Dating of the Giant Huize Zn-Pb Ore Field of Yunnan Province, Southwest China: Constraints from the Sm-Nd System in Hydrothermal Calcite

The Huize ore field, which is the most famous high‐grade Mississippi Valley‐type Zn‐Pb ore field in China, consists of the Kuangshanchang and Qilinchang deposits. The Sm‐Nd isotopic compositions of gangue calcite were analyzed to constrain the timing of mineralization. Eight calcite samples from the No. 6 orebody in the Qilinchang deposit have Sm and Nd concentrations of 1.82–25.93 and 15.25–79.02 ppm, respectively, and yielded an age of 225 ± 9.9 Ma with epsilon Nd =?10.6 and MSWD = 0.13. Five calcites from the No. 1 orebody in the Kuangshanchang deposit contain 2.37–2.90 ppm Sm and 8.18–16.85 ppm Nd, and yielded an age of 228 ± 16 Ma, with epsilon Nd =?10.6 and MSWD = 0.28. These two ages are close to the age of the Emeishan flood basalt, which is ca 255 Ma, and agree with the reported ⁴⁰Ar/³⁹Ar plateau and isochron ages of the native copper mineralization related to the Emeishan flood basalt in this region, which are 226–228 Ma. Moreover, previous study shows that the magnitude of uplift resulting from the Emeishan flood basalts is >1000 m. It indicates that the Kuangshanchang and the Qilinchang deposit formed during the same geological event and originated by fluid migration during uplift resulting from the Emeishan flood basalt.     

峨眉山玄武岩与铅锌矿床成矿关系初探—以云南会泽铅锌矿床为例

本文以云南会泽铅锌矿为例，从成矿时代、成矿物来源、成矿流体来源和成矿热动力等方面初步讲座主峨眉山玄武岩与铅锌矿床成矿的关系。结果表明：矿床成矿时代可能与峨眉山玄武岩岩浆活动时代相近；峨眉山玄武岩在成矿过程中提供了部分成矿物质；伴随峨眉山玄武岩岩浆活动过程去气作用（包括地幔去气作用和岩浆去气作用）形成的流体参与了会泽铅锌矿成矿流体的形成；峨眉山玄武岩岩浆活动为成矿热动力的主要来源。     

亚洲3个大火成岩省(峨眉山、西伯利亚、德干)对比研究

峨眉山(～260 Ma)、西伯利亚(～250 Ma)和德干(～66 Ma)大陆溢流玄武岩是世界上3个重要的大火成岩省.大火成岩省至少具有4个通常被用于识别古地幔柱的标志:(1)先于岩浆作用的地表隆升;(2)与大陆裂谷化和裂解事件相伴;(3)与生物灭绝事件联系密切;(4)地幔柱源玄武岩的化学特征.虽然这3个大火成岩省都是来源于原始地幔柱,但是它们的地球化学特征有本质上的差异,反映其地幔柱曾与不同的上地幔库相互作用.(1)峨眉山和西伯利亚大陆溢流玄武岩的母岩浆,在上升过程中经受了与地球化学上和古老克拉通岩石圈地幔相同的上地幔库(EM1型幔源)的相互作用;(2)而德干大火成岩省没有受到地壳(或岩石圈)混染的原生玄武岩则显示地幔柱和EM2之间的Sr-Nd同位素变化.这种差异有可能制约了3个大火成岩省的成矿潜力.峨眉山和西伯利亚大火成岩省含有世界级岩浆矿床,而德干大火成岩省则不含矿.     

Age and petrogenesis of Anisian magnesian alkali basalts and their genetic association with the Kafang stratiform Cu deposit in the Gejiu supergiant tin-polymetallic district,SW China

Gejiu is geographically located near Gejiu city, SW China. It is one of the largest tin-polymetallic districts in the world and contains approximately 3 million tons (Mt) of Sn and smaller quantities of Cu, Pb, and Zn. The deposit primarily yields three different types of ore: skarn-hosted ore, basalt-hosted stratiform ore, and carbonate-hosted stratiform ore. Kafang is one of the primary ore deposits in the Gejiu district and is an unusual occurrence hosted in basaltic rocks. Genetic models of the Kafang deposit suggest that it is related either to Anisian (Lower stage of Middle Triassic) Gejiu basalts or to Cretaceous Gejiu granite. In this study, we performed zircon SIMS U–Pb dating, major and trace element analyses, and Sr–Nd–Pb isotopic analyses for the Gejiu basalts and S isotopic analyses for stratiform Cu ore. Our results and previous studies are used to interpret the petrogenesis of the Gejiu basalts and the origin of the basalt-hosted stratiform Cu deposit. The SIMS zircon U–Pb analyses of the Gejiu basalts yield an age of 244.4 Ma. The trace element ratios of the Gejiu basalts are similar to those of ocean island basalt and have positive εNd(t) values (ranging from 0.6 to 2.5) and uniform (⁸⁷Sr/⁸⁶Sr)_i values (ranging from 0.70424 to 0.70488). These ratios are close to those of the Permian Emeishan flood basalt. Thus, the Gejiu basalts may represent coeval volcanisms within the plate involving remelting of the Emeishan plume head through a stress relaxation process after the main plume event. The Pb and S isotopic compositions of the Gejiu basalts and the stratiform Cu ores indicate that the source of Cu and S is primarily derived from the Gejiu basalts. However, the age of sulfide mineralization (84.2–79.6 Ma) and the age of hydrothermal alteration (85.5–81.9 Ma) are temporally consistent with the age of the Cretaceous granite emplacement (85.5–83.3 Ma). From a petrological and geochemical study, we determine that the Gejiu basalts may have been subjected to pervasive granite-related hydrothermal alteration during the emplacement of granite. These processes increase the K and Mg contents of basalt and probably caused the formation of the Cu ores. Thus, the Kafang stratiform Cu deposit can be considered as a granite-related hydrothermal deposit.     

云南会泽铅锌矿田控矿构造体系及成矿预测

确认了会泽Pb-Zn矿田逆冲推覆构造的存在，认为矿山厂、麒麟厂矿区构造为一双重逆冲推覆构造体系，由顶板逆冲断层与底板逆冲断层和夹于其间的一套叠瓦式逆冲断层和断层夹块组合而成。指出逆冲推覆断层引起的褶皱是控矿的主要构造。结合矿床地质特征及地球化学背景，指出了矿区深部及外围找矿方向。     

Geochronology of layered mafic intrusions from the Pan–Xi area in the Emeishan large igneous province, SW China

The Panzhihua–Xichang (Pan-Xi) area hosts mafic/ultramafic intrusions, which are part of the Permian Emeishan large igneous province. Some of these intrusions host giant Fe–Ti–V deposits and minor Ni–Cu–PGE mineralization. In the present study, zircon U–Pb ages of 259.3±1.3 and 260.7±0.8 Ma have been obtained from the giant Fe–Ti–V ore-bearing Hongge and the unmineralized Binggu intrusions, respectively, by isotope dilution thermal ionization mass spectrometry method. In combination with the ages of other ore-bearing intrusions, this age shows that these mafic/ultramafic intrusions were emplaced at ca. 260 Ma. The Hongge and Binggu intrusions cut the lower part of the rapidly deposited Emeishan flood basalt sequence but no further into the upper volcanic sequence in the Pan-Xi area. Thus, emplacement and mineralization of the mafic/ultramafic intrusions were almost contemporaneous with the eruption of the Emeishan flood basalts during a relatively short time span.     

黔西北福来厂铅锌矿床Pb同位素研究及地质意义

单阶段演化正常铅用H-H法可获得高准确性的模式年龄,在黔西北福来厂铅锌矿床中采集16件矿脉和围岩样品,测定它们的Pb同位素组成,206 pb/204 Pb为18.5346 ～ 18.7294(均值18.5935),207pb/204 Pb为15.7408～15.7603(均值15.7519),208 pb/204 Pb...     

黔西北地区隆起裂陷、逆冲推覆作用与铅锌成矿关系

黔西北地区是上扬子西缘成矿带重要矿集区,区内分布许多大中型铅锌矿床,其构造复杂,找矿难度大。为实现黔西北地区铅锌找矿突破,系统收集该区及邻区勘查和研究资料,通过类比美国密西西比地区铅锌矿床和相邻云南矿山厂、麒麟厂、毛坪等铅锌矿床,结合在黔西北地区实施的调查和勘查项目,开展野外调查和取样测试等,解剖区内典型矿床;以地史时期构造演化为线索,探索黔西北地区地壳裂陷、地壳隆升、玄武岩浆喷发、地层褶皱倒转、逆冲推覆与铅锌成矿关系。研究表明,海西期裂陷作用产生裂陷槽,深部成矿流体沿裂陷槽边界断裂上升,Pb、Zn等组分在裂陷槽内与岩层同沉积,形成高含量背景层;裂陷槽两侧地壳隆升拉张变薄,玄武岩浆喷发,强大的岩浆热能驱动,岩层中Pb、Zn等组分与岩浆携带的含矿热液,运移至垭都-紫云等大断裂及次级断裂、断裂旁侧的有利岩层中聚集,形成铅锌矿体（矿化）;印支早期构造运动,地层褶皱倒转、断裂、逆冲推覆,沿断裂上升的含矿热液,改造早期的铅锌矿体（矿化）。该区的铅锌矿床不属于MVT型,是叠加（复合/改造）型矿床。印支晚期、燕山期、喜山期的构造运动,没有明显铅锌成矿作用发生,破坏早期形成的矿床。     

黔西北赫章地区铅锌矿远景

文章从赫章地区铅锌的成矿地质条件、地球化学特征、地球物理特征、以及砂矿储量和物化探异常找矿勘查的研究,对比邻区同成矿区域同类铅锌矿床（矿山厂、麒麟厂）的矿化地质特征,经过综合分析,认为本区具有找矿潜力。     

REE and C-O Isotopic Geochemistry of Calcites from the World-class Huize Pb-Zn Deposits, Yunnan, China: Implications for the Ore Genesis

<正>The world-class Huize Pb-Zn deposits of Yunnan province,in southwestern China,located in the center of the Sichuan-Yunnan-Guizhou Pb-Zn polymetallic metallogenic province,has Pb+Zn reserves of more than 5 million tons at Pb+Zn grade of higher than 25%and contains abundant associated metals,such as Ag,Ge,Cd,and Ga.The deposits are hosted in the Lower Carboniferous carbonate strata and the Permian Emeishan basalts which distributed in the northern and southwestern parts of the orefield.Calcite is the only gangue mineral in the primary ores of the deposits and can be classified into three types,namely lumpy,patch and vein calcites in accordance with their occurrence.There is not intercalated contact between calcite and ore minerals and among the three types of calcite,indicating that they are the same ore-forming age with different stages and its forming sequence is from lumpy to patch to vein calcites. This paper presents the rare earth element(REE) and C-O isotopic compositions of calcites in the Huize Pb-Zn deposits.From lumpy to patch to vein calcites,REE contents decrease as LREE/ HREE ratios increase.The chondrite-normalized REE patterns of the three types of calcites are characterized by LREE-rich shaped,in which the lumpy calcite shows(La)_N(Ce)_N(Pr)_N≈(Nd)_N with Eu/Eu~*1,the patch calcite has(La)_N(Ce)_N(Pr)_N≈(Nd)_N with Eu/Eu~*1,and the vein calcite displays(La)_N(Ce)_N(Pr)_N(Nd)_N with Eu/Eu~*1.The REE geochemistry of the three types of calcite is different from those of the strata of various age and Permian Emeishan basalt exposed in the orefield.Theδ~(13) C_(PDb) andδ~(18)O_(Smow) values of the three types of calcites vary from-3.5‰to-2.1‰and 16.7‰to 18.6‰,respectively,falling within a small field between primary mantle and marine carbonate in theδ~(13)C_(PDb) vsδ~(18)O_(Smow) diagram. Various lines of evidence demonstrate that the three types of calcites in the deposits are produced from the same source with different stages.The ore-forming fluids of the deposits resulted from crustal -mantle mixing processes,in which the mantle-derived fluid components might be formed from degassing of mantle or/and magmatism of the Permian Emeishan basalts,and the crustal fluid was mainly provided by carbonate strata in the orefield.The ore-forming fluids in the deposits were homogenized before mineralization,and the ore-forming environment varied from relatively reducing to oxidizing.     

滇东北会泽超大型铅锌矿床矿质来源与改造成矿作用

"改造成矿作用"理论是中国科学院涂光炽院士提出的完善矿床成因分类学"四分法"的新理论,是中国学者对世界地球科学的重要贡献。该文根据会泽铅-锌(银、锗)矿床地质地球化学特征,列举其沉积改造的充分证据,用改造成矿的四大要素审视其矿床成因,认同它是典型而独特的沉积—强烈改造矿床,并以重要的宏观地质为依据,注意到峨眉山玄武岩(260 Ma)本身及昆阳群褶皱基底均未赋存一定规模的铅锌矿床,认为玄武岩与基底供给会泽铅锌矿(245~246 Ma)成矿物质有限,成岩与成矿时差太大,且成矿断层切割玄武岩,说明玄武岩成岩在先,铅、锌成矿在后,二者无直接成因联系。对会泽铅锌矿床的物质来源,有主张来自地层、基底、玄武岩或多来源者,但以何者为主,多种金属是否同源尚缺深入讨论,文章特别对地层、基底、峨眉山玄武岩中各成矿元素的含量、富集系数及富集类型进行系统的求算与分析研究,以讨论各种成矿金属的可能来源几率及其对成矿的贡献估计。结果显示:银在各地质体中均高倍富集,可提供充沛矿质,铅次之;锌则相反,多为正常元素或亏损元素,锗、镓、铟亦然,故矿石中的锌、锗、镓、铟,更可能为深部提供。结合大量的微量元素、稀土元素、铅、硫、锶、碳、氢、氧同位素等地球化学资料分析研究,认为地层,特别是震旦—寒武系、泥盆系、下石炭统摆佐组(C1b)与深部是主要的矿质来源,不同金属可同源或异源。矿床受地层岩性与构造的双重控制,与岩浆活动无关,具备改造成矿要素,属典型的沉积—强烈改造铅锌矿床,且具超大、特富、多金属富集的独特性。海西期下石炭统摆佐组已沉积成岩成矿或形成矿源层,后经印支期构造运动强烈改造而超常富集成矿,多掩盖其沉积特征,它属于沉积改造矿床"会泽式"。     

Isotopes and Geochronology of the Meixian-type Pb-Zn-(Ag)Deposits,Central Fujian Rift,South China:Implications for Geological Events

Central Fujian Rift is another new and important volcanogenic massive sulfide Pb-Zn polymetallic metallogenetic belt. In order to find out the material genesis and mineralization period of Meixian-type Pb-Zn-Ag deposits, S and Pb isotope analysis and isotope geochronology of ores and wall rocks for five major deposits are discussed. It is concluded that the composition of sulfur isotope from sulfide ore vary slightly in different deposits and the mean value is close to zero with the 834S ranging from -3.5‰ to ＋5.6‰ averaging at ＋2.0‰, which indicates that the sulfur might originate from magma or possibly erupted directly from volcano or was leached from ore-hosted volcanic rock. The lead from ores in most deposits displays radioactive genesis character （206pb/204pb〉18.140, 207Pb/204pb〉15.584, 208pb/204pb〉38.569） and lead isotope values of ores are higher than those of wall rocks, which indicates that the lead was likely leached from the ore-hosted volcanic rocks. Based on isotope data, two significant Pb-Zn metallogenesis are delineated, which are Mid- and Late-Proterozoic sedimentary exhalative metailogenesis （The single zircon U-Pb, Sm-Nd isochronal and Ar-Ar dating ages of ore- hosted wall rocks are calculated to be among 933-1788 Ma.） and Yanshanian magmatic hydrothermal superimposed and alternated metallogenesis （intrusive SHRIMP zircon U-Pb and Rb-Sr isochronal ages between 127-154 Ma）.     

Ore genesis of the Tianbaoshan carbonate-hosted Pb–Zn deposit,Southwest China: geologic and isotopic (C–H–O–S–Pb) evidence

The Tianbaoshan Pb–Zn deposit, part of the Sichuan–Yunnan–Guizhou (SYG) Pb–Zn metallogenic province, is located in the western Yangtze Block and contains 2.6 million tonnes of 10–15 wt.% Pb + Zn metals. Ore bodies occur as vein or tubular types and are hosted in Sinian (late Proterozoic) carbonate rocks and are structurally controlled by the SN-trending Anninghe tectonic belt and NW-trending concealed fractures. The deposits are simple in mineralogy, with sphalerite, galena, pyrite, chalcopyrite, arsenopyrite, freibergite, and pyrargyrite as ore minerals and dolomite, calcite, and quartz as gangue minerals. These phases occur as massive, brecciated, veinlet, and dissemination in dolostone of the upper Sinian Dengying Formation. Hydrogen and oxygen isotope compositions of hydrothermal fluids range from –47.6 to –51.2‰ and –1.7 to +3.7‰, respectively. These data suggest that H₂O in hydrothermal fluids had a mixed origin of metamorphic and meteoric waters. Carbon and oxygen isotope compositions range from –6.5 to –4.9‰ and +19.3 to +20.2‰, respectively. These compositions plot in the field between mantle and marine carbonate rocks with a negative correlation, suggesting that CO₂ in the ore-forming fluids had multiple sources, including the Permian Emeishan flood basalts, Sinian-to-Permian marine carbonate rocks, and organic matters in Cambrian-to-Permian sedimentary rocks. Sulphur isotope compositions range from –0.4 to +9.6‰, significantly lower than Cambrian-to-Permian seawater sulphate (+15 to +35‰) and sulphate (+15 to +28‰) from evaporates in Cambrian-to-Permian strata, implicating that the S was derived from host-strata evaporates by thermal–chemical sulphate reduction. ²⁰⁶Pb/²⁰⁴Pb, ²⁰⁷Pb/²⁰⁴Pb, and ²⁰⁸Pb/²⁰⁴Pb ratios range from 18.110 to 18.596, 15.514 to 15.878, and 38.032 to 39.221, respectively, which plot in field of the upper crust Pb evolution curve, unlike those of Proterozoic basement rocks, Sinian dolostone, Devonian-to-Permian carbonate rocks, and the Permian Emeishan flood basalts, implying complex derivation of Pb metal in the ore-forming fluids. Geological and isotopic studies of the Tianbaoshan Pb–Zn deposit reveal that constituents in the hydrothermal fluids were derived from multiple sources and that fluid mixing was a possible metallogenic mechanism. The studied deposit is not distal magmatic–hydrothermal, sedimentary exhalative (SEDEX), or Mississippi Valley (MVT) types, rather, it represents a unique ore deposit type, named in this article the SYG type.     

江西石门寺钨多金属矿床花岗岩独居石U-Pb精确定年及地质意义

石门寺钨多金属矿床位于大湖塘矿田的北部,赣北九岭成矿带中段,是目前世界上最大的几个钨矿之一。本文对矿区出露的似斑状黑云母二长花岗岩、细粒黑云母二长花岗岩和花岗斑岩的独居石进行了LA-ICP-MS U-Pb年龄测定,其年龄分别为150.0±0.7 Ma、149±1 Ma和148.2±1.2 Ma。独居石测年数据显示,三种岩性的样品Tera-Wasserburg反向谐和图的下交点年龄与206Pb/238U加权平均年龄一致,反映了花岗岩的结晶年龄为燕山期,结合矿区辉钼矿的Re-Os成矿年龄(150.4±1.4 Ma),表明石门寺钨矿成矿作用与花岗岩的形成密切相关。大湖塘钨矿区的成岩成矿作用与钦杭成矿带的大规模钨锡多金属成矿作用在时间上一致(~(150) Ma),具有统一的地球动力学背景,形成于岩石圈拉张减薄的动力环境下。     

湖北银洞沟银矿床地质特征与成因类型

湖北银洞沟矿床是中国为数不多的较为典型的大型银矿床。文中系统总结了该矿床的地质特征,初步提出了矿床的成因类型。研究结果表明:银洞沟矿床产于秦岭造山带东南部武当群变质火山岩中,矿体受韧性剪切带控制,矿石类型主要为石英脉型和少量蚀变岩型,围岩蚀变矿物组合主要为石英、铁白云石、白云母、钠长石、绿泥石、黄铁矿等,成矿流体特征为低盐度、低密度、富含CO2±CH4±N2的水溶液,矿床上部为低品位银金矿体,中部为高品位银金矿体和少量铅锌矿体,深部银品位降低,金品位增高,同时出现较厚大铅锌矿体。其地质特征与典型的造山型矿床一致,表明其为一造山型银矿床,矿床矿化分带符合造山型矿床成矿模式——地壳连续模型,因此应该充分重视寻找矿山深部金、铅、锌、铜、钼等接替资源。     

云南个旧锡矿的玄武岩成矿

个旧锡矿产于个旧东区,是一个以锡铜为主的超大型多金属矿床,具有火山沉积成矿的某些特征。因遭受燕山期花岗岩的叠加改造,区内个旧组卡房段中玄武岩遭受强烈的变质,它又具有花岗岩热液成矿的特征。区内玄武岩的地质地球化学特征表明,印支期玄武岩中的Sn、Cu、Pb、Zn、Ag和Au的质量分数大多数高于世界玄武岩平均值的若干倍;矿石硫化物的硫同位素δ³⁴S为-1.5‰~4.0‰,平均+0.207‰,在幔源硫附近;铅同位素模式年龄分为两组：第一组为180~240 Ma,反映了印支期的火山沉积成矿作用;第二组为80~140 Ma,反映了燕山期花岗岩的叠加改造成矿作用。区内印支期玄武岩为个旧锡铜多金属矿床的形成提供了主要的成矿物质,与成矿有直接联系。     

大兴安岭南段维拉斯托锡多金属矿床LA-ICP-MS锡石和锆石U-Pb年龄及其地质意义

维拉斯托锡多金属矿床位于大兴安岭南段西坡的内蒙古克什克腾旗,是近年来发现的一个以锡为主,共伴生钨、锌、铜、钼、铷、铌和钽的大型矿床。矿化类型包括深部以锡为主,伴生锌、铷、铌和钽的蚀变花岗岩型矿体;中部以锡为主,伴生铜和锌的隐爆角砾岩型矿体及浅部锡、钨、锌、铜和钼的石英大脉型和网脉型矿体。该矿床的主要工业矿体为石英脉型,呈北北东向产于古元古界宝音图群和华力西期石英闪长岩中的断裂破碎带内,而蚀变花岗岩型和隐爆角砾岩型矿石的品位较低。文中选取1件石英脉型锡矿体中的锡石样品进行了LA-ICP-MS锡石U-Pb定年,获得锡石的206Pb/207Pb238U/207Pb等时线年龄为(136.0±6.1) Ma(MSWD=0.94),207Pb/206Pb238U/206Pb谐和年龄为(132.3±5.4) Ma(MSWD=2.8),表明维拉斯托锡多金属矿床形成于早白垩世;选取1件与成矿相关的北大山岩体花岗岩样品开展了LA-ICP-MS锆石U-Pb定年,获得206Pb/238U年龄为(140±2) Ma(MSWD=0.10),表明成矿岩体亦形成于早白垩世。维拉斯托锡多金属矿床属于与花岗岩有关的岩浆热液型矿床。通过统计大兴安岭南段主要锡多金属矿床的成矿年龄和成矿岩体的年龄,发现几乎所有的锡多金属矿床均形成于140～135 Ma期间,表明早白垩世是大兴安岭南段锡多金属矿床成矿高峰期。     

Signatures of the source for the Emeishan flood basalts in the Ertan area： Pb isotope evidence

The Emeishan flood basalts can be divided into high-Ti (HT) basalt (Ti/Y>500) and low-Ti (LT) basalt (Ti/Y<500). Sr, Nd isotopic characteristics of the lavas indicate that the LT- and the HT-type magmas originated from distinct mantle sources and parental magmas. The LT-type magma was derived from a shallower lithospheric mantle, whereas the HT-type magma was derived from a deeper mantle source that may be possibly a mantle plume. However, few studies on the Emeishan flood basalts involved their Pb isotopes, especially the Ertan basalts. In this paper, the authors investigated basalt samples from the Ertan area in terms of Pb isotopes, in order to constrain the source of the Emeishan flood basalts. The ratios of 206Pb/204Pb (18.31–18.41), 207Pb/204Pb (15.55–15.56) and 208Pb/204Pb (38.81–38.94) are significantly higher than those of the depleted mantle, just lying between EM I and EM II. This indicates that the Emeishan HT basalts (in the Ertan area) are the result of mixing of EMI end-member and EMII end-member.     

江西武山和永平铜矿含矿花岗质岩体锆石SIMSU—Pb年代学

江西武山和永平铜矿床是长江中下游金属成矿带中的两个重要矿床。对武山铜矿的花岗闪长斑岩和永平铜矿的花岗斑岩中锆石分别进行了,离子探针（SIMS）U—Pb定年研究,发现两个矿区的锆石年龄可分作两期,武山铜矿含矿岩体锆石^206Pb/^238U年龄分别为145±3．9Ma和121±2．5Ma,永平铜矿含矿岩体锆石^206Ph／^238U年龄分别为160±2．3Ma和135±7．4Ma。这两期不同的年龄可能反映了锆石在岩浆侵位时的结晶年龄和后期热液蚀变作用的年龄。因此确定武山铜矿花岗质岩体的侵位年龄为145Ma,永平铜矿花岗质岩体的侵位年龄为160Ma。该年龄可能也反映了这两个矿床中与燕山期岩浆侵入有关的矽卡岩型矿床和斑岩型矿床的形成时代。     

Geological significance of nickeliferous minerals in the Fule Pb–Zn deposit,Yunnan Province,China

The Fule Pb–Zn deposit is located in the Sichuan–Yunnan–Guizhou Province, and it is an important and giant low temperature metallogenic domain in China. In our research area, the Pb–Zn deposits are mainly hosted in the Permian Yangxin Formation and are composed of dolostone and limestone. The distance between the ore bodies and the Permian Emeishan basalt ranged from 50 to 160 m. In this study, the nickel rich minerals, including vaesite, polydymite and millerite, were reported for the first time in the Fule deposit. These minerals occurred as xenomorphic mineral aggregate and were sporadically distributed in the sphalerite–galena–calcite vein, which is the main ore type in the deposit. Our study indicated that the paragenetic sequence of minerals in the Fule deposit is the following order: polydymite?→?vaesite?→?millerite?→?sphalerite?→?galena?→?tetrahedrite (tennantite). The geological occurrence characteristics of those nickeliferous minerals suggested that the Permian Emeishan basalt is a possible barrier layer of Pb–Zn ore-forming fluid, and it is an important source for the Ni and part of the Cu in the deposit. The Sichuan–Yunnan–Guizhou Pb–Zn mineralization province is a world-class production base of Pb and Zn, in which the Permian Emeishan basalt and Pb–Zn deposits have uniformly spatial distribution, but the relationship of mineralization between them is still under debate. This report provides new evidence for understanding the relationship between Pb–Zn mineralization and Permian Emeishan basalt in the Sichuan–Yunnan–Guizhou Pb–Zn mineralization province.