Multidecadally resolved polarity oscillations during a geomagnetic excursion

Polarity reversals of the geomagnetic field have occurred through billions of years of Earth history and were first revealed in the early 20th century. Almost a century later, details of transitional field behavior during geomagnetic reversals and excursions remain poorly known. Here, we present a m...

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Published inProceedings of the National Academy of Sciences - PNAS Vol. 115; no. 36; pp. 8913 - 8918
Main Authors Chou, Yu-Min, Jiang, Xiuyang, Liu, Qingsong, Hu, Hsun-Ming, Wu, Chung-Che, Liu, Jianxing, Jiang, Zhaoxia, Lee, Teh-Quei, Wang, Chun-Chieh, Song, Yen-Fang, Chiang, Cheng-Cheng, Tan, Liangcheng, Lone, Mahjoor A., Pan, Yongxin, Zhu, Rixiang, He, Yaoqi, Chou, Yu-Chen, Tan, An-Hung, Roberts, Andrew P., Zhao, Xiang, Shen, Chuan-Chou
Format Journal Article
LanguageEnglish
Published United States National Academy of Sciences 04.09.2018
Subjects
Cerebral hemispheres
Cosmic rays
Dynamo theory
Earth
Geomagnetic field
Geomagnetism
Magnetism
Mesoscale convective complexes
Oscillations
Physical Sciences
Polarity
Satellites
Stability
multidecadally resolved polarity oscillations
stalagmite U-Th dating
abrupt reversal transition
asymmetrical interhemispheric polarity drifts
geomagnetic excursion
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Summary:Polarity reversals of the geomagnetic field have occurred through billions of years of Earth history and were first revealed in the early 20th century. Almost a century later, details of transitional field behavior during geomagnetic reversals and excursions remain poorly known. Here, we present a multidecadally resolved geomagnetic excursion record from a radioisotopically dated Chinese stalagmite at 107–91 thousand years before present with age precision of several decades. The duration of geomagnetic directional oscillations ranged from several centuries at 106–103 thousand years before present to millennia at 98–92 thousand years before present, with one abrupt reversal transition occurring in one to two centuries when the field was weakest. These features indicate prolonged geodynamo instability. Repeated asymmetrical interhemispheric polarity drifts associated with weak dipole fields likely originated in Earth’s deep interior. If such rapid polarity changes occurred in future, they could severely affect satellites and human society.
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1Y.-M.C., X.J., and Q.L. contributed equally to this work.
Author contributions: C.-C.S. directed this project; Y.-M.C., Q.L., T.-Q.L., and C.-C.S. designed research; Y.-M.C., X.J., H.-M.H., C.-C. Wu, J.L., Z.J., C.-C. Wang, Y.-F.S., C.-C.C., L.T., M.A.L., Y.P., R.Z., Y.H., Y.-C.C., A.-H.T., and C.-C.S. performed research; Y.-M.C., X.J., Q.L., H.-M.H., C.-C. Wu, J.L., Z.J., T.-Q.L., C.-C. Wang, Y.-F.S., C.-C.C., L.T., M.A.L., Y.P., R.Z., Y.H., Y.-C.C., A.-H.T., A.P.R., X.Z., and C.-C.S. analyzed data; and Y.-M.C., X.J., Q.L., H.-M.H., C.-C. Wu, T.-Q.L., A.P.R., X.Z., and C.-C.S. wrote the paper.
Edited by Lisa Tauxe, University of California, San Diego, La Jolla, CA, and approved July 23, 2018 (received for review November 22, 2017)
ISSN:0027-8424
1091-6490
DOI:10.1073/pnas.1720404115