Latitude dependence of geomagnetic paleosecular variation and its relation to the frequency of magnetic reversals: Observations from the Cretaceous and Jurassic

Pavel V. Doubrovine, Toni Veikkolainen, Lauri J. Pesonen, Elisa Piispa, Siim Ots, Aleksey V. Smirnov, Evgeniy V. Kulakov, Andrew J. Biggin

Research output: Contribution to journalArticleScientificpeer-review

Abstract

Nearly three decades ago paleomagnetists suggested that there existed a clear link between latitude dependence of geomagnetic paleosecular variation (PSV) and reversal frequency. Here we compare the latitude behavior of PSV for the Cretaceous Normal Superchron (CNS, 84–126 Ma, stable normal polarity) and the preceding Early Cretaceous‐Jurassic interval (pre‐CNS, 126–198 Ma, average reversal rate of ~4.6 Myr−1). We find that the CNS was characterized by a strong increase in the angular dispersion of virtual geomagnetic poles (VGPs) with latitude, which is consistent with the results of earlier studies, whereas the VGP dispersion for the pre‐CNS period was nearly invariant with latitude. However, the PSV behavior for the last 5 or 10 million years (average reversal frequency of ~4.4–4.8 Myr−1) shows that the latitude invariance of VGP scatter cannot be considered as a characteristic feature of a frequently reversing field and that a strong increase in VGP dispersion with latitude was not restricted to the long periods of stable polarity. We discuss models describing the latitude dependence of PSV and show that their parameters are not reliable proxies for reversal frequency and should not be used to make inferences about the geomagnetic field stability. During the pre‐CNS interval, the geodynamo may have operated in a regime characterized by a high degree of equatorial symmetry. In contrast, more asymmetric geodynamos suggested for 0–10 Ma and the CNS were evidently capable of producing a very wide range of reversal frequencies.
Original languageEnglish
JournalGeochemistry, geophysics, geosystems G³.
Volume20
Issue number3
Pages (from-to)1240-1279
Number of pages40
ISSN1525-2027
DOIs
Publication statusPublished - Mar 2019
MoE publication typeA1 Journal article-refereed

Fields of Science

  • 1171 Geosciences
  • paleosecular variation
  • geomagnetic reversal frequency
  • geodynamo
  • robust statistics
  • Cretaceous
  • Jurassic
  • APPARENT POLAR WANDER
  • DRONNING MAUD LAND
  • SECULAR VARIATION
  • PALAEOSECULAR VARIATION
  • VOLCANIC-ROCKS
  • DYKE SWARM
  • LAVA FLOWS
  • PALEOMAGNETIC CONSTRAINTS
  • MAGMATIC PROVINCE
  • NORMAL SUPERCHRON

Cite this

@article{55002596b6e446b68cf76fcf5c8e0626,
title = "Latitude dependence of geomagnetic paleosecular variation and its relation to the frequency of magnetic reversals: Observations from the Cretaceous and Jurassic",
abstract = "Nearly three decades ago paleomagnetists suggested that there existed a clear link between latitude dependence of geomagnetic paleosecular variation (PSV) and reversal frequency. Here we compare the latitude behavior of PSV for the Cretaceous Normal Superchron (CNS, 84–126 Ma, stable normal polarity) and the preceding Early Cretaceous‐Jurassic interval (pre‐CNS, 126–198 Ma, average reversal rate of ~4.6 Myr−1). We find that the CNS was characterized by a strong increase in the angular dispersion of virtual geomagnetic poles (VGPs) with latitude, which is consistent with the results of earlier studies, whereas the VGP dispersion for the pre‐CNS period was nearly invariant with latitude. However, the PSV behavior for the last 5 or 10 million years (average reversal frequency of ~4.4–4.8 Myr−1) shows that the latitude invariance of VGP scatter cannot be considered as a characteristic feature of a frequently reversing field and that a strong increase in VGP dispersion with latitude was not restricted to the long periods of stable polarity. We discuss models describing the latitude dependence of PSV and show that their parameters are not reliable proxies for reversal frequency and should not be used to make inferences about the geomagnetic field stability. During the pre‐CNS interval, the geodynamo may have operated in a regime characterized by a high degree of equatorial symmetry. In contrast, more asymmetric geodynamos suggested for 0–10 Ma and the CNS were evidently capable of producing a very wide range of reversal frequencies.",
keywords = "1171 Geosciences, paleosecular variation, geomagnetic reversal frequency, geodynamo, robust statistics, Cretaceous, Jurassic, APPARENT POLAR WANDER, DRONNING MAUD LAND, SECULAR VARIATION, PALAEOSECULAR VARIATION, VOLCANIC-ROCKS, DYKE SWARM, LAVA FLOWS, PALEOMAGNETIC CONSTRAINTS, MAGMATIC PROVINCE, NORMAL SUPERCHRON",
author = "Doubrovine, {Pavel V.} and Toni Veikkolainen and Pesonen, {Lauri J.} and Elisa Piispa and Siim Ots and Smirnov, {Aleksey V.} and Kulakov, {Evgeniy V.} and Biggin, {Andrew J.}",
year = "2019",
month = "3",
doi = "10.1029/2018GC007863",
language = "English",
volume = "20",
pages = "1240--1279",
journal = "Geochemistry, geophysics, geosystems G³.",
issn = "1525-2027",
publisher = "American Geophysical Union",
number = "3",

}

Latitude dependence of geomagnetic paleosecular variation and its relation to the frequency of magnetic reversals : Observations from the Cretaceous and Jurassic. / Doubrovine, Pavel V.; Veikkolainen, Toni; Pesonen, Lauri J.; Piispa, Elisa; Ots, Siim; Smirnov, Aleksey V.; Kulakov, Evgeniy V.; Biggin, Andrew J.

In: Geochemistry, geophysics, geosystems G³., Vol. 20, No. 3, 03.2019, p. 1240-1279.

Research output: Contribution to journalArticleScientificpeer-review

TY - JOUR

T1 - Latitude dependence of geomagnetic paleosecular variation and its relation to the frequency of magnetic reversals

T2 - Observations from the Cretaceous and Jurassic

AU - Doubrovine, Pavel V.

AU - Veikkolainen, Toni

AU - Pesonen, Lauri J.

AU - Piispa, Elisa

AU - Ots, Siim

AU - Smirnov, Aleksey V.

AU - Kulakov, Evgeniy V.

AU - Biggin, Andrew J.

PY - 2019/3

Y1 - 2019/3

N2 - Nearly three decades ago paleomagnetists suggested that there existed a clear link between latitude dependence of geomagnetic paleosecular variation (PSV) and reversal frequency. Here we compare the latitude behavior of PSV for the Cretaceous Normal Superchron (CNS, 84–126 Ma, stable normal polarity) and the preceding Early Cretaceous‐Jurassic interval (pre‐CNS, 126–198 Ma, average reversal rate of ~4.6 Myr−1). We find that the CNS was characterized by a strong increase in the angular dispersion of virtual geomagnetic poles (VGPs) with latitude, which is consistent with the results of earlier studies, whereas the VGP dispersion for the pre‐CNS period was nearly invariant with latitude. However, the PSV behavior for the last 5 or 10 million years (average reversal frequency of ~4.4–4.8 Myr−1) shows that the latitude invariance of VGP scatter cannot be considered as a characteristic feature of a frequently reversing field and that a strong increase in VGP dispersion with latitude was not restricted to the long periods of stable polarity. We discuss models describing the latitude dependence of PSV and show that their parameters are not reliable proxies for reversal frequency and should not be used to make inferences about the geomagnetic field stability. During the pre‐CNS interval, the geodynamo may have operated in a regime characterized by a high degree of equatorial symmetry. In contrast, more asymmetric geodynamos suggested for 0–10 Ma and the CNS were evidently capable of producing a very wide range of reversal frequencies.

AB - Nearly three decades ago paleomagnetists suggested that there existed a clear link between latitude dependence of geomagnetic paleosecular variation (PSV) and reversal frequency. Here we compare the latitude behavior of PSV for the Cretaceous Normal Superchron (CNS, 84–126 Ma, stable normal polarity) and the preceding Early Cretaceous‐Jurassic interval (pre‐CNS, 126–198 Ma, average reversal rate of ~4.6 Myr−1). We find that the CNS was characterized by a strong increase in the angular dispersion of virtual geomagnetic poles (VGPs) with latitude, which is consistent with the results of earlier studies, whereas the VGP dispersion for the pre‐CNS period was nearly invariant with latitude. However, the PSV behavior for the last 5 or 10 million years (average reversal frequency of ~4.4–4.8 Myr−1) shows that the latitude invariance of VGP scatter cannot be considered as a characteristic feature of a frequently reversing field and that a strong increase in VGP dispersion with latitude was not restricted to the long periods of stable polarity. We discuss models describing the latitude dependence of PSV and show that their parameters are not reliable proxies for reversal frequency and should not be used to make inferences about the geomagnetic field stability. During the pre‐CNS interval, the geodynamo may have operated in a regime characterized by a high degree of equatorial symmetry. In contrast, more asymmetric geodynamos suggested for 0–10 Ma and the CNS were evidently capable of producing a very wide range of reversal frequencies.

KW - 1171 Geosciences

KW - paleosecular variation

KW - geomagnetic reversal frequency

KW - geodynamo

KW - robust statistics

KW - Cretaceous

KW - Jurassic

KW - APPARENT POLAR WANDER

KW - DRONNING MAUD LAND

KW - SECULAR VARIATION

KW - PALAEOSECULAR VARIATION

KW - VOLCANIC-ROCKS

KW - DYKE SWARM

KW - LAVA FLOWS

KW - PALEOMAGNETIC CONSTRAINTS

KW - MAGMATIC PROVINCE

KW - NORMAL SUPERCHRON

U2 - 10.1029/2018GC007863

DO - 10.1029/2018GC007863

M3 - Article

VL - 20

SP - 1240

EP - 1279

JO - Geochemistry, geophysics, geosystems G³.

JF - Geochemistry, geophysics, geosystems G³.

SN - 1525-2027

IS - 3

ER -