| Research Abstract |
The following results have become clear as a result of "Research on the ridge subduction, late Cretaceous to Paleogene tectonics in the Shimanto accretionary complex" in the 1999 - 2001 years.
1. The Shimanto accretionary complex are widely distributed arong the Paleo Japanese Island arc, and "in situ basalt" occure in Kyushu, Shikoku, Kii Peninsula, and Akaishi Mountains, and Hidaka Belt of Hokkaido which suggests subduction of ridge in alignment with Paleo Japanese-Islands arc applied to end of Cretaceous to Paleogene in age. The Shimanto accretionary complex of the southern Shima peninsula as the gap of the above-mentioned area are investigated, the occurrence of "in situ basalt" in natute is not seen, so the possibilities, such as discontinuity of the ridge by transform fault and that ridge subcluction had not taken place, are presumed in this area.
2. In order to establish high resolution radiolarian biostratigraphy of late Cretaceous to early Paleogene in age, samples were collecte
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d from the Nemuro Group distributed over Shiranuka Hill in Hokkaido, and it is under examination. As the processing method of a sample, when the "BORON method" was applied as the separation method of the radiolarian fossil from consolidated sedimentary rocks, the very effective thing has been checked.
3. Electronic flle-ization of the picture of the scanned type electron microscope photograph and penetrated type microphotograph of radiolarian fossils are advanced form database and public presentation is under preparation.
4. As a part of fossil radiolaria researchuwe started the research of living radiolarians. We set a fixed point in Kii Channel and started investigation, the seasonal variation of radiolaria is under investigation, and the result of seasonal change of radiolaria is being settled.
5. By debating CJ.Hollis who studied the radiolarian fossil from New Zealand the late Cretaceous to Paleogene of New Zealand, it showed that contrast of the radiolarian fossil in a Northern Hemisphere area and a Southern Hemisphere area could be considered. Less
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