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1.
《资源调查与环境》2016,(4):246-251
江西省铅山县中二叠统车头组硅质岩内见夹多层凝灰岩。通过研究该凝灰岩锆石U-Pb年龄及Lu-Hf同位素组成特征,探讨该区海底火山喷流活动的时间、成岩环境及成岩物源。凝灰岩的LA-ICP-MS锆石U-Pb加权平均年龄为264.8±4.4Ma,表明其形成环境为大陆边缘拉张性台盆环境,作为直接地质证据说明这一时期存在海底火山喷发活动。凝灰岩的Lu-Hf同位素二阶段模式年龄为1170~1670Ma(平均值1320 Ma),为中元古代,代表了成岩物源可能与区域性地壳重熔增生有关。  相似文献   

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扬子板块东北缘存在四条主要的中元古代变质带,自南向北依次为江南变质带、沿江变质带、云台-张八岭变质带和连云港-泗阳变质带.它们分别为中元古代的古弧后盆地、火山岛弧、裂谷及弧前盆地,扬子板块东北缘中元古代为活动大陆边缘构造体系.苏(北)胶(南)变质造山带应解体,其中一部分属扬子大陆边缘体系.  相似文献   

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华南板块的构造格局与太平洋板块和印度板块的共同作用相关.华南板块中,由于绍兴-鹰潭-藤县-北海断裂带内中元古代蛇绿混杂岩的确认并恢复为消减的大洋,其两侧古老的扬子地块和华夏地块及其演化历史的追溯也日见清晰.它们是在两个克拉通地块基础上发展起来的.1998年在浙江省龙游首次发现的原生金刚石,产于这条深断裂旁侧白垩纪盆地中的似金伯利岩岩管内,含矿岩管生成深度大,构造部位有利;金刚石呈八面体外形、纯度高;类似的岩管有100多个,但研究程度较低,因而具有良好的找矿前景.  相似文献   

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亚洲东南地区在西伯利亚板块与塔里木—中朝板块之间有天山(北天山)-兴安地槽褶皱带;在塔里木-中朝板块与杨子板块之间有秦岭-大别褶皱带(东部);扬子板块与华南板块之间有赣(东北)-浙(西)-皖(南)对冲带。东部沿海地区北北东向滨太平洋板块则横切以上近东西向和北东向诸板块,展现出太平洋西海岸最新板块的格局。各板块对接带上发育开阔和长期发展的火山-侵入岩带。不同类型的火山-侵入岩有不同的矿产:金(铜铅锌)多与中-基性火山-侵入岩有关;铜铅锌、锡(钨);铁多与中-酸性火山-侵入岩有关;铜镍多与基性、超基性侵入岩有关。  相似文献   

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利用地球物理参数块体填图并结合地表资料,推断浙东南中生代火山岩覆盖层下的中深部构造特征:变质基底呈东西向展布,为早元古代华夏板块的一部分。其后,发展为浙西钱塘裂陷槽、华夏古陆和沿海裂隙槽,进而形成巨形花岗岩环、中生代酸性火山岩以及沿NW向深断裂活动的双峰式火山岩。现尚处于脉动式裂解,蠕散的初级阶段。因此,构造活动非常活跃。  相似文献   

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通过研究福建龙海深澳变质岩岩石学、岩石地球化学、锆石U-Pb同位素年代学特征,探讨研究区变质岩的源岩、原岩和构造动力变质的年代学特征及其地质意义。结果表明该区变质岩属副变质岩,原岩为火山—沉积岩类。锆石U-Pb同位素定年的结果主要有:(1)1572±39 Ma及2149±39 Ma,为中元古代和古元古代基底的区域变质年龄;(2)248.1±8.1Ma及250.4±2.4Ma,为早、晚三叠世火山—岩浆年龄;(3)186.4±6.6 Ma,为早侏罗世火山—沉积岩形成年龄;(4)156.7±2.0Ma,为晚侏罗世韧性剪切变形、变质形成二云石英糜棱岩或片岩的峰期年龄。  相似文献   

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本文讨论了云南易门狮山铜矿床的地质背景、含矿建造、火山岩及矿床地质地球化学特征。成矿地质背景为中元古代后期的裂陷槽。含矿建造为火山沉积黑色页岩碳酸盐含铜建造。胶状、变胶状黄铁矿及黄铜矿砂状碎屑构造是矿床同生成因的新证据。建立了海底喷气沉积矿床成因模式,论述了狮山铜矿床的成矿作用。  相似文献   

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在对西秦岭重点地区地质建造、结构构造等研究基础上 ,结合前人工作成果 ,对西秦岭造山带地质结构、构造演化及成矿作用等提出了新的认识 ,包括 :1,首次对前人在西秦岭北带厘定的晚泥盆世磨拉石地层 -大草滩群 (D3dc)进行分解 ,认为它是晚泥盆世滨浅海相砂岩、粉砂岩及碳酸盐岩在不同地段分别逆冲到二叠系、侏罗系及白垩系之上所形成的岩片叠置体系。并根据构造解析的原则 ,结合区域地层结构 ,将西秦岭北带构造 -地层体划分为三个单元 ,即上古生界 -中生界表构造层次准原地系统、古生界浅构造层次推覆岩片及元古界中深构造层次推覆岩片 ,它们相互叠置而成的西秦岭北带的岩片堆垛体系 ;2 ,对西秦岭西成矿田的研究表明 ,西成矿田的容矿地层不仅包括泥盆系 ,而且还包括元古宇 ,其中最大的矿床 -厂坝 -李家沟超大型铅锌矿床产于元古宇而不是泥盆系 ,西成矿田是后生热液矿床而不是海底喷流沉积矿床 ,它的形成完全受元古宇构造岩片由西向东的逆冲 -推覆及其所造成一系列构造效应所控制 ;3 ,西秦岭南带勉略构造带为一构造走滑体系 ,产于勉略带的蛇绿岩与产于勉略宁地块内部的蛇绿岩是同一时期、同一构造背景的产物 ,为中新元古代板快构造演化的记录 ,在南秦岭 ,不存在可靠的晚古生代蛇绿岩  相似文献   

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新疆地处世界三个巨型银成矿带中两个成矿带的文汇部位,西伯利亚板块、准噶尔-哈萨克斯坦板块和塔里木板块以及伊犁微板块碰任产生的三条碰撞带都经过北疆地区,因而,该区火山-侵入活动强烈,断裂构造发育,银的区域背景值高,这些对银成矿均有利。近几年发现了一批银矿点和矿化带,构成数个银矿化密集区。这些密集区与火山-侵入活动密切相关。表明北疆地区有很好的银成矿前景。  相似文献   

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华东地区前寒武纪主要地质事件及构造演化   总被引:3,自引:0,他引:3  
通过对地层分区与板块构造关系的分析,依据华东地区前寒武纪地质事件主要特点及划分原则.在充分了解现代构造观和基本地质事实基础上,建议将华东地区“晋宁运动二幕”改为“休宁上升‘”;“栏杆运动”和“霍丘运动”改为“栏杆上升”和“霍丘上升”.因为它们不具备造山运动性质。通过对新太古代末蚌埠运动、古元古代末龙川运动、迪口运动,中元古代末凤阳运动、青白田纪内部神功运动的特点分析,认为区内经历了新太古代陆核的生成;占元占代褶皱变质和混合岩化;凤阳运动和神功运动造成了华北古板块、扬子古板块和华夏古板块的拼合等演化阶段;并发生了四次造山运动和三次裂陷运动。  相似文献   

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<正>"我们处在世界正在发生重大变革的时代,中国也正在实现着民族伟大复兴的关键时刻。青年人要承担什么责任?""我们应该团结更多的青年人,向全社会积极宣传环保理念,保护我们共同生存的家园。"一名青年使者刚刚回答完贾峰主任的问题,全场响起的是掌声——雷鸣般的掌声!8月17日,2015年"千名青年环境友好使者夏令营"在成都市温江区正式开营。环境保护部宣传教育中心主任贾峰亲临现场,并为青年学子们讲授了热情  相似文献   

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Types of asbestos are distinguished not only by structure, chemical compositon, shape of aggregates, and length and quality of fibers, but also by its formation. Though consisting of quite common elements, deposits are formed only under very special conditions. Its unique combination of properties has created over 3000 fields of application (about 70% in asbestos cement). Great efforts have been made to substitute all types of asbestos by harmless, similarly cheap and versatile synthetic fibers, owing to the unquestioned carcinogenic properties of all asbestos dusts. However, development of such fibers has not made any remarkable progress until recently. Consequently risk to workers in mining and manufactoring, consumers, outsiders, and the environment should be kept as low as possible by intensifying precautions and diminishing emissions.  相似文献   

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This work was conducted to evaluate whether Ca-bearing additives used during coal combustion can also help with the retention of some other elements. This work was focused on the evaluation of bottom ashes collected during four full-scale combustion tests at an operating thermal fluidized-bed power station. Bottom ashes were preferred to fly ashes for the study to avoid interference from condensation processes usually occurring in the post-combustion zone. This work focused on the behaviors of S, Cl, Br, As, Mn, V, Cr, Ni, Cu,Zn, W, and Pb. Strong positive correlations with CaO content in bottom ashes were observed(for all four combustion tests) for S, As, Cl and Br(R = 0.917-0.999). Strong inverse proportionality was calculated between the contents of Pb, Zn, Ni, Cr and Mn and CaO, so these elements showed association to materials other than Ca-bearing compounds(e.g., to aluminosilicates, organic matter, etc.). Somewhat unclear behaviors were observed for W, Cu, and V. Their correlation coefficients were evaluated as statistically "not significant", i.e., these elements were not thought to be significantly associated with CaO. It was also discovered that major enrichment of CaO in the finest bottom ash fractions could be advantageously used for simple separation of elements strongly associated with these fractions, mainly S and As, but also Cl or Br. Removal of5% of the finest ash particles brings about a decrease in As concentration down to 77%-80% of its original bulk ash content, which can be conveniently used e.g., when high As content complicates further ash utilization.  相似文献   

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我们曾对从意大利收集的金枪鱼、箭鱼、普通鸬鹚以及家燕体内的p,p'-DDE、多氯联苯同类物(PCBs)、多氯二苯-p-二恶英(PCDDs)、多氯二苯并呋喃(PCDFs)以及多氯萘(PCNs)浓度进行过测量.  相似文献   

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In this paper, we present an overview of guidelinesdeveloped for the monitoring, evaluation, reporting,verification, and certification (MERVC) ofenergy-efficiency projects for climate changemitigation. The monitoring and evaluation ofenergy-efficiency projects is needed to determine moreaccurately their impact on greenhouse gas (GHG)emissions and other attributes, and to ensure that theglobal climate is protected and that countryobligations are met. Reporting, verification andcertification will be needed for addressing therequirements of the Kyoto Protocol. While the cost ofmonitoring and evaluation of energy-efficiencyprojects is expected to be about 5–10% of a project'sbudget, the actual cost of monitoring and evaluationwill vary depending on many factors, including thelevel of precision required for measuring energy andGHG reductions, type of project, and amount of fundingavailable.  相似文献   

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In order to say something substantial about the fundamental limits of machines (especially of computers) and of human calculations, we must explicate the concept of algorithm. Such an explication is provided by the Turing machine. Thus, problems have been discovered which cannot be solved algorithmically. For other problems there are problem-solving procedures, but no elegant algorithms. That men are fundamentally superior to machines has not been shown as yet.  相似文献   

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