High geomagnetic field intensity recorded by anorthosite xenoliths requires a strongly powered late Mesoproterozoic geodynamo
Proceedings of the National Academy of Sciences
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Abstract
Acquiring high-fidelity ancient magnetic field intensity records from rocks is crucial for constraining the long-term evolution of Earth’s core. However, robust estimates of ancient field strengths are often difficult to recover due to alteration or nonideal behavior. We use rocks known as anorthosite that formed in the deep crust and were brought to the near surface where they acquired thermal remanent magnetizations. These rocks have experienced minimal postformation alteration and yield high-quality paleointensity estimates. In contrast to scenarios of a progressively decaying field leading up to a proposed late nucleation of Earth’s inner core, these data record a strong field 1.1 Ga. A strong field that persisted over a 14-My interval indicates the existence of appreciable power sources for Earth’s dynamo at this time.
Suggested Citation
Zhang, Y., Swanson-Hysell, N., Avery, M.S., and Fu, R., 2022, High geomagnetic field intensity recorded by anorthosite xenoliths requires a strongly powered late Mesoproterozoic geodynamo: Proceedings of the National Academy of Sciences, v. 119, no. 29, e2202875119, 11 p., https://doi.org/10.1073/pnas.2202875119.
Study Area
| Publication type | Article |
|---|---|
| Publication Subtype | Journal Article |
| Title | High geomagnetic field intensity recorded by anorthosite xenoliths requires a strongly powered late Mesoproterozoic geodynamo |
| Series title | Proceedings of the National Academy of Sciences |
| DOI | 10.1073/pnas.2202875119 |
| Volume | 119 |
| Issue | 29 |
| Publication Date | July 11, 2022 |
| Year Published | 2022 |
| Language | English |
| Publisher | National Academy of Sciences |
| Contributing office(s) | Geology, Minerals, Energy, and Geophysics Science Center |
| Description | e2202875119, 11 p. |
| Country | United States |
| State | Michigan, Minnesota, Wisconsin |