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西昆仑山构造格架与成矿堆积环境 总被引:2,自引:1,他引:2
本文在对西昆仑山广布的岩浆岩尤其是风岗岩研究取得的成果基础上,结合区域构造、沉积建造等其它地质特征,再造了西昆仑山地质构造发展历程,进而研究了区内成矿堆积环境及其矿床地质特征。结果表明,昆仑山经历了复杂的地质构造演化,是一条由北而南分别由加里东造山带、华力西造山带和燕山早期造山带组成的复合型造山带。区内存在以下5种主要成矿堆积环境:洋脊(蛇绿岩)成矿堆积环境(塞浦路斯型含铜黄铁矿矿床,豆莱状铬、镍矿床),被动陆缘成矿堆积环境(MVT铅锌矿床,Sedex型铅矿成床),火山弧成矿堆积环境(斑岩型铜矿床,黑矿型铜锌铅矿床,矽卡岩型铜铅锌多金属矿床),弧后盆地成矿堆积环境(海底火山喷发沉积型铁铜金矿床,气液充填型铜金铁矿床)和同碰撞成矿堆积环境(伟晶岩型稀有金属矿床,伟晶岩型多金属银矿床)。 相似文献
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20多年来,中国海陆及邻域的地质地球物理调查在不断进步,尤其是海域取得很多新认识,但中国海陆及邻域的大范围编图,尤其是大地构造图,没有随之更新;中国海陆的编图还一直存在海陆不接、海域编图相比陆域落后的问题;亟需编制一幅中国海陆及邻域的大地构造图.1992年编制的"中国海域及邻区地质地球物理系列图"的大地构造图,运用以活动论为内涵的全球构造理论作为指导思想,对中国海区及邻域的大地构造特征做出了较好的诠释.最近,中国海陆地质地球物理系列图编制项目,把1:500万中国海陆及邻域大地构造格架图作为图种之一.在全球构造理论基础上发展而来的块体构造学说,作为本次编图的指导思想,根据其大地构造体系,板块和板块边界作为一级构造单元,块体和结合带(缝合带等)作为二级构造单元,结合系列图中重力图、磁力图、地质图等图件成果,以及最近的其他调查研究资料,完善了对特提斯在南海周边的界线、东海陆架的基底构造属性等认识,在研究区内共划分出了欧亚板块、菲律宾海板块和印度—澳大利亚三大板块,6个板块边界构造单元,30个块体、14个结合带和10个缝合带. 相似文献
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渤海、黄海和东海等中国东部海域在地质构造上是大陆向海的自然延伸,海域内的构造方向与大陆一致,均为NNE-NE向,但属于不同的二级大地构造单元,渤海和北黄海属于华北地块,南黄海属于扬子地块,东海属于华南地块。由于各地块与现今活动板块边界位置不同,构造与地震活动性差异较大,渤海和北黄海地区地震活动主要受印度板块与欧亚板块碰撞形成的东喜马拉雅构造节远场效应影响,地震活动强烈;南黄海地区以中强地震活动为主;东海地区地震活动主要受菲律宾海板块与欧亚板块碰撞形成的琉球俯冲带影响。冲绳海槽是正在形成的(活动的)边缘海盆地,不仅有浅源地震,且有中源地震活动。东海陆架盆地由于受冲绳海槽扩张的影响,停止发育,构造与地震活动相对较弱。 相似文献
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近几十年来,对月球的遥感观测以及对月岩样品的分析揭示了月海玄武岩、镁铁质月球玻璃等的时间和空间分布特征,其被认为与月幔的热化学演化密切相关,并且引出了许多解释模型.本文考虑月球结晶末期在上部形成的致密的钛铁矿层和下部的月幔,由于密度原因钛铁矿层发生倒转,之后受热上涌产生玄武质岩浆等的演化过程,从热化学演化的角度为月海玄武岩、月球玻璃等的形成提供了一种可能的机制.然而,上述演化过程时间尺度和形态结果很大程度上是由月球内部生热决定的.我们使用包括月核演化的三维月幔对流模型来研究不同生热元素丰度对月幔倒转和之后火山喷发的影响效果,我们的模型揭示了不同的内部生热将会保持相似的演化模式,但会改变热化学演化的时间,同时结果表明,在月幔参考黏度为1×1021Pa·s的情况下,在3.9 Ga集中喷发月海玄武岩要求月球的生热元素丰度至少与地球相当.
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依据克莱门汀号和月球勘探者号月球探测器所获得的数据所建立最新的地球重力模型和地形模型,为人类深入了解月球内部性质及其演化特征,提供新的平台.M.T. Zuber (1994) 和 M. A. Wieczorek (1998) 所建立的月壳全球模型,为利用最新月球着力资料研究月球内部构造和演化,揭示月球上独特的“物质瘤”之成因等科学问题,开凿了先河.本文通过对现有的月球重力和地形数进行分析和计算,提出作者对月球内部物质分布特征的理解和一些认识.从宏观角度看,月球布格重力异常与月球地形起伏是相关的,统计结果表明它们呈弱负相关,从均衡角度来说,在月球停止大规模内部物质运动之前,月球壳幔可能已基本达到均衡;从Mascon深度估算结果来看,一些大型的Mascon基本属于玄武岩浆“充填”型的,少数Mascon可能与月幔柱有关,如东方海Mascon. 相似文献
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抚顺盆地构造演化动力学研究 总被引:5,自引:1,他引:5
研究表明,抚顺盆地基底的裂陷作用并非一种短暂的“瞬间拉张”过程,而是由弱渐强且在古城子组沉积期达到极点,随后迅速减弱并停止;拗陷作用也非裂陷后才发生的,两者基本上同时开始;拗陷作用一开始就具有较高的速率,直至西露天组沉积期才逐步减弱,并延续到耿家街组沉积期.抚顺盆地的构造演化经历了6个阶段:慢速裂陷和快速拗陷→加速裂陷和快速拗陷→快速裂陷和快速拗陷→减速裂陷和快速拗陷→裂陷终止和减速拗陷→慢速拗陷和拗陷终止.构造演化的结果形成了很具特色的 “下断上拗”结构.这种二元结构的形成,可能起因于区域构造应力场转变造成裂陷作用中断,而拗陷作用仍在继续.采用同沉积构造格架分析、基底沉降史反揭和热衰减模拟相结合的方法,计算出“上拗”部分所需的巨大沉积空间,40%来自于下伏沉积物的压实,60%来自于盆地基底的长期低速拗陷.拗陷作用的终止,可能是渐新世初期新一轮深部热事件及其伴随的巨厚辉绿岩床侵入,导致岩石圈热衰减和重力均衡调整的逆转. 相似文献
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The updated study shows that the taphrogenesis of basement of the Fushun Basin is not a kind of instantaneous process. It intensified gradually and went to extreme in the sedimentary stage of the Guchengzi formation, and then, it weakened rapidly and stopped soon afterwards; the depression did not take place after the taphrogenesis. On the contrary, it almost happened simultaneously with the taphrogenesis. The depression went at a high speed from the beginning of the sedimentary period of the Xilutian formation, and then weakened gradually in the sedimentary period of the Gengjiajie formation. The evolution course of the synsedimentary structure of the Fushun Basin can be summarized as the following six stages: slow taphrogenesis and high speed depression to accelerated taphrogenesis and high speed depression to high speed taphrogenesis and high speed depression to retarded taphrogenesis and high speed depression to gradual halt of taphrogenesis and reduced depression to slow depression and gradual halt of depression. The tectonic evolution resulted in the formation of the "lower taphrogenesis and upper depression" structure. The formation of the binary structure might be due to the suspension of taphrogenesis and the change of the regional structure stress field, but the depression kept going. The result of calculation combining the analysis of the synsedimentary structural frame, the back-stripping method of the subsidence history of the basin basement and the simulation of thermo-settlement history indicates that the great sedimentary space required by the "upper depression part" consists of two parts, namely, 40% from compaction of sediments and 60% from slow depression of the basin basement during a long period of time. Gradual halt of the depression in the Fushun Basin may be attributed to the reversal of the lithosphere hot-recession and gravity isostasy adjustment which may be the result of new hot-events in the depths and accompanied invasion of extremely thick diabase sill, thus revealing a new forming mechanism of "fault subsidence at the base and depression on the top" structure. 相似文献
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Texture and tectonic attribute of Cenozoic basin basement in the northern South China Sea 总被引:1,自引:0,他引:1
SUN XiaoMeng ZHANG XuQing ZHANG GongCheng LU BaoLiang YUE JunPei ZHANG Bin 《中国科学:地球科学(英文版)》2014,57(6):1199-1211
Based on the drilling data,the geological characteristics of the coast in South China,and the interpretation of the long seismic profiles covering the Pearl River Mouth Basin and southeastern Hainan Basin,the basin basement in the northern South China Sea is divided into four structural layers,namely,Pre-Sinian crystalline basement,Sinian-lower Paleozoic,upper Paleozoic,and Mesozoic structural layers.This paper discusses the distribution range and law and reveals the tectonic attribute of each structural layer.The Pre-Sinian crystalline basement is distributed in the northern South China Sea,which is linked to the Pre-Sinian crystalline basement of the Cathaysian Block and together they constitute a larger-scale continental block—the Cathaysian-northern South China Sea continental block.The Sinian-lower Paleozoic structural layer is distributed in the northern South China Sea,which is the natural extension of the Caledonian fold belt in South China to the sea area.The sediments are derived from southern East China Sea-Taiwan,Zhongsha-Xisha islands and Yunkai ancient uplifts,and some small basement uplifts.The Caledonian fold belt in the northern South China Sea is linked with that in South China and they constitute the wider fold belt.The upper Paleozoic structural layer is unevenly distributed in the northern South China.In the basement of Beibu Gulf Basin and southwestern Taiwan Basin,the structural layer is composed of the stable epicontinental sea deposit.The distribution areas in the Pearl River Mouth Basin and the southeastern Hainan Basin belong to ancient uplifts in the late Paleozoic,lacking the upper Paleozoic structural layers.The stratigraphic distribution and sedimentary environment in Middle-Late Jurassic to Cretaceous are characteristic of differentiation in the east and the west.The marine,paralic deposit is well developed in the basin basement of southwestern Taiwan but the volcanic activity is not obvious.The marine and paralic facies deposit is distributed in the eastern Pearl River Mouth Basin basement and the volcanic activity is stronger.The continental facies volcano-sediment in the Early Cretaceous is distributed in the basement of the western Pearl River Mouth Basin and Southeastern Hainan Basin.The Upper Cretaceous red continental facies clastic rocks are distributed in the Beibu Gulf Basin and Yinggehai Basin.The NE direction granitic volcanic-intrusive complex,volcano-sedimentary basin,fold and fault in Mesozoic basement have the similar temporal and spatial distribution,geological feature,and tectonic attribute with the coastal land in South China,and they belong to the same magma-deposition-tectonic system,which demonstrates that the late Mesozoic structural layer was formed in the background of active continental margin.Based on the analysis of basement structure and the study on tectonic attribute,the paleogeographic map of the basin basement in different periods in the northern South China Sea is compiled. 相似文献
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赣南区域地质构造特征与地震分布关系研究 总被引:2,自引:0,他引:2
利用赣南地区的基础地质资料,分析了该区域在大受力背景下的应力调整方式。赣南新构造运动特征明显。NNE向,NW向及EW向构造体系受近东西向应力场作用在局部形成应力集中,并在多组构造交接复合处释放;新构造在对老构造的改造复合过程中,构造带上岩石常处于强烈破碎状态。积聚不了大的能量。因而不太可能发生较大(Ms≥6.0级)地震。 相似文献
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Preliminary study on weathering and pedogenesis of carbonate rock 总被引:23,自引:0,他引:23
Shijie Wang Hongbing Ji Ziyuan Ouyang Dequan Zhou Leping Zhen Tingyu Li 《中国科学D辑(英文版)》1999,42(6):572-581
South China is the largest continuous distribution area of carbonate rock in the world. The origin of the soils over the bedrock
carbonate rock has long been a controversial topic. Here further exploration is made by taking five soil profiles as examples,
which are developed over the bedrock dolomitite and limestone and morphologically located in upland in karst terrain in the
central, west and north Guizhou as well as west Hunan, and proved to be the weathering profiles of carbonate rock by the research
results of acid-dissolved extraction experiment of bedrock, mineralogy and trace element geochemistry. Field, mineralogical
and trace element geochemical characteristics of weathering and pedogenesis for carbonate rock are discussed in detail. It
is pointed out that weathering and pedogenesis of carbonate rock are important pedogenetic mechanisms for soil resources in
karst area, providing a basis for further researches on the origin of soils widely overlying bedrock carbonate rocks in South
China.
Project supported by the National Natural Science Foundation of China (Grant No. 498330003) and National Key Basic Research
Project (Grant No. 95pre-39). 相似文献
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2001年印度布季7.8级大震与日月同纬效应 总被引:3,自引:1,他引:3
2001年1月26日位于印度西海岩的布季发生了7.8级大震,根据天文资料可知,2001年是日月同纬或近于日月同纬之年,用日月同纬效应讨论了布季地震的发震时间。许多震例表明日月同纬之年在北回归线上有发生大震的可能,而且发震时间多在夏季和冬季。 相似文献
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黑龙江及邻区地壳应力场初步研究 总被引:1,自引:0,他引:1
采用综合震源机制方法,利用5 002条P波极性数据反演黑龙江地区二维应力结构,求得该区0.5°×0.5°综合震源机制解.初步研究表明:21世纪以来,构造应力场总特征基本一致,具有明显的继承性,主压应力和主张应力的优势方向明显,与板块运动关系具有成因上的联系. 相似文献
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Introduction Analyzing tectonic stress field based on focal mechanism data is an important way to the study tectonic evolvement of lithosphere and associated dynamic process. Such studies growrapidly in China and abroad (Zoback, 1992; Plenefisch, Bonjer, 1997; XU, 1985; CUI, XIE, 1999). At present most of the studies focus on the inversion of focal mechanism data for the direction and relative magnitude of stress tensor, and few on absolute stress. Using focal mechanism and fault scratch,… 相似文献