共查询到20条相似文献，搜索用时 31 毫秒
1.
2.
Run-Sheng Han Cong-Qiang Liu Zhi-Long Huang Jin Chen De-Yun Ma Li Lei Geng-Sheng Ma 《Ore Geology Reviews》2007,31(1-4):360
The Huize Zn–Pb–(Ag) district, in the Sichuan–Yunnan–Guizhou Zn–Pb–(Ag) metallogenic region, contains significant high-grade, Zn–Pb–(Ag) deposits. The total metal reserve of Zn and Pb exceeds 5 Mt. The district has the following geological characteristics: (1) high ore grade (Zn + Pb ≥ 25 wt.%); (2) enrichment in Ag and a range of other trace elements (Ge, In, Ga, Cd, and Tl), with galena, sphalerite, and pyrite being the major carriers of Ag, Ge, Cd and Tl; (3) ore distribution controlled by both structural and lithological features; (4) simple and limited wall-rock alteration; (5) mineral zonation within the orebodies; and (6) the presence of evaporite layers in the ore-hosting wall rocks of the Early Carboniferous Baizuo Formation and the underlying basement.Fluid-inclusion and isotope geochemical data indicate that the ore fluid has homogenisation temperatures of 165–220 °C, and salinities of 6.6–12 wt.% NaCl equiv., and that the ore-forming fluids and metals were predominantly derived from the Kunyang Group basement rocks and the evaporite-bearing rocks of the cover strata. Ores were deposited along favourable, specific ore-controlling structures. The new laboratory and field studies indicate that the Huize Zn–Pb–(Ag) district is not a carbonate-replacement deposit containing massive sulphides, but rather the deposits can be designated as deformed, carbonate-hosted, MVT-type deposits. Detailed study of the deposits has provided new clues to the localisation of concealed orebodies in the Huize Zn–Pb–(Ag) district and of the potential for similar carbonate-hosted sulphide deposits elsewhere in NE Yunnan Province, as well as the Sichuan–Yunnan–Guizhou Zn–Pb–(Ag) metallogenic region. 相似文献
3.
4.
Xuexiang Gu Oskar Schulz Franz Vavtar Jianming Liu Minghua Zheng Shaohong Fu 《Ore Geology Reviews》2007,31(1-4):319
The Woxi W–Sb–Au deposit in Hunan, South China, is hosted by Proterozoic metasedimentary rocks, a turbiditic sequence of slightly metamorphosed (greenschist facies), gray-green and purplish red graywacke, siltstone, sandy slate, and slate. The mineralization occurs predominantly (> 70%) as stratabound/stratiform ore layers and subordinately as stringer stockworks. The former consists of rhythmically interbedded, banded to finely laminated stibnite, scheelite, quartz, pyrite and silty clays, whereas the latter occurs immediately beneath the stratabound ore layers and is characterized by numerous quartz + pyrite + gold + scheelite stringer veins or veinlets that are typically either subparallel or subvertical to the overlying stratabound ore layers. The deposit has been the subject of continued debate in regard to its genesis. Rare earth element geochemistry is used here to support a sedimentary exhalative (sedex) origin for the Woxi deposit. The REE signatures of the metasedimentary rocks and associated ores from the Woxi W–Sb–Au deposit remained unchanged during post-depositional processes and were mainly controlled by their provenance. The original ore-forming hydrothermal fluids, as demonstrated by fluid inclusions in quartz from the banded ores, are characterized by variable total REE concentrations (3.5 to 136 ppm), marked LREE enrichment (LaN/YbN = 28–248, ∑LREE/∑HREE = 16 to 34) and no significant Eu-anomalies (Eu/Eu = 0.83 to 1.18). They were most probably derived from evolved seawater that circulated in the clastic sediment pile and subsequently erupted on the seafloor. The bulk banded ores are enriched in HREE (LaN/YbN = 4.6–11.4, ∑LREE/∑HREE = 3 to 14) and slightly depleted in Eu (Eu/Eu = 0.63 to 1.14) relative to their parent fluids. This is interpreted as indicating the influence of seawater rather than a crystallographic control on REE content of the ores. Within a single ore layer, the degree of HREE enrichment tends to increase upward while the total REE concentrations decrease, reflecting greater influence and dilution of seawater. There is a broad similarity in chondrite-normalized REE patterns and the amount of REE fractionation of the banded ores in this study and exhalites from other sedex-type polymetallic ore deposits, suggesting a similar genesis for these deposits. This conclusion is in agreement with geologic evidence supporting a syngenetic (sedex) model for the Woxi deposit. 相似文献
5.
青城子铅锌矿床成因分析 总被引：7，自引：0，他引：7
青城子铅锌矿床是我国北方的大型铅锌矿床,矿区赋矿层位下部产出层状矿体,上部产出脉状及不规则状矿体。经过对矿区矿石及岩石的铅、硫同位素研究表明,层状及脉状矿体成矿物质来源相同,主要来自地层。根据矿区内含硫矿物的组合特征、成矿流体的pH值及含硫矿物δ34S分布特征可以推断矿床成因不属于海相沉积成因。矿石中石英流体包裹体特征表明矿床形成后未遭受区域变质作用,成矿流体的温度180～280℃,流体成分Na+K+,Ca2+Mg2+,K+/Na+为0.66,Ca2+/Mg2+为6.67,(CH4+H2+N2)/CO2值为0.012～0.048,为Na+?Ca2+?Cl-弱还原型溶液,pH值为6.31。流体特征与矿区内的花岗岩相差较大,与变质热液有所差异,经流体的氢氧同位素测定,成矿热液具地热水氢氧同位素特征相似。综合研究表明,矿床的成因与区域变质期后局部地区的的混合岩化作用关系密切,由混合岩化作用分异的气水热液与地下水、层间水等混合后沿早期形成的层间滑脱部位和断裂充填成矿,形成了青城子矿田‘下层上脉’的空间组合。 相似文献
6.
Gang Yu Jiangfeng Chen Chunji Xue Yuchuan Chen Fukun Chen Xiaoyue Du 《Ore Geology Reviews》2009,35(3-4):367-382
The Qingchengzi orefield in northeastern China, is a concentration of several Pb–Zn, Ag, and Au ore deposits. A combination of geochronological and Pb, Sr isotopic investigations was conducted. Zircon SHRIMP U–Pb ages of 225.3 ± 1.8 Ma and 184.5 ± 1.6 Ma were obtained for the Xinling and Yaojiagou granites, respectively. By step-dissolution Rb–Sr dating, ages of 221 ± 12 Ma and 138.7 ± 4.1 Ma were obtained for the sphalerite of the Zhenzigou Zn–Pb deposit and pyrargyrite of the Ag ore in the Gaojiabaozi Ag deposit, respectively. Pb isotopic ratios of the Ag ore at Gaojiabaozi (206Pb/204Pb = 18.38 to 18.53) are higher than those of the Pb–Zn ores (206Pb/204Pb = 17.66 to 17.96; Chen et al. [Chen, J.F., Yu, G., Xue, C.J., Qian, H., He, J.F., Xing, Z., Zhang, X., 2005. Pb isotope geochemistry of lead, zinc, gold and silver deposit clustered region, Liaodong rift zone, northeastern China. Science in China Series D 48, 467–476.]). Triassic granites show low Pb isotopic ratios (206Pb/204Pb = 17.12 to 17.41, 207Pb/204Pb = 15.47 to 15.54, 208Pb/204Pb = 37.51 to 37.89) and metamorphic rocks of the Liaohe Group have high ratios (206Pb/204Pb = 18.20 to 24.28 and 18.32 to 20.06, 207Pb/204Pb = 15.69 to 16.44 and 15.66 to 15.98, 208Pb/204Pb = 37.29 to 38.61 and 38.69 to 40.00 for the marble of the Dashiqiao Formation and schist of the Gaixian Formation, respectively).Magmatic activities at Qingchengzi and in adjacent regions took place in three stages, and each contained several magmatic pulses: ca. 220 to 225 Ma and 211 to 216 Ma in the Triassic; 179 to 185 Ma, 163 to 168 Ma, 155 Ma and 149 Ma in the Jurassic, as well as ca. 140 to 130 Ma in the Early Cretaceous. The Triassic magmatism was part of the Triassic magmatic belt along the northern margin of the North China Craton produced in a post-collisional extensional setting, and granites in it formed by crustal melting induced by mantle magma. The Jurassic and Early Cretaceous magmatism was related to the lithospheric delamination in eastern China. The Triassic is the most important metallogenic stage at Qingchengzi. The Pb–Zn deposits, the Pb–Zn–Ag ore at Gaojiabaozi, and the gold deposits were all formed in this stage. They are temporally and spatially associated with the Triassic magmatic activity. Mineralization is very weak in the Jurassic. Ag ore at Gaojiabaozi was formed in the Early Cretaceous, which is suggested by the young Rb–Sr isochron age, field relations, and significantly different Pb isotopic ratios between the Pb–Zn–Ag and Ag ores. Pb isotopic compositions of the Pb–Zn ores suggest binary mixing for the source of the deposits. The magmatic end-member is the Triassic granites and the other metamorphic rocks of the Liaohe Group. Slightly different proportions of the two end-members, or an involvement of materials from hidden Cretaceous granites with slightly different Pb isotopic ratios, is postulated to interpret the difference of Pb isotopic compositions between the Pb–Zn–(Ag) and Ag ores. Sr isotopic ratios support this conclusion. At the western part of the Qingchengzi orefield, hydrothermal fluid driven by the heat provided by the now exposed Triassic granites deposited ore-forming materials in the low and middle horizons of the marbles of the Dashiqiao Formation near the intrusions to form mesothermal Zn–Pb deposits. In the eastern part, hydrothermal fluids associated with deep, hidden Triassic intrusions moved upward along a regional fault over a long distance and then deposited the ore-forming materials to form epithermal Au and Pb–Zn–Ag ores. Young magmatic activities are all represented by dykes across the entire orefield, suggesting that the corresponding main intrusion bodies are situated in the deep part of the crust. Among these, only intrusions with age of ca. 140 Ma might have released sufficient amounts of fluid to be responsible for the formation of the Ag ore at Gaojiabaozi.Our age results support previous conclusions that sphalerite can provide a reliable Rb–Sr age as long as the fluid inclusion phase is effectively separated from the “sulfide” phase. Our work suggests that the separation can be achieved by a step-resolution technique. Moreover, we suggest that pyrargyrite is a promising mineral for Rb–Sr isochron dating. 相似文献
7.
原生晕法在长期大量的勘探实践中,已被证明是一种能有效研究异常分布、地球化学特征、剥蚀程度,推测隐伏矿体,评价深部潜力,进行找矿预测的地球化学勘探方法。在西藏扎西康铅锌多金属矿床的实际勘查基础上,研究矿体的元素分带性特征,即原生晕轴向分带特征,可为研究控矿因素、成矿物质来源、围岩蚀变、成矿期次、矿床成因等方面提供地球化学依据。本文通过采集扎西康矿区0号线剖面ZK006、ZK007、ZK009、ZK010等4个钻孔的岩石样品,选取Cu、Pb、Zn、W、Mo、Sb、Bi、Ga、Sn、In、Au、Ag等成矿元素进行分析,来研究该矿床的原生晕地球化学特征及规律。结果表明,元素异常及原生晕集中分布在4400m以下,成矿物源不仅由周围地层提供,还可能来自于深部的隐伏岩体,成矿过程可能经历了多期次的叠加作用。这些研究成果暗示扎西康的工业矿体在深部还有继续下延的良好前景。 相似文献
8.
Indium Mineralization in Copper–Tin Stratiform Skarn Ores at the Saishitang–Rilonggou Ore Field,Qinghai, Northwest China 
下载免费PDF全文
下载免费PDF全文 Jianping Liu Xiangping Gu Yongjun Shao Yuzhou Feng Jianqing Lai 《Resource Geology》2016,66(4):351-367
The Saishitang–Rilonggou Ore Field (SROF), which includes the Saishitang, Tongyugou, and Rilonggou ore deposits as well as other scattered occurrences, is located in the Elashan region in Qinghai Province, and is a significant Cu–Sn ore field in NW China. These ores are hosted in stratiform skarn deposits with the main metals being Cu and Sn, as well as Zn, Pb, Au, Ag, and trace elements (e.g. Ga, Ge, Se, and In). Bulk‐rock geochemical analyses of 50 ore samples from the three deposits show that In contents in the Saishitang deposit range from 0.03 to 39 ppm (average 12.7 ppm, n = 19), with 1000 In/Zn values that vary from >0.01 to 29.83 (average 4.29). Indium contents in the Tongyugou deposit vary from 7.51 to 131 ppm (average 28.37 ppm, n = 13), with 1000 In/Zn values from 0.74 to 48 (average 17.55). Finally, indium contents in the Rilonggou deposit vary from 0.73 to 120 ppm (average 36.15 ppm, n = 18), with 1000 In/Zn values from 0.33 to 47 (average 8.52). Indium is hosted mainly in sphalerite, while some other In‐bearing minerals (e.g., roquesite, stannoidite, and stannite) are present locally within the ore field. Roquesite, which replace or fill bornite, occurs in bornite‐rich ores in the Saishitang deposit. This is the first reported Chinese locality of roquesite. Based on previously reported Zn resources, a total of 136 tons of In is calculated to be hosted in the SROF, with 30, 66, and 40 tons of In attributed to the Saishitang, Tongyugou, and Rilonggou deposits, respectively. The differences in indium contents among the deposits and their respective geological histories and characteristics suggest that the origin of indium relates to volcanogenic metallogenesis in an early Permian volcano‐sedimentary basin. Based on the evaluation of In resources, future mining operations should include the recovery of indium in the Tongyugou and Rilonggou deposits. 相似文献
9.
The Baizhangyan skarn‐porphyry type W–Mo deposit is located in a newly defined Mo–W–Pb–Zn metallogenic belt, which is in the south of Middle‐Lower Yangtze Valley Cu–Fe–Au polymetallic metallogenic belt in SE China. The W–Mo orebodies occur mainly within the contact zone between fine‐grained granite and Sinian limestone strata. There are two types of W–Mo mineralization: major skarn W–Mo mineralization and minor granite‐hosted disseminated Mo mineralization which was traced by drilling at depth. Eight molybdenite samples from Mo‐bearing ores yield Re–Os dates that overlap within analytical error, with a weighted average age of 134.1 ± 2.2 Ma. These dates are in close agreement with SIMS U–Pb concordant zircon age for fine‐grained granite at 133.3 ± 1.3 Ma, indicating that crystallization of the granite and hydrothermal molybdenite formation were coeval and likely cogenetic. The Baizhangyan W–Mo deposit formed in the Early Cretaceous extensional tectonic setting at the Middle‐Lower Yangtze Valley metallogenic belt and the Jaingnan Ancient Continent. Based on mineral compositions and crosscutting relationships of veinlets, hydrothermal alteration and mineralization, the ore mineral paragenesis of the Baizhangyan deposit is divided into four stages: skarn stage (I), oxide stage (II), sulfide stage (III), and carbonate stage (IV). Fluid inclusions in garnet, scheelite, quartz and calcite from W–Mo ores are mainly aqueous‐rich (L + V) type inclusions. Following garnet deposition at stage I, the high‐temperature fluids gave way to progressively cooler, more dilute fluids associated with tungsten–molybdenite–base metal sulfide deposition (stage II and stage III) (162–360°C, 2.7–13.2 wt % NaCl equivalent) and carbonate deposition (stage IV) (137–190°C, 0.9–5 wt % NaCl equiv.). Hydrogen‐oxygen isotope data from minerals of different stages suggest that the ore‐forming fluids consisted of magmatic water, mixed in various proportions with meteoric water. From stage I to stage IV, there is a systematic decrease in the homogenization temperature of the fluid‐inclusion fluids and calculated δ18O values of the fluids. These suggest that increasing involvement of formation water or meteoric water during the fluid ascent resulted in successive deposition of scheelite and molybdenite at Baizhangyan. 相似文献
10.
Qingdong Zeng Yongbin Wang Song Zhang Jianming Liu Kezhang Qin Jinhui Yang Weidong Sun Wenjun Qu 《Resource Geology》2013,63(1):99-109
Mesozoic ore deposits in Zhejiang Province, Southeast China, are divided into the northwestern and southeastern Zhejiang metallogenic belts along the Jiangshan–Shaoxing Fault. The metal ore deposits found in these belts are epithermal Au–Ag deposits, hydrothermal‐vein Ag–Pb–Zn deposits, porphyry–skarn Mo (Fe) deposits, and vein‐type Mo deposits. There is a close spatial–temporal relationship between the Mesozoic ore deposits and Mesozoic volcanic–intrusive complexes. Zircon U–Pb dating of the ore‐related intrusive rocks and molybdenite Re–Os dating from two typical deposits (Tongcun Mo deposit and Zhilingtou Au–Ag deposit) in the two metallogenic belts show the early and late Yanshanian ages for mineralization. SIMS U–Pb data of zircons from the Tongcun Mo deposit and Zhilingtou Au–Ag deposit indicate that the host granitoids crystallized at 169.7 ± 9.7 Ma (2σ) and 113.6 ± 1 Ma (2σ), respectively. Re–Os analysis of six molybdenite samples from the Tongcun Mo deposit yields an isochron age of 163.9 ± 1.9 Ma (2σ). Re–Os analyses of five molybdenite samples from the porphyry Mo orebodies of the Zhilingtou Au‐Ag deposit yield an isochron age of 110.1 ± 1.8 Ma (2σ). Our results suggest that the metal mineralization in the Zhejiang Province, southeast China formed during at least two stages, i.e., Middle Jurassic and Early Cretaceous, coeval with the granitic magmatism. 相似文献
11.
The Xiaoxinancha Au–Cu deposit is located at the eastern segment of the Tianshan–Xingmeng orogenic belt in northeast China. The deposit includes porphyry Au–Cu orebodies, veined Au–Cu orebodies and veined Mo mineralizations. All of them occur within the diorite intrusion. The Late Permian diorite, Late Triassic granodiorite, Early Cretaceous granite and granite porphyry are developed in the ore area. The studies on geological features show that the porphyry Au–Cu mineralization is related to the Late Permian diorite intrusion. New geochronologic data for the Xiaoxinancha porphyry Au–Cu deposit yield Permian crystallization zircon U–Pb age of 257 ± 3 Ma for the diorite that hosts the Au–Cu mineralization. Six molybdenite samples from quartz + molybdenite veins imposed on the porphyry Au–Cu orebodies yield an isochron age of 110.3 ± 1.5 Ma. The ages of the molybdenites coeval to zircon ages of the granite within the errors suggest that the Mo mineralization was genetically related to the Early Cretaceous granite intrusion. The formation of the diorite and the related Au–Cu mineralization were caused by the partial melting of the subduction slab during the Late Palaeozoic palaeo‐Asia Ocean tectonic stage. The Re contents and Re–Os isotopic data indicate that the crustal resource is dominated for the Mo mineralization during the Cretaceous extensional setting caused by the roll‐back of the palaeo‐Pacific plate. Copyright © 2014 John Wiley & Sons, Ltd. 相似文献
12.
本文通过矿区地层、岩石、矿石和矿物中成矿元素及其伴生元素的分布分配,矿床原生晕的特征,矿石中流、铅同位素的组成以及反映环境特点的元素对比值等方面,结合矿床地质特征,综合论述了该矿床成岩、成矿、成晕的地质—地球化学环境,成矿物质来源,以及后期热液改造元素的活动特点.确认该矿床应属沉积富集为主的层控型矿床. 相似文献
13.
《Resource Geology》2018,68(3):275-286
The volcanic‐hosted Xiangshan uranium orefield is the largest uranium deposit in South China. Recent exploration has discovered extensive Pb–Zn mineralization beneath the uranium orebodies. Detailed geological investigation reveals that the major metallic minerals include pyrite, sphalerite, galena, and chalcopyrite, whilst the major non‐metallic minerals include quartz, sericite, and calcite. New δ18Ofluid and δDfluid data indicate that the ore‐forming fluids were mainly derived from magmatic, and the sulfide δ34S values (2.2–6.9‰) suggest a dominantly magmatic sulfur source. The Pb isotope compositions are homogeneous (206Pb/204Pb = 18.120–18.233, 207Pb/204Pb = 15.575–15.698, and 208Pb/204Pb = 37.047–38.446). The 87Sr/86Sr ratios of sulfide minerals range from 0.7197 to 0.7204, which is much higher than volcanic rocks and fall into the range of metamorphic basement. Lead and strontium isotopic compositions indicate that the metallogenic materials probably were derived from metamorphic basement. Pyrite Rb–Sr dating of the ores yielded 131.3 ± 4.0 Ma, indicating that the Pb–Zn mineralization occurred in the Early Cretaceous. 相似文献
14.
为预测和评价山东蓬莱石家金矿床的深部找矿远景,延长矿山服务年限,着重论述了该矿床的原生晕地球化学特征,对矿床的深部找矿潜力进行了探讨。原生晕元素组合特征分析表明,石家金矿床的矿体及近矿晕元素组合为Au、Ag、Cu、Pb、Zn、S、Te,前缘晕为Hg、As、Sb、Ba,尾晕为Mo、W、Sn。元素异常形态特征显示,326号矿脉南段以前缘晕和近矿晕为主,北段以前缘晕和尾晕为主,近矿晕元素异常较弱,矿体总体具有向南侧伏的特点。原生晕轴向分带序列在36线和84线均呈现反分带和前缘晕、尾晕共存的特点,结合地球化学参数在垂向上呈振荡波动变化的特征,说明矿体由多期次成矿作用叠加形成,同时预示矿体向深部还有一定延伸或有盲矿体存在。综合分析认为,326号矿脉南段为成矿的有利部位,深部仍有较大的找矿空间;矿体北段深部矿化减弱,但出现了前缘晕、尾晕元素的共存,预示深部可能还有盲矿体存在。 相似文献
15.
安徽五河荣渡金矿床成矿控制因素 总被引：2，自引：0，他引：2
五河荣渡金矿区有较好的成矿地质构造条件,迄今为止已在大巩山基岩裸露区发现20多个矿点或小型矿体,荣渡-钱台子地区发现中小型隐伏金矿床。矿床具有多成因、多来源、多阶段特点,成矿为燕山晚期的脆-韧性变形环境。 相似文献
16.
Two tin-polymetallic vein-type deposits widely separated in time and space but with strong similarities in terms of mineralization style, ore mineralogy and chemistry have been studied comparatively with the aim of understanding the mineralogical evolution of In-rich hydrothermal systems. The Tosham deposit, Bhiwani district, Haryana, India, is of Neoproterozoic age and constitutes a Sn–Cu prospect with unusually high In content. The disseminated, crude stockwork and vein mineralization is hosted by greisenised metasedimentary rocks intruded by a porphyritic granite stock and by later rhyolitic effusives. The Goka deposit, Naegi district, Japan is probably of uppermost Cretaceous age and occurs close to a well fractionated ilmenite series granitoid body. The tin-polymetallic vein in the Goka deposit is hosted by a welded tuff unit close to a subvolcanic granodiorite porphyry.The main host minerals of indium in the Tosham and Goka ores are sphalerite, stannite, unidentified Zn–Cu–Fe–In–Sn–S phases and chalcopyrite. Up to 0.48 wt.% In has been noted in the Goka chalcopyrite, whereas at Tosham, the mineral has a maximum In concentration of 1220 ppm. At Goka the sphalerite contains up to 1.89 wt.% In, whereas In-bearing stannite carries up to ca. 9 wt.% of the metal. Roquesite is the other indium mineral present in the Tosham ores, but is absent in Goka. The mineral chemistry of the Tosham and Goka ores suggest that the In-bearing minerals belong to a multi-component Zn–Cu–Fe–(Ag)–Sn–In–S system. Based on various triangular plots of the atomic proportions of the main metals, it is inferred that there are end-member phases, roquesite and stannite, in the Tosham ores co-existing with chalcopyrite. The sphalerite is both pure end-member and Cu–In-bearing in both the Tosham and Goka ores. Some of the analysed stannite grains in Tosham ores could possibly be petrukite. The Zn–Cu–Fe–Sn–In–S system in the two ores has a Sn-poor, high-In solid solution phase and also a Sn-rich, low-In solid solution phase. It seems possible that these two solid solutions were the first to form during hydrothermal ore deposition at high temperatures from a disordered solid solution located at the (Cu + Ag):(Zn + Fe):(In + Sn) = 3:5:2 intersection in the (Cu + Ag)–(Zn + Fe)–(In + Sn) field. With decreasing temperatures, the Sn-poor, In-rich solid solution exsolved the Zn–In-mineral of Ohta [Ohta, E., 1980. Mineralization of Izumo and Sorachi veins of the Toyoha mine, Hokkaido, Japan. Bulletin, Geological Survey of Japan 31, 585–597. (in Japanese with English abstract).] and sphalerite, while the Sn-rich, In-poor solid solution was broken down to stannite and relatively-Cu-rich sphalerite. 相似文献
17.
Geologic, fluid inclusion and isotopic characteristics of the Jinding Zn–Pb deposit, western Yunnan, South China: A review 总被引：1，自引：1，他引：0
Chunji Xue Rong Zeng Shuwen Liu Guoxiang Chi Hairuo Qing Yuchuan Chen Jianmin Yang Denghong Wang 《Ore Geology Reviews》2007,31(1-4):337-359
With a reserve of 200 Mt ore grading 6.08% Zn and 1.29% Pb (i.e., a metal reserve of 15 Mt) hosted in Cretaceous and Tertiary terrestrial rocks, the Jinding deposit is the largest Zn–Pb deposit in China, and also the youngest sediment-hosted super giant Zn–Pb deposit in the world. The deposit mainly occurs in the Jinding dome structure as tabular orebodies within breccia-bearing sandstones of the Palaeocene Yunlong Formation (autochthonous) and in the overlying sandstones of the Early Cretaceous Jingxing Formation (allochthonous). The deposit is not stratiform and no exhalative sedimentary rocks have been observed. The occurrence of the orebodies, presence of hangingwall alteration, and replacement and open-space filling textures all indicate an epigenetic origin. Formation of the Jinding Zn–Pb deposit is related to a period of major continental crust movement during the collision of the Indian and Eurasian Plates. The westward thrusts and dome structure were successively developed in the Palaeocene sedimentary rocks in the ore district, and Zn–Pb mineralisation appears to have taken place in the early stage of the doming processes.The study of fluid inclusions in sphalerite and associated gangue minerals (quartz, celestine, calcite and gypsum) shows that homogenisation temperatures ranged from 54 to 309 °C and cluster around 110 to 150 °C, with salinities of 1.6 to 18.0 wt.% NaCl equiv. Inert gas isotope studies from inclusions in ore- and gangue-minerals reveal 2.0 to 15.6% mantle He, 53% mantle Ne and a considerable amount of mantle Xe in the ore-forming fluids. The Pb-isotope composition of ores shows that the metal is mainly of mantle origin, mixed with a lesser amount of crustal lead. The widely variable and negative δ34S values of Jinding sulphides suggest that thermo-chemical or bacterial sulphate reduction produced reduced sulphur for deposition of the Zn–Pb sulphides. The mixing of a mantle-sourced fluid enriched in metals and CO2 with reduced sulphide-bearing saline formation water in a structural–lithologic trap may have been the key mechanism for the formation of the Jinding deposit.The Jinding deposit differs from known major types of sediment-hosted Zn–Pb deposits in the world, including sandstone-type (SST), Mississippi Valley type (MVT) and sedimentary-exhalative (SEDEX). Although the fine-grained ore texture and high Zn/Pb ratios are similar to those in SEDEX deposits, the Jinding deposit lacks any exhalative sedimentary rocks. Like MVT deposits, Jinding is characterised by simple mineralogy, epigenetic features and involvement of basinal brines in mineralisation, but its host rocks are mainly sandstones and breccia-bearing sandstones. The Jinding deposit is also different from SST deposits with its high Zn/Pb ratios, among other characteristics. Most importantly, the Jinding deposit was formed in an intracontinental terrestrial basin with an active tectonic history in relation to plate collision, and mantle-sourced fluids and metals played a major role in ore formation, which is not the case for SEDEX, MVT, and SST. We propose that Jinding represents a new type of sediment-hosted Zn–Pb deposit, named the ‘Jinding type’. 相似文献
18.
19.
20.
冬瓜林金矿床位于哀牢山金矿带的镇沅金矿田。文章在野外地质工作的基础上,运用多元统计的方法,求得微量元素找矿标志;并根据地球化学各参数信息,计算出元素轴向分带序列,建立原生叠加晕理想模型,构建深部矿体预测指标,明确下一步的找矿方向。研究表明:(1)该矿床的成矿元素Au与元素Ni、Co、Cu、Mn、Sb、Sn关系密切,原生晕轴向分带序列从上到下为As-Bi-Mn-Pb-Sb-B-Sn-Cu-Co-Hg-Ni-Zn-Au-Ag-Mo;(2)矿体中前缘晕、尾晕共存现象明显,预示着矿体向下还有很大的延伸,深部找矿应在矿体的北东方向进行;(3)评价指标(B×As×Hg×Sb)D/(Mn×Ni×Co×Sn)D,是有效的预测深部矿体资源潜力指标。 相似文献