珪藻化石群集の形成過程と古生態解析

概要

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As a fundamental study on paleoenvironmental reconstructions based on fossil diatom assemblages, information on processes of their formation is indespensible, because well preserved celles of diatom, composed of silica, make a mixture both autochthonous and allochthonous member in an assemblage. In the present paper such fundamental problems were examined. As a result, it turned out that dead diatom cells were widely transported in a tidal zone, especially to make mixed assemblages in mud flats, residual ones in sand flats and autochthonous community in salt ponds. In-flow of allochthonous cells made the preservation ratio of a assemblage lewered and the structure changed depending on the addition of them. And a model on formations of fossil assemblages in some environments was introduced. On the basis of those fundamental studies, fossil diatom assemblages formed at the Jomon transgression in Holocene were analyzed. As a result, such phenomena as reworked cells from older sediments, transportation of allochthonous cells to the offshore from the coastal area, concentration of allochthonous cells in the tidal area, were observed in fossil assemblages.
日本ベントス学会の論文