武夷山新元古代蛇绿混杂岩岩石地球化学特征   总被引：5，自引：0，他引：5       下载免费PDF全文

王淼  舒良树 《中国地质》2007,34(4):572-583

岩石地球化学研究表明,华南造山带东段武夷山新元古代蛇绿混杂岩中的玄武岩和安山岩可以分为两种类型:一种为拉斑玄武岩类,TiO2含量为2.26%～2.59%(平均2.43%),轻稀土元素比重稀土元素富集,(La)N/(Yb)N=6.4～9.4(平均7.8),相对富集Nb、Ta和Ti,微量元素特征类似于洋岛玄武岩;另一种岩石属于钙碱系列,TiO2含量为0.69%～0.93%(平均0.83%),表现为轻稀土元素富集,(La)N/(Yb)N=4.2～12.6(平均8.4),略显Eu负异常,并以低Nb、Ta、Ti等元素为特征,富集Ba、Rb、Th、K等大离子亲石元素,具有岛弧玄武岩的特征,属于俯冲作用的产物。蛇绿混杂岩中这两类岩石共生,记录了扬子地块和华夏地块之间古大洋消减闭合和弧-弧碰撞拼贴的历史。  相似文献   

昆仑造山带晚泥盆世沉积特征及构造古地理环境   总被引：6，自引：4，他引：6  

陈守建  李荣社  计文化  赵振明  孟勇  史秉德 《大地构造与成矿学》2007,31(1):44-51

昆仑造山带基本构造-地层格架奠基于古生代,晚泥盆世是加里东造山旋回和华力西造山旋回转换的关键阶段,加里东碰撞造山和其后的伸展裂陷等记录均存在于晚泥盆世沉积地层中。西昆仑晚泥盆世奇自拉夫组为一套紫红色碎屑岩沉积,属典型的碰撞造山型磨拉石建造,为加里东碰撞造山的产物;东昆仑晚泥盆世黑山沟组和哈尔扎组岩性组合特征与牦牛山组极为相似,均为一套陆相、滨浅海相的碎屑岩、碳酸盐岩和中酸性火山岩组合,为典型的裂陷伸展型磨拉石建造,是晚古生代裂陷伸展盆地演化开始的标志。  相似文献   

台湾西部前陆盆地和帝汶海前陆盆地的比较学研究     

王海荣  王英民  刘振湖  黄奇志  齐立新 《大地构造与成矿学》2007,31(2):137-144

台湾西部前陆盆地和帝汶海前陆盆地均是新生代环太平洋巨型沟-弧-盆体系的一部分。Huang et al.(2000)认为,帝汶海前陆盆地目前相当于台湾南部陆海域所处的弧-陆碰撞的初始阶段。我们认为,该研究中存在着一种潜在的逻辑上的矛盾。在研究单个前陆盆地时,造山过程和板块的挠曲特性均会成为关注的焦点;而一旦进行盆地之间的对比研究,则往往会倾向于关注造山过程、机制以及构造现象的异同等,并由此得出相应结论,却忽视了在现象异同的背后所隐藏着的板块挠曲特性所起的控制性作用。事实上,帝汶海前陆盆地和台湾西部前陆盆地的根本差异并不在其造山作用和过程,而在于其板块挠曲特性的巨大差异。正是这种差异决定了二者具有完全不同的演化特性,构造、层序上的异同只是这种差异的外在体现。忽视这种差异,仅根据构造上的异同以推断前陆的演化过程会导致认识的偏差。  相似文献   

A strong seismic velocity contrast in the shallow mantle across the Zagros collision zone (Iran)   总被引：1，自引：0，他引：1  

A. Kaviani  A. Paul  E. Bourova  D. Hatzfeld  H. Pedersen  M. Mokhtari 《Geophysical Journal International》2007,171(1):399-410

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北喜马拉雅及藏南伸展构造综述   总被引：6，自引：1，他引：6  

张进江 《地质通报》2007,26(6):39-649

印度与欧亚大陆碰撞发生于65Ma左右,造山作用则开始于中新世初期,该造山运动形成南喜马拉雅的逆冲推覆体系,导致喜马拉雅山脉的隆起。然而,与造山作用的同时,北喜马拉雅及藏南地区却经历了广泛的伸展作用,所形成的伸展构造包括:①北喜马拉雅地区,开始于24Ma左右的藏南拆离系(STDS);②北喜马拉雅及藏南地区,开始于14Ma左右的南北向裂谷;③北喜马拉雅穹隆带,形成时间大致与南北向裂谷相同;④广布于青藏高原、开始于中新世末期、随机分布的高角度正断层。上述不同阶段的伸展构造形成于不同机制,并在喜马拉雅造山带的发展过程中起着不同的地质作用。其中,北喜马拉雅穹隆是一种特殊的伸展构造,并可能形成于多种机制。  相似文献   

焉耆盆地活动断层的晚第四纪右行走滑   总被引：4，自引：0，他引：4  

林爱明  傅碧宏  狩野谦一  丸山正  郭建明 《新疆地质》2003,21(1):103-115

本研究对天山东南侧山间盆地——焉耆盆地的晚第四纪右行走滑活动断层的位移和滑动速率进行了测量.详细的卫星图像分析和野外调查表明活动断层(开都河断层带)主要分布在盆地的南缘,具典型的走滑断层特征.发育在晚更新世—全新世冲积扇中的水系记录了3～250 m的右行错断和位移的累积.冲积扇中的断层陡坎高1 m到25 m,沿断层带走向左行雁列状断层崖呈现,向NE和SW倾.基于河道的错断,14C数据和断层岩组构的分析可以得出:①活动断层的平均右行走滑速率为8 mm/a,垂直分量的速率为1 mm/a,(②典型的单次地震断裂事件产生的错断量为3～7 m,③大地震事件(Ms>7)的平均重复间隔约为500年,④开都河断层带最新的地震断裂事件发生在过去2 500 a间.与印度—欧亚板块碰撞相关联的天山是一个逆冲构造占主导地位的造山带,而山间盆地中晚第四纪的走滑断层表明了这种造山机制中具有水平滑动.  相似文献   

Motion between the Indian, Capricorn and Somalian plates since 20 Ma: implications for the timing and magnitude of distributed lithospheric deformation in the equatorial Indian ocean   总被引：1，自引：0，他引：1  

Charles DeMets  Richard G. Gordon  Jean-Yves Royer 《Geophysical Journal International》2005,161(2):445-468

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盆山耦合与前陆盆地成藏区带分析   总被引：9，自引：2，他引：9  

刘和甫  李晓清  刘立群  李小军 《现代地质》2004,18(4):389-403

经济全球化导致油气勘探全球化,板块学说在理论上提供全球油气勘探基础,亚洲大陆与北美大陆盆山体系在实践上提供全球油气勘探经验。盆山耦合体系存在3类造山带与3类前陆盆地即:(1)俯冲造山带与弧后前陆盆地;(2)碰撞造山带与周缘前陆盆地;(3)陆内造山带与陆内前陆盆地。前陆盆地成藏区带勘探中,在空间上应将造山带前麓褶皱—冲断带层与前陆盆地作为统一应变场,在时间上应将前冲断作用沉积层序,同冲断作用沉积层序和后冲断作用沉积层序作为整体来进行勘探。  相似文献   

Mapping upper mantle anisotropy beneath SE France by SKS splitting indicates Neogene asthenospheric flow induced by Apenninic slab roll-back and deflected by the deep Alpine roots     

Guilhem Barruol  Anne Deschamps  Olivier Coutant   《Tectonophysics》2004,394(1-2):125-138

The presence of two regional seismic networks in southeastern France provides us high-quality data to investigate upper mantle flow by measuring the splitting of teleseismic shear waves induced by seismic anisotropy. The 10 three-component and broadband stations installed in Corsica, Provence, and western Alps efficiently complete the geographic coverage of anisotropy measurements performed in southern France using temporary experiments deployed on geodynamic targets such as the Pyrenees and the Massif Central. Teleseismic shear waves (mainly SKS and SKKS) are used to determine the splitting parameters: the fast polarization direction and the delay time. Delay times ranging between 1.0 and 1.5 s have been observed at most sites, but some larger delay times, above 2.0 s, have been observed at some stations, such as in northern Alps or Corsica, suggesting the presence of high strain zones in the upper mantle. The azimuths of the fast split shear waves define a simple and smooth pattern, trending homogeneously WNW–ESE in the Nice area and progressively rotating to NW–SE and to NS for stations located further North in the Alps. This pattern is in continuity with the measurements performed in the southern Massif Central and could be related to a large asthenospheric flow induced by the rotation of the Corsica–Sardinia lithospheric block and the retreat of the Apenninic slab. We show that seismic anisotropy nicely maps the route of the slab from the initial rifting phase along the Gulf of Lion (30–22 Ma) to the drifting of the Corsica–Sardinia lithospheric block accompanied by the creation of new oceanic lithosphere in the Liguro–Provençal basin (22–17 Ma). In the external and internal Alps, the pattern of the azimuth of the fast split waves follows the bend of the alpine arc. We propose that the mantle flow beneath this area could be influenced or perhaps controlled by the Alpine deep penetrative structures and that the Alpine lithospheric roots may have deflected part of the horizontal asthenospheric flow around its southernmost tip.  相似文献   

Kanfenggou UHP Metamorphic Fragment in Eastern Qinling Orogen and Its Relationship to Dabie-Sulu UHP and HP Metamorphic Belts, Central China   总被引：3，自引：0，他引：3  

SuoShutian ZhongZengqiu ZhouHanwen YouZhendong 《中国地质大学学报(英文版)》2003,14(2):95-102

In the Central Orogenic Belt, China, two UHP metamorphic belts are discriminated mainly based on a detailed structural analysis of the Kanfenggou UHP metamorphic fragment exposed in the eastern Qinling orogen, and together with previous regional structural, petrological and geochronological data at the scale of the orogenic domain. The first one corresponds to the South Altun-North QaidamNorth Qinling UHP metarnorphic belt. The other is the Dabie-Sulu UHP and HP metamorphic belts. The two UHP metamorphic belts are separated by a series of tectonic slices composed by the Qiniing rock group, Danfeng rock group and Liuling or Foziling rock group etc. respectively, and are different in age of the peak UHP metamorphism and geodynamic implications for continental deep subduction and collision. Regional field and petrological relationships suggest that the Kanfenggou UHP metamorphic fragment that contains a large volume of the coesite- and microdiamond-bearing eclogite lenses is compatible with the structures recognized in the South Altun and North Qaidam UHP metamorphic fragments exposed in the western part of China, thereby forming a large UHP metamorphic belt up to 1000 km long along the orogen strike. This UHP metamorphic belt represents an intercontinental deep subduction and collision belt between the Yangtze and Sino-Korean cratons, occurred during the Paleozoic. On the other hand, the well-constrained Dabie-Sulu UHP and HP metamorphic belts occurred mainly during Triassic time (250-220 Ma), and were produced by the intracontinental deep subduction and collision within the Yangtze craton. The Kanfenggou UHP metamorphic fragment does not appear to link with the DabieSulu UHP and HP metamorphic belts along the orogen. There is no reason to assume the two UHP metamorphic belts as a single giant deep subduction and collision zone in the Central Orogenic Belt situated between the Yangtze and Sino-Korean cratons. Therefore, any dynamic model for the orogen must ac-count for the development of UHP metarnorphic rocks belonging to the separate two tectonic belts of different age and tectono-metamorphic history.  相似文献