High geomagnetic field intensity recorded by anorthosite xenoliths requires a strongly powered late Mesoproterozoic geodynamo.

ABSTRACT: Obtaining estimates of Earth's magnetic field strength in deep time is complicated by nonideal rock magnetic behavior in many igneous rocks. In this study, we target anorthosite xenoliths that cooled and acquired their magnetization within ca. 1,092 Ma shallowly emplaced diabase intrusions of the North American Midcontinent Rift. In contrast to the diabase which fails to provide reliable paleointensity estimates, the anorthosite xenoliths are unusually high-fidelity recorders yielding high-quality, single-slope paleointensity results that are consistent at specimen and site levels. An average value of ∼83 ZAm² for the virtual dipole moment from the anorthosite xenoliths, with the highest site-level values up to ∼129 ZAm², is higher than that of the dipole component of

SUBMITTER: Zhang Y 

PROVIDER: S-EPMC9304012 | biostudies-literature | 2022 Jul

REPOSITORIES: biostudies-literature