云南德钦加仁铜矿含矿岩体构造及含矿性     

张宗勇 《云南地质》2010,29(2):123-127,122

与加仁岩体有关的铜多金属矿床(点)较多,岩体构造复杂。在岩体分布区,划分岩体内部和外部宏观构造,查明不同构造之间的区别和联系,应是找矿的前题和基础,更是评价和预测矿产资源潜力的必要条件和首要任务。  相似文献   

云南麻栗坡洒西丫口白钨矿成矿规律   总被引：1，自引：0，他引：1  

许翠芳  舒培华  王建萍 《云南地质》2010,29(3):318-322

晚志留世和白垩纪岩浆活动为成矿提供热源,碳酸盐岩为成矿提供化学反应场所、溶矿空间。圈出的3条白钨矿体以简单似层状沿Pt3s/Pt3n间构造面理(韧性剪切断裂带)产出,受Pt3s底部的层状矽卡岩(钙硅酸盐岩)控制。进一步工作,可望在接触带两侧找到理想白钨矿床。  相似文献   

柴达木盆地断裂体系划分及其成盆动力学意义     

吕宝凤  杨永强  李丽 《西北地质》2010,43(4):143-151

断裂体系是具有成生联系的各项不同产状、不同等级、不同性质和不同序次的断层组合,柴达木盆地受到印度、西伯利亚和太平洋三大板块的共同影响,围绕中部刚性基底周边发育北部祁连山、南部东昆仑山及西部阿尔金山三大断裂体系,每个断裂体系都是由主要断裂及其伴生的断层相关褶皱组成三排波浪式冲断构造,低序次断层及其相关褶皱呈斜列式分布于其间,整个盆地可以看成三大断裂体系叠合的产物,其根本动力学背景是柴达木地块受到南部印度板块向北挤压、北部阿拉善地块的阻挡及东侧华北板块和西侧塔里木板块的侧滑而形成的力偶环境,结合平衡剖面分析结果提出盆地发展经历了早—中侏罗世南北向拉张、新生代多次幕式挤压并叠加东西向侧向走滑、并于第四纪形成现今的构造面貌的发展历史。  相似文献   

Structural architecture of the northern composite terrane, the Eastern Ghats Mobile Belt, India: Implications for Gondwana tectonics     

T.R.K. Chetty   《Gondwana Research》2010,18(4):565-582

New data from structural mapping and tectonic evaluation in the northern parts of the Eastern Ghats Mobile Belt (EGMB-north) involving the interpretation of satellite images, field traverses, critical outcrop mapping and kinematic studies of macro- as well as microstructures of the shear zone rocks together with the geometry and disposition of Gondwana basins led to, for the first time, the elucidation of post-Grenvillian structural architecture of the terrane. This helps in assessing the sequence of successive tectonothermal events that were responsible for the origin and progressive evolution of the Permo-Carboniferous coal bearing sediments along the Mahanadi rift that forms significant in the reconstruction models of east Gondwana.The composite terrane of high-grade metamorphic rocks (EGMB-north), strikes E–W in contrast to the regional NE–SW trend of the EGMB. The structural architecture obtained from this study is controlled by the boundary shear zones and associated link shear zones. The dextral kinematic displacements along the Northern Boundary Shear Zone (NBSZ) as well as the Mahanadi Shear Zone (MSZ) and Koraput–Sonapur–Rairakhol Shear Zone (KSRSZ) were derived from multi-scale field based structural observations. A N–S structural cross-section presents a crustal-scale ‘flower structure’ across the composite terrane exposing different domains displaying distinctive internal structures with widely varying different geological evolution history and strain partitioning, separated by crustal-scale shear zones. Deep seismic imaging and gravity signatures support ‘flower structure’ model. The pervasive first formed gneissic fabrics were continuously reworked and partitioned into a series of E–W, crustal-scale shear zones.The Neoproterozoic regional dextral transpressional tectonics along the shear zones and their repeated reactivation could be responsible for initiation and successive evolution of Gondwana basins and different episodes of sedimentation. Available geochronological data shows that the structural architecture presented here is post-Grenvillian, which has been repeatedly reactivated through long-lived transpressional tectonics. The composite terrane is characterized by all the typical features of an oblique convergent orogen with transpressional kinematics in the middle to lower crust. The kinematic changes from transpression to transtensional stresses were found to be associated with global geodynamics related to the transformation from Rodinia to Gondwana configuration.  相似文献   

Developing a robust simplified method for structural integrity monitoring of offshore jacket-type platform using recorded dynamic responses     

《Applied Ocean Research》2016

  相似文献   

龙门山中段山前带浅层冲断系统的结构、形成与演化   总被引：4，自引：0，他引：4  

鲁人齐  何登发  John Suppe  马晓鸣  桂宝玲  王明健  高金尉 《地质科学》2010,45(4):997-1010

本文依据断层相关褶皱几何学原理,对龙门山中段地震剖面进行了精细解释。研究发现,龙门山中段山前带浅层冲断系统存在多套滑脱层,具有上下分层变形特征。浅层滑脱层为上三叠统须家河组三段(T_3~x3)的碳质页岩夹煤层,其上发育双重构造和叠瓦构造;下三叠统嘉陵江组四、五段(T_1j~(4-5))的膏岩层,发育断层传播褶皱、冲起构造和构造楔;深层为下寒武统的泥页岩层,发育断层转折褶皱和滑脱褶皱。该区滑脱断层所控制的地层变形和缩短量各不相同,其中三叠系上统缩短量最大,大于30 km;三叠系下统至古生界地层缩短量约为14.5 km;侏罗系以上的地层缩短量则较小。研究区内的通济场断裂(F_3)为印支末期形成的一套逆冲断层组,其下部交于下寒武统滑脱层,深度约为10 km;关口断层(F_4)和彭县断裂(F_5)为晚侏罗世一早白垩世形成的逆冲断层,下部交与下三叠统嘉陵江组滑脱层,深度大约为8～10 km。这些断层以前展的方式破裂,并且长期活动。龙门山中段自中生代以来存在多期构造事件,主要发生诺利末期、印支晚幕、燕山期和喜马拉雅期。其中,燕山期和喜马拉雅期是龙门山活动最强烈的两个阶段,在龙门山中段山前带表现为大量断裂的长期活动,地壳缩短和龙门山快速隆升,并形成多种构造样式。  相似文献   

徐家围子断陷构造地质特征研究新进展   总被引：14，自引：1，他引：13  

张元高  陈树民  张尔华  姜传金 《岩石学报》2010,26(1):142-148

在徐家围子断陷深层连片三维地震精细解释的基础上,结合前人的研究成果,系统的刻画了深大断裂的性质、产状和时空分布规律。从区域构造应力场着手,详细剖析了徐家围子断陷的构造地质特征,重新构建了深大断裂体系。依据剖面特征和断陷的地质结构,首次在徐家围子断陷内解释出两条深大走滑断裂带,发现深大走滑断裂控制了营城组火山岩的形成和分布。明确了徐家围子断陷"两凹夹一隆、东西分带、南北分块"构造格局的动态演化过程及其控制因素。详细剖析了断陷期地层的沉积发育过程、后期改造过程以及现今赋存特征。为庆深气田火山岩储层分布规律预测奠定了基础。  相似文献   

GPS in dynamic monitoring of long-period structures   总被引：6，自引：0，他引：6  

M.   《Soil Dynamics and Earthquake Engineering》2000,20(5-8):477-483

Global Positioning System (GPS) technology with high sampling rates (10 samples per second) allows scientifically justified and economically feasible dynamic measurements of relative displacements of long-period structures—otherwise difficult to measure directly by other means, such as the most commonly used accelerometers that require post-processing including double integration. We describe an experiment whereby the displacement responses of a simulated tall building are measured clearly and accurately in real-time. Such measurements can be used to assess average drift ratios and changes in dynamic characteristics, and therefore can be used by engineers and building owners or managers to assess the building performance during extreme motions caused by earthquakes and strong winds. By establishing threshold displacements or drift ratios and identifying changing dynamic characteristics, procedures can be developed to use such information to secure public safety and/or take steps to improve the performance of the building.  相似文献   

High-precision relative thermobarometry: theory and a worked example   总被引：7，自引：1，他引：6  

Worley  & Powell 《Journal of Metamorphic Geology》2000,18(1):91-101

A number of sources of uncertainty are involved in thermobarometric calculations, the most important of which are associated with analytical precision, activity–composition ( a – x ) relationships, and thermodynamic data. Statistical treatment of these uncertainties results in relatively large uncertainties on the calculated values of pressure and temperature. Little can be done, at least in the short term, about the magnitude of such uncertainties, and any thermobarometric calculations in which they are not taken into account should be treated with caution. Given that uncertainties associated with a–x models and thermodynamic data are systematic when applied to multiple samples with the same mineral assemblage, a solution to the problem of imprecise absolute thermobarometry can be obtained via a relative thermobarometric technique referred to as the Δ PT  approach. The Δ PT  approach offers a major improvement in the precision of thermobarometry if the calculations can be presented in a Δ PT  context.  相似文献   

Earthquake resistant building design codes and safety standards: The California experience     

Stephen H. Cutcliffe 《GeoJournal》2000,51(3):259-262

Seismologists and earthquake engineers have sought to understand and predict earthquakes and to develop better building designs to withstand them for well over a century. In the United States, the 1906 San Francisco earthquake provided the first real impetus for establishing building design codes and safety standards. Subsequent major California earthquakes in Santa Barbara (1925), Long Beach (1933), San Fernando (1971), Loma Prieta (1989), and Northridge (1994) each led to additional seismological understanding and engineering response in the form of enhanced building design codes. Nonetheless, the process to incorporate good seismic design and mitigation efforts has been slow, and by no means failsafe, especially in the Eastern U.S. where much of the building stock predates more recent design codes, and hence where a major earthquake could collapse large numbers of buildings. Even in the absence of catastrophe, it is still important to guard against a false sense of security.  相似文献