Paleomagnetism indicates that primary magnetite in zircon records a strong Hadean geodynamo.

ABSTRACT: Determining the age of the geomagnetic field is of paramount importance for understanding the evolution of the planet because the field shields the atmosphere from erosion by the solar wind. The absence or presence of the geomagnetic field also provides a unique gauge of early core conditions. Evidence for a geomagnetic field 4.2 billion-year (Gy) old, just a few hundred million years after the lunar-forming giant impact, has come from paleomagnetic analyses of zircons of the Jack Hills (Western Australia). Herein, we provide new paleomagnetic and electron microscope analyses that attest to the presence of a primary magnetic remanence carried by magnetite in these zircons and new geochemical data indicating that select Hadean zircons have escaped magnetic resetting since their formation. N

SUBMITTER: Tarduno JA 

PROVIDER: S-EPMC7007582 | biostudies-literature | 2020 Feb

REPOSITORIES: biostudies-literature