Using mineral compositions to indicate the origin of sediments in a tidal flat of an estuarine marsh

Given the importance of tidal flats as habitats for a wide range of organisms, a considerable amount of related research has accumulated. However, in Japan, as elsewhere in the world, tidal flats are disappearing because of increasing seaside population, urbanization, and development of coastal industries. We investigated the sediment characteristics of Tsuyabaru Marsh in Japan, using X-ray fluorescence and X-ray diffraction (XRD) analyses to trace their sources. The estuarine Tsuyabaru Marsh comprises a tidal flat, the peripheral basin, the Ooyodo River, and the Yae River. The mineral components of the tidal flat sediment were quartz, mica minerals, kaolinite, plagioclase, and dolomite. To trace the sediment source and characterize the sediment in the Tsuyabaru Marsh, cluster analysis was applied to the peak XRD intensity ratios. A strong similarity was demonstrated between the sediments collected from the tidal flat and the Ooyodo River. A comparably strong similarity was found between sediments from the bottom of Tsuyabaru Marsh and the upstream Yae River section. Our analysis helps understand the sources and distribution of sediments in estuarine marshes.