豫西宜阳地区晚二叠世晚期—早三叠世沉积记录及其对古气候变化的响应

晚二叠世-早三叠世宜阳地区位于东特提斯低纬度地区的华北板块南缘,发育一套连续且沉积特征显著的陆相碎屑 岩相沉积,是研究陆相晚二叠世-早三叠世古环境与古气候变化的理想地层。本文在前人研究与野外实测的基础上,采用 岩石学、沉积学、古生物学方法综合分析研究区的沉积记录,识别出宜阳地区在该时期由陆源近海的滨湖沉积环境向河流 沉积环境过渡的古环境,重建了晚二叠世晚期-早三叠世宜阳地区的古地理面貌。沉积特征显示,此期整体气候条件为炎 热-半干旱,并且在长兴期末期与奥伦尼克期早期出现了极端干旱气候,可能是受到当时全球性巨型季风环流的影响。这 一时期的古气候与古环境的变化可能对二叠纪末陆地大灭绝事件起到了推动作用,并抑制了早三叠世生物复苏的进展。     

Advances and Practices on the Research,Prevention and Control of Land Subsidence in Coastal Cities

Land subsidence severely threatens most of the coastal plains around the world where high productive industrial and agricultural activities and urban centers are concentrated. Coastal subsidence damages infrastructures and exacerbates the effect of the sea-level rise at regional scale. Although it is a well-known process, there is still much more to be improved on the monitoring, mapping and modeling of ground movements, as well as the understanding of controlling mechanisms. The International Geoscience Programme recently approved an international project (IGCP 663) aiming to bring together worldwide researchers to share expertise on subsidence processes typically occurring in coastal areas and cities, including basic research, monitoring and observation, modelling and management. In this paper, we provide the research communities and potential stakeholders with the basic information to join the participating teams in developing this project. Specifically, major advances on coastal subsidence studies and information on well-known and new case studies of land subsidence in China, Italy, The Netherlands, Indonesia, Vietnam and Thailand are highlighted and summarized. Meanwhile, the networking, dissemination, annual meeting and field trip are briefly introduced.     

澜沧江—湄公河水电梯级开发的生态影响

针对次澜沦江－湄公河区域快速增长的能源需求,以及国际社会对该流域水电开发的经济、生态和社会问题的关注,集中分析了流域干流水电梯级开发对生态环境的综合影响,提出了能满足各流域国对能源、防洪、灌溉、水生生态保护和减轻海水倒灌等多方面需求的对策措施。     

三角洲感潮河段洪潮水位频率分析方法的初步研究

根据珠江三角洲感潮河段年最高洪潮水位存在长期上升趋势的事实，提出了河口区感潮河段洪潮水位频率分析一种新的计算方法，新方法的分析结果表明，未来不同年代同频率的设计洪潮水位各不相同，也存在相应的长期变化趋势。以灯笼山站为例，新方法计算的2030年和2050年的百年一遇设计洪潮水位分别为3.12m和3.28m，比传统频率分析方法计算的结果分别高出0.24m和0.40m。建立有关部门在制定河口区的防洪标准时，根据洪潮水位的长期变化趋势作相应的动态调整，以适应河口区洪潮水位变化的实际情况。     

黄骅坳陷中区中生代构造演化

渤海湾盆地地区中生代构造演化与样式始终不明朗,特别是对燕山期变形始终存在争议,故选择黄骅坳陷中区中生界作为重点剖析对象,通过大量地震剖面的解释和平衡剖面技术复原古构造演化的研究,并结合前人研究成果和区域构造背景,提出黄骅坳陷中区中生代演化过程可大致分为4个阶段:印支晚期东西向宽缓褶皱及后期逆冲构造变形期、燕山早期挤压走滑构造变形期、燕山中期继承性挤压与右旋张扭构造变形期、燕山晚期—喜山期区域性伸展构造变形期。     

川中地区龙王庙组高频层序与沉积微相及其对有利储层的控制

为明确川中地区龙王庙组沉积微相时空分布及其对储层的控制,利用地震、钻井及岩心资料,开展了精细的沉积、层序和储层研究,深入讨论了高频层序与沉积微相对有利储层的控制.龙王庙组主要发育鲕粒颗粒云岩、砂屑颗粒云岩、花斑状粉晶云岩等8种岩相,垂向上发育深水台地-滩间海型、颗粒滩型和局限潮坪型等3种岩相组合.龙王庙组构成1个三级层序,可分为2个四级层序(SQ1和SQ2),各四级层序可分为3～5个五级层序.高频层序格架内,颗粒滩和局限潮坪具明显的加积和朝东南方向进积趋势,SQ2颗粒滩和局限潮坪的发育优于SQ1.局限潮坪微相的窗格孔细晶-粉晶云岩和花斑状粉晶云岩孔隙度最好,主要分布于四级和五级层序的顶部;其次为高频层序中-上部的颗粒滩微相.与高频海平面变化相关的早期溶蚀是优质储层形成的关键,并为后期储层改造奠定了基础.     

L_n范数准则和地学模型误差及模型参数估计

本文论述了模型误差及模型参数估计的有关问题,具体包括:1)L_n范数准则;2)模型误差的一般表达式;3)线性化模型及模型含误差时的模型参数估计;4)模型的改善与优化;5)计算方案;6)模型误差与L_n范数准则。本文的论述为建立和分析各种具体的地学模型提供了必要的理论和方法。     

我国地理学发展的回顾与展望--地理学:方向正在变化的科学

我国地理学自新中国成立以来取得了辉煌的成就，在跨入21世纪之时面临着一系列挑战和重大任务。我国经济和社会的迅速发展，强烈地改变了我国自然结构和社会经济结构，我国及各地区的“人－地”关系协调和可持续发展是我们面临的重大任务，地理学是实现这些国家重大任务的重要支撑科学之一，肩负着责无旁贷的重任，有着广阔的发展空间。     

Cyclic load testing of pre-stressed rock anchors for slope stabilization

The objective of this research was to assess the characteristics of seismic induced damage and the deformation patterns of pre-stressed cement-grouted cables that are used for rock slope stabilization projects subjected to quasi-static cyclic loading. The experimental configuration includes the installation of 15 pre-stressed cables in a slope model made of concrete blocks (theoretically rigid rock mass) on top of a pre-existing sliding surface. The study showed that: (i) The pre-stressed cables exhibited great seismic performance. Rapid displacement of the model blocks was observed after the complete loss of the initial pre-stress load under continued applied cyclic loads and exceedance of the state of equilibrium, which implies the higher the initial pre-stress load, the better the seismic performance of the rock anchor; (ii) The failure of the pre-stressed cables was due to fracture at the connection of the tendons and cable heads under cyclic loading. The sequence of failure had a distinct pattern. Failure was first observed at the upper row of cables, which experienced the most severe damage, including the ejection of cable heads. No evidence of de-bonding was observed during the cyclic loading; (iii) The stress distribution of the bond length for pre-stressed cables was highly non-uniform. High stress concentrations were observed at both the fixed end and the free end of the bond length both before and immediately after the state of equilibrium is exceeded. The results obtained can be used to evaluate the overall performance of pre-stressed rock anchors subject to seismic loading and their potential as rockfall prevention and stabilization measures.     

现代海洋牧场建设之我见

现代海洋牧场建设是实现我国海洋渔业与近海生态系统和谐发展的重要途径之一,作为一种海洋经济新业态,海洋牧场既能养护渔业资源,又能修复生态环境。本文论述了现代海洋牧场建设的必要性,分析了我国海洋牧场建设中存在的建设技术缺乏标准化、承载力评估缺乏模型化、建设理念缺乏生态化、管理缺乏信息化等问题,探讨了现代海洋牧场相关理念及分类模式。针对现代海洋牧场建设存在的突出问题,提出了构建陆海统筹现代海洋牧场亟待解决的技术先导和"四化"突破(工程化、机械化、自动化和信息化)等对策和建议。