| Co-Investigator(Kenkyū-buntansha) |
SUZUKI Noritoshi Tohoku University, Dept.of Earth & Planetary Science, Assistant Professor, 理学部, 助手 (60312542)
MATSUOKA Atsushi Niigata University, Department of Geology, Professor, 理学部, 教授 (00183947)
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| Research Abstract |
We have obtained the following results through this Triassic/Jurassic (T/J) boundary research project on micropaleontology,
1) Pantanellium tanuense is considered to be one of global index species of Hettangian age (Earliest Jurassic). Archaeocenosphaera laseekensis and Praehexasaturnalis tetraradiatus are also good indicators for the Hettangian.
2) The end of Triassic is marked by the final occurrences of Globolaxtorum tozeri, Hagiastrid? gen.et sp.Indet A, and Risella spp.
3) The characteristic taxa, Spongotrochus sp.(Carter 1994) and Canoptum spp.are recognized, which occur across the T/J boundary surviving the mass extinction at the end of Triassic. Observation of Living Radiolaria suggests that the Canoptum spp.have tolerance of the crisis of end of the Triassic because of its unique feeding system that differs from other extinct multicyrtids.
4) The pattern of the faunal turnover across the T/J boundary is similar between Japan (Inuyama) and Canada (Queen Charlotte Islands) although there are differences among faunal contents and dominated species. The faunal change is subdivided into 3 stages.
5) Trough faunal comparison between Japan, Philippine, New Zealand and Canada, the faunal affinity around the T/J boundary is strong between Japan and Philippine, and also New Zealand and Canada.
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