沿海城市海水入侵问题研究   总被引：5，自引：0，他引：5  

丁玲  李碧英  张树深 《海洋技术学报》2003,22(2):79-83

近年来，沿海城市的海水入侵问题逐渐成为人们关心的焦点之一。文章通过资料搜集与整理，对沿海城市的海水入侵状况作了全面描述与分析。系统地总结了海水入侵的若干特点及海水入侵的成因分析与规律，较为详细的分析了海水入侵的基本事实、基本矛盾和各发展阶段的发展原因，在此基础上总结了海水入侵的基本理论。为进一步的研究打下良好的基础。  相似文献   

Paleoenvironment and sea-level change in the early Cretaceous Barents Sea—implications from near-shore marine sapropels     

Uwe?LangrockEmail author  Ruediger?Stein  Marcus?Lipinski  Hans-Jürgen?Brumsack 《Geo-Marine Letters》2003,23(1):34-42

The late Volgian (early "Boreal" Berriasian) sapropels of the Hekkingen Formation of the central Barents Sea show total organic carbon (TOC) contents from 3 to 36 wt%. The relationship between TOC content and sedimentation rate (SR), and the high Mo/Al ratios indicate deposition under oxygen-free bottom-water conditions, and suggest that preservation under anoxic conditions has largely contributed to the high accumulation of organic carbon. Hydrogen index values obtained from Rock-Eval pyrolysis are exceptionally high, and the organic matter is characterized by well-preserved type II kerogen. However, the occurrence of spores, freshwater algae, coal fragments, and charred land-plant remains strongly suggests proximity to land. Short-term oscillations, probably reflecting Milankovitch-type cyclicity, are superimposed on the long-term trend of constantly changing depositional conditions during most of the late Volgian. Progressively smaller amounts of terrestrial organic matter and larger amounts of marine organic matter upwards in the core section may have been caused by a continuous sea-level rise.  相似文献   

九龙江河口区水体中的226Ra和228Ra   总被引：8，自引：0，他引：8  

谢永臻  黄奕普 《台湾海峡》1994,13(4):394-399

用ＭｎＯ２－纤维富集大体积水样中的Ｒａ同位素，并用直接射气法测定２２６Ｒａ和２２８Ａｃ的β计数法测定２２８Ｒａ的方法，研究了九龙江河口区２２６Ｒａ，２２８Ｒａ的行为，结果表明：在该河口区２２６Ｒａ，２２８Ｒａ均呈非保守行为，２２６Ｒａ，２２８Ｒａ的最高值分别在盐度为１９和９处测得。２２８Ｒａ／２２６Ｒａ）Ａ．Ｒ．值在盐度小于１９的区域约为３左右。与世界其他河口区相比，九龙江河口区的２２６Ｒａ，２２  相似文献   

Evidence of NW extension of the North Anatolian Fault Zone in the Marmara Sea: a new interpretation of the Marmara Sea (Izmit) earthquake on 17 August 1999     

Erkan G?ka?an  Cem Gazio?lu  Bedri Alpar  Zeki Yücel  ?ükrü Ersoy  O?uz Gündo?du  Cenk Yalt?rak  Buser Tok 《Geo-Marine Letters》2002,21(4):183-199

Active faults aligning in NW–SE direction and forming flower structures of strike-slip faults were observed in shallow seismic data from the shelf offshore of Avcılar in the northern Marmara Sea. By following the parallel drainage pattern and scarps, these faults were traced as NW–SE-directed lineaments in the morphology of the northern onshore sector of the Marmara Sea (eastern Thrace Peninsula). Right-lateral displacements in two watersheds of drainage and on the coast of the Marmara Sea and Black Sea are associated with these lineaments. This right-lateral displacement along the course of these faults suggests a new, active strike-slip fault zone located at the NW extension of the northern boundary fault of the ?ınarcık Basin in the Marmara Sea. This new fault zone is interpreted as the NW extension of the northern branch of the North Anatolian Fault Zone (NAFZ), extending from the ?ınarcık Basin of the Marmara Sea to the Black Sea coast of the Thrace Peninsula, and passing through B üy ük ?ekmece and K ü ? ük ?ekmece lagoons. These data suggest that the rupture of the 17 August 1999 earthquake in the NAFZ may have extended through Avcılar. Indeed, Avcılar and İzmit, both located on the Marmara Sea coast along the rupture route, were strongly struck by the earthquake whereas the settlements between Avcılar and İzmit were much less affected. Therefore, this interpretation can explain the extraordinary damage in Avcılar, based on the newly discovered rupture of the NAFZ in the Marmara Sea. However, this suggestion needs to be confirmed by further seismological studies.  相似文献   

冲绳海槽中段沉积岩芯碳酸盐和烧失量的古环境意义     

吴世迎  刘焱光  王湘芹  白黎明  吴军瑞 《海洋科学进展》2001,19(2):17-24

对冲绳海槽中段 3个沉积岩芯碳酸盐和烧失量的系统分析得知 ,岩芯沉积物的CaCO3含量一般 >1 0 % ,最高含量接近 30 % ,烧失量大都在 1 0 %～ 30 %之间变化 ,反映了该海区处于溶跃面之上钙质生物极为发育的生物地球化学环境。结合δ1 8O曲线所反映的气候环境变化 ,探讨了 1 2 0kaB .P .以来碳酸盐旋回的“大西洋型”演变特点 ,同时对该区沉积地层中的火山热液活动印记作了一定的探讨。  相似文献   

南沙海域万安盆地地质构造特征   总被引：1，自引：3，他引：1  

彭学超  陈玲 《海洋地质与第四纪地质》1995,15(2):35-48

利用在南沙海域万安盆地所采集的地震、重磁资料及钻井、地质资料，对该盆地的地震反向特征，沉积特征、区域地质、构造特征及构造发展史进行了的简要的论述，本文以该区Ｔｇ深度资料为基础，并利用ＣＣＯＰ年刊发表的新生代基底深度资料，初步圈定了万安盆地的边界，并对盆地二级构造单元进行了划分，将盆地划分为５坳３隆、坳隆相间的构造格局。  相似文献   

秦山核电站邻近水域石油降解细菌的生态学研究     

陈忠元  史君贤 《海洋学研究》1991,9(2):48-53

本文分析了1989年4月(春),7月(夏),10月(秋)和1990年1月(冬)秦山邻近水域表层水中石油降解细菌的丰度和分布规律,同时比较了温度、含油量、营养盐、溶解氧、盐度等环境因素对其数量变动的影响。分析结果发现,测区表层水中石油降解菌数量最高值达1.1×10~5个/dm~3,最低值为400个/dm~3,季节变化波动于97～4.9×10~4个/dm~3之间,菌量变化与水温,含油量呈正相关,与盐度呈负相关趋势,认为测区高营养盐、高溶解氧状况可能不成为石油降解细菌生长繁殖的限制因子,并指出测区低丰度的石油降解菌数量与该海区低水平的油污是一致的。  相似文献   

辽宁菊花岛海域沉积物中某些化学要素分布特征研究     

杨新梅  周义华 《海洋湖沼通报》1991,(1):29-34

菊花岛周围海域38个站表层沉积物的铁、锰、铝、钛、磷、有机质、氮、铜、锌、铅、镉、镍和汞等化学要素含量的Q型因子分析计算表明,本区可划分为三个化学元素沉积区:1.海流悬浮沉积区;2.近岸波浪作用区;3.波浪海流作用区。柱状沉积物中铁等化学元素的迁移、富集受氧化——还原界面的控制。  相似文献   

Morphodynamics of a bar-trough surf zone   总被引：3，自引：0，他引：3  

L.D. Wright  P. Nielsen  N.C. Shi  J.H. List 《Marine Geology》1986,70(3-4):251-285

A field study was made of the distinguishing morphodynamic processes operating in a surf zone which perennially exhibits accentuated bar-trough topography (the “longshore-bar-trough” and “rhytmic-bar-and-beach” states as described by Wright and Short, 1984). Characteristic features of the morphology include a shallow bar with a steep shoreward face, a deep trough, and a steep beach face. This morphology, which is favored by moderate breaker heights and small tidal ranges, strongly controls the coupled suite of hydrodynamic processes. In contrast to fully dissipative surf zones, the bar-trough surf zone is not at all saturated and oscillations at incident wave frequency remain dominant from the break point to the subaerial beach. The degree of incident wave groupiness does not change appreciably across the surf zone. Infragravity standing waves which, in dissipative surf zones, dominate the inshore energy, remain energetically secondary and occur at higher frequencies in the bar trough surf zone. Analyses of the field data combined with numerical simulations of leaky mode and edge wave nodal—antinodal positions over observed surf-zone profiles, indicate that the frequencies which prevail are favored by the resonant condition of antinodes over the bar and nodes in the trough. Standing waves which would have nodes over the bar are suppressed. Sediment resuspension in the surf zone appears to be largely attributable to the incident waves which are the main source of bed shear stress. In addition, the extra near-bottom eddy viscosity provided by the reformed, non-breaking waves traversing the trough significantly affects the vertical velocity profile of the longshore current. Whereas the bar is highly mobile in terms of onshore—offshore migration rates, the beach face and inner regions of the trough are remarkably stable over time.  相似文献   

长江河口硼的测定及分布规律研究     

韩庆平  吴玲  奚建风  陈邦林 《海洋科学》1997,21(2):35-38

采用ＨＰＴＡ方法对长江口水中硼进行分析，并与姜黄素法进行比较，方法的标准偏差为０．００５，变动系数小于５％，对长江口水样分析结果与姜黄素法相比较，其相对误差为－０．４％。  相似文献