Multi-layer Tectonic Model for Intraplate Deformation and Plastic-Flow Network in the Asian Continental Lithosphere

In a large area of the east—central Asian continent there is a unified seismic network system composed of two families of large—seismic belts that intersect conjugately. Such a seismic network in the middle—upper crust is actually a response to the plastic flow network in the lower lithosphere including the lower crust and lithospheric mantle. The existence of the unified plastic flow system confirms that the driving force for intraplate tectonic deformation results mainly from the compression of the India plate, while the long-range transmission of the force is carried out chiefly by means of plastic flow. The plastic flow network has a control over the intraplate tectonic deformation.     

论湿陷起始压力

本文以实测数据为依据,以工程应用为主题,从七个方面对湿陷起始压力进行了广泛的讨论,为工程中多方面应用湿陷起始压力提供了系统允分的依据。     

载金石英的阳离子效应及其对含矿性的指示意义

石英的阳离子效应指石英结构中Al~(3+)与Si~(4+)的置换作用.在分析海南戈枕断裂金成矿带石英中普遍存在的这一作用,以及由此造成的石英粉末红外谱(IR)、顺磁共振谱(EPR)及热释光曲线(TL)特征,进而讨论了这些特征与金成矿的关系.     

北京大海坨4.9级地震前白家疃井地热地形变前兆异常

北京大海坨ＭＬ＝４．９地震前，白家疃地热，地形变两种观测项目，同时观测记录到明显的异常变化，具有短期和短促，突发的临震异常特点，采取针对性的分析方法，结果较好，为单台项（前兆方法）综合预报提供了震兆观测实例。     

山西及其邻近地区地壳垂直形变与地震危险性分析

山西及其邻近地区地壳垂直形变出现的两升三降的分布格局,反映出现代构造块体活动在不断增强.通过地震活动和区域形变场分析,可以看出山西地区自50年代以来地震释放能量有不断加强趋势,区域形变出现了有规律的四象限分布.预计今后10年内本区若干危险点有可能成为地震能量大释放地区.     

阿尔泰高山区金矿带的确定和意义

根据地质、地球化学和资源总量预测等方法的综合研究表明,在阿尔泰高山区红山咀断裂以北宽20～30km,东西长约150km地带为一重要金成矿带。金矿赋存于晚古生代陆相酸—中酸性火山岩地层中,空间上受冰长石-黄铁绢英岩化蚀变带严格控制,是以毒砂、辉锑矿等金属硫化物为主要载体的层控浅成低温热液溶滤型金矿,也是一种新的重要的金矿工业类型。     

短路线岩石地球化学测量在地质工作中的应用

短路线岩石地球化学测量在地质找矿工作中是一种简便、快速、经济的方法之一,应用范围广,对解决某些地质问题能发挥较好的作用。此方法在构造地球化学与地质找矿中被实际应用,具有简便、快速经济等特点。     

Active deformation in the Vrancea region,Rumania

Recent and historical seismicity as well as reliable fault plane solutions are used to study the active deformation caused by the occurrence of intermediate depth (60–170 km) earthquakes of the Vrancea region, Rumania. In this area, located in the southeastern part of the Carpathian arc, the westward subduction of the Carpathian trench has terminated, leaving continental lithosphere, at present, at the arc. The principalT axis of the intermediate depth events trends N159°E and has a plunge of 74°, which is the same as the dip of the subducted plate. TheP axis has a trend of 314° and a shallow plunge of 15°. The analysis of the moment tensor of six focal mechanisms showed that the dominant mode of deformation of the subducted lithosphere is a down-dip extension at a rate of about 2 cm/yr, based on seismicity data.     

Strain segmentation and lateral membrane deformation rate of the subducted Ryukyu slab

Abstract Focal mechanisms of intermediate-depth earthquakes within the subducted Ryukyu slab indicate a systematic pattern of down-dip extension in the northern part under Kyushu. These mechanisms switch rapidly around the Tokara channel to down-dip compression in the southern part toward Taiwan. This intriguing pattern of strain segmentation, together with the differences between the slab geometry of the northern and southern parts, has raised the question of whether stress segmentation, as defined possibly by a tear fault, might exist in the slab. However the Ryukyu trench has a concave oceanward shape in the northern segment while it is convex in the southern oceanward part toward Taiwan. The inflection zone is located around the Tokara channel. The concept of Gaussian curvature of a curved surface suggests that the along-arc variation of the geometric configuration of a subducted slab is related to the shape of the trench. This is in order to accommodate the lateral membrane deformation of the slab as the oceanic lithosphere subducts from a spherical shell to the geometry delineated by the Wadati-Benioff zone. The membrane deformation regime of the subducted Ryukyu slab and its relation with the trench geometry was examined by assuming that the subduction be modelled by the flow field of a thin viscous sheet. A projection operator was utilized to compute the membrane strain-rate tensor of an arbitrary non-Euclidean surface. Numerical experiments indicated that the northern segment of the slab was dominated by lateral compression and down-dip extension and the southern part by lateral extension and down-dip compression. This transition is sharply located near the Tokara channel. These patterns were compatible with what had been observed from studies of focal mechanisms, suggesting that the strain segmentation might be controlled, at least in part, by the lateral membrane deformation within the slab due to the trench shape in this subduction zone. The slab geometry was predicted by minimizing the integrated total dissipation power; this revealed distinct features that were consistent with observations. This implies that the slab geometry may also be affected by the membrane deformation in a systematic fashion.     

冀东太古宙高级变质岩区若干地质问题的研究

在1∶5万区域地质填图及专题研究的基础上探讨了变质岩石中的岩浆侵位变形构造、褶皱构造及变形与变质作用的关系等三个方面的问题。研究表明冀东太古宙高级区变质岩石中不同程度地发育岩浆岩构造,包括在不同类型片麻岩之间所表现的穿切构造、基性岩墙中的矿物定向构造以及基性岩体边缘及其围岩的变形构造等,褶皱构造可分为表壳岩褶皱及片麻岩褶皱,高级区可能不存在大型的片麻岩褶皱,通过镜下特征矿物相的研究并结合野外变质基性岩墙的产状及特征,建立区域变质与变形作用的关系,从而为区域地质事件表的建立提供依据。