Tectonic Evolution of the Middle Frontal Area of the Longmen Mountain Thrust Belt, Western Sichuan Basin, China     

JIN Wenzheng  TANG Liangjie  YANG Keming  WAN Guimei  L ZhiZhou  YU Yixinx 《《地质学报》英文版》2009,83(1)

By analyzing the balanced cross sections and subsidence history of the Longmen Mountain thrust belt,China,we concluded that it had experienced five tectonic stages:(1)the formation stage (T3x) of the miniature of Longmen Mountain, early Indosinian movement, and Anxian tectonic movement created the Longmen Mountain;(2)the stable tectonic stage(J1)where weaker tectonic movement resulted in the Longmen Mountain thrust belt being slightly uplifted and slightly subsiding the foreland basin;(3)the intense tectonic stage(J2-3),namely the early Yanshan movement;(4) continuous tectonic movement(K-E),namely the late Yaushan movement and early Himalayan movement;and(5)the formation of Longrnen Mountain(N-Q),namely the late Himalayan movement. During those tectonic deformation stages, the Anxian movement and Himalayan movement played important roles in the Longmen Mountain'S formation.The Himalayan movement affected Longmen Mountain the most;the strata thrust intensively and were eroded severely.There are some klippes in the middle part of the Longmen Mountain thrust belt because a few nappes were pushed southeastward in later tectonic deformation.  相似文献   

河北省丰宁县茶棚银矿地质、地球物理特征及找矿意义     

郭长华  高明  张翔军  高州  孟令革  高雄  李会凯 《矿产与地质》2009,23(5):462-468

茶棚银矿位于河北省北部坝上草原向山区过渡地带,风成砂覆盖严重,示矿标志不明显,地表找矿难度大;地表矿体断续出露,而深部银矿体主要以隐伏矿体的形式赋存于近南北向展布的构造破碎带中,数量明显增多、品位变富、厚度变大;在这种特殊的景观地质特征下,利用激电中梯扫面,可发现厚覆盖状态下构造矿化蚀变带,利用EH4连续导电率测量可厘定矿化蚀变带的规模、产状并可提供隐爆角砾岩体等深部控矿地质信息,利用可控源音频大地电磁测深的中低阻陡变带和中阻带,特别是陡变带中的转折部位（形态呈耳状部位）可具体定位银矿体的赋存空间。  相似文献   

Kinematics of Convergence and Deformation in Luzon Island and Adjacent Sea Areas:2-D Finite-Element Simulation     

Liu Zaifeng  Zhan Wenhuan  Yao Yantao  Zhan Meizhen  Zhang Dianguang 《中国地质大学学报(英文版)》2009,20(1)

The Luzon Island is a volcanic arc sandwiched by the eastward subducting South China Sea and the northwestward subducting Philippine Sea plate.Through experiments of plane-stress,elastic,and 2-dimensional finite-element modeling,we evaluated the relationship between plate kinematics and present-day deformation of Luzon Island and adjacent sea areas.The concept of coupling rate was applied to define the boundary velocities along the subduction zones.The distribution of velocity fields calculated in our models was compared with the velocity field revealed by recent geodetic (GPS) observations.The best model was obtained that accounts for the observed velocity field within the limits of acceptable mechanical parameters and reasonable boundary conditions.Sensitivity of the selection of parameters and boundary conditions were evaluated.The model is sensitive to the direction of convergence between the South China Sea and the Philippine Sea plates,and to different coupling rates in the Manila trench,Philippine trench and eastern Luzon trough.We suggest that a change of±15° of the di rection of motion of the Philippine Sea plate can induce important changes in the distribution of the computed displacement trajectories,and the movement of the Philippine Sea plate toward azimuth330° best explains the velocity pattern observed in Luzon Island.In addition,through sensitivity analysis we conclude that the coupling rate in the Manila trench is much smaller compared with the rates in the eastern Luzon trough and the Philippine trench.This indicates that a significant part of momentum of the Philippine Sea plate motion has been absorbed by the Manila trench;whereas,a part of the momentum has been transmitted into Luzon Island through the eastern Luzon trough and the Philippine trench.  相似文献   

控制论与人工影响天气II.工程控制论在人工增雨作业中的应用与建模   总被引：1，自引：1，他引：0  

吴琳  曾庆存  洪钟祥 《气候与环境研究》2012,17(6):979-985

人工增雨已有60余年历史,虽已取得很多成绩,仍存在很多亟待解决的科学技术问题,典型问题如作业具有一定的主观性及其与效果检验有脱节.控制论研究如何对系统施加控制作用使其表现出预定行为.作者研究工程控制论在人工增雨作业中的应用与建模问题,将工程控制论引入人工增雨作业,称作“局部控制”方法.以冷云的人工催化过程为例,以单容加延迟的过程来简化单块冷云催化核化过程,建立了有反馈的冷云催化框架模型.根据效果调整催化剂的播撒率以实施控制作用,使作业后的雨云关键参数达到预期值.这种“局部控制”方法,可使现有作业更科学化和客观定量化,只在作业设备中增加一通讯单元和作为传感/变送器以及控制器的一套专业软件即可.“局部控制”方案也可嵌入以自然控制论为框架的大范围全面全程控制问题中,简化作业的方案.  相似文献   

改进SPIHT算法及硬件高速实现     

曹圣群  黄普明  于伟  鞠德航 《地球信息科学学报》2005,7(4):50-53

基于小波变换的SPIHT图像压缩方案是一种实用高性能图象压缩编码算法,但原始SPIHT算法链表式编码限制了其在高速处理中的应用。本文提出了一种改进的SPIHT压缩编码算法,在确保恢复图像质量与原始算法基本相当的基础上,改进算法可以采用并行流水结构实现,有利于高速处理中的应用,可以对高达40×8Mbit／s的原始图像实时压缩和去压缩。  相似文献   

高温高压条件下辉长岩的摩擦强度及其速率依赖性   总被引：9，自引：4，他引：5       下载免费PDF全文

何昌荣  陶青峰  王泽利 《地震地质》2004,26(3):450-460

在干燥条件下对辉长岩的摩擦本构参数进行了实验研究。结果表明 :1 )辉长岩模拟断层泥的摩擦速度依赖性参数 (a -b)基本为正或者接近于没有速度依赖性 ,表明在干燥条件下不具备不稳定滑动的成核条件 ,对下地壳地震成核的可能性有参考意义 ;2 )摩擦强度在干燥条件下与Byerlee定律高度一致 ,表明在下地壳的高温环境下Byerlee定律仍可给出适当的强度估计 ,至少在干燥条件下如此 ;3)Byerlee定律给出的剪应力强度与正应力的关系中有一个截距 ,但是本研究中关于模拟断层泥的结果却没有明显的截距 ,表明断层物质的有无在摩擦强度的表现上存在重要差异  相似文献   

Developmental energetics of the southern pigfish (Teleostei: Congiopodidae)     

D. A. Robertson 《新西兰海洋与淡水研究杂志》2013,47(4):611-620

The embryonic wet weight, dry weight, yolk volume, energy content, and oxygen consumption of the southern pigfish Congiopodus leucopaecilus (Richardson, 1846) were followed from fertilisation to yolk sac absorption, at 11.5°c and salinity of 34.5%6. Measurements of yolk energy and catabolic energy changes did not show any evidence of an energy deficit before the onset of feeding capability.  相似文献   

Behavior of soil plugs in open‐ended model piles driven into sands     

Kyu‐Ho Paik  Seung‐Rae Lee 《Marine Georesources & Geotechnology》2013,31(4):353-373

Calibration chamber tests were conducted on open‐ended model piles driven into dried siliceous sands with different soil conditions in order to clarify the effect of soil conditions on load transfer mechanism in the soil plug. The model pile used in the test series was devised so that the bearing capacity of an open‐ended pile could be measured as three components: outside shaft resistance, plug resistance, and tip resistance. Under the assumption that the unit shaft resistance due to pile‐soil plug interaction varies linearly near the pile tip, the plug resistance was estimated. The plug capacity, which was defined as the plug resistance at ultimate condition, is mainly dependent on the ambient lateral pressure and relative density. The length of wedged plug that transfers the load decreases with the decrease of relative density, but it is independent of the ambient pressure and penetration depth. Under several assumptions, the value of earth pressure coefficient in the soil plug can be calculated. It gradually reduces with increase in the longitudinal distance from the pile tip. At the bottom of the soil plug, it tends to decrease with increase in the penetration depth and relative density, and to increase with the increase of ambient pressure. This may be attributed to (1) the decrease of friction angle as a result of increase in the effective vertical stress, (2) the difference in the dilation degree of the soil plug during driving with ambient pressures, and (3) the difference in compaction degree of soil plug during driving with relative densities. Based on the test results, an empirical equation was suggested to compute the earth pressure coefficient to be used in the calculation of plug capacity using one‐dimensional analysis, and it produces proper plug capacities for all soil conditions.  相似文献   

Experimental Study on Complete Consolidation Behavior of Hong Kong Marine Deposits     

Fei Tong  Jian-Hua Yin  Huafu Pei 《Marine Georesources & Geotechnology》2013,31(4):291-304

The time-dependent feature of soft soils has gained intensive attraction in recent years. Due to the high water content and viscous property, the Hong Kong marine deposit (HKMD) frequently poses a challenge to geotechnical practice, particularly to the reclamation in Hong Kong. A key issue related to reclamation design, foundation construction and maintenance is excess settlement/deformation of the ground. Formation of HKMD typically goes through sedimentation and self-weight consolidation. A series of one-dimensional settling column consolidation tests, together with conventional oedometer tests were conducted on the HKMD. By normalizing parameter in settling stage, a unique global relationship of effective stress, σ_z′ and strain, ?_z could be established. Results reveal that the settling curve and settling rate are significantly affected by the sediment concentration in self-weight consolidation. After the primary self-weight consolidation, the settling rate is reduced in the “secondary self-weight consolidation.”  相似文献   

Experimental Evaluation of Leaching Effects on the Compressibility of Marine Clay and its Strain Rate Dependency     

Yun-Tae Kim  Thanh-Hai Do 《Marine Georesources & Geotechnology》2013,31(1):16-29

This study investigated how leaching affects compressibility behavior of marine clay and its strain rate dependency based on laboratory tests using three pairs of specimens. Each pair of specimens consisted of leached and unleached samples with identical geotechnical properties except soil salinity. The behavior characteristics of the leached and unleached specimens were evaluated using several series of constant rate-of-strain (CRS) tests with differing strain rates. The results revealed that the compressibility of leached clay increased as its salinity decreased. However, void ratio, Atterberg limits, and preconsolidation pressure in leached samples were lower than those in unleached clay. The increased compressibility and decreased preconsolidation pressure may be induced from a weakening of the interparticle bonds in the leached soil skeleton. The CRS test results with differing strain rates revealed that higher strain rates corresponded with higher levels of effective stress and higher apparent preconsolidation pressure in both leached and unleached clays.  相似文献