在沉积学香山会议（北京，2016年9月25-28日）上我的发言摘要为：

Understanding modern sediment dynamic processes: importance in the interpretation ofsedimentary records

Shu Gao

State Key Laboratory for Estuarine and Coastal Research, East China NormalUniversity, Shanghai 200062, China

E-mail: sgao@sklec.ecnu.edu.cn

Sediment dynamics and morphodynamics deal with the transport and accumulation of sedimentary materials and the resultant geomorphological changes. In such studies, the threshold of initial sediment movement, the settling velocity of particles, fine-grained sediment resuspension, sediment transport and accumulation are quantified, based on an understanding of the relevant physical, chemical and biological processes. Various techniques are developed to measure the hydrodynamics, water mass properties and sedimentary characteristics.Mathematical models are established to predict the intensity of transport and accumulation, and the resultant bed elevation change. River water flows, waves, tides, oceanic circulations and gravity flows are important physical processes. Likewise, weathering, transformation between dissolved and particulatematerials, biologically induced particles, flocculation, diagenetic modifications and the formation of minerals are associated with chemical, geochemical or biogeochemical processes. Although the research in these aspects is stillin sufficient (biological processes in particular), the knowledge of modern processes is beneficial to our understanding of the Holocene sedimentary systems, e.g. the estuarine and coastal systems formed during the last 6500years.

In addition, there is a potential for sediment dynamics and morphodynamics to be applied to the interpretation ofsedimentary records. Sediment cores are often analyzed to obtain the information on environmental characteristics, on the basis of the data set of sediment particle size, geochemical parameters and age dating. In combination with sediment dynamic and morphodynamic analysis, the sedimentary cores may also provide information on the processes and mechanisms responsible for theenvironmental characteristics identified. The methodology is the interaction between the core data and process modeling. For a tidal flat environment, vertical sediment distributions and deposition rates can be derived from core analysis; the deposition rate is controlled by the level of suspended sedimentconcentration in association with the water mass that enters the tidal flat during the flood phase of the tide, and the suspended sediment concentration depends on the intensity of resuspension which is related to tidal currents incoastal waters. Therefore, the data from the core can be used to constrain the tidal process, which can be quantified by a process model. Subsequently, the model output provides guidelines for further core analysis. This simplified case indicates that by interaction/feedbacks between the core data and process modeling, it is possible to derive both environmental characteristics and the processes that are responsible. Further, such an approach may be used to reveal the processes that could not be seen from conventional core analysis.