Jurassic Tectonics of North China: A Synthetic View

This paper gives a synthetic view on the Jurassic tectonics of North China, with an attempt to propose a framework for the stepwise tectonic evolution history. Jurassic sedimentation, deformation and magmatism in North China have been divided into three stages. The earliest Jurassic is marked by a period of magmatism quiescence （in 205-190 Ma） and regional uplift, which are considered to be the continuation of the “Indosinian movement” characterized by continent-continent collision between the North and South China blocks. The Early to Middle Jurassic （in 190-170 Ma） was predominated by weak lithospheric extension expressed by mantle-derived plutonism and volcanism along the Yanshan belt and alongside the Tan-Lu fault zone, normal faulting and graben formation along the Yinshan- Yanshan tectonic belt, depression and resuming of coal-bearing sedimentation in vast regions of the North China block （NCB）. The Middle to Late Jurassic stage started at 165y.5 Ma and ended up before 136 Ma; it was dominated by intensive intraplate deformation resulting from multi-directional compressions. Two major deformation events have been identified. One is marked by stratigraphic unconformity beneath the thick Upper Jurassic molasic series in the foreland zones of the western Ordos thrust-fold belt and along the Yinshan-Yanshan belt; it was predated 160 Ma. The other one is indicated by stratigraphic unconformity at the base of the Lower Cretaceous and predated 135 Ma. During this last stage, two latitudinal tectonic belts, the Yinshan-Yanshan belt in the north and the Qinling-Dabie belt in the south, and the western margin of the Ordos basin were all activated by thrusting; the NCB itself was deformed by the NE to NNE-trending structural system involving thrusting, associated folding and sinistral strike-slip faulting, which were spatially partitioned. Foliated S-type granitic plutons aged 160-150 Ma were massively emplaced in the Jiao-Liao massif east of the Tan-Lu fault zone and indicate important crustal thicken     

变形分析的神经网络技术应用实例

大型工程施工过程中的变形监测、分析与预报极为重要。变形分析建模的方法很多,神经网络技术的应用是其中之一。文中结合某深基坑工程的监测资料和工作经验,运用神经网络BP算法进行预测分析。简述BP神经网络的基本概念,介绍基坑变形分析的BP神经网络的具体模型结构,将神经网络方法预报结果与实测数据对比效果较好。该成果对生产实践具有参考价值。     

中国西部现今地壳形变与地震活动特征

以1999-2004年间中国西部地区近650个GPS站点的观测资料为基础,采用二维“高张力样条”函数内插算法获得了连续地壳形变场。结果表明,相对于稳定欧亚参考框架,中国西部现今地壳运动西强东弱,北向运动从西向东逐渐减弱,东向运动逐渐增强,青藏高原东缘及附近地区是东向运动的消减区带;主应变从西向东由压缩应变转变为拉伸应变;最大剪应变主要位于喜马拉雅地块及其东部地区;中国西部地区地震活动在空间分布上似乎集中发生在印度板块北东向挤压欧亚板块的两条共扼带内,与地壳形变场有一定对应关系,地壳形变的高应变率区为中强地震多发地带。     

经验模式分解的尺度阈值滤波在变形分析中的应用

本文将信号处理领域的经验模式分解算法应用于变形信息的提取中,通过引入阈值函数,建立了基于经验模式分解的尺度阈值滤波模型,采用优化模型确定了经验模式分解的次数。分别通过模拟试验和实测数据与小波阈值法和多项式拟合法进行了比对,分析表明:在低噪声情况下,三种方法都有一定的滤波效果;在高噪声情况下,经验模式分解的尺度阈值滤波法具有与小波阈值去噪法相等的精度,而且瞬时强噪声识别能力更好,优于多项式拟合法。     

跨带土地利用规划图的编制研究

在县级土地利用规划用图中,常涉及到跨投影带的地图拼接问题,一般使用邻带转换法实现跨带区域的地图显示,该方法在实际应用中存在面积和角度变形相对较大的不足.本文采用自定义中央经线的投影转带方法,经过高斯投影变换,较好地解决了县域范围的跨带拼接显示并有效控制了相关变形.     

New data on the present-day active fluid regime of fractured zones of crystalline basement and sedimentary cover in the eastern part of Volga-Ural region

The study area is the South Tatarstan Arch located in the Volgo-Ural Region, which is an enigmatic crustal segment occupying one third of the East European Platform. Monitoring studies have shown that fluid discharge processes are still active and time-dependent. This paper presents an integrated review of the geological, geophysical, hydrochemical and geochemical studies of the crystalline basement of Tatarstan. These studies are based on the stratigraphic and compositional schemes within the crystalline basement, the drilling of deep wells, the geodynamic activity of the fractured zones of the crystalline basement and the presence of fluids therein. Furthermore, the changes in the chemical composition of the basement waters are taken into account.     

The Glarus thrust: excursion guide and report of a field trip of the Swiss Tectonic Studies Group (Swiss Geological Society, 14.–16. 09. 2006)

This excursion guide results form a field trip to the Glarus nappe complex organized by the Swiss Tectonic Studies Group in 2006. The aim of the excursion was to discuss old and recent concepts related to the evolution of the Glarus thrust. The major aspects were (i) the interplay between deformation, fluid flow and geochemical alteration, (ii) episodic versus continuous deformation and fluid flow, and (iii) the link between large-scale structures, microstructures, and geochemical aspects. Despite 150 years of research in the Glarus nappe complex and the new results discussed during the excursion, there exist controversies that still are unsolved.     

俯冲带榴辉岩的变形作用及其对俯冲-折返过程的意义

榴辉岩是大洋和大陆俯冲带的重要岩石类型,在研究俯冲带的形成过程、热结构、壳幔相互作用等方面有重要意义。通过对天然和实验样品中石榴子石、绿辉石等矿物的变形特征、变形机制、变形的影响因素等的综合分析,系统总结了高压变质带中榴辉岩矿物显微和超微变形研究的进展,探讨了榴辉岩的变形特征在恢复俯冲与折返过程研究中的意义及一些尚待解决的一些问题。     

利用DInSAR和GPS综合方法估计地表3维形变速率

在分析基于贝叶斯统计和马尔科夫随机场理论的解析优化法的基础上,提出以GPS提供的高精度的水平形变速率作为约束,利用直接分解法,将DInSAR的斜距向形变速率分解成垂直形变速率。试验结果表明,直接分解法有效地综合了GPS的高水平精度与DInSAR的高垂直精度优点,且计算简单,克服了解析优化法可能出现的数值不稳定问题。     

基于GPS技术监测高层建筑物变形的研究

以武汉大学信息学部教学实验大楼为实验对象,分析了大楼在N、E、U方向上的每h变化、d变化及变形规律,阐明GPS技术在高层建筑变形监测中的应用。