EGU General Assembly 2022
© Author(s) 2022. This work is distributed under
the Creative Commons Attribution 4.0 License.

Chirality of the Geodynamo from the Core’s buoyancy and Sense of Spinning

Gunther Kletetschka1,2
Gunther Kletetschka
  • 1Faculty of Science, Charles University, Prague, Czechia (
  • 2Geophysical Institute, University of Alaska, Fairbanks, USA

The geodynamo inside the liquid core is part of the Earth’s rotation. We discovered that electric currents in the heat exchanging liquid core need to follow the handedness of the spiraling liquids given by Coriolis force. Coriolis force splits the buoyant heat exchanging liquid into the two, north and south hemispheres, each with its unique handedness of spiraling convection systems. Convection spiraling model of the core fluid revealed that any planetary dynamo with a liquid conducitng core must have a two-component bimodal structure magnetic contribution, where, for Earth, the southern hemisphere is always associated with a dominating normal polarity component and northern hemisphere with a dominating component of reverse magnetic polarity. We show that the geodynamo would have a non-random distribution of the probability of generation of dynamo’s magnetic polarity, depending on a difference in a degree of buoyancy vigorousness between the two hemispheres.  In this work, the individual treatment of normal and reversed polarity durations revealed that while before 80 Ma geodynamo was generating predominantly normal polarity durations, after the Tertiary transition at ~ 60 Ma, the geodynamo produced predominantly reverse polarity durations. This observation of predominance of magnetic polarity durations is constrained by the existing temperature models near the core/mantle boundary (CMB) and we show a novel connection how a lower mantle temperature distribution may reorganize its convection pattern in the core and change the stability of the dipolar field in favor of a specific polarity.

How to cite: Kletetschka, G.: Chirality of the Geodynamo from the Core’s buoyancy and Sense of Spinning, EGU General Assembly 2022, Vienna, Austria, 23–27 May 2022, EGU22-9908,, 2022.