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Coupling controls of neotec-tonism and paleoclimate on the Quaternary sediments of the Yangtze (Changjiang) coast

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Science Bulletin 2005年第16期 105-114页

作者： WANG Zhangjiao1, CHEN Zhongyuan2. WEI Zixin3, WANG Zhanghua1 & WEI Taoyuan1 1. Department of Geography, east china normal university, shanghai 200062,{2. 2. state key laboratory for estuarine and coastal research, east china normal university, shanghai 200062,{2. 3. shanghai Institute of Geological Survey, shanghai 2.0072.{2.

Attempt has been made to discuss the coupling relation of neotectonism and paleoclimate that have played a critical role in controlling the Quaternary sediment distribu-tion and sedimentary facies evolution on the Yangtze coast. On the basis of petrological analysis, up to six sedimentary cyclicities have been identified in the Quaternary sediment boreholes on the time scale of 0.4―0.5 Ma. The lower sedi-mentary cyclicities (Pliocene to Early Pleistocene) are char-acterized largely by thicker gravelly coarse sands, topped by thinner fine silt and silty clay. Gravels are very angular and clayey gravels prevail. Sediments are usually of poor sorting, rich in log fragments and have no microfossils. Bedload as denoted by C-M plot occurs throughout the section. This evidence represents the alluvial fan sedimentation which took place as the basin began to subside. The middle sedimentary cyclicities (often including Early to Middle Pleistocene) con-sist of basal gravelly sands and clayey silt at the middle and upper sediment sections. Sorting becomes relatively better, and foraminifer appears sporadically. C-M plot reveals the mixture of sediment transport media via bedload, saltation and suspension, representing sedimentation of braided river system at the early stage and subsequently, the sedimentation of meandering river pattern. The upper sedimentary cyclic-ities (including Late Pleistocene to Holocene) comprise basal gravelly sands (exclusive of the Holocene sediment) and thick fine sand and silty clay on the upper section. Sorting becomes fine and foraminifer appears throughout the sediment sec-tion. C-M plot shows that saltation and suspension serve as the main sediment transport media in the sediment section and bedload transport weakens. These evidence the sedi-mentation of meandering river pattern near coast during Late Pleistocene and Holocene time, when marine transgres-sion invaded into the paleoriver valleys, which often forms drowned-valley facies and shallo

关键词： Quaternary sediments grain size neotectonic subsidence paleoclimate/sea-level fluctuations Yangtze delta.

长江口新生沙洲底栖动物群落组成及多样性特征

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海洋学报 2002年第2期24卷 133-139页

作者：袁兴中刘红陆健健重庆大学资源与环境科学学院重庆400044 华东师范大学河口海岸国家重点实验室上海200062

1 引言沙洲岛屿是河口生态系统的重要组成部分,是河口海岸带资源开发、自然保护及全球变化研究的重要对象.沙洲岛屿潮滩的底栖动物群落与其生活的底质构成了河口生态系统的底栖亚系统,是河口地区生物多样性最直接和最易于观察研究的... 详细信息

1 引言沙洲岛屿是河口生态系统的重要组成部分,是河口海岸带资源开发、自然保护及全球变化研究的重要对象.沙洲岛屿潮滩的底栖动物群落与其生活的底质构成了河口生态系统的底栖亚系统,是河口地区生物多样性最直接和最易于观察研究的一个层次,它们在揭示群落与环境变化的关系上具有重要的作用[1-2.. 九段沙是长江口现代发育过程中产生的一个新生沙洲,是继崇明岛、长兴岛和横沙岛之后的又一成陆冲积沙洲,是一块重要的河口沙洲型滨海湿地[3].九段沙受人类干扰较少,其生物资源保持着天然状态.作为世界上特大型河口的新生沙洲。

关键词：底栖动物群落生态多样性新生沙洲长江口环境变化生态系统

Impact on the Yangtze (Changjiang) Estuary from its drainage basin: Sediment load and discharge

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Chinese Science Bulletin 2001年第S1期46卷 73-80页

作者： CHEN Zhongyuan & ZHAO Yiwenstate key {2. for estuarine and coastal research, east china normal university, shanghai 200062, china Department of Geography, east china normal university, shanghai 200062, china 1. state key {2. for estuarine and coastal research East China Normal University 200062 Shanghai China 2. Department of Geography East China Normal University 200062 Shanghai China

This paper focuses on the sediment transport and freshwater discharging from upper Yangtze drainage basin downstream, primarily on the basis of multiyear hy-drological data collected from three major hydrological gauge stations (Yichang, Hankou and Datong). Data indicate highest sediment load in Yichang (5.6×108 t/a), lowest in Hankou (5.1×108t) and second highest in Datong (5.4×108 t). This fluctuations are identical with what has been observed from the annual flood season. About one thirds of the sediment load are trapped in the middle Yangtze River course, where meandering river pattern prevails; rest of them are directly transported to the river mouth area via lower Yangtze River channel, where the river is typically confined by the exposed base rock and almost none is being trapped, instead, minor being drained to the mainstream from the local tributaries. To recognize this sediment delivery and river flow media is vital, because it can highlight morphologic/topographic correlation between the

关键词： sediment load discharge estuarine impact the Yangtze River.

Denitrification in Chongming east tidal flat sediment, Yangtze estuary, china

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Science china Earth Sciences 2006年第10期49卷 1090-1097页

作者： WANG Dongqi1,2. CHEN Zhenlou1,3, XU Shiyuan1,2. HU Lingzhen1 & WANG Jun1,2.1. College of Resources & Environment, east china normal university, shanghai 200062,{2. 2. state key laboratory of estuarine and coastal Sediment Dynamics and Morphodynamics, east china normal university, shanghai 200062,{2. 3. key laboratory of Geographical Information Science of Ministry of Education,east{2. normal university,shanghai 200062,{2. 1. College of Resources & Environment East China Normal University Shanghai 200062 China 2. state key {2. of estuarine and coastal Sediment Dynamics and Morphodynamics East China Normal University Shanghai 200062 China 3. key laboratory of Geographical Information Science of Ministry of Education East China Normal University Shanghai 200062 China

From July 2.03 to July 2.04, samples were collected on Chongming Island east tidal flat every two months. The research showed that the nitrous oxide (N2.) production rate was very low in the water, Chongming east tidal flat (CM) sediment was the N2. source of the water. Sediment N2. natural production rate was between -0.08 and 1.74 μmolN·m-2.h-1. N2. natural production rate was higher in the summer. The difference of the N2. natural production rate in the different tidal flats, the correlation between the N2. natural production rate and the denitrification rate, and those with the temperature and DO indicate that middle tidal flat sediment denitrification was the main process of the N2. production, while in the low tidal flat sediment, the production of the N2. came from several processes of the nitrogen cycling. Tidal flat sediment denitrification reaction was stronger in summer and winter but relatively lower in the late autumn and early spring. Seasonal change of the sediment denitrification rate was wide, from 1.12.to 33.34 μmolN·m-2.h-1. Temperature, DO and the coactions of them had the prominent effect on the tidal flat sediment denitrification.

关键词： Yangtze estuary, tidal flat sediment, denitrification, nitrous oxide, effect factor.

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Journal of Geographical Sciences 2002年第4期12卷 489-494页

作者： LI Yuzhong, CHEN Shenliang(state key {2. of estuarine && coastal research, east china normal university, shanghai 200062, china) state key {2. of estuarine & coastal research East China Normal UniversityShanghai 200062 China

By analysis of published papers on the Yangtze estuary and hydrological and sediments data in Yangshan Harbor area, many similarities are found between Yangshan Harbor area and the Yangtze estuary. These similarities include the phenomenon of stagnating flow areas, the distributive characteristics of the highest suspended sediment concentration areas, superficial sediments and shoal bars. The stagnating flow area is the major similarity which causes other similarities. These similarities indicate that: 1) Turbidity Maximum and mouth bars in estuaries are mainly caused by the hydraulic balance of stagnating flow areas of estuaries; 2. The stagnating sand area of sands caused by stagnating flow area often locates on the narrower side of the stagnating flow area; 3) The location (or shape) of fine sediments area caused by stagnating flow area reflects the location (or shape) of the stagnating flow area. Both Yangshan Harbor area and the Yangtze estuary are the important developmental areas in the future (man-made similarity). In-depth studies on these similarities between Yangshan Harbor area and the Yangtze estuary will have momentous theoretical and practical significance.

关键词： Yangshan Harbor Yangtze estuary similarity stagnating flow area turbidity maximum mouth bar

Dynamic mechanism of the upwelling on the west side of the submerged river valley off the Changjiang mouth in summertime

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Chinese Science Bulletin 2003年第24期48卷 2754-2758页

作者： ZHU Jianrong state key {2. of estuarine and coastal research, east china normal university, shanghai 200062, china Correspondence should be addressed to Zhu Jianrong (e-mail: jrzhu@ ***) state key {2. of estuarine and coastal research East China Normal University Shanghai

Based on the analysis of the field observation data off the Changjiang mouth in August 2.00 and satellite image of sea surface temperature (SST) in summer of 1997, it indicates that there exists the upwelling event on the west side of the submerged river valley (SRV) off the Changjiang mouth. The calculated results of the three-dimensional nu-merical model show that this upwelling is induced by the barotropic effect, baroclinic effect, bottom Ekman effect and their interaction with the slope bottom topography. The baroclinic effect is the main cause producing the upwelling at the northern SRV (on the east side of the South Passage of the Changjiang estuary), while the barotropic effect is the main cause at the southern SRV (on the east side of the cen-ter of the Hangzhou Bay mouth). The dynamic mechanism producing the upwelling off the Changjiang mouth is differ-ent with the general one along coast and on the continental shelf.

关键词：动力学机制长江口夏季上升流数字仿真

Characteristics and generation mechanism of turbidity maximum in the Changjiang Estuary

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Acta Oceanologica Sinica 2000年第1期19卷 47-57页

作者： Pan Ding’an Shen Huanting Mao Zhichang and Liu Xincheng (1. state key Lab of {2. and coastal research, east china normal university, shanghai 200062, china) state key Lab. {2. Coast. Res. East China Normal University Shanghai 200062 China

Sediment convergence and resuspension are the two major mechanisms in forming turbidity maximum (TM) in the Changjiang Estuary. Sediment convergence is mainly controlled by the interaction between runoff and tidal current, the mixing of freshwater and salt water, the former forming tidal TM, whereas the latter forming brackish TM. The TM in the Changjiang Estuary is characterized by a combination of tidal TM and brackish TM, which varies temporally and spatially.

关键词： Changjiang Estuary turbidity maximum sediment convergence resuspension

Simulation of three-dimensional cohesive sediment transport in Hangzhou Bay,china

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Acta Oceanologica Sinica 2010年第2期29卷 98-106页

作者： DU Panjun DING Pingxing HU Kelin state key of {2. and coastal research East China Normal University Shanghai 200062 China Forecast Centers for east china Sea State Oceanic Administration Shanghai 200062 China

Sediment transport in the Hangzhou Bay is extremely complicated due to its bathymetry and hydrodynamic conditions. The ECOMSED model is employed to simulate three-dimensional （3-D） cohesive sediment transport in Hangzhou Bay. Dynamical factors such as Coriolis force, tides, salinity, river discharges, and waves are considered in the model. The wave parameters, including the significant wave height, period, and direction, are calculated with the SWAN model. The Grant-Madsen model is introduced for the bed shear stress due to the combined effect of waves and currents. The formulation of bed shear stress used to calculate the sink/source terms is modified based on previous research that sufficiently validated the formulation with measurement data. The integrated model of the above-mentioned models is applied to simulate sediment transport in Hangzhou Bay. The results of the simulation agree well with field observations concerning the distribution of suspended sediment, indicating that the sediments are remarkably suspended in Hangzhou Bay under the action of waves and currents.

关键词： waves currents suspended sediment deposition erosion Grant-Madsen Model

FLUSHING TIME OF THE YANGTZE ESTUARY BY DISCHARGE: A MODEL STUDY

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Journal of Hydrodynamics 2003年第3期15卷 63-71页

作者： QiDing-man ShenHuan-ting, ZhuJian-rong ScientificresearchInstituteoftheMinistryofCommunication EstuarineandCoastalResearchCenterShanghai201201China statekey{2.ofestuarineandcoastalresearch EastChinaNormalUniversityShanghai200062China

Flushing time of the Yangtze estuary by discharge is one of the importantfactors responsible for the transport of pollutants from various sources located along the Yangtzeestuary: Therefore, an objective of the present stud-y, which analysis flushing time in the case ofdifferent discharge is very helpful to evaluate the water environmental of the Yangtze *** a dissolved conservative material as a tracer in the water, a three-dimensionadvection-diffusion water exchange numerical model was used to study the flushing time by dischargeand the discharge dominated region of the Yangtze estuary. The initial tracer concentration is setto 0.0 in the numerical domain of the Yangtze estuary, and the concentration value is set to 1. 0 onthe inflow boundary. The tracer flux normal to the solid boundary is set to 0. 0. The flushing timeand the out limit of discharge dominated region can be calculated in terms of the tracerconcentration. estuarine, {2. and Ocean Model (ECOM) is used as the hydro-dynamic model. Theresult shows that the flushing time is approximately in inverse proportion to the discharge at theupper stream. The out limit is farther from the upper inflow boundary as discharge increases. Theout limit at the north branch is different from that of the south branch because the discharge intothe north branch is much less than that into the south branch. The data is qualitative similar tothe observed data, which show the three-dimensional advection-diffusion equation can be used toestimate the flushing time and the discharge dominated region of the Yangtze estuary.

关键词： ECOM flushing time discharge dominated region