Paleomagnetic Secular Variations in North Greenland Around 81°N Over the Last 6,000 Years
We investigate full vector paleomagnetic changes recorded in high‐resolution sediments of Petermann Fjord, North Greenland, deposited over the last 6 kyr, in the context of the recent rapid changes in the geomagnetic field. A Paleomagnetic Secular Variation (PSV) stack (inclination, declination, and...
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Veröffentlicht in: | Geochemistry, geophysics, geosystems : G3 geophysics, geosystems : G3, 2024-10, Vol.25 (10), p.n/a |
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Zusammenfassung: | We investigate full vector paleomagnetic changes recorded in high‐resolution sediments of Petermann Fjord, North Greenland, deposited over the last 6 kyr, in the context of the recent rapid changes in the geomagnetic field. A Paleomagnetic Secular Variation (PSV) stack (inclination, declination, and relative paleointensity) was reconstructed using four marine sediment cores with an independent age model constrained by seven radiocarbon ages. Magnetic investigations demonstrate that the paleomagnetic signal is carried by low coercivity ferrimagnetic minerals and is well reproduced in all cores, attesting to the quality and reliability of the paleomagnetic recording of these sediments. This signal is broadly consistent in directional changes with distant records in North America and the northern North Atlantic at centennial and millennial timescales, and has millennial scale intensity variations that are consistent with model predictions. The offset between a magnetization age determined through comparison with a northern North Atlantic PSV reference curve, GREENICE, and the radiocarbon age model indicates either a reasonable lock‐in depth of magnetization (∼11 cm from the coretop) or centennial‐scale reservoir age variation through time in the fjord. Reconstructed virtual geomagnetic pole (VGP) migration for the last 6 kyr shows that the recent migration of the magnetic North Pole is consistent with secular paleomagnetic variations on geologic timescales. Our results suggest that magnetic field intensity variations (temporal and spatial) are linked to magnetic flux lobe dynamics and influence the VGP migration.
Plain Language Summary
The magnetic field of the Earth is generated by convection in the outer core of the Earth. Magnetic sediments deposited on the ocean seafloor record the Earth's magnetic field and are important archives of its past fluctuations (intensity and direction). Studying the geomagnetic field is important as it gives us information about processes in the Earth's core and can be used for correlating sediment cores together and for establishing the chronology of sedimentary sequences. In this study, we used sediment cores from Petermann Fjord (Nares Strait, Northern Greenland) to study past geomagnetic variations. Petermann Fjord is an excellent site to conduct such studies because of its close location to the North Magnetic Pole (NMP) and because of the high sediment accumulation rates that enable us to conduct studies with a high tempo |
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ISSN: | 1525-2027 1525-2027 |
DOI: | 10.1029/2024GC011620 |