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721.
复合成矿系统理论:揭开西南特提斯成矿之谜的关键   总被引:2,自引:1,他引:1  
邓军  王长明  李龚健  周道卿 《岩石学报》2019,35(5):1303-1323
本文总结了"三江特提斯复合造山与成矿作用"和"中国西南特提斯典型复合成矿系统及其深部驱动机制"两轮国家重点基础研究发展规划项目研究进展及其重大突破,主要内容包括以下四个方面:(1)构建了西南特提斯从原特提斯、古特提斯、中特提斯到新特提斯增生-碰撞造山演化模式,揭示复合造山与构造体制转换机制;(2)创建复合成矿系统理论体系,揭示复合造山带巨量金属富集机理。通过对西南特提斯成矿域典型矿床系统剖析,厘定了增生造山海底喷流型Cu-Pb-Zn-Ag、增生-碰撞造山岩浆热液型Cu-Mo-Sn-W、碰撞造山盆地卤水-热液型Pb-Zn-Ag-Cu和碰撞造山斑岩-矽卡岩型Au-Cu-Mo四类复合成矿系统;(3)通过同位素地球化学、地球物理场和成矿系统等综合研究,分析了西南特提斯岩石圈结构以及大规模成矿作用,解析深部动力学机制和成矿机制;(4)构建矿床成因模式和勘查模型,理论指导找矿取得突破。  相似文献   
722.
在收集甘肃北山和金川地区与铜镍硫化物矿床有关的超基性岩数据的基础上,与GEOROC和PetDB两个数据库中的全球板内超基性岩数据进行对比,发现甘肃北山、金川地区与铜镍有关的超基性岩与全球板内超基性岩各元素平均值较接近(除稍富集LILE之外),而北山地区以高的Th/Nb和富集HREE与金川区分,同时Cu、Cs、Nb、Ta、Rb/Nb、CaO/REE等元素或元素比可作为甘肃北山和金川地区超基性岩是否含矿的重要地球化学标志。皮尔逊相关系数研究表明,虽然甘肃北山和金川地区与铜镍硫化物矿床有关的超基性岩的产出位置、形成时代及源区特征均不同,但是具有很高的地球化学相关性,而WPU(板内超基性岩)与WPUT(大陆溢流、大陆裂谷和板内超基性岩合并)及WPU中坐标值相近的数据相关性较差。WPUT内部本身相似性极差,但其平均值却与甘肃北山和金川地区的超基性岩相似性极高。同时,笔者选取了白石泉、石西、葫芦、黄山东等26个与铜镍硫化物矿床有关的超基性岩数据,与甘肃北山、金川铜镍硫化物矿床有关的超基性岩数据进行比对,整体显示出极高的相关性。因此我们推断与铜镍硫化物矿床有关的超基性岩在形成过程中虽受到其他地质作用的改造,但总体上具相似的地球化学特征。  相似文献   
723.
通过总结福建省南靖县南坑钼矿床的地质特征,认为该钼矿床为斑岩型钼矿床,钼矿体主要赋存于燕山早期花岗岩与文宾山组接触带,主要产在燕山早期花岗岩体内,受缓倾斜的石英脉和网脉状石英细脉控制,矿石类型为石英粗脉型和石英细脉型。该钼矿床具有弱磁异常,原生晕、次生晕异常发育,钼次生晕异常在深部见矿效果较好;与钼矿体关系密切的蚀变主要有云英岩化和硅化,找矿标志主要为燕山早期花岗岩、白楼—下楼断裂带、晚三叠世文宾山组、云英岩化、硅化及物化探异常,以上认识对区域寻找类似钼矿床具有参考价值。  相似文献   
724.
The significance of stromatolites as depositional environmental indicators and the underlying causes of lamination in the lacustrine realm are poorly understood. Stromatolites in a ca 600 m thick Miocene succession in the Ebro Basin are good candidates to shed light on these issues because they are intimately related to other lacustrine carbonate and sulphate facies, grew under variable environmental conditions and show distinct lamination patterns. These stromatolites are associated with wave‐related, clastic‐carbonate laminated limestones. Both facies consist of calcite and variable amounts of dolomite. Thin planar stromatolites (up to 10 cm thick and less than 6 m long) occurred in very shallow water. These stromatolites represented first biological colonization after: (i) subaerial exposure in the palustrine environment (i.e. at the beginning of deepening cycles); or (ii) erosion due to surge action, then coating very irregular surfaces on laminated limestones (i.e. through shallowing or deepening cycles). Sometimes they are associated with evaporative pumping. Stratiform stromatolites (10 to 30 cm high and tens of metres long) and domed stromatolites (10 to 30 cm high and long) developed in deeper settings, between the surge periods that produced hummocky cross‐stratification and horizontal lamination offshore. Changes in stromatolite lamina shape, and thus in the growth forms through time, can be attributed to changes in water depth, whereas variations in lamina continuity are linked to water energy and sediment supply. Growth of the stromatolites resulted from in situ calcite precipitation and capture of minor amounts of fine‐grained carbonate particles. Based on texture, four types of simple laminae are distinguished. The simple micrite and microsparite laminae can be grouped into light and dark composite laminae, which represent, respectively, high and low Precipitation/Evaporation ratio periods. Different lamination patterns provide new ideas for the interpretation of microbial laminations as a function of variations in climate‐dependent parameters (primarily the Precipitation/Evaporation ratio) over variable timescales.  相似文献   
725.
Subsequent to an initial wet season flood event in the Brisbane River, Australia, both fast (naked disk) and slow (membrane-covered) variants of SDB-RPS Empore disk passive sampling devices were deployed with an automated grab sampling program. A trend increase in the aquatic dissolved concentrations of diuron and simazine was observed over a 10-day period. Kinetic and equilibrium parameters for each sampler were calculated based on the dynamic concentration. Absolute percent difference for duplicate passive samples was <10% in the fast and <25% in the slow samplers. For kinetic sampling, significantly shortened integrative periods are available with the fast compared with the slow variant, with higher sampling rates offering improved detection limits. The study demonstrates a method for determining kinetic parameters of passive samplers in a variable concentration field deployment, and illustrates the differences in quality between active and passive data, in terms of capturing changes in concentration associated with rainfall events.  相似文献   
726.
通过估计中国农村居民收入分配的lorenz曲线测算了2006、2007年中国农村贫困和收入不平等的状况,并运用shapley分解法对贫困指数的变动进行分解,分析物价水平、经济增长、收入分配对贫困变化的影响。研究结果表明:(1)2007年农村贫困发生率较2006年有所下降,但下降速度比较缓慢;(2)农村居民的收入差距逐渐在拉大,收入不平等程度有所加重;(3)经济增长减缓了农村贫困,但由于物价水平的上涨和收入分配的恶化,贫困人口整体的贫困状况不轻反重。  相似文献   
727.
With the rapid urbanization in Shanghai, China, suitable fill materials have been reported to be in great shortage in recent years. A prospective solution to these issues is to convert the huge amount of existing dredged marine soils to construction materials via solidification. However, there have been no studies on the shear behavior of solidified dredged materials from Shanghai region so far, while it has been reported by various researchers that the available data obtained from certain types of clay cannot be confidently and readily applied to other types of soils. To address this challenging issue, in this article, samples of Shanghai marine dredged soils were retrieved from the world’s largest reclamation project in Shanghai Lin-gang New City. A series of laboratory tests have been conducted to investigate the shear behavior of Shanghai dredged marine soils solidified using a new composite curing agent made of cement and lignin. The test results and the effect of this cement–lignin agent on the shear behavior of Shanghai marine soils, including the stress–strain behavior, shear strength properties, and failure characteristics are presented and discussed, which can provide valuable reference for the use of dredged soils as construction materials in the Shanghai region.  相似文献   
728.
随着经济体制的转变,经济的转型已成为促进发展中国家城市发展的重要因素。为了解城乡地域结构的转变特点和影响因素,本研究多角度量化了宁波市城乡结构的发展与经济转型的关系。提出量化城乡地域结构的指标体系:土地利用面积与景观格局的变化,并提出衡量经济转轨的角度:全球化、去行政化以及市场化。结果表明:城市地区受市场化和行政分权政策影响,整体景观格局趋于破碎化、不规则化。乡村地区由于财政分权,整体格局呈现破碎化和单一化。城市建筑用地扩张受市场化和全球化影响,农田的减少与市场化政策有关。本研究得到了不同城市规划区域对经济转型的响应形式,为政策制定提供建议。  相似文献   
729.
The most prominent ‘victim’ of the global financial crisis in 2007/2008 has been Greece, which is, even now, in the middle of an economic and social storm that is threatening its economic and social cohesion and its membership of the Eurozone. Using the social well-being conceptual framework as a benchmark and exploiting the literature of composite indicators, the paper aims to assess and measure the regional impact of the crisis in a systematic and comprehensive way. Differing from most of previous studies, both at national and international levels, this study is based on the assumption that the effects of the crisis go far beyond economics and create a social crisis strongly associated with significant human and social costs that might transform Greece’s regional status and threaten its regional well-being, probably in a very unequal way. The main finding of the analysis is that although all regions were severely affected by the dynamics and intensity of the crisis, some regions were more affected than others, leading to ‘winners’ and ‘losers’. From a policy point of view, the results of this study have serious implications for crisis management, recovery policy actions and a country’s social cohesion, especially in Greece where austerity policy measures not only imposed considerable cutbacks in regional development policies but also ignored the spatial dimension of the crisis.  相似文献   
730.
Territorial cohesion is a concept that is generating growing interest in both the academic-scientific and political arenas. This paper presents an approach to the analysis of territorial cohesion and, more specifically, proposes a definition of the concept and its dimensions in order to empirically test the approach on the Colombian departmental model. To this effect, a methodology was designed that, by using Data Envelopment Analysis (DEA) to calculate composite indices, measures and evaluates the level of territorial cohesion in Colombian departments from a multidimensional and integrative perspective, and identifies the factors that influence that cohesion. The results could provide useful data for policy makers in the design of public policies to influence factors that facilitate more balanced and inclusive territorial development. This is especially relevant in light of the recent signing and ratification of the Peace Agreement in November 2016, given that the Colombian Government is currently in the process of designing policies that have the potential to promote cohesion within its territories.  相似文献   
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