of solid solutions between ZnS and CuInS2. These differences reflect the extent of mutual solid solution. The composition profiles of these rims at different temperatures and sulfur fugacities are calculated to diffusion coefficients for the coupled substitution of Cu+ + In3+ versus 2 Zn2+. The interdiffusion coefficients of (Cu + In) in Fe-free sphalerite at the Fe/FeS sulfur fugacity of the sources obey to the relation: 相似文献
2.
云南兰坪盆地西缘脉状铜多金属矿床硫、铅同位素组成及成矿示踪 总被引：2，自引：0，他引：2
云南兰坪盆地西缘脉状铜多金属矿床主要赋存于由砂岩、粉砂岩和页岩组成的碎屑岩建造中.为了查明兰坪盆地西缘脉状铜多金属矿床成矿物质来源,对盆地西缘四个典型脉状铜多金属矿床(科登涧、连城、金满和水泄)的硫、铅同位素的组成进行了分析和对比研究.结果表明,这些矿床的铅同位素组成总体变化较小,且大部分落在盆地沉积地层铅范围内,金满、连城铜矿床可能有部分深源铅的加入.硫同位素特征表明,兰坪盆地西缘脉状铜多金属矿床的硫主要来源于地层硫酸盐的还原作用,其中金满铜矿床和连城铜钼多金属矿床可能有深源硫的混入.各矿床硫同位素不同的特点,除反映各矿床源区硫同位素组成的差异外,可能还与各矿床成矿时不同的物理化学条件(温度、氧逸度、pH 值和离子强度等)差异有关 相似文献
3.
黑云母的化学组成特征对揭示花岗岩的源区特征、形成环境、后期热液作用以及成矿元素富集特征具有重要的指示意义.对与锡田钨锡多金属矿床成矿作用密切相关的锡田燕山早期花岗岩黑云母和长石成分进行了系统的电子探针分析.分析结果表明,黑云母具有富铁贫镁、高铝低钠的特征,其MgO和FeOT含量分别为0.12%~1.35%和15.47%~23.24%,类似于高铁黑云母;其含铁指数Fe/(Fe+Mg)较高,集中在0.87~0.99,属于铁叶云母;其长石主要以正长石和钠长石为主.这些特征暗示了寄主岩石源区以壳源为主.结合相关区域地质资料,表明锡田燕山早期花岗质岩浆具有较高的温度和较低的氧逸度.黑云母具有高的含铁指数、较高的结晶温度和低的氧逸度等特征均有利于锡成矿,可以作为勘探锡矿的标志之一.综合分析认为,在锡田花岗质岩浆演化过程中,岩浆结晶期后分异出的流体趋向于向富锡的方向演化,是锡田多金属矿床成矿流体的重要来源. 相似文献
4.
阿尔山地区是大兴安岭中南段多金属成矿带的重要地段。该区热液脉型铁锰多金属矿、热液脉型钼（铜）矿和矽卡岩型铅锌多金属矿等3种代表性矿床（点）的成矿花岗岩的形成时代一直是研究的薄弱环节。通过多种高精度的U-Pb年龄测定,区内成矿花岗岩的形成时代分别为印支早期（(237.8±2.3) Ma）和燕山中期（(152.2±2.9) Ma）、燕山晚期（(135.1±0.4) Ma）,与邻区乌兰浩特－索伦地区基本可以对应。而前人划定的海西期花岗岩,实际为燕山晚期;划定的燕山早期花岗岩,实际为印支早期、燕山中期。研究成果对于区内花岗岩浆及期后热液与多金属成矿作用在时间上的关系提供了重要依据,对确定区內相应多金属矿类型的成矿花岗岩时代亦提供了可资对比的依据。 相似文献
5.
Abstract. A detail investigation of ore and gangue minerals was performed on the Doyashiki Kuroko deposits, Hokuroku basin, Japan for the first time. Main ore minerals are sphalerite, galena, pyrite, chalcopyrite, tetrahedrite-tennantite and digen-ite. Small amounts of enargite, wittichenite, electrum, covellite, bornite, marcasite and hematite are also observed. Quartz, barite and gypsum are common gangue minerals. Homogenization temperatures and salinities of fluid inclusions in quartz, sphalerite and barite range from 190 to 240C and 3.0 to 5.5 wt% NaCl equivalent, respectively. The FeS contents of sphalerite and Ag contents of electrum were 0.12 to 0.18 mol %, 39.0 to 39.6 atom %, respectively. The chemical composition of digenite as a primary mineral shows high sulfur contents.
These data indicate that ore fluid responsible for digenite and associated ore minerals was characterized by a range of high sulfur fugacity with a moderate formation temperature. This is concordant with the mineral assemblage of bornite-pyrite and chalcopyrite, which shows high sulfur fugacity conditions. It seems that the mineralization closely associated with acidic volcanism has occurred around 13 Ma of Middle Miocene on the seafloor at the depth of about 1500 m. 相似文献
These data indicate that ore fluid responsible for digenite and associated ore minerals was characterized by a range of high sulfur fugacity with a moderate formation temperature. This is concordant with the mineral assemblage of bornite-pyrite and chalcopyrite, which shows high sulfur fugacity conditions. It seems that the mineralization closely associated with acidic volcanism has occurred around 13 Ma of Middle Miocene on the seafloor at the depth of about 1500 m. 相似文献
6.
Abstract. Formation conditions of some vein-type copper deposits of the Tocopilla district (Deseada, San Jose, Santa Rosa) and the Gatico district (Yohanita, Toldo-Velarde, Argentina) in the Coastal Cordillera of northern Chile were inferred from mineral paragenesis and fluid inclusion data, and were compared with those of neighboring stratiform copper deposits. The vein-type copper deposits are hosted in Late Jurassic dioritic to quartz-dioritic plutons intruding extensively an andesite-dominant volcanic pile of the Jurassic La Negra Formation. Primary mineralization is characterized by chalcopyrite + magnetite + pyrite + bornite, and supergene alteration of these minerals produced anilite, covellite, atacamite and chrysocolla. The hypogene mineral assemblage indicates relatively high sulfur fugacity and weakly oxidized conditions, distinct from the stratiform copper deposits formed under low sulfur fugacity and moderately oxidized conditions. Furthermore, the fluid inclusion data of the vein-type deposits indicate high temperature (401–560C) and high salinity (39–68 wt% NaCl equiv.) ranges in contrast to the stratiform deposits, suggesting that this type of deposits formed by magma-associated hypersaline ore fluids. 相似文献
7.
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
8.
内蒙古东升庙矿床岩浆热液叠加成矿作用——来自地质与矿物包裹体测温的证据 总被引：1，自引：0，他引：1
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
9.
T. Urabe 《Mineralium Deposita》1977,12(3):319-330
Sphalerites from Japanese epithermal Pb-Zn vein-type deposits, namely, Yatani, Oizumi and Hosokura, contain 2900–3400 ppm cadmium and 760–2100 ppm manganese. And galenas from the same deposits contain cadmium and manganese 19.2–26.9 ppm and 7.8–218.3 ppm, respectively. The temperatures, evaluated from the partition of cadmium between coexisting sphalerite and galena, are consistent within a total range of 150°C at maximum within an individual deposit. No systematic change with depth can be observed at the Shoko-hi vein, Hosokura mine and Hompi vein, Yatani mine. In several samples, the temperatures obtained from the partition of cadmium have been compared with those obtained from sulfur isotope fractionations. Iron content in sphalerite coexisting with pyrite indicates that the deposition of ore minerals at these deposits may have taken place from ore-forming solutions in which H2S or HS– was the predominant dissolved sulfur species, and the solutions may have been free from in situ oxidation or reduction. 相似文献
10.
东昆仑野马泉地区矽卡岩矿床地球化学特征及其成因意义 总被引：8，自引：0，他引：8
东昆仑西段(祁曼塔格)的野马泉地区,是青海省内一个重要的多金属成矿区.该区以往的工作程度较低,与花岗岩有关的铁、铜、多金属矿床多是近几年地质大调查中新发现的.本文通过对野马泉地区铁、铜、多金属矿床矿石矿物组合、围岩蚀变分带、黄铁矿Co/Ni比值、矿石稀土元素特征、矿床硫、铅同位素组成特征等的研究.结果表明,野马泉地区矽卡岩型多金属矿床的形成与东昆仑晚古生代-早中生代构造岩浆旋回造山后期的伸展引张环境形成的碱性A型花岗岩有关,成矿物质主要来自岩浆,具有深部来源特征,与幔源基性岩浆底侵及其与壳源酸性岩浆的混合作用有关,属于典型的钙、镁矽卡岩型矿床. 相似文献
11.
Huaibei area is an important iron-copper metallogenic area in northern Anhui Province. In order to summarize the metallogenic series and regularity of skarn-type deposits systematically in this area, based on recent prospecting results and the diagenesis and metallogenic chronology, the authors systematically investigated the geological characteristics and metallogenic conditions of the known deposits and divided thern into three metallogenic series. They are skarn-type iron-copper-gold metallogenic series related to high-K calc-alkali intrusive rocks, skarn-type iron-gypsum metallogenic series related to high-K calc-alkaline intrusive rocks and skarn-type iron-light rare earth metallogenic series related to monzogranite. Then the geological characteristics and metallogenic regularity of four typical deposits were discussed respectively. The results show that the deposit formation can be divided into two stages in this area, and the metallogenic space is controlled by deep faults, arc structures and magmatic belts. Finally, the regional metallogenic models of Qianchang type, Yangqiaozi type and Wangchang type iron polymetallic deposits in the early stage of Early Cretaceous and Qiganlou type iron-light rare earth deposits in the late stage of Early Cretaceous were established. 相似文献
12.
Fractal and multi-fractal content area method finds application in a wide variety of geological, geochemical and geophysical fields. In this study, the fractal content-gradient method was used on 1:10,000 scale to delineate geochemical anomalies associated with copper mineralization. Analysis of geochemical data from the Yangla super large Cu-Pb-Zn polymetallic ore district using the fractal content-gradient method, combined with other geological data from this area, indicates that ore-prospecting in the ore district should focus on Cu as the main metal and Pb-Zn and Au as the auxiliary metals. The types of deposits include (in chronological order) re-formed sedimentary exhalative (SEDEX), skarns, porphyries, and hydrothermal vein-type deposits. Three ore-prospecting targets are divided on a S–N basis: (1) the Qulong exploration area, in which the targets are porphyry-type Cu deposits; (2) the Zongya exploration area, where the targets are porphyry-type Cu and hydrothermal vein-type Cu-Pb polymetallic deposits; and (3) the Zarelongma exploration area, characterized mainly skarn-type “Yangla-style” massive sulfide Cu-Pb deposits. Our study demonstrates that the fractal content-gradient method is convenient, simple, rapid, and direct for delineating geochemical anomalies and for outlining potential exploration targets. 相似文献
13.
James E. Mungall David R.A. Andrews Paul J. Sylvester 《Geochimica et cosmochimica acta》2005,69(17):4349-4360
We have performed six experiments in which we equilibrated monosulfide solid solution (mss) with sulfide melt in evacuated silica capsules containing solid buffers to fix oxygen and sulfur fugacity, at temperatures of 950°C, 1000°C and 1050°C at bulk concentrations of ∼50 ppm for each of the PGE and Au, 5% Ni, and 7% Cu. Concentrations of O, S, Fe, Ni and Cu were determined by electron microprobe, whereas precious metal concentrations were determined by laser-ablation inductively-coupled mass spectrometry. Partition coefficients of all elements studied show minimal dependences on oxygen fugacity from the IW to the QFM buffers when sulfur fugacity is fixed at the Pt-PtS buffer. Cu, Pt, Pd and Au are strongly incompatible and Ru remains moderately to strongly compatible under all conditions studied. At all oxygen fugacities, at the Pt-PtS sulfur buffer, Ir and Rh remain highly compatible in mss. In the single run at both low oxygen and low sulfur fugacity Ir and Rh were found to be strongly incompatible in mss. At QFM and Pt-PtS the partition coefficient for Ni shows weak temperature dependence, ranging from 0.66 at 1050°C to 0.94 at 950°C. At lower oxygen and sulfur fugacity Ni showed much more incompatible behavior. Comparison with the compositions of sulfide ores from the Lindsley deposit of Sudbury suggests that the sulfide magma evolved under conditions close to the QFM and Pt-PtS buffers. The compatible behavior observed for Ni, Ir and Rh at Lindsley and most other magmatic sulfide deposits hosted by mafic rocks requires equilibration of mss and sulfide liquid at moderately high sulfur fugacity and low temperatures near to the solidus of the sulfide magma. We argue that this constraint requires that the sulfide magma must have evolved by equilibrium crystallization, rather than fractional segregation of mss as is commonly supposed. 相似文献
14.
本文阐述了我国几个不同成因矿床闪锌矿的化学成分、晶胞参数和物理性质,如硬度、密度、反射率、吸收边能量、磁化率等的特征;根据闪锌矿的内部电子结构和微量元素的晶体化学特征讨论了成分、结构与物理性质之间的相互关系;并探讨了这些标型特征在矿床成因和地质找矿上的意义。 相似文献
15.
黑云母作为花岗岩中含量最高的暗色矿物,其成分特征对指示岩石成因与成矿起着重要作用。云南个旧卡房锡多
金属矿床的形成与花岗质岩浆活动密切相关,卡房花岗岩包含有大量黑云母,通过电子探针测试方法,对该花岗岩中的
黑云母成分进行了系统的研究。结果显示,黑云母为富铁黑云母,具有富硅、铁、铝、钾、钛,贫锰、镁、钙、钠等特
征,含铁指数为0.67~0.83。黑云母的成分特征暗示其结晶温度为500~708 ℃,结晶压力为202~538 MPa,对应的结晶深度为
7.64~20.35 km,表明卡房花岗岩形成于中低温环境、属于中深成相。综合研究认为,卡房锡矿田花岗岩具有高铁指数以及
氧逸度由高到低变化趋势等特征是锡成矿的有利条件,可以作为在本区寻找锡矿的重要标志。 相似文献
16.
大兴安岭南段发育大井、双尖子山、布金黑、拜仁达坝、维拉斯托等多个具有典型后生特征的热液脉状铅锌银锡多金属矿床。为了查明上述矿床在成矿流体、成矿物质等方面的特征与差异,进而总结大兴安岭南段热液脉状矿床成矿作用特点,本次研究在野外地质调研的基础上,对上述矿床进行了流体包裹体、激光拉曼和氢氧硫同位素的研究,并取得了如下主要的认识:(1)双尖子山银多金属矿床成矿流体属简单盐水体系热液,维拉斯托和布金黑矿床成矿流体属富碳质盐水体系热液,而大井铜矿成矿流体则为含子矿物的不均匀盐水体系热液;(2)大井、布金黑、拜仁达坝和维拉斯托等矿床早期成矿流体均来自于岩浆热液,但布金黑、拜仁达坝和维拉斯托矿床成矿流体在运移过程中明显地受到了大气降水和地层中有机质的影响;(3)大兴安岭南段多数热液脉状多金属矿床矿石硫同位素δ34S值具有岩浆来源特点,个别矿床硫同位素δ34S值偏高可能是由复杂的岩浆源区性质及地层硫混入所引起。总的来说,大兴安岭南段不同热液脉状矿床在物质来源和流体演化方面的差异明显,而这也体现了该区中生代热液成矿作用的多样性和复杂性特点。 相似文献
17.
The partitioning of Fe and Zn between coexisting fahlore and sphalerite and fluid inclusions in sphalerite from the Darasun gold deposit have been studied. These data were used to estimate the formation temperature of the minerals by the sphalerite–fahlore geothermometer. The calculated crystallization temperature of 175–355°С is close to the homogenization temperature of fluid inclusions in sphalerite of 225–385°С.The estimated pressure for fluid inclusion trapping ranged from 340 to 1420 bar. The sulfur fugacity obtained from the FeS content in sphalerite associated with pyrite and the calculated temperature ranges from 10–5.5 to 10–11 bar. 相似文献
18.
淮北地区是皖北重要的铁铜成矿区,为系统总结该区矽卡岩型矿床成矿系列及成矿规律,基于近年来在该地区取得的找矿成果,通过系统研究已知矿床地质特征和成矿地质条件,结合成岩、成矿年代学特征,认为该区有3个成矿系列: 与高钾钙碱性侵入岩有关的矽卡岩型铁铜金成矿系列、与高钾钙碱性侵入岩有关的矽卡岩型铁-石膏成矿系列和与二长花岗岩有关的矽卡岩型铁-轻稀土成矿系列。分别论述了该区4个典型矿床的地质特征及成矿规律,认为该区为两阶段成矿,成矿空间受深断裂、弧形构造和岩浆岩带的共同控制。最终建立了该区早白垩世早期“前常式”、“杨桥孜式”和“王场式”铁多金属矿床和早白垩世晚期“旗杆楼式”铁-轻稀土矿床的区域成矿模式。 相似文献
19.
M. G. Dobrovol’skaya A. D. Genkin N. S. Bortnikov T. I. Golovanova 《Geology of Ore Deposits》2008,50(1):75-85
Unusual intergrowths of sphalerite, chalcopyrite, and stannite have been described in two samples from the St. Agnes (Cornwall) and Sinancha (southern Primorye) tin deposits. Possible origins of these sulfide intergrowths and their implications for understanding the formation conditions of the deposits are discussed on the basis of ore microscopy and analytical data. At the St. Agnes deposit, the intergrowths appeared due to the breakdown of a high-temperature solid solution with formation of a Zn-stannite matrix, chalcopyrite lamellae, and rounded drop-shaped inclusions of sphalerite. At the Sinancha deposit, the rare myrmekite stannite-sphalerite intergrowths are interpreted as eutectic textures of mutual penetration that resulted from ore metamorphism at the contact of a dike. 相似文献