Ridge subduction and the tectonics around the paleo-Japanese islamd arc during late Cretaceous to Paleogene, an example of the shimanto accretinary complexes

以下是1999-2001年《岛曼托增生杂岩晚白垩世至古近纪隆起俯冲构造研究》的成果。岛曼托增生杂岩广泛分布于古日本岛弧上，在九州、四国岛、麒麟半岛、赤石山脉和北海道的东道带中均有“原地玄武岩”产出，其时代为白垩纪末期至古近纪。石马半岛南部的岛曼托增生杂岩作为上述地区的空隙进行了调查，在自然界中没有发现“原地玄武岩”的存在，因此推测该地区可能存在因转换断层导致海脊不连续和海脊俯冲作用未发生的可能性。为了建立晚白垩世-早古近纪高分辨率放射虫生物地层学，采集了…样品来自Nemuro集团的更多d分布在北海道的Shiranuka山，正在进行检查。作为样品的处理方法，将“硼法”应用于放射虫化石与固结沉积岩的分离，取得了很好的效果。放射虫化石扫描式电子显微镜照片和穿透式显微照片的图像电子化已在数据库中推进，并正在准备公开展示。作为放射虫化石研究的一部分，我们开始了对活体放射虫的研究。在KII海峡设置定点并开始调查，目前正在调查放射虫的季节变化，正在确定放射虫的季节变化结果。通过与研究新西兰晚白垩世至古近纪新西兰放射虫化石的CJ.Hollis的争论，可以考虑北半球地区和南半球地区的放射虫化石的对比。较少

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 … More 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