橄榄石的晶格优选定向、含水量与地震波各向异性:对大陆俯冲带变形环境的约束

橄榄石在不同热动力学条件下形成的晶格优选定向是认识上地幔塑性变形与地震波各向异性的基础.本文通过总结橄榄石的晶格优选定向、含水量与地震波各向异性的研究进展,探讨大陆俯冲带的变形环境.绝大部分天然变形橄榄岩中的橄榄石都发育了[100](010)组构[100]轴近平行于线理,(010)面平行或近平行于面理,使橄榄岩的最快P波速度近平行于线理,最大S波分裂平行面理并垂直线理.但来自超高压变质带的石榴石橄榄岩可发育[001](100)组构,使橄榄岩的最快P波速度和最小S渡分裂方向垂直面理.近年来的变形实验与理论计算表明超高压和低温是橄榄石组构从[100](010)向[001](100)转变的关键因素,而水对橄榄石流变行为的影响还有待进一步研究.对170个天然橄榄石结构水含量的统计结果表明橄榄石含水量变化很大(0～170×10-6H2O),玄武岩中橄榄岩包体的橄榄石比较贫水,而所有富水橄榄石均来自克拉通金伯利岩中的石榴石橄榄岩.因此,除了水在上地幔的不均匀分布,橄榄岩折返过程中氢的扩散会强烈影响橄榄石的含水量.苏鲁芝麻房橄榄岩提供了以超高压、低温、贫流体为特征的大陆俯冲带中[001](100)橄榄石组构的实例.在俯冲的大陆板片中,橄榄石组构在120～220 km从[100](010)向[001](100)的转变可导致地震波各向异性突然降低,而且最快P波速度垂直于俯冲方向.     

东海陆架盆地伸展率和压缩率及构造跃迁

东海陆架盆地位于欧亚板块的东南缘和西太平洋活动大陆边缘,本文选取了东海陆架盆地主要凹陷的17条地震剖面,采用平衡剖面技术,计算了主要凹陷新生代不同演化阶段的伸展率和压缩率。分析表明,东海陆架盆地构造演化总体由西向东跃迁。晚白垩世至晚古新世东海陆架盆地裂陷中心在西部坳陷带,始新世东迁至东部坳陷带,上新世东迁至东海陆架盆地东侧的冲绳海槽盆地。古新世中后期东海陆架盆地西部坳陷带北侧昆山凹陷反转; 中新世东部坳陷带的西湖凹陷反转。东海陆架盆地西部坳陷带与东部坳陷带构造演化不同,证明了东海陆架盆地的东西分带。西部坳陷带北部的长江坳陷和南部的台北坳陷构造演化不同,东部坳陷带北部的西湖凹陷和南部的钓北凹陷构造演化不同,证明了东海陆架盆地的南北分块.     

羌塘盆地中央隆起带的重磁场证据及其构造意义

对于羌塘盆地是否存在横贯东西的中央隆起带,目前学术界仍有分歧.本文提供的最新高精度航空重、磁资料证实存在呈东西向贯通羌塘盆地的中央隆起带,并对该带的构造特征进行了精细刻画.隆起带受南北两侧深大断裂控制,其空间跨度（宽度）由西向东逐渐收敛,并被一组近南北向的隐伏断裂系切割、左滑错动.重、磁场资料还显示中央隆起带在双湖东、西两侧存在明显差异：西段基底大规模隆起,基岩深度一般在3~5 km以内,明显浅于南北羌塘坳陷7~15 km的基底埋深;东段基底隆起幅度明显降低,主要表现为潜伏的低隆起,其中双湖—雅曲段基底埋深5~7 km,雅曲—岗尼段基底埋深7~9 km;即中央隆起带基底自西向东"台阶状"降低,隆起的幅度和分布范围受到近南北向断裂控制.构造分层表明,与南羌塘地块相比,北羌塘地块的基底隆起幅度小、稳定性更好.南北羌塘基底地球物理属性的显著差异说明羌塘盆地并不存在统一的前寒武系变质基底,中央隆起带的形成应该与古特提斯洋关闭时形成的混杂岩带有关.     

文莱-沙巴盆地深水褶皱冲断带构造变形特征及成因机制

为揭示活动陆缘深水褶皱冲断带的特征及成因,本文利用地震和区域地质资料的综合分析,系统阐述了文莱—沙巴盆地深水褶皱冲断带的构造变形特征,并结合盆地演化动力学特点,探讨其构造变形机制及其对深水区油气成藏的影响.研究结果表明,文莱—沙巴盆地深水褶皱冲断带具有"垂向分期、平面分段"的特点,垂向上,以中中新统底界面为界可划分为下部（始新世-早中新世）和上部（中中新世-现今）两套逆冲褶皱冲断体系,其中下部逆冲褶皱冲断带的形成与古南海的俯冲作用密切相关,上部逆冲褶皱冲断带是中中新世以来三角洲前缘重力滑动与苏禄海扩张造成的区域挤压应力远程效应共同作用的结果,且苏禄海扩张造成的远程挤压效应主控平面上南北段褶皱冲断带变形的差异性,导致北段褶皱变形强度大于南段,具有背斜褶皱数量多、褶皱间距离短、逆冲断层倾角陡的特点,南段反之;且晚上新世以来北段深水区地层缩短量大于陆架区伸展量,两者之差为2~6 km,而南段两者相当,仅受三角洲前缘重力滑动影响.整个褶皱冲断带发育断弯、断展、断滑褶皱等3种断层相关褶皱以及叠瓦扇和冲起构造2种逆冲构造组合,是多期NW向挤压应力作用下形成的大型逆冲推覆构造,以前展式向盆地扩展.此外,由于中中新世以来逆冲断层的持续活动,研究区深水褶皱冲断带发育众多构造圈闭,油气成藏条件优越,且南段优于北段,靠近陆坡的近端优于远端,可作为勘探部署重点.     

渭河盆地北缘断裂带活动特征的初步研究

本文从渭河盆地北缘断裂的形成和活动时代,活动特征等资料出发,结合北缘断裂带及整个盆地历史地震活动和新生界地层发育特征的综合分析,对北缘断裂带的活动期次,主要断层的运动幅度和滑动速率及其时空演变规律和机制等问题进行了探讨。文章指出,北缘断裂带的形成是一个由盆地中心向北逐渐扩展的过程,自上新世起,断层活动明显有东强西弱的变化特征,而且扩展方向也发生了偏转。这一转变及活动强度的东西差异与山西剪切带对渭河盆地的影响密切相关     

The future of industrial cities and regions in central and eastern Europe

Economic transition in central and eastern Europe (CEE) has had a particularly strong impact on industrial cities and regions. Following their economic collapse, most of them are now confronted with serious problems such as high unemployment and vast ecological damage. The paper presents findings from a pan European research project that investigated the problems of these cities and regions as well as the strategies being adopted to cope with structural change. It examines the differences in approaches and addresses the question whether existing EU policy is suitable for supporting the redevelopment of old industrial cities and regions in CEE countries. The paper concludes with recommendations for future directions in policy making.     

http://www.sciencedirect.com/science/article/pii/S1674987111000508

This paper presents the results of a set of numerical models focussing on structural controls on hydrothermal mineralization.We first give an overview of natural phenomena of structurally-controlled ore formation and the background theory and mechanisms for such controls. We then provide the results of a group of simple 2D numerical models validated through comparison with Cu-vein structure observed near the Shilu Copper deposit(Yangchun,Guangdong Province, China) and finally a case study of 3D numerical modelling applied to the Hodgkinson Province in North Queensland(Australia).Two modelling approaches,discrete deformation modelling and continuum coupled deformation and fluid flow modelling,are involved.The 2D model-derived patterns are remarkably consistent with the Cu-vein structure from the Shilu Copper deposit,and show that both modelling approaches can realistically simulate the mechanical behaviours of shear and dilatant fractures.The continuum coupled deformation and fluid flow model indicates that pattern of the Cuveins near the Shilu deposit is the result of shear strain localization,development of dilation and fluid focussing into the dilatant fracture segments.The 3D case-study models(with deformation and fluid flow coupling) on the Hodgkinson Province generated a number of potential gold mineralization targets.     

羊石坑汞矿床包裹体地球化学特征研究

羊石坑汞矿是80年代后期勘探的大型汞矿床,矿床位于川黔汞矿带北部,矿体以细脉、网脉浸染状为主。包裹体地球化学研究表明,成矿温度120～250℃,成矿流体盐度为10.6％(NaCl),流体沸腾发生在250℃左右,包裹体圈闭的最小压力为40×10~5Pa,成矿深度约为400m。结合成矿构造环境、构造演化、探讨了构造改造成矿机制和规律。     

Structural monitoring of offshore platforms using impulse and relaxation response

Monitoring offshore platforms, long span bridges, high rise buildings, TV towers and other similar structures is essential for ensuring their safety in service. Continuous monitoring assumes even greater significance in the case of offshore platforms, which are highly susceptible to damage due to the corrosive environment and the continuous action of waves. Also, since a major part of the structure is under water and covered by marine growth, even a trained diver cannot easily detect damage in the structure. In the present work, vibration criterion is adopted for structural monitoring of jacket platforms. Artificial excitation of these structures is not always practicable and ambient excitation due to wind and waves may not be sufficient for collecting the required vibration data. Alternate methods can be adopted for the same purpose, for example, the application of an impact or a sudden relaxation of an applied force for exciting the structure. For jacket platforms, impact can be applied by gently pushing the structure at the fender while relaxation can be accomplished by pulling the structure and then suddenly releasing it using a tug or a supply vessel in both cases. The present study is an experimental investigation on a laboratory model of a jacket platform, for exploring the feasibility of adapting vibration responses due to impulse and relaxation, for structural monitoring. Effects of damage in six members of the platform as well as changes in deck masses were studied. A finite element model of the structure was used to analyze all the cases for comparison of the results as well as system identification. A data acquisition and analysis procedure for obtaining the response signatures of the platform due to the impulse and relaxation procedure was also developed for possible adoption in on-line monitoring of offshore platforms. From the study, it has been concluded that both impulse and relaxation responses are useful tools for monitoring offshore jacket platforms. The present work forms the basis for the development of an automated, on-line monitoring system for offshore platforms, using neural networks.     

大别山东北缘构造片麻岩中锆石U-Pb年代学分析及构造意义

大别造山带是由华北板块和扬子板块经过长期构造演化、最终碰撞拼合的产物。大别山东北缘发育地壳深部构造层次上的构造片麻岩,通过对构造片麻岩的应力场恢复,认为大别山东北缘主要受到NE-SW向的特提斯构造体制和NW-SE向的太平洋构造体制两个体制的作用,并不是受单一的构造体制控制。锆石LA-ICP-MS微区U-Pb同位素测年结果显示,大别山东北缘至少存在3期构造事件。第一期是750±50 Ma的岩浆活动;第二期是210±10 Ma的变质活动;第三期是130±5 Ma的岩浆活动。大别山在碰撞造山后期发生了近水平东西向沿造山带的塑形流变,导致大别山中片麻理和线理走向均为NWW-SEE向,大别造山带发生塑形流变的时间在210±10 Ma左右,大概在195±5 Ma左右郯庐断裂带开始活动,改造了大别山原有的NWW-SEE向构造,使得大别山东端片麻理走向出现NE向转变。