A Study of the Correlation between and Chronology of Sites of human Habitation and Volcanic Ejecta in the Izu Islands
| Project/Area Number |
63580199
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| Research Category |
Grant-in-Aid for General Scientific Research (C)
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| Allocation Type | Single-year Grants |
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| Research Field |
自然地理学
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| Research Institution | Meiji University |
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Principal Investigator |
SUGIHARA Shigeo (1989) 三重大学, 教育学部, 教授 (60024494)
杉原 重夫 明治大学, 文学部, 教授 (90061978)
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| Project Period (FY) |
1987 – 1989
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| Project Status |
Completed (Fiscal Year 1989)
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| Budget Amount *help |
¥2,000,000 (Direct Cost: ¥2,000,000)
Fiscal Year 1989: ¥600,000 (Direct Cost: ¥600,000)
Fiscal Year 1988: ¥1,400,000 (Direct Cost: ¥1,400,000)
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| Keywords | Izu Islands / Hchijo-jima / Tephrochronology / Aira-Tanzawa-volcanic ash / Kikai-Akahoya volcanic ash / Caldera / Jomon period / Radiocarbondating / 姶良Tn火山灰 / 鬼界-アカホヤ火山灰 / カルデラ / 縄文時代 / 放射性炭素による年代測定 / 鬼界アカホヤ火山灰 / カルデラの形成 / 降下テフラ |
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| Research Abstract |
Buried under the volcanic ejecta of the Izu Islands there have been discovered a great many sites and relics dating from the Jomon period and later. A study of the tephrochronology of the Izu Islands was undertaken by investigating the correlation between and chronology of these remains and the ejecta. The results may be summarized as follows.
1)Following an examination of widespread tephra in the Izu Islands. the stratigraphic relationship between the ejecta and Kikai-Akahoya Volcanic ash(K-Ah) on Hachijo-Jima, Miyake-jima, et.al. was clarified, and Aira-Tanzawa volcanic ash (AT) was discovered at the Hachijo-jima.
2)On the basis of its stratigraphic relationship with the sites and relies discovered in ejecta on the Izu Islands. it was ascertained that Kikai-Akahoya volcanic ash represents a maker bed for the late Initial Jomon period.
3)Following an examination of the history of the formation of Higashi-yama on the basis of tephra stratigraphy, widespread tephra, earthenware types and radiocarbon dating, it was established that the caldera was formed at a time extremely close to the ejection of Aira-Tanzawa volcanic ash 21,000 to 22,000 years ago.
4)The rhyolite and daite volcanic ash thought to originate from Kozu-shima. Ni-Jima, Bayonnaise Rocks will in the future serve as an important marker bed in Izu Island. Tephra fall from the Izu Islands was discovered in the Izu Peninsula and in the Boso peninsula. This should prove to be of considerable assistance in studies on tephrochronology of these regions.
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Report
(3 results)
Research Products
(6 results)
