Global seesaw oscillation of botom water redox condition through Cretaceous OAE2

2014 Fiscal Year Final Research Report

• Project/Area Number: 24403012
• Research Category: Grant-in-Aid for Scientific Research (B)
• Allocation Type: Partial Multi-year Fund
• Section: 海外学術
• Research Field: Stratigraphy/Paleontology
• Research Institution: Kanazawa University
• Principal Investigator: HASEGAWA Takashi 金沢大学, 自然システム学系, 教授 (50272943)
• Co-Investigator(Kenkyū-buntansha): FUKUSHI Keisuke 金沢大学, 環日本海域環境研究センター, 准教授 (90444207) ; MORISHITA Tomoaki 金沢大学, 自然システム学系, 教授 (80334746)
• Co-Investigator(Renkei-kenkyūsha): MORIYA Kazuyoshi 金沢大学, 自然システム学系, 博士研究員 (60447662)
• Research Collaborator: 後藤 晶子 (桜井 晶子) 金沢大学, 自然システム学系, 博士研究員 ; 柿崎 喜弘 金沢大学, 自然システム学系, 博士研究員 ; HAGGART James W. カナダ国地質調査所, 主任研究員 ; CRAMPTON James ニュージーランド地質核科学研究所, 主任研究員
• Project Period (FY): 2012-04-01 – 2015-03-31
• Keywords: 白亜紀 / OAE / セノマニアン / チューロニアン / 無酸素

Outline of Final Research Achievements

Cretacous OAE2 is an oceanic event that induced deposition of large amout of organic carbon on the extended sea bottom. We surveyed New Zealand (NZ) and Canadian Pacific Coast (CPC) and designated OAE2 horizon with carbon isotope and microbiostratigraphy. In NZ, red mudstone bed indicate oxigenation of bottom environment during OAE2 interval. In CPC, anoxia below the OAE2 horizon and gradual recovery of oxygen environment toward OAE2 were observed. Oscillation of bottom water redox condition with inverted phase in middle-high latitude Pacific against proto-Atlantic regions are documented showing complicated nature of OAE2 as a global event. We also obtained an evidence of incleasing seasonal aridity toward OAE2 time in CPC. Evidence of such climatic response on land across OAE2 was rarely presented through this interval and will be further studied.

Free Research Field

地質学，古環境学