钱塘—钦防古板块结合带及其地质意义     

郦逸根 《浙江国土资源》2000,(1)

作为扬子、华夏古板块的结合带 ,奠基于四堡—晋宁期形成的陆间造山带 ,表现出有别于两翼而独特的地球物理、地质构造特征。其发展演化主要是伴随华南板块的形成过程 ,历史比较复杂。由于活动性较大、多期次裂谷、造山作用和多期岩浆活动 ,使结合带成为一条深源岩浆活动带。结合带的构造—岩浆—成矿基本特点表明 ,燕山期的成矿作用具“成因多类型 ,定位多部位”特点 ,是一条潜在的巨大弧型斑岩成矿带。  相似文献   

Junction and Evolution of the Qinling, Qilian and Kunlun Orogenic Belts   总被引：2，自引：0，他引：2  

SUN Yangui  CHEN Zhengxing  LIU Yong''an  WANG TongqingQinghai Regional Survey  Comprehensive Geological Party  Nanchuan West Ro  Xining  Qinghai Province  ZHANG Zhiyong Qinghai Institute of Geological  Mineral Exploration  Xining  Qinghai 《《地质学报》英文版》2000,74(2):223-228

As the main part of the "central mountain system" in the continent of China, the Qinling, Qilian and Kunlun orogenic belts have been comprehensively and deeply studied since the 1970s and rich fruits have been reaped. However, these achievements were mostly confined to an individual orogenic belt and the study of the mutual relationship among the three orogenic belts was obliged to depend on comparative studies. Different views were produced therefrom. The material composition and structural features of the junction region show that there are several epicontinental and intracontinental transform faults developed in different periods. Restricted by these transform faults, the large-scale lateral movements and, as a consequence, complicated magrnatism and tectonic deformation took place in the orogenic belts. According to these features, the authors put forward a three-stage junction and evolution model and point out that there is not a single junction zone traversing from west to east but that the three  相似文献   

MAPGIS库管理子系统的运用方法及其意义     

张艳玲  叶萍  王国良 《吉林地质》2000,19(3):71-73,82

本文通过应用ＭＡＰＧＩＳ软件的实践,初步总结出其库管理子系统的运用方法,主要谈及以下三方面的问题：１．建库;２．图幅接边;３．图幅的检索输出。作者以１：５万地质图数据库为例,讨论了１：５万数据库的基础性,现实性以及重要性。  相似文献   

电容扫描法热电偶多路温度数据采集仪     

张耀南 《冰川冻土》1991,13(4):359-362,358

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板块三节点     

李三忠  吕海青  侯方辉  郭晓玉  金宠  刘保华 《海洋地质前沿》2004,20(11):29-39

三条板块边界常相交于一点，这一个交点就叫做板块三联接合点(简称三联点，或称三节点)。三联点相接的3个板块之间的边界可以是拉张型、挤压型或剪切型的边界，它们的组合类型比较复杂，而且稳定性不同，这对精细研究海底构造格局与演化具有重要的意义。三节点的稳定性取决于相邻板块运动的方向，一个空间位置稳定的三节点不一定在演化期间其构造活动性是稳定的或空间位置永远不变，一个不稳定的三节点必然发展到稳定的三节点。文中系统分析了海沟、洋脊以及转换断层的16种组合的几何学和相关三节点的稳定性。  相似文献   

The Rodriguez Triple Junction (Indian Ocean): Structure and evolution for the past one million years   总被引：1，自引：0，他引：1  

M. Munschy  R. Schlich 《Marine Geophysical Researches》1989,11(1):1-14

The Rodriguez Triple Junction (RTJ) corresponds to the junction of the three Indian Ocean spreading ridges. A detailed survey of an area of 90 km by 85 km, centered at 25°30 S and 70° E, allows detailed mapping (at a scale of 1/100 000) of the bathymetry (Seabeam) and the magnetic anomalies. The Southeast Indian Ridge, close to the triple junction, is a typical intermediate spreading rate ridge (2.99 cm a^-1 half rate), trending N140°. The Central Indian Ridge rift valley prolongs the Southeast Indian Ridge rift valley with a slight change of orientation (12°). The half spreading rate and trend of this ridge are 2.73 cm a^-1 and N152° respectively. In contrast, the Southwest Indian Ridge close to the triple junction is expressed by two deep-valleys (4300 and 5000 m deep) which abut the southwestcrn flanks of the two other ridges, and appears to be a stretched area without axial neovolcanic zone. The evolution of the RTJ is analysed for the past one million years. The instantaneous velocity triangle formed by the three ridges cannot be closed indicating that the RTJ is unstable. A model is proposed to explain the evolution of the unstable RRF Rodriguez Triple Junction. The model shows that the axis of the Central Indian Ridge is propressively offset from the axis of the Southeast Indian Ridge at a velocity of 0.14 cm a^-1, the RTJ being restored by small jumps. This unstable RRF model explains the directions and offsets which are observed in the vicinity of the triple junction. The structure and evolution of the RTJ is similar to that of the Galapagos Triple Junction located in the East Pacific Ocean and the Azores Triple Junction located in the Central Atlantic Ocean.  相似文献   

米仓山与龙门山结合部构造分带性特征     

谢志良  刘树根  赵磊  邓宾  孙东 《四川地质学报》2012,(4):385-388

通过褶劈理化、叠加变形、褶皱和破裂等构造发育强度、构造形迹、岩性地层单元等研究认为,米仓山与龙门山结合部具有明显的构造分带性,从北往南构造变形强度逐渐减弱,大致可分为四个构造带。这种分带变形特征是由于秦岭、龙门山、米仓山不同时期综合作用的结果,并主要受秦岭构造带控制,往南受龙门山和米仓山构造的改造和限制作用,变形强度逐渐减弱,形成分带性特征。  相似文献   

River system discontinuities due to lateral inputs: generic styles and controls     

Robert I. Ferguson  Judith R. Cudden  Trevor B. Hoey  Stephen P. Rice 《地球表面变化过程与地形》2006,31(9):1149-1166

In alluvial river systems, lateral inputs of water and/or sediment at junctions or undercut hillsides can disrupt what would otherwise be smooth downstream trends in mainstream bed elevation, channel gradient, and bed grain size. Generic styles of mainstream response to lateral inputs are investigated using a one‐dimensional sediment routing model with multiple grain size fractions. Numerical experiments isolate the effects of three para‐meters: ratio of tributary to mainstream water flux (QR), ratio of tributary to mainstream bedload flux (FR), and ratio of tributary to mainstream bedload diameter (DR). The findings are not unduly sensitive to the choice of initial conditions or to approximations made in the model. The primary distinction is between junctions that aggrade, causing local profile convexity with interrupted downstream fining, and junctions that degrade. The immediate effects of aggradation extend further upstream than downstream, whereas degradation is much more subdued and has no upstream impact. Aggradation is typical of coarse inputs (DR > 2), and degradation of fine inputs (DR < 1), but very high ratios of QR to FR also promote degradation. Both aggrading and degrading junctions can lead to a change in mainstream bed grain size well below the junction, with higher ratios of QR to FR producing a coarser distal bed. The effect of a tributary reflects the interplay between additional bed load and additional discharge to transport it. Copyright © 2006 John Wiley & Sons, Ltd.  相似文献   

Joint interpretation of the size and time distributions of seismic activity around the Hengill triple junction (SW Iceland) between 1993 and 1999     

Christoph Sens-Schönfelder  Michael Korn  Ragnar Stefánsson 《Journal of Seismology》2006,10(2):237-246

A newly developed clustering algorithm is described which uses the Unified Scaling Law for earthquakes to identify correlations between events that lead to clustering. This algorithm is applied to a dataset from the Hengill triple junction in south west Iceland to separate spatially and temporally overlapping earthquake sequences. We show that the algorithm successfully identifies spatio-temporally clustered events.A search for certain patterns in the identified clusters is performed. These patterns emerged in numerical simulations of seismicity performed by Hainzl (2003) when viscous coupling was introduced in order to reproduce features of swarm earthquakes. Namely we look for a combination of increased Gutenberg-Richter b-value and decreased exponent of the waiting-time distribution α. This pattern, indicating the strongest influence of viscous coupling on the characteristics of the seismicity, could be localized beneath an extinct volcano approximately 5 km north of an area of recent crustal uplift.  相似文献   

西昆仑—塔里木盆地盆-山结合带的中、新生代变形构造及其动力学   总被引：15，自引：0，他引：15  

崔军文  郭宪璞  丁孝忠  李朋武  张晓卫 《地学前缘》2006,13(4):103-118

西昆仑—塔里木盆地盆-山结合带可划分为西昆仑北带和塔里木地块南缘拗陷带(塔南拗陷带)两个构造单元,后者由塔西南拗陷带和塔东南断陷带两部分组成。西昆北带分别以库地—喀什塔什断裂和西昆北冲断裂与西昆中带和塔里木地块南缘拗陷带相隔。盆-山构造经历了长期、叠次的形成、演化过程,但不同时期、不同层次的变形构造具有极大的统一性,总体表现为以西昆中断裂(其主体为库地—喀什塔什断裂)为根带,以北向逆冲扩展作用为主导,向北至塔南拗陷带腹部,逐渐转化为以垂直向上的构造伸展作用为主导。塔南拗陷带的逆冲断裂与具强烈深层流变组构的西昆北逆冲断裂属统一地球动力学系统中不同构造层次的成分,前者是后者向浅层脆性应变域扩展的产物。导致盆-山构造形成的驱动力来自昆仑构造带以南的持续、强烈的北向逆冲扩展作用,至少在塔南拗陷带的前早更新统地层分布区不存在塔里木地块自北向南俯冲的直接证据。西昆仑—塔里木盆地南缘的造盆、造山作用过程可简单地归纳为三个形成演化阶段:晚侏罗世—早白垩世的快速隆升和快速拗陷(沉降)期、晚白垩世—古近纪的深层拆离-缓慢隆升和均匀拗陷(沉降)期和新近纪至今的挤压-急剧隆升和强烈拗陷(沉降)期。造盆、造山作用的动力学过程表明,中—上新世是造盆造山作用机制发生重大转折时期,早更新世末的构造运动基本上奠定了西昆仑—塔里木盆地南缘的盆-山构造格架。  相似文献