A DISCUSSION ON SEDIMENT DYNAMICS

In the past decades, sedimentologists have made great efforts to investigate the relation of the grain size and structures or bedforms of a sediment with its hydrodynamic environment through experiments, in-situ monitoring and the study of ancient sedimentary records. This paper recalled the history of sediment dynamics, and discussed the dynamic implication of grain size and structures of sediments. Grain size and structures are useful tools for environmental reconstruction. But they are both multi-variable functions, which are influenced by various dynamic factors including the source of sediments and the dynamic field of a sink. It is impossible to get a single solution through either grain size or structures. The author suggests learning from history the experiences in reconstruction of dynamic environments upon depositional features. Integrated study of sedimentary sequences is required to approach a rationale conclusion. The achievements of the study of grain size and structures, however, have certainly paved the way for the hydrodynamic reconstruction of an environment, and further study of these features should not be ignored.