Full‐Vector Paleosecular Variation Curve for the Azores: Enabling Reliable Paleomagnetic Dating for the Past 2 kyr

Béguin, Annemarieke; Pimentel, Adriano; Groot, Lennart de

doi:10.1029/2020jb019745

Cited by 2 publications

(2 citation statements)

References 73 publications

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“…Here we follow the interpretation protocol outlined by ref. 55 , and combine the results of different selection criteria sets. We used six predefined sets of selection criteria: TTA and TTB (ref.…”

Section: Paleointensitiesmentioning

confidence: 99%

Persistent anomalies in the geomagnetic field arise from top-down control on the geodynamo

Beguin,

Panovska,

de Groot

2023

Preprint

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The most prominent feature of the current geomagnetic field is arguably the South Atlantic Anomaly (SAA), a region where the geomagnetic field is exceptionally weak. The origin and evolution of the SAA are still enigmatic. Recent geomagnetic field models put its origin under the Indian Ocean, but this contradicts a suggested link between the SAA and the large low-shear-velocity province (LLSVP) underneath the African continent. This contradiction arises from a sparse paleomagnetic data kernel especially lacking Southern Hemisphere data. Here we present a global geomagnetic field model that includes new paleomagnetic data from Réunion Island located in the Indian Ocean – a key region to unravel the history of the SAA. Our model reveals that not only the SAA but also other anomalous features of the geomagnetic field arise from two distinct latitudinal bands just East of both LLSVPs. This suggests that the LLSVPs disturb the generally westward flow in the top of the outer core, either through topography on the core-mantle-boundary, by thermal gradients, or a combination of both. Such local disturbances in the geodynamo may then evolve chaotically while moving slowly westwards and dwindling in strength.

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Section: Paleointensitiesmentioning

confidence: 99%

Persistent anomalies in the geomagnetic field arise from top-down control on the geodynamo

Beguin,

Panovska,

de Groot

2023

Preprint

Self Cite

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“…Global field models have been developed that allow for extrapolation to low-data-density regions that lack reference curves, but these are accompanied by greater uncertainty (e.g., Korte and Constable 2005;Korte et al 2011;Pavón-Carrasco et al 2014;Constable et al 2016). The increasing number of high-resolution regional reference curves and better-constrained global models that have emerged in the past decades, as well as increased study of global paleointensity records, has opened a wide geographic range of volcanoes for numerical PSV dating (e.g., Panovska et al 2018;Di Chiara 2020;Béguin et al 2021;Mochizuki et al 2021). The development of PSV dating tools (Pavón-Carrasco et al 2011;Hnatyshin and Kravchinsky 2014) that use Bayesian statistics to compare the results of volcanic samples to the reference curve has allowed recent studies to obtain one or multiple discrete age ranges for a specific result, allowing for more precise dating of historic and prehistoric eruptions (Roperch et al 2015;Yasuda et al 2020).…”

Section: From Relative To Numerical Datingmentioning

confidence: 99%

Paleomagnetism and rock magnetism as tools for volcanology

et al. 2022

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Paleomagnetic and rock magnetic methods for studying volcanoes and their products have been developed since the second half of the twentieth century. These methods have been used to find tephra in sediment cores, date volcanic eruptions and deposits, determine emplacement temperatures of volcanic deposits, and estimate flow directions of dikes, lava flows, and pyroclastic flow deposits. In the twenty-first century, these techniques have steadily improved and expanded, resulting in more probing and precise studies of volcanoes using paleomagnetism. We believe that continual improvement of existing techniques and the increased awareness and interest in paleomagnetic methods should allow more studies to enhance the understanding of volcanic processes.

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Full‐Vector Paleosecular Variation Curve for the Azores: Enabling Reliable Paleomagnetic Dating for the Past 2 kyr

Cited by 2 publications

References 73 publications

Persistent anomalies in the geomagnetic field arise from top-down control on the geodynamo

Persistent anomalies in the geomagnetic field arise from top-down control on the geodynamo

Paleomagnetism and rock magnetism as tools for volcanology

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