MCADAM: A Continuous Paleomagnetic Dipole Moment Model for at Least 3.7 Billion Years

Understanding the evolution of Earth's magnetic field can provide insights into core processes and can constrain plate tectonics and atmospheric shielding. The absolute paleointensity database PINT provides a curated repository of site mean (i.e., cooling unit), estimates of the strength of the magnetic field. We present a minor update to the PINT database to version 8.1.1 by adding 295 records from 34 studies. The PINT database is used to define a continuous model of the dipole field, using an approach combining non‐parametric and Monte Carlo (MC) resampling termed Monte Carlo Axial Dipole Average Model (MCADAM). Three dipole field strength models spanning 50 ka to 3.7–4.2 Ga (MCADAM.1a‐c) are presented, reflecting three tiers of increasingly more stringent data selection. The MCADAM models allow for the estimation of the magnetic standoff distance, constraining the shielding of Earth's atmosphere against solar wind erosion provided by the geodynamo. Plain Language Summary The geomagnetic field is a long‐lived feature that provides critical shielding of Earth's atmosphere from solar wind erosion. Understanding changes in field strength can provide insight into the evolution of Earth's core. Here we use an updated database of paleointensity estimates to develop new continuous models of the strength of Earth's magnetic field. These models include plausible uncertainties, and capture variations in field strength spanning 50 thousand to over 3.7 billion years ago. Using our models, we suggest that the atmospheric shielding provided by the field was about 60% the present‐day shielding for most of the Precambrian. Key Points Continuous dipole moment models for the past 3.7–4.2 billion years are presented Our model reproduces salient features of the paleomagnetic dipole field Paleomagnetosphere estimates suggest Precambrian atmospheric shielding was much weaker than present day