Sequence framework of two different kinds of margins and their response to tectonic activity during the Middle-Late Triassic, Ordos Basin     

YANG MingHui  LIU ChiYang  ZHENG MengLin  LAN ChaoLi  TANG Xuan 《中国科学D辑(英文版)》2007,50(Z2):203-216

  相似文献   

歧南凹陷沙河街组重力流水道砂体成岩作用和孔隙演化模式     

刘正华  杨香华  汪贵峰  黄海龙  张帆 《沉积学报》2007,25(2):183-191

储层物性既受沉积相平面分区性的控制，又受成岩作用的垂向分带性的控制。因此，根据不同地质背景与微相类型，建立具体的成岩作用模式，对储层评价具有指导作用。本文在分析歧南地区沉积相平面展布和垂向层序特征的基础上，对该地区沙河街组的42块样品进行铸体薄片、扫描电镜、阴级发光、X 衍射、古地温分析，总结了重力流主水道砂体和重力流水道侧翼、水道末梢砂体的成岩作用特征以及孔隙演化模式，指出在进行重力流水道砂体进行勘探部署时，应选择主水道中心部位进行钻探。  相似文献   

Complexity in a cellular model of river avulsion   总被引：2，自引：1，他引：2  

Douglas J. Jerolmack  Chris Paola 《Geomorphology》2007,91(3-4):259

We propose a new model of river avulsion that emphasizes simplicity, self-organization, and unprogrammed behavior rather than detailed simulation. The model runs on a fixed cellular grid and tracks two elevations in each cell, a high elevation representing the channel (levee) top and a low one representing the channel bottom. The channel aggrades in place until a superelevation threshold for avulsion is met. After an avulsion is triggered a new flow path is selected by steepest descent based on the low values of elevation. Flow path depends sensitively on floodplain topography, particularly the presence of former abandoned channels. Several behavioral characteristics emerge consistently from this simple model: (1) a tendency of the active flow to switch among a small number of channel paths, which we term the active channel set, over extended periods, leading to clustering and formation of multistory sand bodies in the resulting deposits; (2) a tendency for avulsed channels to return to their previous paths, so that new channel length tends to be generated in relatively short segments; and (3) avulsion-related sediment storage and release, leading to pulsed sediment output even for constant input. Each of these behaviors is consistent with observations from depositional river systems. A single-valued threshold produces a wide variety of avulsion sizes and styles. Larger “nodal” avulsions are rarer because pre-existing floodplain topography acts to steer flow back to the active channel. Channel stacking pattern is very sensitive to floodplain deposition. This work highlights the need to develop models of floodplain evolution at large time and space scales to complement the improving models of river channel evolution.  相似文献   

The politics of design: architecture, tall buildings and the skyline of central London     

Igal Charney 《Area》2007,39(2):195-205

After 2000 a handful of very tall buildings were approved in central London, a circumstance that challenged well-established planning practices in that part of the city. Their promotion by Ken Livingstone, the mayor, but opposition to them by conservation groups, seemed to signal a fierce campaign ahead; in fact, it was all over in an instant. This article examines how this debate was framed to dismiss the arguments and concerns of those who oppose tall buildings. To make tall buildings acceptable, London's mayor drew on the merits associated with iconic architecture and high-profile architects. Under Livingstone's incumbency tall buildings were affirmed by the expertise and clout of global architects who provided legitimacy for mayoral ambitions to reach for the sky. Stressing the significance of high-quality design and iconic architecture helped to wear down deep-rooted antagonism and to channel the debate to improving the aesthetic qualities of London, a goal that enjoys wide consensus.  相似文献   

Stratigraphic Dip Analysis – A Novel Application for Detailed Geological Modeling of Point Bars,and Predicting Bitumen Grade,McMurray Formation,Muskeg River Mine,Northeast Alberta     

Milovan Fustic 《Natural Resources Research》2007,16(1):31-43

At the Muskeg River Mine, bitumen is hosted in the clastic sediments of the lower Cretaceous McMurray Formation. Within the mine area, the McMurray Formation is divided informally into mappable units representing fluvial, continental floodplain, open estuarine, estuarine channel complex (ECC), and marine environments. Fluvial, open estuarine, and ECC deposits host more than 90% of the mineable bitumen reserves. Bitumen grade is more consistent within the fluvial and open estuarine units (12–15 mass%), whereas ECC sediments are characterized by significant lateral and vertical grade variability (0–15 mass%). In the ECC deposits, bitumen grade is controlled by significant reservoir heterogeneity. Facies assemblages including point-bar deposits (PB), abandoned channel-fills (AC), and tidal flat deposits (TF), create complex internal geometries, architectures and associated reservoir properties. Traditional facies mapping and correlation has proven to be difficult even in closely spaced wells for the ECC deposits of the McMurray Formation; thus, an alternative technique using concepts of Stratigraphic Dip Analysis (SDA) was developed to assess bitumen grade for the deposits at the Muskeg River Mine. This approach involves three main steps: (l) juxtaposing azimuth maps (rose diagrams) over horizon slice facies maps for selected stratigraphic intervals to identify major channel trends (paleo-current directions); (2) comparison of dips, with corresponding sedimentary structures allows for a better prediction and geometries of point bars and abandoned channel-fills; and (3) comparison of dip trends with dominant lithology of facies assemblages and available bitumen grades provides a base for accurate delineation of architectural elements. A detailed case study is presented and shows that this approach provides a base for accurate delineation of architectural elements and confirms that bitumen grade decreases laterally with inferred maturity of point bar successions.  相似文献   

构造断阶对沉积的控制:来自地震、测井和露头的实例   总被引：10，自引：0，他引：10  

程日辉  王璞珺  刘万洙 《沉积学报》2003,21(2):255-259

构造断阶是裂谷盆地(特别是裂谷盆地发育早期)或断陷盆地边缘发育的一种构造样式,反映盆地边缘因断块差异沉降所形成的沉积斜坡地形的阶梯变化。在地震剖面可以解释出许多不同类型的断阶带,并在此框架下根据地震反射结构解释地震相和沉积相。构造断阶带的不同类型控制了不同的沉积样式。构造断阶的识别约束了地震解释的多解性。测井资料的运用可以证实断阶带的沉积控制作用,约束地震解释,也可以进行沉积微相及空间分布的精细研究.地震、测井的实例分别来自松辽盆地徐家围子断陷和渤海湾盆地沾化凹陷。来自胶莱盆地野外露头的实例从另一方面证实了这种控制作用。与钻井或测井资料相比,露头资料具有连续性。露头的详细分析可得到构造断阶对沉积和地层结构控制的细节。构造断阶(带)与沉积作用关系的模式可以提供油气勘探的地质模型。  相似文献   

Thirteen plus one: a comparison of global climate policy architectures   总被引：3，自引：0，他引：3  

Joseph E Aldy  Scott Barrett  Robert N Stavins 《Climate Policy》2003,3(4):373-397

We critically review the Kyoto Protocol and thirteen alternative policy architectures for addressing the threat of global climate change. We employ six criteria to evaluate the policy proposals: environmental outcome, dynamic efficiency, cost-effectiveness, equity, flexibility in the presence of new information, and incentives for participation and compliance. The Kyoto Protocol does not fare well on a number of criteria, but none of the alternative proposals fare well along all six dimensions. We identify several major themes among the alternative proposals: Kyoto is “too little, too fast”; developing countries (DCs) should play a more substantial role and receive incentives to participate; implementation should focus on market-based approaches, especially those with price mechanisms; and participation and compliance incentives are inadequately addressed by most proposals. Our investigation reveals tensions among several of the evaluative criteria, such as between environmental outcome and efficiency, and between cost-effectiveness and incentives for participation and compliance.  相似文献   

Polyvocalism and the public: 'doing' a critical historical geography of architecture     

Mark Llewellyn 《Area》2003,35(3):264-270

Loretta Lees' recent call for a 'critical geography of architecture' argued that a more nuanced and truly interpretative methodology for analysing the relationship between space, place and architecture would involve active engagement with such architectural spaces. This paper argues that, in the same way, by broadening our approach to historical architectural geographies more meaningful interpretations will result. Utilizing a 'polyvocal' methodological approach, by which not only architects and planners but also residents of these spaces are considered as important actors, will facilitate this 'critical' engagement with architectural spaces. Further, by taking this polyvocal approach, interesting conclusions can be reached about the production, consumption and re-production of space, both in the past and also in the present.  相似文献   

基于WEB的三层B/S模型的探讨与应用   总被引：1，自引：1，他引：1  

刘燕  王作云 《物探化探计算技术》2004,26(3):278-282

随着Internet／Intranet的飞速发展以及WWW技术的广泛应用，以Web技术为核心的企业信息管理平台越来越受到企业管理人员的欢迎。对基于动态Web技术的三层B／S计算模型，以及Sybase公司在此基础上提出的企业级Web解决方案——Sybase EA Studio进行了详细的论述。以某信托投资公司资金计划查询管理系统为例，对Sybase的企业级解决方案进行了实例化地探讨．从而起到抛砖引玉的作用。  相似文献   

建筑风荷载风压计算中的若干问题   总被引：2，自引：3，他引：2  

袁春红  薛桁  杨振斌 《气象》2002,28(1):39-42

根据最新“建筑荷载规范”修订本讨论了应用气象台站的风观测资料来计算建筑风荷载中的几个需要注意的问题，其中包括风速资料的坡度订正、高度订正、时次订正以及应用极值Ⅰ型分布函数来估算R年重现期的最大风速等问题。  相似文献