Paleomagnetic Evidence for Inverse Correspondence between the Relative Contribution of the Axial Dipole Field and CMB Heat Flux for the Past 270 Myr

• Published in: Scientific reports 2019-01, Vol.9 (1), p.282-282, Article 282
• Main Authors: Franco, Daniel Ribeiro, de Oliveira, Wellington Paulo, Freitas, Felipe Barbosa Venâncio de, Takahashi, Diego, da Ponte Neto, Cosme Ferreira, Peixoto, Ian Muzy Camarão
• Format: Article
• Language: English
• Subjects: 704/2151/412; 704/445/123; 704/445/210; Geomagnetic field; Humanities and Social Sciences; Jurassic; Magnetism; Mesozoic; multidisciplinary; Paleomagnetism; Paleozoic; Polarity; Science; Science (multidisciplinary)
• ISSN: 2045-2322; 2045-2322
• DOI: 10.1038/s41598-018-36494-x

We provide an evaluation of the paleolatitudinal dependence of the paleosecular variation throughout the Paleozoic-Mesozoic transition – linked to the high geomagnetic reversal frequency interval Illawarra Hyperzone of Mixed Polarity (IHMP; ~266.7–228.7 Myr). Our findings were compared with those for intervals of distinctive geomagnetic reversal frequencies within the Phanerozoic. Our results for the IHMP were conducted through estimates of angular dispersion ( S B ) of virtual geomagnetic pole (VGP) data groups, taken from a high quality paleomagnetic database. Model G was fitted to these data, providing its shape parameters a and b (respectively related to the antisymmetric and symmetric harmonic terms for the time-average geomagnetic field). Results for the IHMP exhibited compatible patterns with two well-known intervals of higher reversal frequency – Jurassic and the last 5 Myr. A comparison of b / a ratio results – considered as an efficient indicator for the relative contribution of the axial dipole field – for the last 270 Myr, indicated an inverse correspondence with the relative core-mantle boundary (CMB) heat flux, according to recent discussions, clarifying the physical meaning of the Model G shape parameters a and b .