Subdivisions of sedimentary dynamic environment based on FCM in the Yellow River subaqueous delta

Reasonably and quantitatively determining subdivisions of sedimentary dynamic environment is an important basis of understanding regional sedimentary dynamic processes. Based on the grain distribution data of the surface sediment samples, the sedimentary dynamic environment in the Yellow River subaqueous delta area has been classified, identified and represented by the methods of fuzzy c-means clustering (FCM), triangle illustration and kriging. The results show that the sedimentary dynamic environment of the study area can been classified into 3 categories and they indicate the dynamic sedimentary environments of scour, deposition and mixing of scour and deposition, respectively. And the membership degree maps of the three categories of sedimentary dynamic environments have a function of indicating the occurance probabilities of the different environments at certain places and also can show their dominant areas. Meanwhile the sedimentary dynamic environment map, generated from the fuzzy membership degree values of the surface sediments, is highly identical with the spatial distribution pattern of the sedimentary dynamics in the study area, which means the mapping results are reasonable and effective. The study results have some reference values for the geomorphic evolution trend analysis and coastal protection work in the area of the Yellow River Delta.