Radiolarian Biostratigraphy and its International Correlation

本研究取得的主要成果如下：1。通过化石个体的对比，将日本侏罗纪放射虫带与北美、欧洲侏罗纪放射虫带进行了对比。虽然国际上还没有建立完善的放射虫分带，但这些研究澄清了相关性中的问题：带间的匹配与错配.利用四国地区新发现的菊石化石标定了部分侏罗纪-白垩纪放射虫组合的年龄。从日本以外的美国、墨西哥、新西兰、澳大利亚、中国、苏联、菲律宾和印度尼西亚等国采集了古生代至中生代含放射虫的硅质岩，并对这些标本的动物群进行了地理、纬度和生态学特征的研究。结果表明：（1）中三叠世-早侏罗世层状硅质岩和中晚侏罗世碎屑岩是沿着亚洲东部陆缘晚中生代增生杂岩的主要岩性标志。(2)在新西兰，通过使用放射虫化石，确认了特提斯和非特提斯动物群的并列。研究了印度洋和太平洋的海洋沉积物，其中含有保存完好且未受干扰的放射虫遗骸。这些钻探资料加强了侏罗纪至新生代陆上放射虫的分带性。通过对侏罗纪的Eucyrtidielum和Tricolocapsa等属的系统发育研究，将日本的放射虫分带与其他地区的放射虫分带进行了对比，并为日本的放射虫分带提供了古生物学依据。

Main results obtained by present co-operative research are summarized as follows :1. Jurassic radiolarian zones in Japan was correlated with those in North America and Europe by means of cross-check using fossil individuals. Although the perfect international radiolarian zonation has not yet been established, these studies clarified the problems in correlation : matching and misma tching among the zones.2. Ages of some Jurassic to Cretaceous radiolarian assemblages were calibrated with newly found ammonite fossils in Shikoku.3. Paleozoic to Mesozoic Radiolaria-bearing siliceous rocks were collected from outside Japan, such as USA, Mexico, New Zealand, Australia, China, USSR, Filippines and Indonesia, and biogeographic, latitudinal and ecological characteristics of the faunas from these specimens were examined. Some of the results are :(1) Middle Triassic to early Jurassic bedded cherts and middle to late Jurassic clastic rocks are the key lithology diagnostic to the late Mesozoic accretionary complex distributed along the eastern continental margin of Asia.(2) In New Zealand, juxtaposition of Tethyan and non-Tethyan faunas was recognized by using radiolarian fossils.4. Oeanic sediments containing well-preserved and not-disturbed radiolarian remains from the Indian and Pacific Oceans were examined. Jurassic to Cenozoic on-land radiolarian zonations were reinforced by these drilling data.5. Phylogenic studies on some genus, such as Jurassic Eucyrtidiellum and Tricolocapsa, made it easy to correlate radiolarian zonations established in Japan with those in other regions, and gave a paleontological basis to the zonations.