TY - JOUR
T1 - Plate motion and a dipolar geomagnetic field at 3.25 Ga
AU - Brenner, Alec R.
AU - Fu, Roger R.
AU - Kylander-Clark, Andrew R.C.
AU - Hudak, George J.
AU - Foley, Bradford J.
N1 - Funding Information:
ACKNOWLEDGMENTS. We thank Arthur Hickman and Martin Van Kranendonk for their insights on the rock units, preservation potential, and structural elements of the East Pilbara and Soanesville Syncline. We thank Rebecca Fischer for the use of the Raman microscope in the Harvard Laboratory for Mineral Physics. We thank Timothy Cavanaugh for imaging our samples with the SEM at the Harvard Center for Nanoscale Systems. We thank Franklin Wolfe and John Shaw for advice on the treatment of structural corrections. We thank Hairuo Fu for assistance with sampling. Finally, we acknowledge the Nyamal and Kariyarra peoples, Traditional Custodians of the land on which we conducted this study and of Kunanganaranga Pool on the Turner River, from which the Kunagunarrina Formation derives its name. This work was supported by grants from the NSF (EAR-1847042 and EAR-1723023).
Funding Information:
We thank Arthur Hickman and Martin Van Kranendonk for their insights on the rock units, preservation potential, and structural elements of the East Pilbara and Soanesville Syncline. We thank Rebecca Fischer for the use of the Raman microscope in the Harvard Laboratory for Mineral Physics. We thank Timothy Cavanaugh for imaging our samples with the SEM at the Harvard Center for Nanoscale Systems. We thank Franklin Wolfe and John Shaw for advice on the treatment of structural corrections. We thank Hairuo Fu for assistance with sampling. Finally, we acknowledge the Nyamal and Kariyarra peoples, Traditional Custodians of the land on which we conducted this study and of Kunanganaranga Pool on the Turner River, from which the Kunagunarrina Formation derives its name. This work was supported by grants from the NSF (EAR-1847042 and EAR-1723023).
Publisher Copyright:
Copyright © 2022 the Author(s). Published by PNAS.
PY - 2022/11/1
Y1 - 2022/11/1
N2 - The paleomagnetic record is an archive of Earth’s geophysical history, informing reconstructions of ancient plate motions and probing the core via the geodynamo. We report a robust 3.25-billion-year-old (Ga) paleomagnetic pole from the East Pilbara Craton, Western Australia. Together with previous results from the East Pilbara between 3.34 and 3.18 Ga, this pole enables the oldest reconstruction of time-resolved lithospheric motions, documenting 160 My of both latitudinal drift and rotation at rates of at least 0.55°/My. Motions of this style, rate, and duration are difficult to reconcile with true polar wander or stagnant-lid geodynamics, arguing strongly for mobile-lid geodynamics by 3.25 Ga. Additionally, this pole includes the oldest documented geomagnetic reversal, reflecting a stably dipolar, core-generated Archean dynamo.
AB - The paleomagnetic record is an archive of Earth’s geophysical history, informing reconstructions of ancient plate motions and probing the core via the geodynamo. We report a robust 3.25-billion-year-old (Ga) paleomagnetic pole from the East Pilbara Craton, Western Australia. Together with previous results from the East Pilbara between 3.34 and 3.18 Ga, this pole enables the oldest reconstruction of time-resolved lithospheric motions, documenting 160 My of both latitudinal drift and rotation at rates of at least 0.55°/My. Motions of this style, rate, and duration are difficult to reconcile with true polar wander or stagnant-lid geodynamics, arguing strongly for mobile-lid geodynamics by 3.25 Ga. Additionally, this pole includes the oldest documented geomagnetic reversal, reflecting a stably dipolar, core-generated Archean dynamo.
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U2 - 10.1073/pnas.2210258119
DO - 10.1073/pnas.2210258119
M3 - Article
C2 - 36279430
AN - SCOPUS:85140541403
SN - 0027-8424
VL - 119
JO - Proceedings of the National Academy of Sciences of the United States of America
JF - Proceedings of the National Academy of Sciences of the United States of America
IS - 44
M1 - e2210258119
ER -