DISTRIBUTIONAL CHARACTERISTICS OF MARINE BOTTOM SEDIMENTARY TYPES IN XIAMEN HARBOUR
Liao Shuimu, Zhou Dingcheng and Yang Baohua (Third Institute of Oceanography, SOA, Xiamen)
The distribution of marine bottom sedimetray types are complicated in the Xiamen Harbour. In the seven types, fine-grained silty mud dominates, accounting for one third of the total area. The horizontal distribution of sedi ments shows its rule of mechanical variation(sPreading of sediments from co arse to fine ones) and the characteristics of coarse sediments in two areas (river mouth and the coast with strong wind and wave) and fine sediments in one area (inside bays and harbours).The vertical distribution of the sadi ments show the characteristics of "finer on the upper part and coarser on the lower part" and "alternation of coarse with fine", reflecting the chan ging tendiency from high energy to low energy in the sedimentary environ ments. This Paper also shows that the sedimentary materials in the Harbour is mainly from terrestial detritus which arc the results of river transportation and coastal errosion. Based on the formation and distribution of grain size, hydrodynamic factors and the characteristics of the sedimentary types, this paper clas sifies the area into four sedimentary subareas, channel scdiaentary subarea, tidal suspension sedimentary subarea, subarea under the interaction of tidal and river flows, and the subarea under wind and wave actions.