大兴安岭东坡中段遥感影像特征与区域成矿预测标志   总被引：1，自引：0，他引：1  

植起汉  王雨 《矿产与地质》1996,10(6):417-422

大兴安岭东坡中段的铜多金属矿产分布，ＮＥ成带，ＥＷ成行，ＮＷ成列，并构成多个矿化－构造带、矿化－构造块体，矿化－构造结。主要是受到区域ＮＥ向与ＥＷ向构造带构成的构造大格局和ＮＷ向与ＳＮ向构造带形成的构造小格局组合而成的“菱格网”状构造所控制。区域构造格局是铜多金属矿成矿构造的基础，据此区域性的遥感成矿预测，指出北段以找铜为主，中段以扩大银铅锌远景为主，深部找铜以及南段深部找铜的找矿方向。  相似文献   

杭州地区石笋稳定同位素古气候探索   总被引：1，自引：0，他引：1  

王兆荣  支霞臣  张汉昌 《沉积学报》1997,(1)

用１４Ｃ测年技术和稳定同位素地球化学古温度方法，对浙江省临安瑞晶洞穴的石笋进行了１４Ｃ的测年和碳、氢、氧同位素测试，获得５～１万年间杭州地区古气候演化记录、该记录表明，在５～１万年间有三次较明显的周期性古温度变化，最高温度为１４．９℃，最低温度为６．６℃，最大温差为８℃左右，平均温差３～５℃。这段时期正处在大理冰期后期，但大理冰期并不是一个持续的低温阶段，它至少有３次温度波动。与我们获得的石笋同位素古温度相一致。另外，我们将５～１万年间杭州地区古气候变化与同期东南沿海的海平面变化进行了对比，在时间上也较为吻合，也就是温度上升、海平面也上升，温度下降、海平面也随之下降  相似文献   

岩体力学试验的理论分析   总被引：1，自引：2，他引：1  

刘钧  郭志 《工程地质学报》1997,5(2):156-162

本文通过对岩石力学试验中岩石试件破坏方式的分析, 在理论上解释了岩体力学试验中经常遇到的一些力学现象并且作出了定量的回答, 同时还建立了岩石的各种破坏模式的判据。  相似文献   

大别山沙村中生代A型花岗岩和基性岩的源区演化关系   总被引：4，自引：5，他引：4  

谢智  郑永飞闫峻　钱卉 《岩石学报》2004,20(5):1175-1184

A型花岗岩的成因虽存在不同的认识模式,但对大别山沙村A型花岗岩的岩石化学和地球化学研究结果表明,其物质源自大陆岩石圈地幔的部分熔融,含有古老地壳信息。结合被侵入基性岩的地球化学和年代学资料,推测大别造山带中生代岩石圈地幔的地球化学性质与下扬子地幔相似。花岗岩中锆石SHRIMP法U-Pb年龄为119.0±3.2Ma,说明其岩浆侵位于早白垩世,与邻近的基性岩侵位时间相近但稍晚。在三叠纪因大陆俯冲碰撞增厚的岩石圈在早白垩世被拉张减薄,含有古老地壳成分的扬子陆下岩石圈地幔及其上覆下地壳发生部分熔融,形成了不同成分的碰撞后岩浆岩。其中部分基性岩浆分异结晶成为辉长岩,而A型花岗岩可能是同一地幔源区物质小比例部分熔融后分异结晶的产物。  相似文献   

湖北省土壤侵蚀景观空间异质性及驱动因子分析     

张志  王少军 《中国地质灾害与防治学报》2004,15(4):49-53

地域分异是地球表层大小不等、内部具有一定相似性地段之间的相互分化以及由此产生的差异。为了研究不同区位土壤侵蚀问题，从土壤生态景观及系统论出发，运用地质学、地理学、景观生态学、环境学的理论和研究方法，研究湖北省土壤侵蚀景观空间格局及其驱动因子，使土壤侵蚀问题研究提高到一个新的水平。湖北省土壤侵蚀景观具有南北分带、东西分区，为一不对称的断块一环组合，土壤流呈现向长江、江汉盆地中心轴带辐聚、单流向特点。景观空间异质性形成的首要驱动因子是大地构造背景，以房县一襄樊一广济断裂带为界，南北两侧地壳物质组成和构造发展史存在较明显的差异，现代气候带、降雨量、温热程度及土地利用等差异，造成了湖北省区域土壤地理、土壤生态的分异，形成湖北省土壤生态带、区具有南北分带，东西分区的宏观格局；其次大兴安岭一武陵山深部构造陡变带两侧新构造运动强度差异、大别造山带构造强烈隆升，导致土壤侵蚀强度的西强东弱、南北强中间弱的态势；成土母岩差异性决定了土壤可蚀性的多变；空间上“土壤侵蚀内城区”分布在湖北省的周边地区，经济贫困、管理落后，这一地区的经济水平与水土流失间形成“自反馈作用”，这一现象在我国水土保持、生态建设工作中应该引起重视。  相似文献   

定点连续形变长周期频段信息研究     

孙毅  汪智 《四川地震》2005,(2):35-39

研究了定点连续形变长周期频段信息和块体构造活动的关系。研究结果表明，在川滇菱形块体内，定点连续形变观测获得的长周期频段信息中的长期趋势变化除去仪器零漂等局部干扰外，基本上都和块体运动方向或者块体边界主干断裂活动方式相一致，表明在定点连续形变长周期频段信息中，也存在有与地震孕育有关的地壳形变信息。对其在预报上的作用做了初步研究。  相似文献   

2-D crustal Poisson's ratio from seismic travel time inversion in Changbaishan Tianchi volcanic region     

LIU Zhi  ZHANG Xian-kang  WANG Fu-Yun  DUAN Yong-Hong  LAI Xiao-Ling 《地震学报(英文版)》2005,18(3)

Based on the inversion method of 2D velocity structure and interface, the crustal velocity structures of P-wave and S-wave along the profile L1 are determined simultaneously with deep seismic sounding data in Changbaishan Tianchi volcanic region, and then its Poisson's ratio is obtained. Calculated results show that this technique overcomes some defects of traditional forward calculation method, and it is also very effective to determine Poisson's ratio distribution of deep seismic sounding profile, especially useful for study on volcanic magma and crustal fault zone. Study result indicates that there is an abnormally high Poisson's ratio body that is about 30 km wide and 12 km high in the low velocity region under Tianchi crater. Its value of Poisson's ratio is 8% higher than that of surrounding medium and it should be the magma chamber formed from melted rock with high temperature. There is a high Poisson's ratio zone ranging from magma chamber to the top of crust, which may be the uprise passage of hot substance. The lower part with high Poisson's ratio, which stretches downward to Moho, is possibly the extrusion way of hot substance from the uppermost mantle. The conclusions above are consistent with the study results of both tomographic determination of 3D crustal structure and magnetotelluric survey in this region.  相似文献   

2-D crustal Poisson’s ratio from seismic travel time inversion in Changbaishan Tianchi volcanic region   总被引：1，自引：0，他引：1  

Liu Zhi  Zhang Xian-kang  Wang Fu-yun  Duan Yong-hong  Lai Xiao-ling 《地震学报(英文版)》2005,18(3):345-353

Based on the inversion method of 2D velocity structure and interface, the crustal velocity structures of P-wave and S-wave along the profile L ₁ are determined simultaneously with deep seismic sounding data in Changbaishan Tianchi volcanic region, and then its Poisson’s ratio is obtained. Calculated results show that this technique overcomes some defects of traditional forward calculation method, and it is also very effective to determine Poisson’s ratio distribution of deep seismic sounding profile, especially useful for study on volcanic magma and crustal fault zone. Study result indicates that there is an abnormally high Poisson’s ratio body that is about 30 km wide and 12 km high in the low velocity region under Tianchi crater. Its value of Poisson’s ratio is 8% higher than that of surrounding medium and it should be the magma chamber formed from melted rock with high temperature. There is a high Poisson’s ratio zone ranging from magma chamber to the top of crust, which may be the uprise passage of hot substance. The lower part with high Poisson’s ratio, which stretches downward to Moho, is possibly the extrusion way of hot substance from the uppermost mantle. The conclusions above are consistent with the study results of both tomographic determination of 3D crustal structure and magnetotelluric survey in this region. Foundation item: Key Project from China Earthquake Administration and the Project (95-11-02-01) from Ministry of Science and Technology (2001DIA10003). Contribution No. RCEG200401, Geophysical Exploration Center, China Earthquake Administration.  相似文献   

Strength Analysis on Brace Structure for Semi-Submersible in Consideration of Wave Slamming     

Fa-li Huo  Zhi Yao  Jian Zhang  Jun-wei Wang  Bin Dong 《中国海洋工程》2018,32(5):536-545

Slamming on bracings of column stabilized units shall be considered as a possible limiting criterion under transit condition based on the requirements in DNV-OS-C103. However, the wave slamming loads under survival condition were ignored for the strength analysis of the brace structures in many semi-submersible projects. In this paper, a method of strength analysis of brace structure is proposed based on the reconstruction and extrapolation of numerical model. The full-scale mooring system, the wind, wave and current loads can be considered simultaneously. Firstly, the model tests of the semi-submersible platform in wind tunnel and wave tanker have been carried out. Secondly, the numerical models of the platform are reconstructed and extrapolated based on the results of model tests. Then, a nonlinear numerical analysis has been conducted to study the wave slamming load on brace in semi-submersible platform through the reconstructed and extrapolated numerical model. For the randomness of wave load, ten subcases under each condition have been carried out. The value of the 90% Gumble distribution values of the ten subcases are used. Finally, the strength on brace structure has been analyzed considering the wave slamming. The wave slamming loads have been compared between the survival condition and transit condition with the method. The results indicate that wave slamming under survival condition is more critical than that under transit condition. Meanwhile, the wave slamming is significant to the structural strength of the brace. It should be overall considered in the strength analysis of the brace structure.  相似文献   

Vortex-Induced Vibrations of A Long Flexible Cylinder in Linear and Exponential Shear Flows     

Gao  Yun  Yang  Bin  Zou  Li  Zong  Zhi  Zhang  Zhuang-zhuang 《中国海洋工程》2019,33(1):44-56

A numerical study based on a wake oscillator model was conducted to determine the response performance of vortex-induced vibration(VIV) on a long flexible cylinder with pinned-pinned boundary conditions subjected to linear and exponential shear flows. The coupling equations of a structural vibration model and wake oscillator model were solved using a standard central finite difference method of the second order. The VIV response characteristics including the structural displacement, structural frequency, structural wavenumber, standing wave behavior,travelling wave behavior, structural velocity, lift force coefficient and transferred energy from the fluid to the structure with different flow profiles were compared. The numerical results show that the VIV displacement is a combination of standing waves and travelling waves. For linear shear flow, standing waves and travelling waves dominate the VIV response within the low-velocity and high-velocity zones, respectively. The negative values of the transferred energy only occur within the low-velocity zone. However, for exponential shear flow, travelling waves dominate the VIV response and the negative energy occurs along the entire length of the cylinder.  相似文献