玄界灘の表層堆積物

概要

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Approximately 250 bottom sediments samples have been otained from the continental shelf of Genkainada off Fukuoka Prefecture, Kyushu, West Japan. These samples were collected by the R/V "GENKAI" (85t) of the Fukuoka Fishery Experiment Station of Fukuoka Prefecture in 1978, 1979 and 1981. Their size parameter and calcium carbonate content have been studied in relation to the submarine topography and current of water. Most of offshore surface sediments in the Genkainada shelf are generally wellsorted medium-to coarse-grained sand. On the contrary, the nearshore sediments have wide range of distribution of grain size. The median diameters of nearshore or shallow-water sediments range between-1.0 to 3.0 in phi unit. The amount of calcium carbonate content in the sediments are over 20% in the offshore area and less than 20% in nearshore area. It is characteristic features that the approaches to the islands or shoals are indicated by rapid increase in the calcium carbonate content. Remarkable example is afforded by the accumulation of abundant calcareous organic debris of marine origin around the Okinoshima Island where the value of calcium carbonate content exceed 80%.
長崎大学教育学部の論文
1988-02-29