Eccentric Dipole Evolution during the Last Reversal, Last Excursions, and Holocene Anomalies. Interpretation Using a 360-Dipole Ring Model

The eccentric dipole (ED) is the next approach of the geomagnetic field after the generally used geocentric dipole. Here, we analyzed the evolution of the ED during extreme events, such as the Matuyama-Brunhes polarity transition (~780 ka), the Laschamp (~41 ka) and Mono Lake (~34 ka) excursions, an...

Descripción completa

Guardado en:

Detalles Bibliográficos
Autores principales:	Alicia González-López, María Luisa Osete, Saioa A. Campuzano, Alberto Molina-Cardín, Pablo Rivera, Francisco Javier Pavón-Carrasco
Formato:	article
Lenguaje:	EN
Publicado:	MDPI AG 2021
Materias:	geomagnetism eccentric dipole geomagnetic reversal geomagnetic excursion geomagnetic anomalies South Atlantic Anomaly Geology QE1-996.5
Acceso en línea:	https://doaj.org/article/ef9981af89134397881cadcdae54a0a3
Etiquetas:	Agregar Etiqueta Sin Etiquetas, Sea el primero en etiquetar este registro!

id	oai:doaj.org-article:ef9981af89134397881cadcdae54a0a3
record_format	dspace
spelling	oai:doaj.org-article:ef9981af89134397881cadcdae54a0a32021-11-25T17:42:42ZEccentric Dipole Evolution during the Last Reversal, Last Excursions, and Holocene Anomalies. Interpretation Using a 360-Dipole Ring Model10.3390/geosciences111104382076-3263https://doaj.org/article/ef9981af89134397881cadcdae54a0a32021-10-01T00:00:00Zhttps://www.mdpi.com/2076-3263/11/11/438https://doaj.org/toc/2076-3263The eccentric dipole (ED) is the next approach of the geomagnetic field after the generally used geocentric dipole. Here, we analyzed the evolution of the ED during extreme events, such as the Matuyama-Brunhes polarity transition (~780 ka), the Laschamp (~41 ka) and Mono Lake (~34 ka) excursions, and during the time of two anomalous features of the geomagnetic field observed during the Holocene: the Levantine Iron Age Anomaly (LIAA, ~1000 BC) and the South Atlantic Anomaly (SAA, analyzed from ~700 AD to present day). The analysis was carried out using the paleoreconstructions that cover the time of the mentioned events (IMMAB4, IMOLEe, LSMOD.2, SHAWQ-Iron Age, and SHAWQ2k). We found that the ED moves around the meridian plane of 0–180° during the reversal and the excursions; it moves towards the region of the LIAA; and it moves away from the SAA. To investigate what information can be extracted from its evolution, we designed a simple model based on 360-point dipoles evenly distributed in a ring close to the inner core boundary that can be reversed and their magnitude changed. We tried to reproduce with our simple model the observed evolution of the ED, and the total field energy at the Earth’s surface. We observed that the modeled ED moves away from the region where we set the dipoles to reverse. If we consider that the ring dipoles could be related to convective columns in the outer core of the Earth, our simple model would indicate the potential of the displacement of the ED to give information about the regions in the outer core where changes start for polarity transitions and for the generation of important anomalies of the geomagnetic field. According to our simple model, the regions in which the most important events of the Holocene occur, or in which the last polarity reversal or excursion begin, are related to the regions of the Core Mantle Boundary (CMB), where the heat flux is low.Alicia González-LópezMaría Luisa OseteSaioa A. CampuzanoAlberto Molina-CardínPablo RiveraFrancisco Javier Pavón-CarrascoMDPI AGarticlegeomagnetismeccentric dipolegeomagnetic reversalgeomagnetic excursiongeomagnetic anomaliesSouth Atlantic AnomalyGeologyQE1-996.5ENGeosciences, Vol 11, Iss 438, p 438 (2021)
institution	DOAJ
collection	DOAJ
language	EN
topic	geomagnetism eccentric dipole geomagnetic reversal geomagnetic excursion geomagnetic anomalies South Atlantic Anomaly Geology QE1-996.5
spellingShingle	geomagnetism eccentric dipole geomagnetic reversal geomagnetic excursion geomagnetic anomalies South Atlantic Anomaly Geology QE1-996.5 Alicia González-López María Luisa Osete Saioa A. Campuzano Alberto Molina-Cardín Pablo Rivera Francisco Javier Pavón-Carrasco Eccentric Dipole Evolution during the Last Reversal, Last Excursions, and Holocene Anomalies. Interpretation Using a 360-Dipole Ring Model
description	The eccentric dipole (ED) is the next approach of the geomagnetic field after the generally used geocentric dipole. Here, we analyzed the evolution of the ED during extreme events, such as the Matuyama-Brunhes polarity transition (~780 ka), the Laschamp (~41 ka) and Mono Lake (~34 ka) excursions, and during the time of two anomalous features of the geomagnetic field observed during the Holocene: the Levantine Iron Age Anomaly (LIAA, ~1000 BC) and the South Atlantic Anomaly (SAA, analyzed from ~700 AD to present day). The analysis was carried out using the paleoreconstructions that cover the time of the mentioned events (IMMAB4, IMOLEe, LSMOD.2, SHAWQ-Iron Age, and SHAWQ2k). We found that the ED moves around the meridian plane of 0–180° during the reversal and the excursions; it moves towards the region of the LIAA; and it moves away from the SAA. To investigate what information can be extracted from its evolution, we designed a simple model based on 360-point dipoles evenly distributed in a ring close to the inner core boundary that can be reversed and their magnitude changed. We tried to reproduce with our simple model the observed evolution of the ED, and the total field energy at the Earth’s surface. We observed that the modeled ED moves away from the region where we set the dipoles to reverse. If we consider that the ring dipoles could be related to convective columns in the outer core of the Earth, our simple model would indicate the potential of the displacement of the ED to give information about the regions in the outer core where changes start for polarity transitions and for the generation of important anomalies of the geomagnetic field. According to our simple model, the regions in which the most important events of the Holocene occur, or in which the last polarity reversal or excursion begin, are related to the regions of the Core Mantle Boundary (CMB), where the heat flux is low.
format	article
author	Alicia González-López María Luisa Osete Saioa A. Campuzano Alberto Molina-Cardín Pablo Rivera Francisco Javier Pavón-Carrasco
author_facet	Alicia González-López María Luisa Osete Saioa A. Campuzano Alberto Molina-Cardín Pablo Rivera Francisco Javier Pavón-Carrasco
author_sort	Alicia González-López
title	Eccentric Dipole Evolution during the Last Reversal, Last Excursions, and Holocene Anomalies. Interpretation Using a 360-Dipole Ring Model
title_short	Eccentric Dipole Evolution during the Last Reversal, Last Excursions, and Holocene Anomalies. Interpretation Using a 360-Dipole Ring Model
title_full	Eccentric Dipole Evolution during the Last Reversal, Last Excursions, and Holocene Anomalies. Interpretation Using a 360-Dipole Ring Model
title_fullStr	Eccentric Dipole Evolution during the Last Reversal, Last Excursions, and Holocene Anomalies. Interpretation Using a 360-Dipole Ring Model
title_full_unstemmed	Eccentric Dipole Evolution during the Last Reversal, Last Excursions, and Holocene Anomalies. Interpretation Using a 360-Dipole Ring Model
title_sort	eccentric dipole evolution during the last reversal, last excursions, and holocene anomalies. interpretation using a 360-dipole ring model
publisher	MDPI AG
publishDate	2021
url	https://doaj.org/article/ef9981af89134397881cadcdae54a0a3
work_keys_str_mv	AT aliciagonzalezlopez eccentricdipoleevolutionduringthelastreversallastexcursionsandholoceneanomaliesinterpretationusinga360dipoleringmodel AT marialuisaosete eccentricdipoleevolutionduringthelastreversallastexcursionsandholoceneanomaliesinterpretationusinga360dipoleringmodel AT saioaacampuzano eccentricdipoleevolutionduringthelastreversallastexcursionsandholoceneanomaliesinterpretationusinga360dipoleringmodel AT albertomolinacardin eccentricdipoleevolutionduringthelastreversallastexcursionsandholoceneanomaliesinterpretationusinga360dipoleringmodel AT pablorivera eccentricdipoleevolutionduringthelastreversallastexcursionsandholoceneanomaliesinterpretationusinga360dipoleringmodel AT franciscojavierpavoncarrasco eccentricdipoleevolutionduringthelastreversallastexcursionsandholoceneanomaliesinterpretationusinga360dipoleringmodel
_version_	1718412139923767296

Eccentric Dipole Evolution during the Last Reversal, Last Excursions, and Holocene Anomalies. Interpretation Using a 360-Dipole Ring Model

Ejemplares similares