| Project/Area Number |
12640457
|
|---|
| Research Category |
Grant-in-Aid for Scientific Research (C)
|
| Allocation Type | Single-year Grants |
|---|
| Section | 一般 |
|---|
| Research Field |
Stratigraphy/Paleontology
|
|---|
| Research Institution | KYUSHU UNIVERSITY |
|---|
Principal Investigator |
NISHI Hiroshi Graduate School of Social and Cultural Studies, Kyushu University, 大学院・比較社会文化研究院, 助教授 (20192685)
|
|---|
| Co-Investigator(Kenkyū-buntansha) |
ISOZAKI Yukio Department of Earth Science & Astronomy, The University of Tokyo, 大学院・総合文化研究科, 教授 (90144914)
KAWAHATA Hodaka National Institute of Advanced Industrial Science and Technology (AIST), 産業技術総合研究所, 主任研究官
HARUTAKA Sakai Graduate School of Social and Cultural Studies, Kyushu University, 大学院・比較社会文化研究院, 教授 (90183045)
|
|---|
| Project Period (FY) |
2000 – 2001
|
| Project Status |
Completed (Fiscal Year 2001)
|
| Budget Amount *help |
¥3,700,000 (Direct Cost: ¥3,700,000)
Fiscal Year 2001: ¥1,100,000 (Direct Cost: ¥1,100,000)
Fiscal Year 2000: ¥2,600,000 (Direct Cost: ¥2,600,000)
|
|---|
| Keywords | Late Eocene / planktonic foraminifers / magnetosstratigraphy / impact bolide / 始新世 |
|---|
| Research Abstract |
Ocean Drilling Program Leg 171 drilled the middle to upper Eocene sequences at Sites 1052 and 1053 on the Blake Nose in the western North Atlantic Ocean.
(1) We can reevaluate the following biostratigraphic events of planktonic foraminifers using magnetostratigraphy : The last occurrences (LOs) of Acarinina praetopilensis, A. rohri and Morozovella spinulosa (Cron C17n3n), the first occurrences (FOs) of Acarinina medizzai and Porticulasphaera semiinvoluta and the LO of Acarinina collactea (Chron C17n2n), The morozovellids and acarininids extinct in the uppermost of Chron C17n3n and within Chron C17n1n, respectively.
(2) The hispid species of morozovellids and acarininids dominates about 20 to 55 % of total assemblages during the Middle Eocene. The major faunal turnover occurred in the upper part of Zone P14 (Chron C17n3n) where those species decreased rapidly to less than 10 %.
(3) At Site 1053A, an extinction event of radiolarians has been recorded in Core 8H (the uppermost part of Chron C16n2n, P15 of planktic foraminiferal zones), This bioevent is considered to be related with the Chesapeake Bay bolide impact. However, no remarkable extinction events of planktonic foraminifer species are not yet recognized between the impact horizons.
|
