Ancient deep roots for Mesozoic world-class gold deposits in the north China craton:An integrated genetic perspective     

Cheng-Xue Yang  M.Santosh 《地学前缘(英文版)》2020,11(1):203-214

The North China Craton(NCC)hosts some of the world-class gold deposits that formed more than 2 billion years after the major orogenic cycles and cratonization.The diverse models for the genesis of these deposits remain equivocal,and mostly focused on the craton margin examples,although synchronous deposits formed in the interior domains.Here we adopt an integrated geological and geophysical perspective to evaluate the possible factors that contributed to the formation of the major gold deposits in the NCC.In the Archean tectonic framework of the NCC,the locations of the major gold deposits fall within or adjacent to greenstone belts or the margins of micro-continents.In the Paleoproterozoic framework,they are markedly aligned along two major collisional sutures-the Trans North China Orogen and the Jiao-Liao-Ji Belt.Since the Mesozoic intrusions hosting these deposits do not carry adequate signals for the source of gold,we explore the deep roots based on available geophysical data.We show that the gold deposits are preferentially distributed above zones of uplifted MOHO and shallow LAB corresponding to thinned crust and eroded sub-lithospheric mantle,and that the mineralization is located above regions of high heat flow representing mantle upwelling.The NCC was at the center of a multi-convergent regime during the Mesozoic which intensely churned the mantle and significantly en riched it.The geophysical data on Moho and LAB upwarp from the centre towards east of the craton is more consistent with paleo-Pacific slab subduction from the east exerting the dominant control on lithospheric thinning.Based on these results,and together with an evaluation of the geochemical and isotopic features of the Mesozoic magmatic intrusions hosting the gold mineralization,we propose a genetic model that invokes reworking of ancient Au archives preserved in the lower crust and metasomatised upper mantle and which were generated through multiple subduction,underplating and cumulation events associated with cratonization of the NCC as well as the subduction-collision of Yangtze Craton with the NCC.The heat and material input along zones of heterogeneously thinned lithosphere from a rising turbulent mantle triggered by Mesozoic convergent margins surrounding the craton aided in reworking the deep roots of the ancient Au reservoirs,leading to the major gold metallogeny along craton margins as well as in the interior of the NCC.  相似文献   

南秦岭柞山地区铅银锌矿成矿规律及找矿模型     

王鹏 《江苏地质》2021,45(4):349-365

南秦岭柞水银洞子—山阳桐木沟铅银锌矿带地处陕西柞山地区中部,位于中秦岭晚古生代弧前盆地的柞水—山阳矿集区内。该带东西长约71 km,南北宽1～7 km。对带内银洞子（铜）铅银菱铁矿床、黑沟铅锌菱铁矿床、桐木沟锌矿床、南沟（银）铅矿床和松林沟铅矿点的地质、矿体、蚀变、矿化规律进行总结,发现矿体均严格产于中-上泥盆统青石垭组,具有明显的时控、层控、岩控及后期热液改造成矿特征,属典型的海底热水喷流沉积-热液改造层控矿床,构成与晚古生代海底热水喷流沉积-热液改造作用有关的铅锌银成矿系列。建立以层控+热液改造为主控矿条件,以青石垭组热水沉积岩+断裂+化探异常+硫化物、重晶石、菱铁矿蚀变分带为组合的找矿模型,对柞山地区金属矿的找矿突破具有重要的指导意义。  相似文献   

铜锡复合成矿研究进展与展望     

李欢  吴经华  孙文博  刘飚 《地质学报》2023,97(1):262-277

铜与锡具有不同的地球化学性质,然而铜锡共生或复合成矿现象在世界主要铜、锡成矿带中比较常见,如中国的右江、南岭(湘南)、大兴安岭南段(内蒙东部)、葡萄牙伊比利亚、秘鲁安第斯、英格兰德文郡、德国厄尔士山、日本西南、俄罗斯远东、加拿大新不伦瑞克等成矿带均为铜锡复合矿床的集中产区。铜锡复合矿床主要为岩浆热液矿床,以矽卡岩型、脉状矿床为主,兼有火山热液沉积型、斑岩型及云英岩型等。铜矿体的主要矿石矿物为黄铜矿,兼有斑铜矿、黝铜矿、辉铜矿等;锡矿体的主要矿石矿物为锡石,兼有黝锡矿。铜锡复合矿床的成矿物质来源(尤其是铜、锡成矿元素的来源是否具有一致性)尚有不少争议,锡普遍被认为是岩浆来源,而铜的来源具有多样性。成矿流体演化过程中的氧化还原环境的改变及流体的混合是导致铜锡复合成矿的主要原因。目前对于铜锡复合成矿的研究,主要是从矿床的年代学、单矿物(黄铜矿、锡石)微量元素及传统同位素地球化学、流体包裹体等方面入手,但对厘定铜锡复合成矿过程的作用有限。铜锡复合矿床的成因及勘查模型的建立具有重要的理论价值及现实意义。本文提出未来研究可以从多种非传统稳定同位素(例如Cu、Sn、W、Zn同位素)的联合示踪探索、成...  相似文献   

安徽铜陵隆起北缘的成矿作用特征及找矿潜力   总被引：2，自引：0，他引：2  

许卫  丁希国  吴礼彬  王克友  丁宁 《安徽地质》2011,21(2):138-142

安徽铜陵隆起北缘是指铜陵矿集区与繁昌火山岩盆地之间的过渡地段,近年来地质找矿工作取得了明显的进展,在总结该地区的成矿作用特征的基础上,认为铜陵隆起自然向北东延伸,在繁昌火山岩盆地下部存在寻找铜陵式铜金(铁)矿床的可能性,分析了地质找矿潜力。  相似文献   

The Koshrabad granite massif in Uzbekistan: petrogenesis, metallogeny, and geodynamic setting     

D.L. Konopelko  Yu S. Biske  K. Kullerud  R. Seltmann  F.K. Divaev 《Russian Geology and Geophysics》2011,52(12):1563-1573

The Koshrabad massif, referred to as the Hercynian postcollisional intrusions of the Tien Shan, is composed of two rock series: (1) mafic and quartz monzonites and (2) granites of the main phase. Porphyritic granitoids of the main phase contain ovoids of alkali feldspar, often rimmed with plagioclase. Mafic rocks developed locally in the massif core resulted from the injections of mafic magma into the still unconsolidated rocks of the main phase, which produced hybrid rocks and various dike series. All rocks of the massif are characterized by high f (Fe/(Fe + Mg)) values and contain fayalite, which points to the reducing conditions of their formation. Mafic rocks are the product of fractional crystallization of alkali-basaltic mantle melt, and granitoids of the main phase show signs of crustal-substance contamination. In high f values and HFSE contents the massif rocks are similar to A-type granites. Data on the geochemical evolution of the massif rocks confirm the genetic relationship of the massif gold deposits with magmatic processes and suggest the accumulation of gold in residual acid melts and the rapid formation of ore quartz veins in the same structures that controlled the intrusion of late dikes. The simultaneous intrusion of compositionally different postcollisional granitoids of the North Nuratau Ridge, including the Koshrabad granitoids, is due to the synchronous melting of different crustal protoliths in the zone of transcrustal shear, which was caused by the ascent of the hot asthenospheric matter in the dilatation setting. The resulting circulation of fluids led to the mobilization of ore elements from the crustal rocks and their accumulation in commercial concentrations.  相似文献   

Geological, geochemical characteristics and isotope systematics of the Longqiao iron deposit in the Lu-Zong volcano-sedimentary basin, Middle-Lower Yangtze (Changjiang) River Valley, Eastern China   总被引：8，自引：0，他引：8  

Zhou Taofa  Wu Mingan  Fan Yu  Duan Chao  Yuan Feng  Zhang Lejun  Liu Jun  Qian Bing  Franco Pirajno  David R. Cooke 《Ore Geology Reviews》2011,43(1):154-169

The Middle-Lower Yangtze (Changjiang) River Valley metallogenic belt is located on the northern margin of the Yangtze Craton of eastern China. Most polymetallic deposits in the Changjiang metallogenic belt are clustered in seven districts where magmatism of Mesozoic age (Yanshanian tectono-thermal event) is particularly extensive. From west to east these districts are: E-dong, Jiu-Rui, Anqing-Guichi, Lu-Zong, Tong-Ling, Ning-Wu and Ning-Zhen. World-class iron ore deposits occur in the Lu-Zong and Ning-Wu ore clusters, which are mainly located in continental fault-bound volcanic-sedimentary basins. One of these deposits is the Longqiao iron deposit, discovered in the northern part of the Lu-Zong Basin in 1985. This deposit consists of a single stratabound and stratiform orebody, hosted in sedimentary carbonate rocks of the Triassic Dongma'anshan Formation. A syenite pluton (Longqiao intrusion) is situated below the deposit. The iron ore is massive and disseminated and the ore minerals are mainly magnetite and minor pyrite. Wall rock alteration mostly consists of skarn minerals, such as diopside, garnet, potassic feldspar, quartz, chlorite, phlogopite and anhydrite. Thin sedimentary siderite beds of Triassic age occur as relict laminated ore at the top and the margin of the magnetite orebody. These sideritic laminae are part of Triassic evaporite-bearing carbonate deposits (Dongma'anshan Formation).Sulfur isotopic compositions show that the sulfur in the deposit was derived from a mixture of magmatic hydrothermal fluids and carbonate–evaporite host rocks. Similarly, the C and O isotopic compositions of limestones from the Dongma'anshan Formation indicate that these rocks interacted with magmatic hydrothermal fluids. The O isotopic compositions of the syenitic rocks and minerals from the deposit show that the hydrothermal magnetite and skarn minerals were formed from magmatic fluids. The Pb isotopic compositions of sulfides are similar to those of the Longqiao syenite. Phlogopite coexisting with magnetite in the magnetite ores yielded a plateau age of 130.5 ± 1.1 Ma (2σ), whereas the LA-ICP MS age of the syenite intrusion is 131.1 ± 1.5 Ma, which is slightly older than the age of phlogopite.The Longqiao syenite intrusion may have crystallized from a parental alkaline magma, generated by partial melting of lithospheric mantle, during extensional tectonics. The ore fluids were probably first derived from magma at depth, later emplaced in the sedimentary rocks of the Dongma'anshan Formation, where it interacted with siderite and evaporite-bearing carbonate strata, resulting in the formation of magnetite and skarn minerals. The Longqiao iron deposit is a skarn-type stratabound and stratiform mineral system, genetically and temporally related to the Longqiao syenite intrusion. The Longqiao syenite is part of the widespread Mesozoic intracontinental magmatism (Yanshanian event) in eastern China, which has been linked to lithospheric delamination and asthenospheric upwelling.  相似文献   

Zircon U-Pb dating of intermediate-acid intrusive rocks in the middle section of Ningzhen district and their metallogenic implicationsEI北大核心CSCD     

Guan J.Wei F.Sun G.Huang J.Wang L. 《大地构造与成矿学》2015,(2):344-354

The Ningzhen metallogenic district is an important part of the Middle-Lower Yangtze River Valley metallogenic belt. LA-ICP-MS zircon U-Pb dating of the three intermediate-acid intrusions, i.e., Anjishan, Xinqiao, and Shima, in the central part of the Ningzhen district, indicates that those intrusions were emplaced in the Late Early Cretaceous, with ages of 107.0±1.1 Ma-108.0±1.6 Ma, 108.0±1.3 Ma, and 102.5±1.1 Ma, respectively. Combined with the molybdenite Re-Os isotope age (106-108 Ma) of porphyry copper deposit in this regions, the Ningzhen district exists an intensively magmatic-metallogenic-thermal event at 102.5-108.0 Ma. The age of this event is similar with the age of the third period of large scale mineralization in South China, however obviously later than the magmatic activity of other ore field (124-148 Ma) in the Middle-Lower Yangtze River Valley metallogenic belt. It is suggested that the tectonic-magmatic-thermal events in the Ningzhen area is formed under regional lithospheric extension environment, which is also consistent with the tectonic background of the third period of large scale mineralization in South China. The zircon U-Pb ages of the intrusions and the Re-Os ages of molybdenites from the porphyry deposits in the study area demonstrate that the Ningzhen district underwent intensive magmatism and hydrothermal mineralization during the period from 102.5 to 108.0 Ma, which is consistent with the third pulse of large scale mineralization in the South China. ©, 2015, Science Press. All right reserved.  相似文献   

滇西北衙斑岩型金多金属矿床成矿流体特征及其演化   总被引：2，自引：2，他引：0  

王建华  李文昌  王可勇  尹光候  吴松  姜文涛 《岩石学报》2015,31(11):3269-3280

北衙超大型金多金属矿床位于扬子陆块西缘与三江特提斯造山带的结合部位。本文通过对北衙矿区内的斑岩体石英斑晶、斑岩型矿化、矽卡岩矿化中的矽卡岩及外围似层状热液型铅锌银矿化的岩(矿)石中发育的流体包裹体进行了系统研究,发现北衙矿区内主要发育CO2、富CO2、含CO2、含子矿物三相、富气相水溶液及气液两相水溶液包裹体六类流体包裹体;与斑岩型矿化有关的成矿流体为中-高温Na Cl-H2O-CO2体系热液,矽卡岩矿化相关成矿流体为一种高温的Na Cl-H2O及Na Cl-H2O-CO2体系热液,而外围似层状铅锌银矿化相关的成矿流体则为中温的Na Cl-H2O-CO2体系热液。对比分析表明,矽卡岩矿化中的矽卡岩矿物(以绿帘石类矿物为主)形成较早,其中发育富气相的流体包裹体,可以推断岩浆侵位后先分异出富水蒸气的流体,此后CO2才从成矿流体中大量分异。斑岩型矿化及外围地层中似层状铅锌银矿化脉体中发育的流体包裹体与斑岩体石英斑晶内发育的流体包裹体组合类型基本一致,表明成矿流体主要来自斑岩体结晶分异出的岩浆热液。流体包裹体研究表明,北衙金多金属矿区内的矽卡岩型(金铜铁)、斑岩型(铜金钼)及外围碳酸盐岩等地层中的似层状热液型(铅锌银)矿床系列为与富碱斑岩体侵位活动有关的,由岩浆分异热液并逐渐演化形成的斑岩型金-铁铜-铅锌(银)多金属成矿系统。  相似文献   

华北克拉通南缘后大陆碰撞背景下的岩石圈演化及金、钼成矿规律探讨     

张灯堂  冯建之  李磊  孟宪锋  何进  刘宗彦  徐文超 《大地构造与成矿学》2015,(2)

通过对华北克拉通南缘大量的岩浆岩和矿床研究表明,矿床的形成与燕山期岩浆岩具有非常密切的关系,豫西矿集区是华北克拉通南缘岩石圈剧烈演化的结果。岩石圈的这种剧烈演化是在两件重大地质事件的共同作用下进行的:一方面,扬子板块与华北板块在印支期拼合,并发生了广泛的陆-陆碰撞造山活动,此后,克拉通边缘转入了后造山演化阶段;另一方面,燕山晚期的J-K之交,太平洋板块向欧亚板块俯冲,导致地幔大规模活动。中国东部大规模的地壳减薄和壳幔作用,使本来就处于造山后演化阶段的华北陆块南缘发生了广泛的岩浆活动。正因为这两大地质作用叠加效应,区域岩浆演化剧烈而复杂,大批重融花岗岩的地球化学特征往往既显示造山带的特点,又具有大规模壳幔作用的特征。这两大地质作用为豫西矿集区的形成提供了良好的成矿地质背景,大量的研究表明,各种矿床与燕山期岩浆岩在形成时间上高度吻合,空间上密切相关,同位素指标极为相近,显示它们在成因上的密切关系。岩浆一方面作为深部赋矿流体的上升通道,另一方面提供持续的高温环境,保证了元素迁移和成矿作用的进行。因此,华北克拉通南缘后大陆碰撞背景下的壳幔演化、大规模岩浆活动是豫西矿集区形成的决定性因素。  相似文献   

成矿流体动力学与大地构造环境的关系(英文)     

池国祥  林舸 《大地构造与成矿学》2015,(3)

热液矿床的形成需要大量流体,而流体的运移需要包括地势差、岩石变形、热梯度及热异常等多种驱动力。这些流体驱动力与构造环境及过程有密切关系。流体压力状态和热场及地势差的组合决定了压性构造环境流体以向上运动为主,如造山型成矿系统,而张性构造环境流体以对流为主,如VMS和SEDEX成矿系统。造山作用造成的地势差及水平挤压作用所产生的超压可以驱动流体侧向迁移数百公里,如MVT成矿系统。但是,具体的成矿流体动力学过程比较复杂,且随构造演化而变化。在经历过多个大地构造演化阶段的地区,如地洼区,老的成矿流体动力系统不断被新的系统叠加或取代;新的构造单元需要来自地幔的流体源补充才有利于成矿。成矿学研究的是成矿作用与大地构造的关系,而流体动力学系统与大地构造环境密切相关,因此,成矿流体动力学应成为成矿学的一个重要组成部分。  相似文献