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1.
The Thalanga volcanic‐hosted massive sulfide deposit occurs in the Cambro‐Ordovician Mt Windsor Subprovince in northern Queensland. The orebody comprises steeply dipping, stratiform, sheet‐like, polymetallic massive sulfide lenses. Overall, the volcanic facies architecture at Thalanga is dominated by quartz‐ and/or feldspar‐phyric lavas and synvolcanic intrusions that comprise coherent facies and in situ and resedimented autoclastic facies. Systematic phenocryst logging (mineralogy, abundance, size) has been used to discriminate separate emplacement units of rhyolite in the footwall and dacite in the hangingwall. Some of the petrographically different rhyolite and dacite types can also be distinguished using immobile‐element geochemistry. Rhyolitic lavas and intrusions in the footwall are weakly to strongly altered. Apparent clastic textures resulting from hydrothermal alteration and metamorphism are widely developed in the coherent facies. Genuine clastic textures are characterised by clasts with randomly oriented internal laminar or banded fabric (e.g. rotated, flow‐laminated clasts), marked and consistent differences in quartz phenocryst abundance and/or size range between clasts and matrix, and normal grading. Mass‐flow‐emplaced, rhyolitic breccia units delineate palaeo‐sea‐floor positions in the footwall that are potentially prospective for exhalative massive sulfide mineralisation. A comparison of the distribution of clastic and coherent facies with the geometry of strongly altered zones in the footwall indicates that intense hydrothermal fluid flow was independent of the facies arrangement. The massive sulfide lenses conformably overly altered footwall rhyolite and occur in a distinctive facies association which includes coarse quartz‐phenocryst‐rich rhyolitic sills with peperitic contacts and crystal‐rich polymictic breccia. The hangingwall to the orebody consists of largely unaltered dacitic lavas and synvolcanic intrusions and minor dacitic pumice breccia, dacitic breccia and polymictic volcanic breccia. The facies architecture shows that the Thalanga massive sulfide deposit formed in a below‐storm‐wave‐base depositional environment on top of an elevated, lava‐dominated, rhyolitic volcanic centre. A modern analogue for the setting of the Thalanga massive sulfide is the PACMANUS hydrothermal field on the crest of the dacite lava‐dominated Pual Ridge in the eastern Manus backarc basin (Papua New Guinea).  相似文献   

2.
现代海底热液活动与块状硫化物矿床成因研究进展   总被引:8,自引:0,他引:8  
现代海底热液活动的发现及对其分布特征和成矿机理的研究是近年来海洋地质学和矿床地质学的一大进展。对现代海底金属硫化物成矿作用的研究大大推动和促进了对古代块状硫化物矿床成因的认识。有关研究成果综合分析表明:(1)深部热液对流循环系统是块状硫化物成矿的核心,对流循环模式有简单的热液对流模式和双扩散对流模式。(2)块状硫化物矿床集中分布在大洋中张裂性活动板块边界,与大地构造活动紧密联系。(3)成矿流体与成矿物质均有多源性,在强调海水循环淋滤的同时,通过应用新的方法技术,岩浆来源物质(流体及成矿金属等)对一些块状硫化物矿床成矿的直接贡献得到初步确认。(4)在高温热液活动区及金属硫化物沉积中发现大量生命活动和生物群体,意义重大。  相似文献   

3.
The Näsliden and Rävliden deposits in the Skellefte field consist of stratiform massive sulfide ores associated with submarine volcanic and clastic rocks. The ores are pretectonic. Consequently, the orebodies are considered to have formed syngenetically with deposition of the host rocks. Banding and interlayering with host sediments are common features. Cu : Zn and Zn : Pb ratios of the ores show stratigraphically and laterally defined trends. Cu : Pb : Zn ratios correspond with those found in other deposits of volcanogenic origin. Nonstratiform breccia Cu mineralizations occur directly under the massive stratiform ores in the footwall rocks where hydrothermal alteration is strongest. Ore formation took place intermittently resulting in clusters of ore systems occurring at slightly different stratigraphical levels within each deposit.  相似文献   

4.
Abstract. The Takara volcanogenic massive sulfide (VMS) deposit occurs in Miocene formation of the Misaka Mountain, the South Fossa Magna region, central Japan. The tectonic setting of the Misaka Mountain is reconstructed to be a part of the paleo Izu-Ogasawara arc which collided with the Honshu arc and to form accreted body in the present position. The Takara deposit, therefore, is considered to have formed in the paleo Izu-Ogasawara arc.
The ores from the Takara deposit are classified into pyrite-type ore, chalcopyrite-type ore, and sphalerite-type ore on the basis of chemical composition and their mineral assemblages. Some pyrite-type ores are characterized by their high Au content. The Au content is hardly recognized in the chalcopyrite-type and sphalerite-type ores.
The ores from the Takara deposit have intermediate bulk chemical composition between those from the Besshi-type deposits and the Kuroko-type deposits that are two representative VMS deposits. However, the bulk chemical composition is closer to that from the Kuroko-type deposits. And moreover, chemical composition of tetrahedrite-tennantite series minerals (tetrahedrite) is similar to that from the Kuroko-type deposits. The bulk chemical composition (Cu, Zn, Co, Pb, and As contents) of ores is affected by the chemical composition of volcanic rocks associated with VMS deposits.  相似文献   

5.
新疆哈密卡拉塔格块状硫化物矿床金银赋存状态研究   总被引:3,自引:0,他引:3  
新疆哈密红海黄土坡VMS矿床位于东天山卡拉塔格隆起带,是卡拉塔格矿集区内新发现的块状硫化物矿床。矿体产于卡拉塔格隆起带核部火山沉积岩建造中,具有典型的VMS型矿床“上层下脉”二元结构特征。该矿床中含金硫化物矿石主要有块状黄铁矿黄铜矿、块状黄铁矿黄铜矿闪锌矿、块状黄铁矿闪锌矿黄铜矿和块状闪锌矿。文中在对各类含金硫化物矿石进行详细的矿相学研究基础上,结合扫描电子显微镜与能谱仪联用技术(SEM/EDS),对硫化物样品中金、银的赋存状态进行研究。结果表明,4种块状硫化物中的主要矿物形成于多个期次,主要包括VMS成矿期(黄铁矿阶段、闪锌矿黄铜矿黝铜矿方铅矿阶段、石英重晶石阶段)、热液叠加期(石英黄铁矿黄铜矿闪锌矿方铅矿阶段)和表生期(铜蓝纤铁矿阶段)。矿区首次发现4颗金银金属互化物(银金矿、碲银矿),其较大的化学成分差异指示了热液环境由中酸性中性转变为更有利于Au、Ag迁移沉淀的偏碱性。后期的偏碱性热液对VMS成矿期形成矿物产生了交代作用,使得Au、Ag活化再富集。由于后期热液叠加改造,红海VMS型矿床中Au、Ag不仅赋存于VMS成矿期后期中低温闪锌矿黄铜矿阶段,也赋存于VMS成矿期早期中高温黄铁矿阶段,并贯穿整个热液叠加期。各含金矿物组合中除4颗金银金属互化物外Au多呈显微不可见状态,推测Au、Ag主要以原子或离子形式赋存于矿物晶格中或矿物空位处。  相似文献   

6.
VMS矿床是中亚造山带的重要矿床类型,在新疆中亚造山带(即新疆北部)主要分布于阿尔泰和东天山的阿舍勒、克兰、麦兹和卡拉塔格矿集区.含矿层位主要有下?中志留统红柳峡组、上志留统?下泥盆统康布铁堡组下亚组和上亚组、下?中泥盆统阿舍勒组和下石炭统小热泉子组海相火山沉积岩系.矿区发育喷流岩,如含铁碧玉岩、重晶石、硅质岩、铁锰质大理岩、黄铁矿层、绿泥石岩.VMS成矿系统中发育多种矿化类型,“双层结构”(层状或透镜状矿体和补给通道相脉状矿体)是其中之一,还有与火山热液有关的脉状矿化、与次火山热液有关的脉状和浸染状矿化.VMS矿床形成于3个成矿期,即早?中志留世(428~438 Ma)、早?中泥盆世(379~413 Ma)和早石炭世(332~359 Ma).硫来自下伏火山岩、海水硫酸盐无机还原作用和硫酸盐细菌还原作用.成矿流体以中低温(300~120 ℃)低盐度(2%~10% NaCleq)为特色,成矿流体为深循环海水混合不同比例的岩浆水.VMS成矿系统中由于受火山机构、岩相、矿化类型、矿化部位、成矿流体来源、物理化学条件等因素影响,造成了成矿元素组合复杂.   相似文献   

7.
崔峤 《矿床地质》1984,3(1):77-82
块状硫化物矿床(黄铁矿型矿床、黑矿型矿床)与玄武岩-流纹岩建造的相互关系是由矿石与围岩形成的近似性所决定的,更确切地说,是矿石有规律地产在火山岩一定的岩相中。近年来,火山岩系的岩相分析已成为火山岩地区区域地质调查、块状硫化物矿床普查勘探工作中最重要的方法之一。这是因为,一方面岩相分析和古火山恢复方法,可以对火山体、火山岩系的喷发沉积旋回,以及火山岩的层序进行详细的研究,从而较为客观地总结出  相似文献   

8.
Zn- and Cu-rich massive sulfide ores of volcanogenic origin [volcanogenic massive sulfide (VMS) deposits] occur as stratiform/stratabound lenses of variable size hosted by gneisses, amphibolites, and schists of the Areachap Group, in the Northern Cape Province of South Africa. The Areachap Group represents the highly deformed and metamorphosed remnants of a Mesoproterozoic volcanic arc that was accreted onto the western margin of the Kaapvaal Craton during the ∼1.0–1.2 Ga Namaquan Orogeny. Sulfur isotope data (δ34S) are presented for 57 sulfide separates and one barite sample from five massive sulfide occurrences in the Areachap Group. Although sulfides from each site have distinct sulfur isotope values, all δ34S values fall within a very limited range (3.0‰ to 8.5‰). Barite has a δ34S value of 18.5‰, very different from that of associated sulfides. At one of the studied sites (Kantienpan), a distinct increase in δ34S of sulfides is observed from the massive sulfide lens into the disseminated sulfides associated with a distinct footwall alteration zone. Sulfide–sulfide and sulfide–barite mineral pairs which recrystallized together during amphibolite- and lower granulite facies metamorphism are not in isotopic equilibrium. Sulfur isotope characteristics of sulfides and sulfates of the Zn–Cu ores in the Areachap Group are, however, very similar to base metal sulfide accumulations associated with modern volcanic arcs and unsedimented mid-ocean ridges. It is thus concluded that profound recrystallization and textural reconstitution associated with high-grade regional metamorphism of the massive sulfide ores of the Areachap Group did not result in extensive sulfur isotopic homogenization. This is similar to observations in other metamorphosed VMS deposit districts and confirms that massive sulfide ores remain effectively a closed system for sulfur isotopes for both sulfides and sulfates during metamorphism.  相似文献   

9.
The Jusa and Barsuchi Log volcanogenic massive sulfide (VMS) deposits formed along a paleo island arc in the east Magnitogrosk zone of the Southern Urals between ca 398 and 390 Ma. By analogy with the VMS deposits of the west Magnitogrosk zone, they are considered to be Baimak type deposits, which are Zn‐Cu‐Ba deposits containing Au, Ag and minor Pb. Detailed mapping and textural analysis of the two deposits shows that they formed as submarine hydrothermal mounds which were subsequently destroyed on the sea floor under the influence of ocean bottom currents and slumping. Both deposits display a ratio of the length to the maximum width of the deposit >15 and are characterized by ribbon‐like layers composed mainly of bedded ore and consisting principally of altered fine clastic ore facies. The Jusa deposit appears to have formed in two stages: deposition of colloform pyrite followed by deposition of copper–zinc–lead sulfides characterized by the close association of pyrite, chalcopyrite, sphalerite, galena, tennantite, arsenopyrite, marcasite, pyrrhotite, bornite, native gold and electrum and high concentrations of gold and silver. The low metamorphic grade of the east Magnitogorsk zone accounts for the exceptional degree of preservation of these deposits.  相似文献   

10.
侯增谦 《地球化学》1996,25(3):228-241
选择西南太平洋冲绳海槽现代海底烟囱硫化物矿床、日本小坂矿山上向黑矿(第三纪)和中国西南呷村黑矿型矿床(三叠纪)进行了矿石地球化学比较研究。黑矿型矿床矿石吨位-品位模式与其他火山成因块状硫化物(VMS)矿床类似,矿田(20-50km^2)矿石吨位与单个喷气-沉积型(Sedex)矿床相当,金属总量4-6Mt,为矿田范围内热液流体搬运的最大金属量。与洋脊环境VMS矿床相比,岛弧裂谷环境产出的黑矿型矿床相  相似文献   

11.
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   

12.
The Snowdon caldera of North Wales is host to base metal sulfide-bearing veins and stockworks, mineralized breccias, disseminated sulfides, and localized zones of semi-massive to massive sulfide, with subordinate magnetite-rich veins. The late Ordovician host volcanic sequence accumulated in a shallow marine, back-arc environment in the Welsh Basin, which forms part of the Avalon Zone of the British and Irish Caledonides. New field evidence, sulfur isotopes, and U-Pb dating indicate that the Snowdon mineralization is genetically and temporally related to Late Ordovician magmatism and caldera formation. It is interpreted to represent volcanogenic pipe-style sulfide mineralization, resulting from focused hydrothermal fluids moving along caldera-related faults and simultaneous dispersal of fluids through the volcaniclastic pile. Sulfur isotope data suggest that, whilst a limited contribution of magmatic S cannot be ruled out, thermochemical reduction of contemporaneous Ordovician seawater sulfate was the dominant mechanism for sulfide production in the Snowdon system, resulting in a mean value of about 12‰ in both the host volcanic strata and the mineralized veins. Despite the tectonic setting being prospective for VMS deposits, strata-bound sulfide accumulations are absent in the caldera. This is attributed to the shallow water depths, which promoted boiling and the formation of sub-seafloor vein-type mineralization. Furthermore, the tectonic instability of the caldera and the high energy, shallow marine environment would have limited preservation of any seafloor deposits. The new U-Pb dates for the base (454.26 ± 0.35 Ma) and top (454.42 ± 0.45 Ma) of the host volcanic rocks, indicate that the Snowdon magmatic activity was short lived, which is likely to have limited the duration and areal extent of the ore-forming system. The absence of massive sulfide mineralization is consistent with the general paucity of economic VMS deposits in the Avalon Zone. Despite the highly prospective geological setting this study further illustrates the importance of volcanic facies mapping and associated paleo-environmental interpretations in VMS exploration.  相似文献   

13.
The ore-formational, ore-facies, lithological, and mineralogical-geochemical criteria are defined for the detection of hydrothermal ecosystem fauna in ores of the volcanic-hosted massive sulfide deposits in the Urals. Abundant mineralized microfauna is found mainly in massive sulfide mounds formed in the jasperous basalt (Buribai, Priorsk, Yubileinoe, Sultanov), rhyolite–basalt (Yaman-Kasy, Blyava, Komosomol’sk, Sibai, Molodezhnoe, Valentorsk), and the less common serpentinite (Dergamysh) formations of the Urals (O–D2). In the ore-formational series of the massive sulfide deposits, probability of the detection of mineralized fauna correlates inversely with the relative abundance of felsic volcanic rocks underlying the ores. This series is also marked by a gradual disappearance of colloform pyrite, marcasite, isocubanite, pyrrhotite, and pyrite pseudomorphoses after pyrrhotite; increase of the amount of bornite, fahlores, and barite; decrease of contents of Se, Te, Co, and Sn in chalcopyrite and sphalerite; and decrease of Tl, As, Sb, and Pb in the colloform pyrite. Probability of the detection of mineralized fauna in the morphogenetic series of massive sulfide deposits decreases from the weakly degraded sulfide mounds to the clastic stratiform deposits. The degradation degree of sulfide mounds and fauna preservation correlates with the attenuation of volcanic intensity, which is reflected in the abundance of sedimentary and volcanosedimentary rocks and the depletion of effusive rocks in the geological sections.  相似文献   

14.
The Karchiga copper massive sulfide deposit is located in the Kurchum block of high-grade metamorphosed rocks. This block is part of the Irtysh shear zone, which belongs to the largest transregional fault in Central Asia. The deposit is associated with the gneiss–amphibolite middle unit of the metamorphic complex, which is distinct in the geochemical fields. The mineralization is spatially and paragenetically related to the amphibolite beds, which are ore-bearing together with terrigenous rocks.The deposit contains two spatially isolated lodes, in which all the discovered commercial reserves concentrate. They conformably overlie the host rocks and are tabular or ribbonlike. The mineralization has a close spatial relationship with Mg-rich anthophyllite-containing rocks. The sulfide ores are disseminated or massive and comprise pyrite, chalcopyrite, pyrrhotite, sphalerite, and magnetite. The ore is of Zn–Cu composition, in which Cu dominates considerably over Zn (average contents 2 and 0.4%, respectively; Cu/(Cu + Zn) = 0.83). The ores are rich in Co (up to 0.16%, averaging 0.02%), poor in Au and Ag (0.3 and 7.2 ppm, respectively), and almost free of Pb and Ba.All the rocks and ores experienced epidote–amphibolitic metamorphism. Meanwhile, the ores experienced a recrystallization and partial regeneration, but the initial shape of the lodes remained unchanged.The essentially chalcopyritic ores, the volcaniclastic ore-bearing rocks, and the spatial and genetic relationship of the mineralization with undifferentiated mafic and siliciclastic rocks suggest that this deposit belongs to the Besshi type, formed in a back-arc environment, near large rises.The studies show that Besshi-type Cu–Zn massive sulfide deposits differ from most of the polymetallic (Kuroko-type) deposits in Rudny Altai in the composition of volcanics and geodynamic settings, but belong to the same evolutionary series in this VMS province. Both types of deposits might have formed in the Paleozoic, during the main peak of VMS generation in the Earth's history.  相似文献   

15.
The Godar Sabz Mn deposit is located in the Nain-Baft ophiolitic belt in the northeast margin of the Sanandaj-Sirjan zone, Iran. The Nain-Baft back-arc extensional basin resulted from the subduction of the oceanic crust of Neo-Tethys under the southern margin of the Iranian Plate in the Early Cretaceous and hosts several mineral deposits, including volcanogenic massive sulfide, chromite, and Mn deposits. The mineralization in the Godar Sabz Mn deposit occurred predominantly as stratabound, massive, banded, layered, and lenticular orebodies in radiolarian cherts within Baft ophiolitic complex. The main ore minerals are pyrolusite, braunite, with minor amounts of todorokite. The significant geochemical features of the Godar Sabz ores, such as the high MnO content (21.82–80.65 wt%, average = 64.91 wt%), high Mn/Fe (average = 278), Si/Al ratios (average = 92.6), high Ba contents (average = 4495.6 ppm), the low average contents of Cu (81.8 ppm), Ni (106.2 ppm), Co (29.4 ppm), LREE > HREE, and trace element discrimination diagrams indicate a hydrothermal-exhalative source for mineralization. Chondrite-normalized REE patterns of studied ores have negative Ce and slightly positive Eu anomalies, which are similar to hydrothermal Mn deposits. The REE patterns of Mn ores coincide with basaltic lavas, suggesting that the Mn-mineralization in the Godar Sabz deposit was genetically related to the leaching of basaltic lavas. The Godar Sabz Mn deposit has many similarities with the main characteristics of the hydrothermal exhalative Mn deposits, including tectonic setting, host rock type, the morphology of orebodies, ore textures, mineralogy, and chemical features of ores.  相似文献   

16.
17.
青海德尔尼铜(锌钴)矿床Re-Os年龄及地质意义   总被引:1,自引:0,他引:1  
东昆仑德尔尼大型铜(锌钴)矿是赋存在蛇绿岩中的块状硫化物矿床,8件块状硫化物矿石的Re-Os同位素等时线年龄为(295.5±7.2) Ma,略小于矿区玄武质熔岩的锆石U-Pb平均年龄(308.2±4.9) Ma,矿床形成于晚石炭世-早二叠世,属于阿尼玛卿洋盆扩张期。成矿时代早于矿区北部印支期花岗岩,证明德尔尼矿床的成因与印支期花岗岩无直接关系。矿石组构、矿物组合和岩石地球化学研究指示,矿床为海底喷流沉积-热液叠加成矿,具有类似于塞浦路斯型块状硫化物矿床的构造背景和矿物组合特征。矿区及外围填图发现,德尔尼铜矿体主要产出在角砾状蛇纹岩中,部分位于蛇纹岩与含碳铁硅质岩之间,这种特殊的赋矿层位可能与晚古生代特提斯洋的快速扩张、岩浆补给少、变质橄榄岩迅速抬升有关。  相似文献   

18.
Abstract: Two adjacent volcanogenic massive sulfide (VMS) deposits, the Main Malusok and the Malusok Southeast, are delineated within Barangay Tabayo, Siocon, Zamboanga del Norte, Mindanao, Philippines. These deposits comprise massive to semi-massive sulfide lenses representing the down-dip equivalent of oxidized gossans. The massive sulfides have a primary mineral assemblage of pyrite-chalcopyrite-sphalerite with significant amounts of supergene copper in the form of chal-cocite. Owing to structural and metamorphic overprinting combined with intense alteration, primary textures are generally obliterated. Rock types are classified according to dominant mineral assemblages whereas the main lithologic units comprising the Malusok volcanic package are divided based on the position of each unit relative to the mineralized zone. The main lithologic units are designated as the hanging wall, the host, and the footwall sequences. In correlating the stratigraphy of the Main Malusok zone with that of the Malusok Southeast zone, a chlorite/epidote-rich interval located at the base of the hanging wall sequence serves as a distinct stratigraphic marker from which all lithologies are referred to. Comparisons between the stratigraphy of the two areas show that massive to semi-massive sulfide lenses are confined within a single stratigraphic interval representing the favorable horizon for the entire Malusok area. However, differences exist relative to style of mineralization and configuration of the altered interval between the Main Malusok and the Malusok Southeast VMS deposits. Based on characteristics exhibited by each individual deposit, it is inferred that the Main Malusok VMS deposit overlies a feeder zone whereas the Malusok Southeast sulfide lenses represent satellite deposits and transported blocks.  相似文献   

19.
The ore-formational, ore-facies, lithological, and mineralogical-geochemical criteria are defined for the detection of hydrothermal ecosystem fauna in ores of the volcanic-hosted massive sulfide deposits in the Urals. Abundant mineralized microfauna is found mainly in massive sulfide mounds formed in the jasperous basalt (Buribai, Priorsk, Yubileinoe, Sultanov), rhyolite—basalt (Yaman-Kasy, Blyava, Komosomol’sk, Sibai, Molodezhnoe, Valentorsk), and the less common serpentinite (Dergamysh) formations of the Urals (O—D2). In the ore-formational series of the massive sulfide deposits, probability of the detection of mineralized fauna correlates inversely with the relative abundance of felsic volcanic rocks underlying the ores. This series is also marked by a gradual disappearance of colloform pyrite, marcasite, isocubanite, pyrrhotite, and pyrite pseudomorphoses after pyrrhotite; increase of the amount of bornite, fahlores, and barite; decrease of contents of Se, Te, Co, and Sn in chalcopyrite and sphalerite; and inсrease of Tl, As, Sb, and Pb in the colloform pyrite. Probability of the detection of mineralized fauna in the morphogenetic series of massive sulfide deposits decreases from the weakly degraded sulfide mounds to the clastic stratiform deposits. The degradation degree of sulfide mounds and fauna preservation correlates with the attenuation of volcanic intensity, which is reflected in the abundance of sedimentary and volcanosedimentary rocks and the depletion of effusive rocks in the geological sections.  相似文献   

20.
云南澜沧老厂是三江成矿带南段最重要的铅锌铜钼多金属矿床之一.根据不同的赋矿特征、含矿岩性、矿石构造及成矿元素将澜沧老厂多金属矿床矿石类型系统地划分为铅锌硫化矿石、铅锌氧化矿石、颗粒状含铜黄铁矿石、块状含铜黄铁矿石、夕卡岩型矿石及斑岩型钼矿石6种类型.矿体产状、微量元素地球化学、年代学证据均表明铅锌硫化矿石、颗粒状含铜黄铁矿石及块状含铜黄铁矿石为火山喷流沉积型成因(VMS型),而铅锌氧化矿石、夕卡岩型矿石及斑岩型钼矿石为斑岩热液型成因.其中,铅锌硫化矿石、颗粒状含铜黄铁矿石及块状含铜黄铁矿石的主控矿因素为地层;铅锌氧化矿石为构造;夕卡岩型矿石为岩性;斑岩型钼矿石为岩体.  相似文献   

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