| Full text | |
| Author(s): |
Poletti, Wilbor
[1, 2]
;
Biggin, Andrew J.
[1]
;
Trindade, Ricardo I. F.
[2]
;
Hartmann, Gelvam A.
[3]
;
Terra-Nova, Filipe
[4]
Total Authors: 5
|
| Affiliation: | [1] Univ Liverpool, Sch Environm Sci, Dept Earth Ocean & Ecol Sci, Geomagnetism Lab, Liverpool, Merseyside - England
[2] Univ Sao Paulo, Dept Geofis, Inst Astron Geofis & Ciencias Atmosfer, Lab Paleomagnetismo USPMag, Rua Matao 1226, BR-05508090 Sao Paulo - Brazil
[3] Univ Estadual Campinas, Inst Geociencias, Rua Joao Pandia Calogeras 51, BR-13083870 Campinas, SP - Brazil
[4] Nantes Atlantiques Univ, Univ Nantes, CNRS, UMR 6112, Lab Planetol & Geodynam, 2 Rue Houssiniere, F-44000 Nantes - France
Total Affiliations: 4
|
| Document type: | Journal article |
| Source: | PHYSICS OF THE EARTH AND PLANETARY INTERIORS; v. 274, p. 72-86, JAN 2018. |
| Web of Science Citations: | 10 |
| Abstract | |
Since the establishment of direct estimations of the Earth's magnetic field intensity in the first half of the nineteenth century, a continuous decay of the axial dipole component has been observed and variously speculated to be linked to an imminent reversal of the geomagnetic field. Furthermore, indirect estimations from anthropologically made materials and volcanic derivatives suggest that this decrease began significantly earlier than direct measurements have been available. Here, we carefully reassess the available archaeointensity dataset for the last two millennia, and show a good correspondence between direct (observatory/satellite) and indirect (archaeomagnetic) estimates of the axial dipole moment creating, in effect, a proxy to expand our analysis back in time. Our results suggest a continuous linear decay as the most parsimonious long-term description of the axial dipole variation for the last millennium. We thus suggest that a break in the symmetry of axial dipole moment advective sources occurred approximately 1100 years earlier than previously described. In addition, based on the observed dipole secular variation timescale, we speculate that the weakening of the axial dipole may end soon. (AU) | |
| FAPESP's process: | 13/16382-0 - Analysis of the historical geomagnetic field in South America |
| Grantee: | Wilbor Poletti Silva |
| Support Opportunities: | Scholarships in Brazil - Doctorate (Direct) |