长江经济带三大城市群城际客运联系网络结构对比分析

“流空间”是人文-经济地理学关注的重要议题。基于城际客运交通流数据,运用ArcGIS空间分析、城市联系强度模型等方法对长江经济带长三角、长江中游、成渝三大城市群城际客运联系网络结构特征进行刻画,结果表明：①长三角城市群城际客运联系网络以上海市为主核心,苏州、南京、杭州为次核心,通过核心城市向外延伸的交通轴线组成相互之间联系紧密的城市网络,西部与南部地区的联系相对较弱;长江中游城市群城际客运联系网络以武汉、长沙、南昌三个省会城市为核心节点,周边次中心城市与其省会交通联系紧密,但城市间跨省联系较弱,本省城市仅与另外两个省会城市存在突出的向心性联系;成渝城市群高等级联系网络大多指向成都、重庆主城区,次级区域中心城市发育不足,成渝城市主轴线在强交通联系推动下发育成型,但川渝接壤地区的城际客运联系存在“断层”。②长江经济带三大城市群在网络化演化进程中,具有城市群“等级-网络”的基本演化特征,其中成渝城市群、长江中游城市群仍处于“核心-边缘”的双核或三核结构,长三角城市群已出现多核网络化发展趋势。③高速铁路作为新兴要素流,对公路、普通铁路等传统要素流具有明显的替代效应,增强了三大城市群核心城市向外延伸的轴线联系,是驱动城市群城际客运联系网络结构演变的新动力。     

Irregular western margin of the Yangtze block as a cause of variation in tectonic activity along the Longmen Shan fault zone,eastern Tibet

On 12 May 2008 and 20 April 2013, respectively, the devastating magnitude 7.9 (Wenchuan) and magnitude 7.0 (Ya’an) earthquakes struck the southwestern Longmen Shan fault zone (LMSFZ), the eastern margin of the Tibetan Plateau. These events were notable because they occurred in a heavily populated area and resulted in severe damage and loss of life. Here we present an integrated analysis of potential field anomalies and a crustal-scale seismic reflection image to investigate the crustal structure and some tectonic relationships associated with these devastating events. Our results show that the western margin of the Yangtze crustal block possesses an irregular margin that extends westward beyond the LMSFZ to the northeast and merges gradually with the LMSFZ to the southwest. We interpret this variation in deep structure to create a lateral heterogeneity in the local stress regime that explains the observed variations in fault geometry and slip distribution, as well as seismicity, of the LMSFZ. This structural complexity results in a differential build-up of stress as the Tibetan Plateau is being extruded eastward. Thus, the results of this research can help identify potential natural hazard zones and focus efforts on hazard mitigation.     

江苏下扬子区二叠系龙潭组-大隆组页岩气勘探前景分析

江苏下扬子区龙潭组-大隆组暗色泥页岩厚度较大（60~100m）,有机碳含量较高（平均为2.0%~3.0%）,热演化程度区域上差异较大（0.5%~3.0%）,总体具有形成页岩气藏的良好潜力。暗色泥页岩中脆性矿物含量较高,利于后期的压裂和开发。根据研究区暗色泥页岩页岩厚度、埋深、有机碳含量和成熟度展布,以矿物成分和含气性特征等特征,运用信息叠合法,最终优选出溧水-句容、丹阳-海安为Ⅰ类有利区,无锡-张家港为Ⅱ类有利区。     

青藏高原春季土壤湿度与我国长江流域夏季降水的联系及其可能机理

土壤湿度作为陆面过程的重要因子,对局地及邻近地区的大气环流和天气气候有重要影响.青藏高原的土壤湿度观测站点稀少,时间较短,鉴于此,本文使用经过部分观测站点检验的卫星反演数据,研究了春季高原土壤湿度的年际变化与后期夏季我国东部降水的联系和可能机理.结果表明：在全球变暖的背景下,高原土壤湿度总体呈现出显著增加的趋势,去除该线性趋势后,我们定义了一个高原土壤湿度指数TPSMI来定量表征高原土壤湿度的年际变化特征,发现表层、中层、深层的土壤湿度年际变率趋于一致,且春季土壤湿度与夏季土壤湿度显著相关（相关系数可达0.56）.当TPSMI偏大时,即高原东部土壤湿度偏大,而西部偏小时,夏季在高原东部（西部）存在一个潜热（感热）热源,二者共同作用下,在对流层中高层从高原西部经我国大陆直至东北地区激发出一个气旋-反气旋-气旋波列,该波列呈相当正压结构,有利于东北冷涡的加强及冷空气向南爆发;与此同时,南亚高压加强东伸,西太副高西伸加强,低空南方暖湿气流与北方干冷气流在长江流域汇合,伴随着上升运动加强,从而有利于夏季长江流域降水增多;反之,当TPSMI偏小时,夏季长江流域降水减少.     

长江中下游地区地下水卤素元素的形成及其分布规律

本文以丰富的实际资料，论证了地下水的卤素元素（F、Cl、Br、I）的形成、含量及其分布规律与含水介质成分、上覆岩土性质、地下水退流条件、氧化还原环境、地下水矿化度之间的关系。根据江汉平原东部区和鄱阳湖区地下水中Br、I元素的调查研究结果及它们形成的控制因素与分布规律，结合长江三角洲南部区水文地球化学环境条件分析对比，指出该区是一个形成Br、I矿泉水的有利地区。     

长江下游鳊鱼遗传多样性的RAPD分析

应用RAPD技术对长江下游鳊鱼群体的遗传多样性进行分析,从40个随机引物中筛选出28个引物对鳊鱼24个个体的基因组DNA进行扩增,共检测到178个位点,分子片段在0.2～2.0kb之间,其中多态位点83个,占46.63%;个体间最大的遗传距离为0.1326,最小的遗传距离为0.0476,平均遗传距离为0.0885;群体的Nei基因多样性指数为0.2593,Shannon多样性指值为0.0986。与其他鱼类的遗传多样性研究结果相比,长江下游鳊鱼群体的遗传多样性处于中等水平。     

长江南京段岸线资源GIS评价与分析

岸线资源是特殊的国土资源,岸线资源评价是岸线资源研究的主要工作之一。以往的研究仅从自然和经济的角度出发,对于生态条件的考虑鲜有涉及。为了达到经济和生态的双赢,根据长江南京段岸线资源的特点,综合考虑自然、经济和生态因素,构建了岸线前沿水深、岸线稳定性、岸线陆域宽度、岸线集疏运条件、水源保护区、风景名胜区六项指标组成的评价指标体系。选取合理的评价单元,运用GIS空间分析技术和ArcGISEngine开发包,在完成单项指标评价的基础上,依据建立的指标体系对研究区内的岸线资源进行综合评价,以期为长江岸线南京段的合理利用与开发提供参考依据。     

扬子地块西北缘后龙门山南华纪—早古生代沉积地层特征及其形成环境

通过对扬子地块西北缘后龙门山构造带南华纪—早古生代沉积地层的分析研究,综合运用岩石学、沉积特征分析的手段,结合与前龙门山构造带、碧口地块、米仓山构造带和汉南地块的沉积特征对比,探讨后龙门山构造带南华纪—早古生代的沉积环境,查明其形成环境。结果表明：在南华纪—早古生代后龙门山构造带沉积环境可分为南华纪—震旦纪裂解-稳定沉积和早古生代伸展裂陷沉积两个阶段,其中在早古生代伸展裂陷阶段后龙门山构造带经历了裂解→抬升→局部裂解→抬升→裂解的反复过程,最终形成了志留系茂县群裂陷槽沉积,主要沉积了一套代表伸展裂陷环境的沉积岩系,并有少量的陆内火山岩系。研究结果进一步证实,龙门山构造带在南华纪—早古生代总体是一个陆内裂谷带,不发育与古缝合线相关的构造混杂岩和蛇绿混杂岩带,是在陆内裂谷的基础上于印支期—燕山期形成的陆内造山带。     

A comparative study of fish community in four main estuaries of China southeastern coastal areas and their adjacent waters

Based on literature and survery data of fish composition collected by bottom trawl investigation from 2006 to 2007 infour main estuaries of China southeastern coastal areas and their adjacent waters,changes of the taxonomic diversity across spatialand temporal scales of fish community were analyzed by taxonomic diversity indices.The results are as follows:a total number of1397 fish species(including some freshwater species),belonging to 2 classes,42 orders,186 families and 593 genera,were collected inthe studied sea areas.The species richness increased with lower latitudes,particularly so with Perciformes.There were 339 fish spe-cies in the Yangtze River Estuary and adjacent waters,belonging to 2 classes,31 orders,101 families and 231 genera.There were 535fish species in the Minjiang River Estuary and adjacent waters,belonging to 2 classes,33 orders,133 families and 323 genera.A totalnumber of 803 fish species were collected in the Jiulongjiang River Estuary and adjacent waters,which belonged to 2 classes,35 orders,155 families and 419 genera.And 1021 fish species which belonged to 2 classes,32 orders,153 families,and 466 genera were collectedin the Pearl River Estuary and adjacent waters.The numbers of orders and families of fish species from the northern to the southern wa-ters first increased and then decreased.The average variation in taxonomic distinctness(Λ+)gradually decreased with lower latitudes inthe four estuaries and adjacent waters.There were no significant differences in the average taxonomic distinctness(△+)among the fourestuaries and adjacent waters,and fish fauna were closely related with each other,and all of them belonged to the same zoogeographicalfauna(Indian-Malaysia fauna).Fish composition in the Minjiang River Estuary and adjacent waters was more similar to that in the Jiu-longjiang River Estuary and adjacent waters among the four estuaries.Compared with the historical data,the average taxonomic dis-tinctness of fish community showed a great decrease in the Minjiang River Estuary and the Jiulongjiang River Estuary and their adjacentwaters.     

襄樊—广济断裂带东段构造变形特征及其演化

襄樊—广济断裂带是分隔大别造山带和扬子板块北缘前陆褶皱逆冲带的边界断裂,其几何学、运动学及构造演化特征记录了南北两大不同性质的大地构造单元发生碰撞、拼贴及相互作用的地质过程。在野外调查、构造解析和年代学研究基础上,结合区域地质和地球物理资料分析,认为襄樊—广济断裂带东段以深部向南逆冲、浅表向北逆冲的“鳄鱼嘴式”对冲构造为特征,与西段的构造变形样式和次序存在显著差异。中扬子地区东部受控于江南—雪峰造山带和大别造山带南北两大构造体系,深部扬子板块北缘向大别造山带之下俯冲导致造山带自北向南挤出,推覆构造可影响至瑞昌一带,由南向北的浅层逆冲推覆可影响至梅川附近,二者在襄樊—广济断裂带东段的蕲春—武穴—浠水一带对接。襄樊—广济断裂带经历了印支早期同碰撞由北向南的逆冲推覆和深层次的韧性剪切变形(T₂末)、燕山早—中期双向对冲构造变形(J_1-3)、燕山晚期伸展正断层变形(K_1-2)、喜山早期由北向南小规模逆冲变形(E₁)阶段。