Geomagnetic paleointensity variations during the last 40 m.y.: Possible relationship between polarity reversal frequency and paleointensity

2012 Fiscal Year Final Research Report

• Project/Area Number: 22340129
• Research Category: Grant-in-Aid for Scientific Research (B)
• Allocation Type: Single-year Grants
• Section: 一般
• Research Field: Solid earth and planetary physics
• Research Institution: The University of Tokyo (2012); National Institute of Advanced Industrial Science and Technology (2010-2011)
• Principal Investigator: YAMAZAKI Toshitsugu 東京大学, 大気海洋研究所, 教授 (80344125)
• Co-Investigator(Kenkyū-buntansha): YAMAMOTO Yuhji 高知大学, 海洋コア総合研究センター, 助教 (00452699)
• Co-Investigator(Renkei-kenkyūsha): TAKAHASHI Futoshi 東京工業大学, 理工学研究科, 助教 (20467012)
• Research Collaborator: ACTON Gary University of California at Davis ; RICHTER Carl University of Louisiana ; SHIMONO Takaya 筑波大学, 大学院・生命環境科学研究科, 博士課程学生
• Project Period (FY): 2010 – 2012
• Keywords: 古地磁気 / 古地磁気強度 / 岩石磁気 / IODP

Research Abstract

A paleomagnetic study was conducted using Eocene to Oligocene sediment cores taken by IODP from the east equatorial Pacific in order to obtain relative paleointensity between 23 and 42 Ma. It was revealed that long-range relative paleointensity records can be contaminated by variations of the relative abundance of biogenic and terrigenous magnetic minerals and sedimentation rates. The positive correlation between polarity reversal frequency and paleointensity that was previously suggested from the data of DSDP Site 522 is not supported. As for short-term variations on the order of 10 kyrs, paleointensity drops were found during stable polarity periods as well as at reversals. This is the same as the characteristics of paleointensity variations known for the last 3 m.y.

Research Products

• [Journal Article] A middle Miocene relative paleointensity record from the Equatorial Pacific. (2013)
  • Author(s): Ohneiser, C., Acton, G., Chanell, J.E.T., Wilson, G.S., Yamamoto, Y., and Yamazaki, T.
  • Journal Title: Earth Planet. Sci. Lett. Volume: (in press)
  • DOI: doi:10.1016/j.epsl.2013.04.038.
• [Journal Article] Oligocene-Miocene magnetic stratigraphy carried by biogenic magnetite at sites U1334 and U1335 (equatorial Pacific Ocean). (2013)
  • Author(s): Channell, J.E.T., Ohneiser C., Yamamoto Y., and Kesler M.S.
  • Journal Title: Geochem. Geophys. Geosyst. Volume: 14
  • DOI: doi:10.1029/2012GC004429.
• [Journal Article] Rock-magnetic artifacts on long-termrelative paleointensity variations in sediments. (2013)
  • Author(s): Yamazaki T., Yamamoto Y., Acton G.,Guidry, E.P., Richter C.
  • Journal Title: Geochem. Geophys. Geosyst. Volume: 14 Pages: 29-43
  • DOI: doi:10.1029/2012GC004546.
• [Journal Article] Data report:temporal variation in natural remanent magnetization observed for Pacific plate basement rocks: compilation from legacy data and new paleomagnetism and rock magnetism data from seafloor basalts cored during Expedition (2013)
  • Author(s): Yamamoto, Y.
  • Journal Title: Proc. IODP Pages: 320-321
  • DOI: doi:10.2204/iodp.proc.320321.213.2013.
• [Journal Article] Oligocene-Miocene magnetostratigraphy of deep-sea sediments from the equatorial Pacific (IODP Site U1333). (2012)
  • Author(s): Guidry, E.P., Richter, C., Acton, G.D.,Channell, J.E.T., Evans, H.F., Ohneiser, C., Yamamoto, Y. and Yamazaki, T.
  • Journal Title: Geological Society, London, Special Publications Volume: 373
  • DOI: doi:10.1144/SP373.7.
• [Journal Article] Paleoposition ofthe Intertropical Convergence Zone in the eastern Pacific inferred from glacial-interglacial changes in terrigenous and biogenic magnetic mineral fractions. (2012)
  • Author(s): Yamazaki, T.
  • Journal Title: Geology Volume: 40 Pages: 151-154
• [Presentation] 相対古地磁気強度記録に見られる堆積物の磁気特性変化の影響. (2013)
  • Author(s): 山崎俊嗣、Acton,G.,Channell,J.,Guidry,E.P.,Richter,C.,山本裕二
  • Organizer: 日本地球惑星科学連合2010年大会
  • Place of Presentation: 幕張メッセ国際会議場(千葉市)
  • Year and Date: 2013-05-21
• [Presentation] 赤道太平洋域から初めて得られた23-41Maにおける相対的地磁気強度変動記録. (2013)
  • Author(s): 山本裕二,山崎俊嗣
  • Organizer: 日本地球惑星科学連合2010年大会
  • Place of Presentation: 幕張メッセ国際会議場(千葉市)
  • Year and Date: 2013-05-21
• [Presentation] IODPSiteU1331,U1332堆積物試料からの漸新世～始新世にかけての古地磁気強度相対値の見積もり. (2012)
  • Author(s): 山本裕二,山崎俊嗣
  • Organizer: 日本地球惑星科学連合2010年大会
  • Place of Presentation: 幕張メッセ国際会議場(千葉市)
  • Year and Date: 2012-05-24
• [Presentation] Long-term changes of relative paleointensity from sediments: geomagnetic field behavior or rock magnetic artifact? (2012)
  • Author(s): 山 崎俊嗣、 Acton, G., Channell, J., Palmer, E., Richter, C., 山本裕二
  • Organizer: 日本地球惑星科学連合2010年大会
  • Place of Presentation: 幕張メッセ国際会議場(千葉市)
  • Year and Date: 2012-05-24
• [Presentation] Paleoposition ofIntertropical Convergence Zone in theeastern Pacific inferred from glacial-interglacial changes in terrigenous and biogenic magnetic mineral fractions at IODP Site 1337. (2012)
  • Author(s): 山崎俊嗣
  • Organizer: 2011年度古海洋シンポジウム
  • Place of Presentation: 東京大学大気海洋研究所(柏市)
  • Year and Date: 2012-01-06
• [Presentation] Long-term changes of relative paleointensity from sediments: geomagnetic field behavior or rock magnetic artifact? (2011)
  • Author(s): Yamazaki, T., Acton, G., Channell,J., Palmer, E., Richter, C., Yamamoto, Y.
  • Organizer: American Geophysical Union 2011 Fall Meeting
  • Place of Presentation: サンフランシスコ(米国)
  • Year and Date: 2011-12-08
• [Presentation] Paleoposition ofIntertropical Convergence Zone in the eastern Pacific inferred from glacial-interglacial changes in terrigenous and biogenic magnetic mineral fractions. (2011)
  • Author(s): Yamazaki, T.
  • Organizer: American Geophysical Union 2011 Fall Meeting
  • Place of Presentation: サンフランシスコ(米国)
  • Year and Date: 2011-12-08
• [Presentation] Paleomagnetic and rock magnetic study of the Site U1332 sediments - relative paleointensity during Eocene and Oligocene. (2011)
  • Author(s): Yamamoto, Y., Acton, G., Channell,J., Palmer,E., Richter, C., Yamazaki, T.
  • Organizer: American Geophysical Union 2011 Fall Meeting
  • Place of Presentation: サンフランシスコ(米国)
  • Year and Date: 2011-12-05
• [Presentation] 東太平洋IODPSiteU1337における陸源・生物源磁性鉱物の氷期-間氷期変動と熱帯収束帯の位置の変化. (2011)
  • Author(s): 山崎俊嗣
  • Organizer: 地球電磁気・地球惑星圏学会2011年秋学会
  • Place of Presentation: 神戸大学(神戸市)
  • Year and Date: 2011-11-04
• [Presentation] IODPSiteU1332で採取された堆積物柱状試料の古地磁気・岩石磁気学的研究-始新世と漸新世における相対古地磁気強度変動. (2011)
  • Author(s): 山崎俊嗣、山本裕二
  • Organizer: 地球電磁気・地球惑星圏学会2011年秋学会
  • Place of Presentation: 神戸大学(神戸市)
  • Year and Date: 2011-11-04
• [Presentation] Paleomagnetic and environmental magnetic properties of sediments from IODP Site U1333 (Equatorial Pacific) (2010)
  • Author(s): Palmer, E.C., Richter, C., Acton, G., Channell, J.E.T., Evans, H.F., Ohneiser, C., Yamamoto, Y., and Yamazaki, T.
  • Organizer: American Geophysical Union 2010 Fall Meeting
  • Place of Presentation: サンフランシスコ(米国)
  • Year and Date: 2010-12-13
• [Presentation] IODP Expedition320/321 Scientific Party (2010) Paleomagnetic and rock magnetic studies of basement basalts recovered duringIODP Expeditions 320/321 (2010)
  • Author(s): Yamamoto Y.
  • Organizer: AmericanGeophysical Union 2010 Fall Meeting
  • Place of Presentation: サンフランシスコ(米国)
  • Year and Date: 2010-12-13
• [Presentation] Expedition 320/321 Shipboard Science Party (2010) IODP Exp.320/321 赤道太平洋年代トランセクトの概要: 特 に、古地磁気層序及び還元による堆積物の 色相変化について. (2010)
  • Author(s): 山 崎俊嗣、 Acton, G., Channell, J., Evans, H., Ohneiser, C., Richiter, C. 山 本裕二、Delaney, M., Gussone, N., Hathorne, E.、木元 克典、沢田 健、山本 真 也
  • Organizer: 日本地質学会第117年学術大会
  • Place of Presentation: 富山大学(富山市)
  • Year and Date: 2010-09-20
• [Presentation] IODP320/321航海乗船研究者一同(2010)IODPExpeditions320/321で採取された海底玄武岩の古地磁気・岩石磁気学的研究. (2010)
  • Author(s): 山本裕二
  • Organizer: 日本地球惑星科学連合2010年大会
  • Place of Presentation: 幕張メッセ国際会議場(千葉市)
  • Year and Date: 2010-05-25
• [Presentation] Expedition320/321ShipboardScienceParty(2010)IODPExp.320/321赤道太平洋年代トランセクトの概要報告:古地磁気層序、還元による堆積物の色相変化. (2010)
  • Author(s): 山崎俊嗣、Acton,G.,Channell,J.,Evans,H.,Ohneiser,C.,Richiter,C.山本裕二、Delaney,M.,Gussone,N.,Hathorne,E.,木元克典、沢田健、山本真也
  • Organizer: 日本地球惑星科学連合2010年大会
  • Place of Presentation: 幕張メッセ国際会議場(千葉市)
  • Year and Date: 2010-05-24