Geomagnetic Superchron: Consequence of Supercontinent’s Breakup or Assembly

Abstract It remains enigmatic why the geomagnetic polarity is frequently reversed and how geomagnetic superchrons were formed during Earth’s evolution. Here we establish a physical model to decipher the relationship among geomagnetic superchron, subducted slab and superplume. During the supercontinent’s breakup or assembly, the subducted slabs concentratively arrive at the core-mantle boundary (CMB) and form “collective graveyards”, leading to increase of radial temperature gradient of CMB. The energy accumulation by the radioactive elements and fertile components from the subducted slab facilitate the subsequent superplume activity which consumes tremendous heat supply from the outer core. The combined results of subducted slabs and superplume activity keep long-term heat supply from the liquid outer core to the “collective graveyard” and the unchanged direction of resultant velocity of the fluid across the outer core, thereby forming a geomagnetic superchron. Our results reveal that a geomagnetic superchron lags supercontinent’s assembly or breakup by 163-239 Myr.