Changes of the paleoenvironments and biological diversity in the Late Eocene impact bolide event

晚始新世撞击火流星事件的古环境和生物多样性变化

• 批准号: 12640457
• 负责人: NISHI Hiroshi
• 金额: $ 2.37万
• 依托单位: KYUSHU UNIVERSITY
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for Scientific Research (C)
• 财政年份: 2000
• 资助国家: 日本
• 起止时间: 2000 至 2001
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-12640457/
• 关键词: Late Eocene; planktonic foraminifers; magnetosstratigraphy; impact bolide; 始新世

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.

大洋钻探计划第171航次在北大西洋西部布莱克鼻的1052和1053号地点钻探了始新世中上部层序。(1)利用磁性地层学可以重新评价以下几个浮游有孔虫生物地层事件：Acarinina praetopilensis、A. rohri和Morozovella spinulosa（Cron C17n3n），Acarinina medizzai和Porticulasphaera semiinvoluta的首次出现（FO）和Acarinina collactea（Chron C17n2n）的首次出现（LO），Morozovellids和acarinids分别在Chron C17n3n的最上部和Chron C17n1n内灭绝。(2)在始新世中期，morozovellids和acarinides的硬毛物种占总组合的20%至55%。主要的动物区系更替发生在P14区的上部（Chron C17n3n），这些物种迅速减少到不到10%。(3)在1053A站，在8H柱（Chron C16 n2n，P15）记录到一次放射虫灭绝事件，该事件被认为与切萨皮克湾火流星撞击事件有关。然而，在撞击视界之间，尚未发现有显著的浮游有孔虫物种灭绝事件。

项目成果

西弘嗣,尾田太良: "浮遊性有孔虫を用いた海洋表層環境の解析法"月刊 地球. Vol.22 No.9. 601-608 (2000)

Hirotsugu Nishi，Tara Oda：“利用浮游有孔虫的海洋表面环境分析方法”月刊第 22 卷第 601-608 期（2000 年）。

西 弘嗣, 尾田太良: "古環境指標としての浮遊性有孔虫"比較社会文化. 7. 139-159 (2001)

Hirotsugu Nishi，Tara Oda：“浮游有孔虫作为古环境指标”比较社会文化。7. 139-159 (2001)

H. Nishi: "Warm climate from late Paleocene to early Eocene based on micropaleontological data"Gekkan Chikyu, Suppl. Vol. No. 29. 116-126 (2000)

H. Nishi：“基于微古生物学数据的古新世晚期到始新世早期的温暖气候”Gekkan Chikyu，增刊。

H. Nishi and M. Oda: "Paleocenographic analysis using planktonic foraminifers"Gekkan Chikyu. Vol. 122, No. 9. 601-608 (2000)

H. Nishi 和 M. Oda：“利用浮游有孔虫进行古生世学分析”Gekkan Chikyu。

R. D. Norris and H. Nishi: "Evolutionary trends in coiling of tropical Paleogene planktonic foraminifera"Paleobiology. Vol. 27, No. 2. 327-347 (2001)

R. D. Norris 和 H. Nishi：“热带古近纪浮游有孔虫盘绕的进化趋势”古生物学。