1999 Fiscal Year Final Research Report Summary
Establishment of paleobiogeography and historical change of distribution based on radiolarian fossils
| Project/Area Number |
10836004
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| Research Category |
Grant-in-Aid for Scientific Research (C)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
自然史科学
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| Research Institution | Utsunomiya University |
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Principal Investigator |
AITA Yoshiaki Utsunomiya University, Faculty of Agriculture, Associate Professor, 農学部, 助教授 (90167768)
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| Co-Investigator(Kenkyū-buntansha) |
SAKAI Toyosaburo Utsunomiya University, Faculty of Agriculture, Professor, 農学部, 教授 (50089778)
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| Project Period (FY) |
1998 – 1999
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| Keywords | Radiolaria / Early & Middle Triassic / Middle & Late Jurassic / database / all morphotypes / New Zealand / high latitude / paleobiogeography |
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| Research Abstract |
All the morphotypes of the radiolarian assemblages from the Early and Middle Triassic and Middle and Late Jurassic time in high and low latitudes have been digitized and established as a paleontological database. These faunas from southern high latitudes are from the Middle Triassic (Anisian-Ladinian) siliceous shale and phosphatic concretions taken from the Waipapa Terrane, North Island, and from phosphatic concretions at Bull Creek, Caples Terrane, South Island, New Zealand. The Middle Jurassic (Toarcian-Aalenian) radiolarian faunas taken from the Ururoa Formation, Kawhia Coast were also addied to the paleontological database. More than 300 radiolarian morphotypes of the Buchenstein Limestone faunas which is representative of low latitude during the Middle Triassic (Ladinian), have been dizitized in order to compare with age-equivalent faunas. Biostratigraphy of the Early and Middle Triassic bedded chert sequences from the Minowa section, Ashio terrane has been carried out. Almost 150 outcrop photos (1mX1m in size) were taken from the continuous Early Triassic siliceous shale succession, Karasawa-san and were dizitized for the detailed geologic study.
Well-preserved Middle Triassic (Ladinian) radiolarian faunas have been documented from phosphatic nodules collected from the Waipapa Terrane, New Zealand and the Omolon Massif, northeastern Siberia, respectively. Both New Zealand and northeastern Siberia faunas include many species that are well-known from European Tethys area as well as abundant non-Tethyan radiolarians that are characteristic of these faunas. Distinctive pylomate spumellarians were described as a new genus Glomeropyle Aita & Bragin together with seven new species. They are only known from northern and southern high latitudes and they are endemic Triassic Radiolaria with a bipolar distribution pattern.
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