2021
DOI: 10.1029/2021gc010063
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Paleosecular Variation and the Time‐Averaged Geomagnetic Field Since 10 Ma

Abstract: Spatial and temporal geomagnetic field variations have been observed over different geological timescales. Ancient field measurements, mainly obtained from geological materials (sedimentary and igneous rocks), allow investigations of directional and intensity variability of the paleomagnetic field that result from processes operating in Earth's fluid core (see, e.g., Hulot et al., 2010). Particularly, information about paleosecular variation (PSV), long-term variations of the order of 10 5 -10 6 years (e.g., J… Show more

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Cited by 20 publications
(23 citation statements)
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“…This Model G fit (Table 4, Figure S3, Table S3 in Supporting Information ) has an a parameter of 15.6° (12.6°–18.5°). An updated PSV database for the past 10 Myrs, PSV10a (de Oliveira et al., 2021), produced a higher a value of 12.2° (10.8°–13.6°) than that of Model G D19 and Model G S19 . However, to calculate the VGP dispersion, de Oliveira et al.…”
Section: Discussionmentioning
confidence: 99%
See 1 more Smart Citation
“…This Model G fit (Table 4, Figure S3, Table S3 in Supporting Information ) has an a parameter of 15.6° (12.6°–18.5°). An updated PSV database for the past 10 Myrs, PSV10a (de Oliveira et al., 2021), produced a higher a value of 12.2° (10.8°–13.6°) than that of Model G D19 and Model G S19 . However, to calculate the VGP dispersion, de Oliveira et al.…”
Section: Discussionmentioning
confidence: 99%
“…However, to calculate the VGP dispersion, de Oliveira et al. (2021) added a criterion proposed by Deenen et al. (2011) defined by an envelope A 95 , to eliminate outliers.…”
Section: Discussionmentioning
confidence: 99%
“…For this study, we obtained a compilation of 6,178 VGPs for the time interval 0 to 0.32 Ga based on measurements made on igneous rocks that had already been deemed suitable for PSV analysis [18][19][20][21][22] and performed a new combined analysis (see methods). The results are best fit by Model G using parameters of 𝑎 = 9.9 −1.5 +1.0 and 𝑏 = 0.26 −0.08 +0.02 (figure 1a).…”
Section: Main Textmentioning
confidence: 99%
“…The studies that established the data filters, investigated PSV and geomagnetic field behavior by determining the between‐site scatter of a set of VGPs (e.g., Cromwell et al., 2018; de Oliveira et al., 2021; Johnson & Constable, 1996; Johnson et al., 2008; Tauxe et al., 2003). To this end, these studies aim to correct for within‐site scatter induced by measuring errors and typically require well‐determined directions with a low maximum angular deviation (MAD) and a minimum number of readings per site, although the cutoff values for these criteria vary between authors (e.g., Asefaw et al., 2021; Biggin et al., 2008; Cromwell et al., 2018; Doubrovine et al., 2019; Johnson et al., 2008).…”
Section: Introductionmentioning
confidence: 99%
“…Paleomagnetic poles, or paleopoles, quantify the past position of rocks relative to the geomagnetic pole and constrain tectonic reconstructions and apparent polar wander paths (APWPs; e.g., Besse & Courtillot, 2002; Torsvik et al., 2012). The calculation of paleopoles relies on the assumption that the time‐averaged geomagnetic field approximates a geocentric axial dipole (GAD), but is complicated by short‐term deviations from this field (e.g., Cromwell et al., 2018; Oliveira et al., 2021) known as paleosecular variation (PSV). To obtain a paleopole, paleomagnetists therefore average virtual geomagnetic poles (VGPs), whereby every VGP is then assumed a “spot reading”: an instantaneous reading of the past geomagnetic field collected from a rock unit (“site”) that represents an increment of geological time, such as a lava flow (Butler, 1992; Tauxe et al., 2010).…”
Section: Introductionmentioning
confidence: 99%