龙川江盆地上第三系芒棒组沉积体系与层序地层分析   总被引：2，自引：1，他引：2  

孙泽轩  姚毅锋  陈勇  李国新 《铀矿地质》2004,20(5):286-293,298

龙川江盆地是造山带内部发育的新生代小型山间断陷盆地。本文结合该盆地晚新世构造、火山活动与沉积作用，对盆地盖层芒棒组沉积体系与层序地层进行了分析。通过分析，建立了龙川江盆地晚新世沉积模式，认为晚新世早期断陷带内快速堆积，主要以发育冲积扇沉积体系为特征，中、晚期冲积扇快速人湖，由此而形成冲积扇一扇三角洲一湖泊沉积体系组合；提出了龙川江盆地芒棒组层序的形成受多期构造活动控制的观点，并建立了3个构造层序，划分了体系域。  相似文献   

合肥—潢川盆地南缘中生代冲积沉积及其构造意义   总被引：4，自引：0，他引：4       下载免费PDF全文

李双应王道轩  刘因李任伟  孟庆任岳书仓 金福全 《地质学报》2005,79(4):465-474

合肥—潢川盆地南缘中生代地层被划分为4个年代体（Chronsome）。年代体Ⅰ包括早侏罗世防虎山组和中晚侏罗世圆筒山组下部，由辫状河、曲流河以及滨一浅湖沉积体系组成，局限于盆地东端；年代体Ⅱ包括中晚侏罗世三尖铺组、朱集组和圆筒山组上部，下部为冲积扇沉积，中、上部为辫状河沉积，早期属于横向水流系统（南北方向），晚期是纵向水流系统（东西方向），近EW向的信阳—金寨—舒城断裂是其南部边界；年代体Ⅲ包括早白垩世早期凤凰台组、段集组、周公山组，前两组为冲积扇沉积，后者为辫状河和越岸沉积，粗碎屑明显向盆进积达数公里，南部边缘发育横向水流，而往盆地方向发育纵向水流。年代体Ⅳ为早白垩世晚期黑石渡组和陈棚组，南部边界是磨子潭晓天断裂和桐柏-商城断裂，断裂以伸展走滑为主，东段早期为冲积扇-扇三角洲沉积，晚期为深湖浊积岩沉积。晚白垩世沉积仅发育在西段局部地区，其余处于隆升状态。平行于大别山造山带的近EW向纵向断裂控制着年代体的南部边界，NE向郯城庐江断裂和商城麻城断裂控制着年代体侧向相的变化。合肥潢川盆地南缘沉积从东往西逐渐超覆，揭示大别造山带折返具有自东而西的递进特征。郯城—庐江断裂和商城—麻城断裂对年代体的发育有明显影响，郯城—庐江断裂控制着早侏罗世沉积，表明构造活动至少始于早侏罗世。  相似文献   

埋地管道震害预测方法简述   总被引：6，自引：0，他引：6       下载免费PDF全文

裴宗厂  刘尧兴  王晓青  刘鹏 《地震工程学报》2005,27(2):186-189

埋地管道是城市生命线工程的重要组成部分,在地震时较易发生震害。影响埋地管道在地震中破坏特点的因素,主要是强烈的地面运动或场地失效以及管材、管径等因素。研究方法以基于经验统计的方法在实际应用中比较多。本文分别对基于理论计算和经验统计的震害预测方法进行了简述和比较,最后提出了基于综合概率的埋地管道分析预测模型。  相似文献   

The Integrated Global Geodetic Observing System (IGGOS) viewed from the perspective of history   总被引：1，自引：0，他引：1  

G. Beutler  H. Drewes  A. Verdun   《Journal of Geodynamics》2005,40(4-5):414

Towards the end of the 19th century, geodetic observation techniques allowed it to create geodetic networks of continental size. The insight that big networks can only be set up through international collaboration led to the establishment of an international collaboration called “Central European Arc Measurement”, the predecessor of the International Association of Geodesy (IAG), in 1864. The scope of IAG activities was extended already in the 19th century to include gravity.At the same time, astrometric observations could be made with an accuracy of a few tenths of an arcsecond. The accuracy stayed roughly on this level, till the space age opened the door for milliarcsecond (mas) astrometry. Astrometric observations allowed it at the end of the 19th century to prove the existence of polar motion. The insight that polar motion is almost unpredictable led to the establishment of the International Latitude Service (ILS) in 1899.The IAG and the ILS were the tools (a) to establish and maintain the terrestrial and the celestial reference systems, including the transformation parameters between the two systems, and (b) to determine the Earth's gravity field.Satellite-geodetic techniques and astrometric radio-interferometric techniques revolutionized geodesy in the second half of the 20th century. Satellite Laser Ranging (SLR) and methods based on the interferometric exploitation of microwave signals (stemming from Quasars and/or from satellites) allow it to realize the celestial reference frame with (sub-)mas accuracy, the global terrestrial reference frame with (sub-)cm accuracy, and to monitor the transformation between the systems with a high time resolution and (sub-)mas accuracy. This development led to the replacement of the ILS through the IERS, the International Earth Rotation Service in 1989.In the pre-space era, the Earth's gravity field could “only” be established by terrestrial methods. The determination of the Earth's gravitational field was revolutionized twice in the space era, first by observing geodetic satellites with optical, Laser, and Doppler techniques, secondly by implementing a continuous tracking with spaceborne GPS receivers in connection with satellite gradiometry. The sequence of the satellite gravity missions CHAMP, GRACE, and GOCE allow it to name the first decade of the 21st century the “decade of gravity field determination”.The techniques to establish and monitor the geometric and gravimetric reference frames are about to reach a mature state and will be the prevailing geodetic tools of the following decades. It is our duty to work in the spirit of our forefathers by creating similarly stable organizations within IAG with the declared goal to produce the geometric and gravimetric reference frames (including their time evolution) with the best available techniques and to make accurate and consistent products available to wider Earth sciences community as a basis for meaningful research in global change. IGGOS, the Integrated Global Geodetic Observing System, is IAG's attempt to achieve these goals. It is based on the well-functioning and well-established network of IAG services.  相似文献   

Multiple criteria decision making and decision support systems for flood risk management   总被引：1，自引：4，他引：1  

Jason K. Levy 《Stochastic Environmental Research and Risk Assessment (SERRA)》2005,19(6):438-447

Multiple criteria decision making (MCDM) is a collection of methodologies to compare, select, or rank multiple alternatives that typically involve incommensurate attributes. MCDM is well-suited for eliciting and modeling the flood preferences of stakeholders and for improving the coordination among flood agencies, organizations and affected citizens. A flood decision support system (DSS) architecture is put forth that integrates the latest advances in MCDM, remote sensing, GIS, hydrologic models, and real-time flood information systems. The analytic network process (ANP) is discussed with application to short-term flood management options for the middle reaches of the Yangtze River. It is shown that DSS and MCDM can improve flood risk planning and management under uncertainty by providing data displays, analytical results, and model output to summarize critical flood information.  相似文献   

酒泉市防震减灾三大工作体系建设     

酒泉市人民政府 《地震工程学报》2005,27(4):361-363

甘肃省酒泉市的防震减灾工作在省委、省政府的领导下，在省地震局的指导帮助下，认真践行“三个代表”重要思想，牢固树立以人为本的科学发展观，贯彻落实“预防为主、防御与救助相结合”的防震减灾工作方针，坚持“监测预报是基础、抗震设防是重点、应急救援是关键”的工作思路，始终把防震减灾工作当作事关人民群众生命财产安全，事关以人为本的执政理念的一件大事来抓。按照四大战略要求，依靠防震减灾法律法规，依靠科学技术进步，依靠各级政府职能的发挥，依靠社会各界及公众的积极参与，建立了比较完善的地震监测预报、震灾预防和地震应急三大工作体系。  相似文献   

TTGs and adakites: are they both slab melts?   总被引：21，自引：0，他引：21  

Kent C. Condie   《Lithos》2005,80(1-4):33-44

Although both high-Al TTG (tonalite–trondhjemite–granodiorite) and adakite show strongly fractionated REE and incompatible element patterns, TTGs have lower Sr, Mg, Ni, Cr, and Nb/Ta than most adakites. These compositional differences cannot be easily related by shallow fractional crystallization. While adakites are probably slab melts, TTGs may be produced by partial melting of hydrous mafic rocks in the lower crust in arc systems or in the Archean, perhaps in the root zones of oceanic plateaus. It is important to emphasize that geochemical data can be used to help constrain tectonic settings, but it cannot be used alone to reconstruct ancient tectonic settings.

Depletion in heavy REE and low Nb/Ta ratios in high-Al TTGs require both garnet and low-Mg amphibole in the restite, whereas moderate to high Sr values allow little, if any, plagioclase in the restite. To meet these requirements requires melting in the hornblende eclogite stability field between 40- and 80-km deep and between 700 and 800 °C.

Some high-Al TTGs produced at 2.7 Ga and perhaps again at about 1.9 Ga show unusually high La/Yb, Sr, Cr, and Ni. These TTGs may reflect catastrophic mantle overturn events at 2.7 and 1.9 Ga, during which a large number of mantle plumes bombarded the base of the lithosphere, producing thick oceanic plateaus that partially melted at depth.  相似文献   

浅海底瞬变电磁探测技术研究新进展     

王艳  刘长胜  林君  周逢道  李慧  周国华 《吉林大学学报(地球科学版)》2005,(Z1)

瞬变电磁法应用于浅海底进行资源勘探或工程地质勘查时,需要将仪器系统和观测装置置于海底,以克服海水屏蔽效应。因此,要求能够远程控制仪器进行自动化数据采集;同时,受工作环境影响,需要将观测装置小型化;另外,通过拖曳式测量提高工作效率。总结课题组目前的研究成果,就仪器系统研制、观测装置小型化、拖曳式测量及海水影响等内容的研究进展进行了简要叙述。  相似文献   

滑雪旅游开发布局影响因素与对策研究——以内蒙古自治区滑雪旅游开发为例   总被引：3，自引：1，他引：3  

刘家明  刘爱利  陈田 《地理科学进展》2005,24(5):105-112

滑雪度假旅游成为欧美山地旅游开发的主要形式。近十几年来，山地滑雪旅游在中国迅速发展，并成为东北一些地方旅游产品的主打品牌。本文从滑雪旅游开发布局影响因素研究出发，通过对中国滑雪旅游市场的需求与供给这对矛盾的全面分析，对照发达国家的滑雪旅游开展状况，总结出中国目前比较缺乏中高端的旅游滑雪场所。据此，作者提出内蒙古应以发展中高端滑雪旅游作为切入点，以阿尔山国际滑雪场为主，建立山地型滑雪网络和滑雪天堂的旅游形象。这些重要结论，对内蒙古发展冰雪旅游业、突破冬季无旅游、延长旅游季节性等方面有重要的指导意义。  相似文献   

基于全球重要农业文化遗产的旅游开发研究——以青田稻鱼共生农业系统为例   总被引：14，自引：0，他引：14  

王欣  闵庆文  吴殿廷  王旭海 《地域研究与开发》2006,25(5):63-67

文章探讨了对农业遗产进行旅游开发的特殊性，确定了在保护遗产的使命之下进行旅游开发的方式。文章认为：青田农业遗产旅游是一种综合型的生态旅游，而且以社区旅游的模式来组织旅游活动较合理。最后还提出了具体的开发思路和建议：通过典型生态旅游社区的构建，展示一个世外山村和谐的生产生活方式，让游客在村民生活和自然环境的充分接触中感受生活，营造现代人精神回归的心灵家园。在人与自然和谐系统之下，梳理出景区的旅游产品体系，包括研修教育、山村风情体验、乡土娱乐、山水休闲和文艺部落休闲等5个主要部分．  相似文献