措勤地区竟柱山组沉积特征及构造意义   总被引：3，自引：0，他引：3       下载免费PDF全文

唐熊  陶晓风 《沉积与特提斯地质》2009,29(1):53-57

上白垩统竟柱山组在西藏措勤地区主要沿班公湖-怒江缝合带、且坎-古昌-阿索断裂带和塔若错北-达瓦错南-秋措麦凹陷带断续分布。主要为一套磨拉石的紫红色碎屑岩,其沉积环境以扇三角洲和三角洲为主。扇三角洲和三角洲的前积层理指示了其进积方向,表明早期物源来自北部,而晚期来自南部的陆源物质增加。竞柱山组磨拉石沉积的发育,是班公湖-怒江缝合带造山运动的证据。  相似文献   

西藏纳当地区永珠组构造变形特征          下载免费PDF全文

李军敏  郑来林  龙斌  夏祥标 《沉积与特提斯地质》2009,29(3):101-104

西藏纳当地区石炭系永珠组主要为浅变质的砂板岩组合,断层和褶皱非常发育的特征。依据岩石和构造特征可以把区内永珠组分成上、中、下三段。永珠组形成于拉张的被动大陆边缘向裂谷转换的次深海环境,并于中晚二叠世至晚三叠世期间经历了三个构造演化阶段。  相似文献   

扬子区震旦纪地层序列和南、北方震旦系对比   总被引：18，自引：7，他引：18  

薛耀松  曹瑞骥  唐天福  尹磊明  俞从流  杨杰东 《地层学杂志》2001,25(3):207-216,234

198 2年“晚前寒武纪地层分类命名会议”决议“震旦系是青白口系之上的晚元古代最上部的一个年代地层单位 ,以三峡地区的剖面为代表 ,暂以莲沱组底界为底界”。但从区域性对比和同位素年代地层学分析 ,莲沱组底至黄陵花岗岩的侵蚀面之间有约 10 0 Ma的沉积缺失 ,莲沱组和南沱组也不能代表 75 0～ 6 6 0 Ma间的沉积历史。峡东地区震旦系下部地层不完整是显而易见的。本文赞同修订震旦系的含义 ,以下冰碛层 (古城组或铁丝坳组 )之底为震旦系的底界 ,年龄为 70 0 Ma。朝鲜飞浪洞组可与古城组、大塘坡组和南沱组对比 ,祥原系及辽南、徐淮地区的相当地层属“南华冰期”前的沉积地层。建议震旦系之下至青白口系顶 (85 0 Ma)之间建立辽南系 ,从而完善我国晚元古代年代地层框架  相似文献   

A Review of “The Middle East Today: Political,Geographical and Cultural Perspectives”     

R. Andrew Worthington 《The Professional geographer》2013,65(3):455-456

The tremendous changes in China's development philosophy and regional economies during the last two decades have carved out selectively new locations of development across the nation. While politicians heatedly debate the acceptable levels of regional inequality, most scholarly studies focus on broad aggregate trends of inequality among provinces and groups of provinces, and pay little attention to identifying and conceptualizing sources and major agents of spatial change. This paper aims at revealing detailed spatial ramifications of the reforms, and at understanding the impacts of the state, local agents, and foreign investors on regional development. To this effect, we conduct a disaggregated and empirical study of Jiangsu, a coastal province experiencing dramatic economic and spatial restructuring. We show that local agents which favor rural industrial enterprises accelerated new growth in selected rural areas, in contrast to slower growth of older cities and state-owned enterprises, resulting in a net decline of intercounty inequality. But the coalescence of state policy, local agents, and foreign investment has widened the historical gap between northern and southern Jiangsu, and is likely to accelerate intercounty inequality in the future. Our study demonstrates the utility of the “developments from above, below and outside” framework for analyzing key forces of regional growth in socialist transitional economies.  相似文献   

北部湾沿海地区土地利用动态模拟与水源涵养服务能力估算——以广西钦州市为例   总被引：2，自引：0，他引：2  

田义超  梁铭忠  吴彬 《云南地理环境研究》2013,(5):69-78

分析北部湾沿海地区广西钦州市土地利用格局及未来变化趋势,为开展该地区土地利用规划和生态服务价值中的水源涵养服务能力估算提供决策依据.以2000年、2010年的TM遥感影像以及各种驱动因子数据为基础,耦合Binary Logistic及CA-Markov模型对研究区2020年的土地利用格局进行模拟,并对研究区的水源涵养服务能力进行估算.结果表明：（1） 2000～2010年各种土地利用类型的转化强度大且比较复杂,尤以耕地、林地和水域之间的流动最为显著,建设占用耕地和林地的面积高达2 003.31 hm2;（2）由Binary Logistic逻辑斯蒂回归方程所得出的各种土地利用类型ROC拟合值中最小为0.686,最大达到0.952,模拟效果良好;（3）预测年2020年建设用地增加的区域主要集中在钦州市钦南区的市区周边,向东方向扩展,变化比较剧烈的地方主要是钦州港区和研究区域的北部;（4）单位面积水源涵养能力的排序依次为：水域＞林地＞草地＞耕地＞建设用地＞未利用地,3个年份的水源涵养服务能力在空间上均呈现出“东南部高西北部低,中心地带持续衰减”的趋势.  相似文献   

基于陆路交通网的空间通达性分析——以兰州-西宁城市区域为例     

白永平  吴常艳  陈博文 《山地学报》2013,31(2):129-139

以兰州-西宁城市区域交通路网为例,基于空间句法模型、日常可达性模型和等时圈通过特征点算法,试图运用GIS技术将节点、轴线和域面结合起来对通达性进行全面阐述,多视角综合测度区域路网通达性的空间格局。研究结果表明:1.区域路网体系较为完善,路网线段集聚相对明显;线段式空间伸展格局呈"点-轴"状,轴线式空间伸展格局呈"干-枝"状,初步形成核心、过渡、外围三大等级圈层以及"X"字型路网骨架,区域交通运输与城镇发展水平表现出较强的共轭协同发展关系。2.等时圈沿国道、省道、县道扩散表现连续,沿封闭铁路、高速公路扩散出现跳跃,其等时圈空间特征多呈现"枝-叶"状。城镇日常可达性在较大程度上取决于区域中心性、周边路网发达程度和城镇密集程度,区域路网单中心极化现象比较明显,兰州市对整个区域路网的控制作用较为突出。3.区域通达度空间分布各异,核心板块破碎而外围板块连片。区域通达性差异极其显著,出现极高值区和极低值区;兰州与西宁通达度中高值区出现断裂,区域南部通达度极低值区连片成带。因此,应当构建兰州地区绕城高速和环状路网,实现路网交通的适度分流;加快兰州-西宁高等级快速交通建设,推进兰州-西宁区域一体化进程;建设兰成铁路和兰州至云南磨憨口岸高速通道,培育临夏为南部区域性中心城市。  相似文献   

Modeling the scale dependences of topological relations between lines and regions induced by reduction of attributes     

Shihong Du  Qiao Wang  Luo Guo 《International journal of geographical information science》2013,27(11):1649-1686

The scale dependences of topological relations are caused by the changes of spatial objects at different scales, which are induced by the reduction of attributes. Generally, the detailed partitions and multi-scale attributes are stored in spatial databases, while the coarse partitions are not. Consequently, the detailed topological relations can be computed and regarded as known information, while the coarse relations stay unknown. However, many applications (e.g., multi-scale spatial data query) need to deal with the topological relations at multiple scales. In this study new methods are proposed to model and derive the scale dependences of topological relations between lines and multi-scale region partitions. The scale dependences of topological relations are modeled and used to derive the relations between lines and coarse partitions from the relations about the detailed partitions. The derivation can be performed in two steps. At the first step, the topological dependences between a line and two meeting, covered and contained regions are computed and stored into composition tables, respectively. At the second step, a graph is used to represent the neighboring relations among the regions in a detailed partition. The scale dependences and detailed relations are then used to derive topological relations at the coarse level. Our methods can also be extended to handle the scale dependences of relations about disconnected regions, or the combinations of connected and disconnected regions. Because our methods use the scale dependences to derive relations at the coarse level, rather than generating coarse partition and computing the relations with geometric information, they are more efficient to support scale-dependent applications.  相似文献   

关中地区3次中小地震前后的重力变化   总被引：1，自引：1，他引：0  

高好林 《中国地震》2013,29(3):367-376

采用拟稳平差方法对关中地区近20 年流动重力观测资料重新进行了处理,并结合其它观测资料和研究结果,对区域内重力场变化过程、3次中小地震前后重力场变化机理、构造活动以及区内外地震间的关系等进行了较深入地分析和研究。  相似文献   

Analytical and experimental investigations on seismic performance of exterior beam–column subassemblages of existing RC‐framed building     

Saptarshi Sasmal  K. Ramanjaneyulu  Balthasar Novák  N. Lakshmanan 《地震工程与结构动力学》2013,42(12):1785-1805

Seismic performance of exterior beam–column subassemblages of reinforced concrete structure designed and detailed on the basis of the provisions of Eurocode and Indian Standards at different stages of their evolution is evaluated. Performance of the subassemblages designed and detailed according to the three different stages of codal evolution (gravity load design, ‘Nonductile’, and ‘Ductile’) is evaluated through analytical formulations and experimental investigations. In the ‘NonDuctile’ specimens, it has been observed that the shear distortion and degradation in stiffness and strength are significantly high. Performance of the ‘Ductile’ specimens based on Eurocode and Indian Standards is almost similar in terms of strength and stiffness degradation. Nevertheless, the specimen designed on the basis of Indian Standard shows higher energy dissipation at a given drift ratio. In the analytical study, shear and flexural failure of members of subassemblage and shear failure of the joint are considered as possible modes of failure of the beam–column subassemblage. For evaluating the shear strength of the joint region, a soften strut‐and‐tie model is used. Analytically obtained strengths based on the failure criteria of different components of the specimens have been first validated with experimental results and then used to determine the strength of the specimens. The investigation could indicate even the mode of failure at local level. It is utmost important to mention here that even the ductile specimens dissipate most of the energy through the development of damage in the joint region, which is neither desirable nor safe for the stability of whole structure. Copyright © 2013 John Wiley & Sons, Ltd.  相似文献   

Coupling of a simultaneous heat and water model with a distributed hydrological model and evaluation of the combined model in a cold region watershed   总被引：2，自引：0，他引：2  

Yanlin Zhang  Guodong Cheng  Xin Li  Xujun Han  Lei Wang  Hongyi Li  Xiaoli Chang  G. N. Flerchinger 《水文研究》2013,27(25):3762-3776

Snow and frozen soil prevail in cold regions worldwide, and the integration of these processes is crucial in hydrological models. In this study, a combined model was developed by fully coupling a simultaneous heat and water model with a geomorphologically based distributed hydrological model. The combined model simulates vertical and lateral water transfer as well as vertical heat fluxes and is capable of representing the effects of frozen soil and snowmelt on hydrological processes in cold regions. This model was evaluated by using in situ observations in the Binggou watershed, an experimental watershed for cold region hydrology of the Watershed Allied Telemetry Experimental Research Project. Results showed that the model was able to predict soil freezing and thawing, unfrozen soil water content, and snow depth reasonably well. The simulated hydrograph was in good agreement with the in situ observation. The Nash–Sutcliffe coefficient of daily discharge was 0.744 for the entire simulation period, 0.472 from April to June, and 0.711 from June to November. This model can improve our understanding of hydrological processes in cold regions and assess the impacts of global warming on hydrological cycles and water resources. Copyright © 2012 John Wiley & Sons, Ltd.  相似文献