| 摘要 | 第1-7页 |
| Abstract | 第7-11页 |
| Acknowledgements | 第11-27页 |
| Notations | 第27-31页 |
| Chapter 1 Introduction | 第31-37页 |
| ·The Scientific Problem | 第31页 |
| ·Purpose of the stuay | 第31-33页 |
| ·Hypothesis | 第33-34页 |
| ·Themes of research | 第34-37页 |
| ·Grain size analysis of sediment cores | 第34页 |
| ·Factors affecting grain size distribution | 第34-35页 |
| ·~(210)Pb dating for sedimentation rates | 第35页 |
| ·Factors affecting the ~(210)Pb_(ex) activities of sediments | 第35页 |
| ·~(210)Pb_(ex) patterns in relation to sediment dynamics | 第35页 |
| ·Tidal cycle measurements | 第35-36页 |
| ·Observed variations in relation to sediment dynamical changes | 第36-37页 |
| Chapter 2 Literature Review | 第37-59页 |
| ·Estuarine processes | 第37-51页 |
| ·River discharges of freshwater and sediment | 第38页 |
| ·Tides and tidal currents in estuaries | 第38-39页 |
| (a) Tides and tidal currents | 第38-39页 |
| (b) Tidal limit and tidal current limit | 第39页 |
| ·Estuarine circulations | 第39页 |
| ·Formation of turbidity maxima | 第39-41页 |
| ·Sediment transport patterns | 第41-51页 |
| (a) Sediment resuspension | 第42-44页 |
| Initiation of sediment motion | 第42页 |
| Shields curve | 第42-44页 |
| (b) Bottom boundary layer | 第44-45页 |
| Bottom shear stress | 第44-45页 |
| Bottom roughness length | 第45页 |
| (c) Sediment transport rate | 第45-46页 |
| Estimation of suspended sediment flux | 第45-46页 |
| Calculation of resuspended flux | 第46页 |
| (d) Gravity currents | 第46-51页 |
| Gravity current | 第47页 |
| Turbidity current | 第47-48页 |
| Hyperpycnal plume | 第48-49页 |
| Fluid mud | 第49-51页 |
| ·River deltas | 第51-54页 |
| ·Types of river deltas | 第51-52页 |
| ·Evolution of river deltas | 第52-53页 |
| ·Sedimentary facies and sequences | 第53-54页 |
| ·Sediment budget | 第54页 |
| ·~(210)Pb in deltaic sedimentation | 第54-59页 |
| ·Analytical techniques | 第56页 |
| ·Spatial distribution patterns | 第56-57页 |
| ·Vertical distribution in relation to accumulation rate | 第57-58页 |
| ·Sediment dynamic factors affecting the burial of ~(210)Pb | 第58-59页 |
| Chapter 3 The Study Area | 第59-89页 |
| ·Regional geology and geomorphology | 第59-68页 |
| ·Geological background | 第59页 |
| ·Geomorphological features | 第59-61页 |
| ·Estuary and delta evolution | 第61-67页 |
| (a) Evolution under sea level rise | 第62-63页 |
| (b) Land progradation since 2000BP | 第63-64页 |
| (c) Development in the last 100 years | 第64-67页 |
| ·Holocene sediment systems | 第67-68页 |
| ·Hydrodynamics | 第68-74页 |
| ·Freshwater discharges | 第68-69页 |
| ·Tides and tidal currents | 第69-71页 |
| ·Waves | 第71页 |
| ·Estuarine and shelf circulations | 第71-73页 |
| ·Modern events | 第73-74页 |
| (a) Floods | 第73-74页 |
| (b) Typhoon | 第74页 |
| ·Sedimentation | 第74-87页 |
| ·Sediment supply | 第74-75页 |
| ·Variations of sediment supply | 第75-78页 |
| (a) Mass flux change,in response to natural oscillations | 第76页 |
| (b) Sediment flux change,in response to deforestation | 第76-77页 |
| (c) Sediment flux change,in response to dam constructions | 第77-78页 |
| (d) Sediment flux change,in response to dredging navigation channels | 第78页 |
| ·Surficial sediment types and distributions | 第78-79页 |
| ·Suspended sediment and turbidity maxima | 第79-80页 |
| ·Sediment transport patterns | 第80-84页 |
| ·Depocenter and sedimentation rates | 第84-87页 |
| ·Biotic influence | 第87-89页 |
| Chapter 4 Material and Methods | 第89-122页 |
| ·Sampling and sample treatment | 第89-94页 |
| ·Sampling locations | 第89-92页 |
| ·Software utilization for geomorphology maps | 第92页 |
| ·Core sample recovery | 第92-93页 |
| ·Sub-sampling and core description | 第93-94页 |
| ·Grain size analysis | 第94-98页 |
| ·Sample preparetion for grain size analysis | 第94页 |
| ·Measurements of grain size distribution | 第94-95页 |
| ·Calculation of grain size parameters | 第95-97页 |
| ·The grading and classification of sediments | 第97-98页 |
| ·Water content analysis | 第98-103页 |
| ·Water content calculation | 第98-99页 |
| ·Data precision of water content | 第99-103页 |
| ·Determination of sedimentation rates | 第103-113页 |
| ·Sample pretreatment for ~(210)pb dating | 第103-104页 |
| ·~(210)Pb activity and sedimentation rates | 第104-107页 |
| ·Sediment flux estimations | 第107页 |
| ·Error correction of accumulation rates | 第107-113页 |
| (a) Grain size correction of accumulation rates | 第107-110页 |
| (b) Compaction correction of accumulation rates | 第110-113页 |
| Approach Ⅰ:Standard layer method | 第110-111页 |
| Approach Ⅱ:Removing of compact effecf | 第111-113页 |
| ·Fine grain sediment resuspension and transport | 第113-122页 |
| ·Tidal cycle measurements | 第113页 |
| ·Laboratory analysis and data processing | 第113-122页 |
| (a) SSCs data analysis | 第113-116页 |
| SSCs data analysis of in situ water samples | 第114页 |
| SSCs data analysis of calibrated ADCP echo intensity information | 第114-115页 |
| Figure producing of SSCs profile | 第115-116页 |
| (b) Data analysis of bottom boundary layer parameters | 第116-119页 |
| (c) Estimation of sediment re-suspension | 第119-120页 |
| (d) Estimation of suspended sediment flux | 第120-122页 |
| Chapter 5 Results | 第122-205页 |
| ·Seafloor morphology of the study area | 第122-125页 |
| ·Sediment types and distributions | 第125-159页 |
| ·Description of sediment cores | 第125-155页 |
| ·Vertical distribution patterns of sediment grain size | 第155-156页 |
| ·Spatial distribution of vertical patterns | 第156-158页 |
| ·Sub-sample selection,for ~(210)Pb dating | 第158-159页 |
| ·Water content and compaction effects | 第159-166页 |
| ·Water content precision in relation to sub-sampling duration | 第159-162页 |
| ·Distributions of compaction effects on core lengths | 第162-165页 |
| ·Compaction effects on core lengths in relation to water content | 第165-166页 |
| ·Distribution patterns of ~(210)pb activities | 第166-173页 |
| ·Vertical distribution patterns of ~(210)Pb activities | 第166-167页 |
| ·Horizontal distributions of ~(210)Pb decay profile types | 第167-168页 |
| ·Horizontal distributions of ~(210)pb activities | 第168-173页 |
| ·Distribution patterns sedimentation rates | 第173-199页 |
| ·Detailed analysis results of each core sample | 第173-197页 |
| (a) Sediment cores with normal ~(210)Pb_(ex) decay profile | 第173-175页 |
| Core CJ06 | 第173-174页 |
| Core CJ08 | 第174页 |
| Core CJ12 | 第174-175页 |
| (b) Sediment cores with unique total 210Pb activity profile | 第175-179页 |
| Core CJ01 | 第176页 |
| Core CJ04 | 第176-177页 |
| Core CJ09 | 第177-178页 |
| Core CJ15 | 第178-179页 |
| (c) Sediment cores with sectional ~(210)Pb_(ex) decay profile | 第179-188页 |
| Core CJ02 | 第179-180页 |
| Core CJ05 | 第180-181页 |
| Core CJ07 | 第181页 |
| Core CJ11 | 第181-182页 |
| Core CJ14 | 第182-183页 |
| Core CJ16 | 第183-184页 |
| Core CJ19 | 第184页 |
| Core CJ23 | 第184-185页 |
| Core CJ24 | 第185-186页 |
| Core CJ25 | 第186-188页 |
| (d) Sediment cores with topsy-turvy ~(210)Pb activity profile(sectional ~(210)pb_(ex) decay and inverse ~(210)Pb_(ex) decay profile) | 第188-197页 |
| Core CJ13 | 第188页 |
| Core CJ17 | 第188-189页 |
| Core CJ18 | 第189-190页 |
| Core CJ20 | 第190-191页 |
| Core CJ21 | 第191-193页 |
| Core CJ22 | 第193页 |
| Core CJ26 | 第193-194页 |
| Core CJ27 | 第194-195页 |
| Core CJ28 | 第195-196页 |
| Core CJ29 | 第196-197页 |
| ·Horizontal distributions of sedimentation rates | 第197-199页 |
| ·Profiles of hydrodynamic observations | 第199-205页 |
| ·Distribution of SSCs and current velocity components | 第199-202页 |
| ·Distribution of bottom boundary layer parameters | 第202-205页 |
| Chapter 6 Discussion | 第205-232页 |
| ·~(210)pb profiles in relation to catchments changes | 第205-207页 |
| ·Catchment changes over the Changjiang Estuary | 第205-206页 |
| (a) Mass discharge changes | 第205页 |
| (b) Deltaic Processes | 第205-206页 |
| ·~(210)Pb profiles in relation to catchments changes | 第206-207页 |
| (a) 1980s(first period in Fig.3.10) | 第206页 |
| (b) After 2003 (third period in Fig.3.10) | 第206-207页 |
| (c) Years in between (second period in Fig.3.10) | 第207页 |
| ·~(210)Pb distribution patterns in relation to sedimentary processes | 第207-212页 |
| ·Surficial ~(210)Pb in relation to turbidity maximum | 第208-209页 |
| ·Sedimentary processes represented by ~(210)Pb patterns | 第209-212页 |
| (a) Sedimentary processes of Pattern 2 | 第209-210页 |
| (b) Sedimentary processes of Pattern 3 | 第210页 |
| (c) Possible sedimentary processes of Pattern 4 | 第210-212页 |
| ·Sedimentation rate variations in response to catchments changes | 第212-220页 |
| ·Variations in sedimentation rates | 第212-217页 |
| (a) Sedimentation rate variations over modern subaqueous delta | 第215-216页 |
| (b) Sedimentation rates over the old Changjiang Delta | 第216页 |
| (c) Sedimentation rates over the delta front-transition region | 第216-217页 |
| ·Sedimentation rates in relation to turbidity maxima | 第217页 |
| ·Sedimentation rates in relation to mass discharge | 第217-218页 |
| ·Relationships between sedimentation rates and ~(210)Pb_(ex) | 第218-219页 |
| ·Distribution of sedimentation rates affected by evolution of biological communities | 第219-220页 |
| ·Conditions for the formation of hyperpycnal flow | 第220-222页 |
| ·Conditions for the generation of hyperpycnal flow | 第220页 |
| ·Possibility of hyperpycnal flow induced by the increase in SSCs within the bottom boundary layer | 第220-221页 |
| ·Relationship between seabed morphology and sediment gravity flow | 第221-222页 |
| ·Factors affecting the distribution of sediment grain size | 第222-229页 |
| ·Locations on different deltaic facies | 第223-224页 |
| ·Material source affecting the distribution of sediment grain size | 第224-225页 |
| ·Possible sedimentation process affecting the distribution of sediment grain size | 第225页 |
| (a) Hyperpycnal depositional sequence | 第225页 |
| (b) Turbidity currents | 第225页 |
| ·Variation in hydrodynamics affecting the distribution of sediment grain size | 第225-229页 |
| (a) Variation over time | 第226-228页 |
| Hydrodynamic events | 第226页 |
| Channel evolution at the Changjiang River mouth | 第226-228页 |
| (b) Variation over the estuary (horizontal hydrodynamic distribution) | 第228-229页 |
| ·Human activities affecting the distribution of sediment grain size | 第229页 |
| ·Future sediment retention | 第229-230页 |
| ·Hydrodynamics data analysis | 第230-232页 |
| ·Analyzing parameters of the bottom boundary layer at estuary | 第230-231页 |
| ·Validity of SSCs data calibrated from echo intensity recorded by ADCP | 第231-232页 |
| Chapter 7 Conclusion | 第232-237页 |
| Basic characteristics of sediment core samples | 第232-233页 |
| Vertical distribution patterns | 第233页 |
| Distribution of sedimentation rates | 第233-234页 |
| Catchments changes | 第234页 |
| Factors affecting the distributions | 第234-235页 |
| Further research in need | 第235-237页 |
| References | 第237-263页 |
| Appendices | 第263-282页 |
| Appendix 1: Results of regression analyses on excess ~(210)Pb activity against depth | 第263-267页 |
| Appendix 2: Sub-sampling duration effects on the precision of the water content data(2009) | 第267-269页 |
| Appendix 3: Relative water content(dimensionless ratio)of sediment cores(2009)(note:Locations shown in Figure 3.7-1) | 第269-281页 |
| Appendix 4: Research articles completed during 2009-2013 | 第281-282页 |
