陕北神木地区早、中侏罗世含煤岩系层序地层特征

以陕北神木地区1：5万区域地质调查成果资料为基础，运用层序地层学的理论和方法，系统分析与研究了该区中生代含煤岩系的层序地层特征、盆地充填样式，初步建立了该地区区域岩石地层模型。本文反映了该区层序地层学研究的新进展，对应用层序地层学理论进行成煤规律分析及成矿预测进行了有益的探索。     

北部湾盆地福山凹陷古近纪湖底扇沉积演化及模式探讨

综合应用地震、测井及岩心观察资料，对福山凹陷古近纪流沙港组的湖底扇沉积进行了详细研究。认为该期的湖底扇沉积主要是由于三角洲前缘带的砂体在重力作用下进入湖泊深水区堆积而形成，部分是由位于湖盆陡坡边缘的河道砂沿水下河道进入湖泊深水区而形成的水下重力流沉积。从空间分布来看，湖底扇主要分布在凹陷的北部和西部，且北部和西部湖底扇的扇体规模较东部大，存活时间较东部长。平面上湖底扇位于三角洲体系的外侧，垂向上由下至上发育着从湖底扇一三角洲前缘远端一三角洲前缘近端的沉积演化序列。湖底扇的总体沉积模式为南部的辫状河三角洲砂岩碎屑体向北推进至深湖区形成孤立的、规模相对较大的湖底扇砂体；而西部及东部的次要物源——辫状河三角洲也在东西两侧活动断层的控制下在湖盆深处形成湖底扇沉积体。     

塔里木板块南缘早古生代沉积特征及构造背景探讨

塔里木板块南缘早古生代时期继承了震旦纪的古地理格局，处于浅海陆棚—半深海环境，沉积了一套海相碳酸盐岩和碎屑岩地层。根据区域地层划分、古生物化石和最新的同位素测年数据，确定了塔里林板块南缘地层时代为早古生代。通过沉积学和地球化学方法初步分析，确定了该地区为早古生代的大地构造背景—具有被动大陆边缘性质。因此，系统研究塔里木板块南缘早古生代沉积地层，对于重塑早生代以来该区板块构造格局及演化历史有重要地质意义。     

新疆普鲁一带下古生界地层岩石组合及构造环境

西昆仑地块是西昆仑造山带的重要组成部分，南北边界分别为康西瓦—苏巴什华力西期缝合带和库地—其曼于特加里东期缝合带。新疆普鲁一带下古生界地层，分布于西昆仑地块东部，主要由一套海相火山岩和浅海陆棚相细碎屑岩组成，并遭受了绿片岩相的变质作用。通过1：25万《于田一伯力克幅)区调工作，将新疆普鲁一带下古生界地层厘定为下古生界奥陶—志留系，认为形成的大地构造环境为大陆活动边缘。     

巴彦浩特盆地火成岩的综合地球物理解释

采用综合地球物理方法识别巴彦浩特盆地火成岩,首先利用高精度重磁资料和大地电磁测深资料,初步确定火成岩的平面位置和深度,然后利用钻遇火成岩的已知测井资料,建立人工合成地震记录,在地震剖面上标定出火成岩并分析其波组特征,采用BP神经网络进行火成岩的精细识别.研究表明,综合地球物理解释是提高反演解释精度的有效途径.     

中国西北叠合盆地的主要构造特征

探讨了中国西北地区大型叠合含油气盆地的主要特征 ,研究表明 ,在中国西北叠合盆地发展演化过程中 ,构造变革和构造耦合起着主导作用。构造变革包括大地构造格局的转变、沉积区和剥蚀区的转换、盆地类型的转换、大型区域性不整合的出现以及发生盆地构造反转等 ,这种构造变革具有多期性。叠合盆地构造耦合的方式主要涉及深部和浅部构造的耦合和盆山耦合等。盆山转换、盆山过渡带深部浅部构造的耦合、盆地沉降与造山带隆升耦合以及不同方向构造的耦合 ,反映了盆山耦合的多样性和复杂性。中国西北叠合盆地构造特征主要表现为构造的分层性、分带性、分段性、交叉性以及区域构造应力场的多变性 ,喜马拉雅运动对于中国西北叠合盆地最后的构造改造以及构造定型起着重要的制约作用。     

Paleocene deep-water sediments and radiolarian faunas: Implications for evolution of Yarlung-Zangbo foreland basin, southern Tibet

Only a few Paleocene radiolarian assemblages have been reported, while the Early Paleocene zonal schemes remain poorly delineated. The Early Paleocene on-land radiolarians were described in the Hidaka melange belt of Japan and the North Island of New Zeal…     

Flexural subsidence by 29 Ma on the NE edge of Tibet from the magnetostratigraphy of Linxia Basin, China

This study provides a detailed magnetostratigraphic record of subsidence in the Linxia Basin, documenting a 27 Myr long sedimentary record from the northeastern edge of the Tibetan Plateau. Deposition in the Linxia Basin began at 29 Ma and continued nearly uninterruptedly until 1.7 Ma. Increasing rates of subsidence between 29 and 6 Ma in the Linxia Basin suggest deposition in the foredeep portion of a flexural basin and constrain the timing of shortening in the northeastern margin of the plateau to Late Oligocene–Late Miocene time. By Late Miocene–Early Pliocene time, a decrease in subsidence rates in the Linxia Basin associated with thrust faulting and a 10° clockwise rotation in the basin indicates that the deformation front of the Tibetan plateau had propagated into the currently deforming region northeast of the plateau.     

Scattering of elastic waves by a general anisotropic basin. Part 2: a 3D model

Scattering of plane harmonic waves by a three‐dimensional basin of arbitrary shape embedded within elastic half‐space is investigated by using an indirect boundary integral equation approach. The materials of the basin and the half‐space are assumed to be the most general anisotropic, homogeneous, linearly elastic solids without any material symmetry (i.e. triclinic). The unknown scattered waves are expressed in terms of three‐dimensional triclinic time harmonic full‐space Green's functions. The results have been tested by comparing the surface response of semi spherical isotropic and transversely isotropic basins for which the numerical solutions are available. Surface displacements are presented for a semicircular basin subjected to a vertical incident plane harmonic pseudo‐P‐, SV‐, or SH‐wave. These results are compared with the motion obtained for the corresponding equivalent isotropic models. The results show that presence of the basin may cause significant amplification of ground motion when compared to the free‐field displacements. The peak amplitude of the predominant component of surface motion is smaller for the anisotropic basin than for the corresponding isotropic one. Anisotropic response may be asymmetric even for symmetric geometry and incidence. Anisotropic surface displacement generally includes all three components of motion which may not be the case for the isotropic results. Furthermore, anisotropic response strongly depends upon the nature of the incident wave, degree of material anisotropy and the azimuthal orientation of the observation station. These results clearly demonstrate the importance of anisotropy in amplification of surface ground motion. Copyright © 2003 John Wiley & Sons, Ltd.     

Steel frames with bracing mechanism and hysteretic dampers

A new earthquake resistant structural system for multi‐storey frame structures, based on a dual function of its bracing components, is developed. This consists of a hysteretic damper device and a cross‐bracing mechanism with a kinetic closed circuit, working only in tension, so that cable members can be used for this purpose. Solutions are presented regarding the connections' design of three types of structural frame system, that are concerned throughout the study: braced moment free frame, braced moment resisting frame with moment free supports, and with moment resisting supports. The dynamic behaviour of the system is investigated on the basis of an SDOF model, and based on the response spectra method an approximate design approach of the controlled structures is shown. From the time history analysis of the structural systems for the El Centro earthquake the areas of appropriate stiffness relations of the frames to the hysteretic dampers and the cable braces are deduced, so that the energy dissipation of the system may be controlled by the damper‐cable bracing mechanism. Based on the results of these studies, a predesign approach is developed for the implementation of the control system in frame structures. Copyright © 2003 John Wiley & Sons, Ltd.