| Abstract |
31 samples were collected along three columns of one locality at Tonda, Koyu-Gun, Miyazaki Prefecture. The each column was settled in an area of about 3m high and 5m wide on an almost vertical cutting.... Grain size, calcium carbonate content and organic carbon content were examined and the benthonic foraminiferal assemblages were analyzed. The benthonic foraminiferal assemblages were divided into four assemblages named as Cassidulina carinata assemblage, Rectobolivina raphana assemblage, Gyroidina orbicularis-Nonion japonicum assemblage and Pseudononion japonicum assemblage. To represent the complexity of benthonic foraminiferal assemblages, the MOTOMURA's formula was applied. Principal factor analysis was applied to infer the cause which determined the faunal assemblage in the sample. In the present study, first four factors can be expressed within both of Q- and R-technique factor analyses. The first four factors of Q-technique factor analysis are interpreted to indicate the province, the mechanism of sedimentation, the bottom sediment in which the benthonic foraminifers lived and the temperature and/or depth of water respectively. Likewise the first four factors of R-technique factor analysis are the depositional mechanism, the thresh. old velocity of bottom current, the bottom sediments in which the benthonic foraminifers lived and the temperature and/or depth of water respectively. Using the preceding results, the environments during deposition of sediments of this sampling locality can be reappeared. The results are promising enough for the author with a perspective for extracting autochthonous assemblages from several thanatocoenoses to make a firm basis for further ecological consideration.show more
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21_02_p177