2007 Fiscal Year Final Research Report Summary
Oligocene and Early Miocene floras in Japan and paleoclimatic analysis based on leaf physiognomy
| Project/Area Number |
17540446
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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 |
Stratigraphy/Paleontology
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| Research Institution | National Museum of Nature and Science, Tokyo |
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Principal Investigator |
UEMURA Kazuhiko National Museum of Nature and Science, Tokyo, National Museum of Nature and Science, Department of Geology and Paleontology, Head (50000138)
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| Co-Investigator(Kenkyū-buntansha) |
YAMADA Toshihiro Kanazawa University, Graduate School of Natural Science and Technology, Lecturer (70392537)
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| Project Period (FY) |
2005 – 2007
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| Keywords | Stratigraphy-Paleontology / Fossil flora / Paleoclimate / Oligocene / Miocene / Paleogeography / Japan Sea origin |
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| Research Abstract |
Oligocene to Early Miocene floras prior to the tectonic episode of the Japan Sea opening are studied in their compositional and chronostratigraphical changes, together with paleoclimatic analysis of these floras based on leaf physiognomic characters. Field surveys and fossil collections are made in Akita, Fukushima, Gifu, Inland region and northern Kyushu, in addition of re-examination of plant megafossil collections and three radiometric datings in Fukushima area. Brief results are as follows:
1) "Oligocene" floras are divided into two types, Late Eocene to Early Oligocene and Late Oligocne floras. Although climatic fluctuation are evident in each floral type, these floras represent a modernized, warm-temperate flora since the Middle Eocene thermal maximum.
2) Early Miocene floras are divided into the older, temperate Aniai-type and younger, warmer Daijima-type floras. The shift from the Aniai-type to Daijima-type occurs ca. 20 Ma. Among the Daijima-type floras, those in 20 Ma to 17 Ma are characterized by Fagus and many other deciduous dicots, accompanied by many deciduous elements of Daijima type, such as Comptonia, Liquidambar, Parrotia and Quercus miovariabilis, differing the typical Daijima-type around 16 Ma.
3) Latitudinal and longitudinal (from inland to maritime areas) change in each Early Miocene flora is analyzed on the basis of the floral composition and leaf physiognomic character. Apart from latitudinal changes in the Aniai-and Daijima-type floras, the longitudinal change is apparent in the Aniai-type floras. The evidence reveals the paleogeographic changes prior to the tectonic episode of the opening of the Japan Sea in ca. 16 Ma.
4) Although these floral and climatic shifts involve the local tectonic episode, they also represent a global paleoclimatic evolution.
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[Book] 日本列島の自然史2006
Author(s)
植村和彦ほか(編)
Total Pages
339
Publisher
東海大学出版会
Description
「研究成果報告書概要(和文)」より
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