Synchronizing volcanic, sedimentary, and ice core records of Earth's last magnetic polarity reversal.

ABSTRACT: Reversal of Earth's magnetic field polarity every 10⁵ to 10⁶ years is among the most far-reaching, yet enigmatic, geophysical phenomena. The short duration of reversals make precise temporal records of past magnetic field behavior paramount to understanding the processes that produce them. We correlate new ⁴⁰Ar/³⁹Ar dates from transitionally magnetized lava flows to astronomically dated sediment and ice records to map the evolution of Earth's last reversal. The final 180° polarity reversal at ~773 ka culminates a complex process beginning at ~795 ka with weakening of the field, succeeded by increased field intensity manifested in sediments and ice, and then by an excursion and weakening of intensity at ~784 ka that heralds a >10 ka period wherein

SUBMITTER: Singer BS 

PROVIDER: S-EPMC6685714 | biostudies-literature | 2019 Aug

REPOSITORIES: biostudies-literature