Paleoenvironmental Significance of Magnetofossils in Pelagic Sediments in the Equatorial Pacific Ocean Before and After the Eocene/Oligocene Boundary
Magnetotactic bacteria (MTB), sensitive to redox status, leave fossil bacterial magnetite (magnetofossils) in sediments. The relative contents of cuboctahedral, elongated prismatic, and bullet-shaped magnetofossils archive changes in redox conditions, which indicate paleoenvironmental variations. Th...
Published in: | Journal of Geophysical Research: Solid Earth |
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Language: | English |
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AMER GEOPHYSICAL UNION
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Online Access: | http://ir.gig.ac.cn/handle/344008/62765 https://doi.org/10.1029/2021JB022221 |
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ftchacadscgigcas:oai:ir.gig.ac.cn:344008/62765 2023-05-15T13:42:06+02:00 Paleoenvironmental Significance of Magnetofossils in Pelagic Sediments in the Equatorial Pacific Ocean Before and After the Eocene/Oligocene Boundary Lu, Yang Wang, Dunfan Jiang, Xiaodong Lin, Zhiyong Yang, Yiping Liu, Qingsong 2021-09-01 http://ir.gig.ac.cn/handle/344008/62765 https://doi.org/10.1029/2021JB022221 英语 eng AMER GEOPHYSICAL UNION JOURNAL OF GEOPHYSICAL RESEARCH-SOLID EARTH http://ir.gig.ac.cn/handle/344008/62765 doi:10.1029/2021JB022221 Geochemistry & Geophysics environmental magnetism magnetofossils EOT equatorial Pacific EOCENE-OLIGOCENE TRANSITION ORGANIC-CARBON FLUX DEEP-SEA BACTERIAL MAGNETITE ICE GROWTH RECORD PRODUCTIVITY TEMPERATURES GLACIATION COMPONENTS 期刊论文 2021 ftchacadscgigcas https://doi.org/10.1029/2021JB022221 2022-03-27T20:33:10Z Magnetotactic bacteria (MTB), sensitive to redox status, leave fossil bacterial magnetite (magnetofossils) in sediments. The relative contents of cuboctahedral, elongated prismatic, and bullet-shaped magnetofossils archive changes in redox conditions, which indicate paleoenvironmental variations. The Eocene-Oligocene transition (EOT) is a turning point in the Cenozoic climate evolution from greenhouse to icehouse. Global cooling, Antarctic glaciation, and/or a new tectonic structure modified the global ocean and atmosphere circulation mode. In the eastern equatorial Pacific Ocean (EEPO), the organic matter and aeolian supply, which are important for the proliferation of MTB, did not vary synchronously. Here, we study the magnetic particles and environmental magnetism characteristics of samples from EEPO to test the hypothesis that magnetofossil assemblages respond to the dramatic paleoclimatic changes across the EOT. Results show that the abundances of all kinds of magnetic particles are significantly decreased with the reduction of aeolian supply after the EOT. However, the relative abundance of magnetofossils and the proportion of bullet-shaped ones both increased. Simultaneously, organic matter input was enhanced as indicated by (a) similar productivity but decreased organic carbon consumption and (b) the increased mass accumulation rates of total organic carbon after the EOT. The enhanced organic matter flux increased redox gradient in pelagic sediment, which together with sufficient iron from aeolian particles, supported the metabolism of MTB, especially those synthesizing bullet-shaped magnetofossils. Therefore, the magnetofossils in the EEPO vary synchronously with the evolution of paleoenvironment before and after the EOT, which thus supports the use of magnetofossil as an effective proxy archiving paleoenvironment. Report Antarc* Antarctic Guangzhou Institute of Geochemistry: GIG OpenIR (Chinese Academy of Sciences) Antarctic Pacific Journal of Geophysical Research: Solid Earth 126 9 |
institution |
Open Polar |
collection |
Guangzhou Institute of Geochemistry: GIG OpenIR (Chinese Academy of Sciences) |
op_collection_id |
ftchacadscgigcas |
language |
English |
topic |
Geochemistry & Geophysics environmental magnetism magnetofossils EOT equatorial Pacific EOCENE-OLIGOCENE TRANSITION ORGANIC-CARBON FLUX DEEP-SEA BACTERIAL MAGNETITE ICE GROWTH RECORD PRODUCTIVITY TEMPERATURES GLACIATION COMPONENTS |
spellingShingle |
Geochemistry & Geophysics environmental magnetism magnetofossils EOT equatorial Pacific EOCENE-OLIGOCENE TRANSITION ORGANIC-CARBON FLUX DEEP-SEA BACTERIAL MAGNETITE ICE GROWTH RECORD PRODUCTIVITY TEMPERATURES GLACIATION COMPONENTS Lu, Yang Wang, Dunfan Jiang, Xiaodong Lin, Zhiyong Yang, Yiping Liu, Qingsong Paleoenvironmental Significance of Magnetofossils in Pelagic Sediments in the Equatorial Pacific Ocean Before and After the Eocene/Oligocene Boundary |
topic_facet |
Geochemistry & Geophysics environmental magnetism magnetofossils EOT equatorial Pacific EOCENE-OLIGOCENE TRANSITION ORGANIC-CARBON FLUX DEEP-SEA BACTERIAL MAGNETITE ICE GROWTH RECORD PRODUCTIVITY TEMPERATURES GLACIATION COMPONENTS |
description |
Magnetotactic bacteria (MTB), sensitive to redox status, leave fossil bacterial magnetite (magnetofossils) in sediments. The relative contents of cuboctahedral, elongated prismatic, and bullet-shaped magnetofossils archive changes in redox conditions, which indicate paleoenvironmental variations. The Eocene-Oligocene transition (EOT) is a turning point in the Cenozoic climate evolution from greenhouse to icehouse. Global cooling, Antarctic glaciation, and/or a new tectonic structure modified the global ocean and atmosphere circulation mode. In the eastern equatorial Pacific Ocean (EEPO), the organic matter and aeolian supply, which are important for the proliferation of MTB, did not vary synchronously. Here, we study the magnetic particles and environmental magnetism characteristics of samples from EEPO to test the hypothesis that magnetofossil assemblages respond to the dramatic paleoclimatic changes across the EOT. Results show that the abundances of all kinds of magnetic particles are significantly decreased with the reduction of aeolian supply after the EOT. However, the relative abundance of magnetofossils and the proportion of bullet-shaped ones both increased. Simultaneously, organic matter input was enhanced as indicated by (a) similar productivity but decreased organic carbon consumption and (b) the increased mass accumulation rates of total organic carbon after the EOT. The enhanced organic matter flux increased redox gradient in pelagic sediment, which together with sufficient iron from aeolian particles, supported the metabolism of MTB, especially those synthesizing bullet-shaped magnetofossils. Therefore, the magnetofossils in the EEPO vary synchronously with the evolution of paleoenvironment before and after the EOT, which thus supports the use of magnetofossil as an effective proxy archiving paleoenvironment. |
format |
Report |
author |
Lu, Yang Wang, Dunfan Jiang, Xiaodong Lin, Zhiyong Yang, Yiping Liu, Qingsong |
author_facet |
Lu, Yang Wang, Dunfan Jiang, Xiaodong Lin, Zhiyong Yang, Yiping Liu, Qingsong |
author_sort |
Lu, Yang |
title |
Paleoenvironmental Significance of Magnetofossils in Pelagic Sediments in the Equatorial Pacific Ocean Before and After the Eocene/Oligocene Boundary |
title_short |
Paleoenvironmental Significance of Magnetofossils in Pelagic Sediments in the Equatorial Pacific Ocean Before and After the Eocene/Oligocene Boundary |
title_full |
Paleoenvironmental Significance of Magnetofossils in Pelagic Sediments in the Equatorial Pacific Ocean Before and After the Eocene/Oligocene Boundary |
title_fullStr |
Paleoenvironmental Significance of Magnetofossils in Pelagic Sediments in the Equatorial Pacific Ocean Before and After the Eocene/Oligocene Boundary |
title_full_unstemmed |
Paleoenvironmental Significance of Magnetofossils in Pelagic Sediments in the Equatorial Pacific Ocean Before and After the Eocene/Oligocene Boundary |
title_sort |
paleoenvironmental significance of magnetofossils in pelagic sediments in the equatorial pacific ocean before and after the eocene/oligocene boundary |
publisher |
AMER GEOPHYSICAL UNION |
publishDate |
2021 |
url |
http://ir.gig.ac.cn/handle/344008/62765 https://doi.org/10.1029/2021JB022221 |
geographic |
Antarctic Pacific |
geographic_facet |
Antarctic Pacific |
genre |
Antarc* Antarctic |
genre_facet |
Antarc* Antarctic |
op_relation |
JOURNAL OF GEOPHYSICAL RESEARCH-SOLID EARTH http://ir.gig.ac.cn/handle/344008/62765 doi:10.1029/2021JB022221 |
op_doi |
https://doi.org/10.1029/2021JB022221 |
container_title |
Journal of Geophysical Research: Solid Earth |
container_volume |
126 |
container_issue |
9 |
_version_ |
1766162706951307264 |