Metallogenic epoch and genesis of the gold deposits in Jiaodong Peninsula, Eastern China: a regional review

Gold deposits are characterized by multi-sources, superimposition, large scale and temporal-spatial concentration in Jiaodong Peninsula, Eastern China. In this paper, we review the history and the development of the study on metallogenic chronology and genesis of gold deposits, summarize the main features of superimposed metallogenesis, provide evidence of the Mesozoic complex metallogenic system, and point out some problems for further research of Jiaodong gold deposit cluster from a regional view. Although gold deposits are different in genetic types, ore-forming materials and geological settings, our research indicates that the accumulation and emplacement of the ore-forming materials are temporally-spatially concentrated on a large scale, and the main metallogenic epoch of Jiaodong gold deposits was concentrated in Mesozoic. Metallogenic chronology and geological-geochemical data indicate that there are two periods of gold mineralizations occurred in 130-110 Ma and 90-80 Ma respectively in Jiaodong ore cluster. The gold deposit cluster results from the superimposition of the polygenetic mineralization, and further study is needed to investigate the formation and evolution of the Mesozoic complex metallogenic system.     

Research advances in the Mesozoic tectonic regimes during the formation of Jiaodong ore cluster area

Based on research advances of the tectonic regime in Jiaodong ore cluster area and the related tectonic regime transformation in Mesozoic era in the eastern region of North China, in this paper, we first summarize some key problems required to be studied further on. Then we suggest an approach to dealing with these problems. It is known that the gold deposits in Jiaodong ore cluster area, which are of different mineralization styles, spatial distributions and geological settings, might be as a result from one or more geologic events in Mesozoic. Till now, this kind of research on the temporal evolution and spatial migration sequence, especially on the geodynamic mechanism of the above events, is far from sufficient. Moreover, quantitatively describing the action mode and the temporal?spatial framework of tectonic dynamic regimes and formulating the relative contribution of every tectonic dynamic regime for the metallogensis are still challenges to the geologists studying on the formation of Jiaodong ore cluster area. According to the interpretation of the regional tectonic analysis, the structural dynamics, the observation and the exploration of the mineralization network, we propose a geological?physical?chemical model with some constraints originated from the comprehensive analysis. We then use this model to simulate the coupled processes of the structural deformation, thermal transport, fluid flow and the chemical reaction. The obtained results indicate that the model is efficient in further analyzing the temporal?spatial evolutional trail of the tectonic regime in Jiaodong ore cluster area and in further understanding the nature of the mass metallogensis.     

Mineralizing age of the Rushan lode gold deposit in the Jiaodong Peninsula：SHRIMP U-Pb dating on hydrothermal zircon

Knowledge of the mineralizing timing is fundamen-tal to understand the genesis of mineral deposits, and ex-act time spectrum of mineralization is essential to com-prehending the relationship among the genesis of en-dogenic hydrothermal deposits, regional tectonic-magma-tism event and the geodynamics of mineral deposits. The Jiaodong or eastern Shandong gold province islocated in the southeastern margin of the North Chinacraton, and belongs to the Mesozoic circum-Pacific oro-genic gold system…     

四川联合村金矿地质特征及成因探讨

四川联合村金矿是超微细粒浸染型金矿,矿床位于两个大地构造单元的断层接合部位,特殊的地质环境为矿床的形成提供了丰富的物源,形成了别具一格的矿床地质特征.笔者以地质观察和测试资料为依据,研究认为该矿床是以沉积地层为主要矿源层,以低温弱酸性强还原低盐度的混合流体为搬运介质、以断裂构造控制矿体就位的浅成低温热液矿床.总结的找矿标志对区内找矿具有指导意义.     

胶东半岛新构造东西分异的水系特征统计分析

水系的发育受气候、构造运动和人类活动的显著影响,构造运动状况的差异必然反映在水系特征上。通过对胶东半岛水系的展布方向、水系分形、诸水系特征的统计分析,揭示出水系受新构造运动有较明显的响应,桃村—东陡山断裂是本地区东、西部新构造上的主要分界。     

河南省钼多金属矿集区重磁异常特征及成矿预测

河南省钼矿资源丰富,集中分布于栾川、大别山地区,多与中酸性浅成-超浅成的岩浆侵入关系密切.省内已知的钼矿床多分布于重力低异常区或外围梯级带上,在航磁异常图上,钼多金属矿集区及附近的ΔT异常分布规律性不强,其异常性质及规模受成矿母岩、成矿类型及围岩性质控制.通过总结钼多金属矿集区的重力和航磁异常特征,建立了矿集区的地质、地球物理成矿模式,据此对夜长坪、南泥湖、东沟、涩港、吴陈河、汤家坪等矿集区进行找矿前景分析及成矿预测,认为夜长坪、南泥湖矿集区及新县岩体的东西两侧、商城岩体南侧找矿潜力大.     

Genesis of Carlin-type gold deposits in southwestern Guizhou Province, China

A solution containing nanometer-sized pure gold particles was prepared with the hydrolysisreduction method. As observed under the electron microscope, the gold particles were as large as 2–20 nm in size. Different kinds of mineral and rock were put into the solution and the experimental result showed that the nanometer-sized gold particles are obviously adsorbed on sulfide minerals, native copper and carbonaceous rocks. This experimental result is consistent with the actual geological observation. On this basis a better explanation is presented of the genesis of the Carlin-type gold deposits.     

河南南召水洞岭锌铜矿床的类型及成矿条件

水洞岭锌铜矿床是北秦岭造山带中铜矿远景区的典型黑矿型矿床，形成于二郎坪弧后盆地，时代为早古生代．成矿期间成矿流体以高Ｋ＋／Ｎａ＋、Ｆ－／Ｃｌ－比值和低ＣＯ／ＣＯ２比值为特征；形成温度为１９７～３３０℃，ｆＯ２为３×１０－３１～８．１×１０－３３Ｐａ，形成时的环境压力为７７．９７×１０５Ｐａ，ｐＨ值为５．７３～６．１２（３００℃）．同位素特征显示，成矿物质来源为下伏火山岩，且具有混合硫源（岩浆和海水硫）共同来源，岩浆热液对成矿起了一定的作用     

Indosinian isotope ages of plutons and deposits in southwestern Miaoershan-Yuechengling,northeastern Guangxi and implications on Indosinian mineralization in South China

The Miaoershan-Yuechengling complex pluton is the largest granitoid complex in the western Nanling metallogenic belt with a surface exposure of >3000 km2.The complex pluton is composed of an early stage granitoid batholith and late stage small intrusions.The early stage batholith contains mainly medium-grained porphyritic mica granite and porphyritic monzonite granite,whereas the late stage intrusions are composed of muscovite granite porphyry and muscovite monzonitic granite.There are many W-Sn-Mo-Pb-Zn-Cu ores in the contact zone between the batholith and strata,forming an ore-rich belt around the batholith.Based on zircon LA-ICP-MS U-Pb ages,the southwestern part of the early stage batholith formed at 228.7 ± 4.1 Ma(MSWD = 2.49),with slightly earlier magmatic activity at 243.0 ± 5.8 Ma(MSWD = 2.62).The Yuntoujie muscovite granite was associated with W-Mo mineralization and has a zircon LA-ICP-MS U-Pb age of 216.8 ± 4.9 Ma(MSWD = 1.44).The Re-Os isochron age of molybdenite from the Yuntoujie W-Mo ore was 216.8 ± 7.5 Ma(MSWD = 11.3).Our new isotope data suggest that the late stage intrusive stocks from the southwestern Miaoershan-Yuechengling batholith were closely associated with W-Mo mineralization from the Indosinian period.These new results together with previous isotope data,suggest that South China underwent not only the well-known Yanshanian mineralization event,but also a widespread Indosinian metallogenic event during the Mesozoic period.Therefore,South China has a greater potential for Indosinian mineralization than previously thought such that more attention should be given to the Indosinian ore prospecting in South China.     

鲁西地区铁矿类型特征及成矿谱系

山东省是中国的铁矿资源大省,其中鲁西地区铁矿成矿地质条件优越,铁矿类型有沉积变质型、接触交代型、热液交代充填-风化淋滤型、沉积型、岩浆型等多个成矿类型;其中尤以沉积变质型铁矿、接触交代型铁矿最为重要,是山东省的主要铁矿石来源。在梳理鲁西地区各种类型铁矿时空分布特点、分析典型铁矿床特征、控矿要素及矿床成因的基础上,以地质演化史为轴线,建立了鲁西地区各类型铁矿的成矿谱系。研究表明,在地质演化过程中,鲁西地区铁矿的形成是在海底火山喷发、地层沉积、岩浆侵入、区域变质、构造运动、风化淋滤等地质及成矿作用的高度耦合下形成的一系列地质产物;即在新太古代时期形成了沉积变质型铁矿(如韩旺式、苍峄式、杨庄式和济宁式铁矿)和岩浆型铁矿(如肖家沟式铁矿),在晚石炭世时期形成了沉积型铁矿(如山西式铁矿),在早白垩世时期形成了接触交代型铁矿(如莱芜式、莲子汪式铁矿)和热液交代充填-风化淋滤型铁矿(如朱崖式铁矿)。各种类型铁矿床具有地层控矿、岩体控矿、构造控矿和多要素共同控矿的特点。在铁矿勘查过程中,应按其成因类型和控矿要素进行有针对性的勘查部署,以此促进鲁西地区的铁矿勘查及研究工作整体水平得以提升。     

The Rb-Sr isochron of ore and pyrite sub-samples from Linglong gold deposit, Jiaodong Peninsula, eastern China and their geological significance

Here we report the first direct Rb-Sr dating of pyrites and ores using sub-sampling from lode gold deposits in Linglong, Jiaodong Peninsula, which is a supra-large lode gold deposit and propose this as a useful geochronological technique for gold mineralization with poor age constraint. The Rb-Sr data of pyrites yield an isochron age of (121.6±8.1) Ma, whereas those of ore and ore-pyrite spread in two ranges from 120.0 to 121.8 Ma and from 110.0 to 111.7 Ma. Studies of characteristic of gold deposit and microscopy of pyrite and quartz indicate that the apparent ages of ore and ore-pyrite are not isochron ages, only mixed by two end members, i.e. the primitive hydrothermal fluids and wall rocks, whereas the isochron age of pyrite sub-samples constrains the age of gold mineralization (121.6±8.1) Ma, i.e. early Cretaceous, which is in good agreement with the published SHRIMP zircon U-Pb ages.     

广西大厂矿田拉么锌铜矿床成矿期次和成矿阶段划分

拉么矿床位于大厂矿田中矿带笼箱盖岩体的南西侧,该矿床既存在矽卡岩型锌铜矿化,又存在中~低热液型钨-锑矿化.矽卡岩型锌铜矿化,根据产状特征可分为两组:似层状矿化、脉状矿化;同时可分为三种类型:缓倾斜似层状锌铜矿化,陡倾斜裂隙充填、交代细脉状矿化,以及陡倾斜大脉状矿化.通过坑下地质调研和室内光片鉴定,拉么锌铜矿矿区的成矿作用可划分为两个成矿期、5个成矿阶段:①矽卡岩型锌(铜)矿成矿期,包括早期硫化物阶段(铁铜矿阶段)、晚期硫化物阶段(铅锌矿阶段);②钨-锑成矿期,包括星散浸染状白钨矿矿化阶段、星散浸染状辉锑矿矿化阶段、脉状辉锑矿-方解石矿化阶段.     

衡阳盆地及周缘铜多金属矿成矿系列与找矿新突破

衡阳盆地大地构造处于华南板块与扬子板块相结合的钦-杭成矿带西段,属钦杭成矿带中部与南岭东西向构造-岩浆-成矿带中段北缘交汇区。铜多金属矿床均分布在中新生代断陷盆地中及周边,其受区域上构造演化特定时期断陷盆地控制下的统一构造岩浆(火山)热液活动的制约,与深大断裂及其交会区强烈的构造-岩浆(火山)热液活动密切相关,主成矿时代为中-新生代。厘定了衡阳盆地内以铜为主的矿床成矿系列,共划分2个成矿系列组合,6个成矿系列,13个成矿亚系列。成矿规律和找矿新突破表明：区内铜多金属矿找矿方向应集中于岩体外接触带、深大断裂交汇部位、斑岩体顶部、不整合面和岩性转换部位。