Estimating Post‐Depositional Detrital Remanent Magnetization (pDRM) Effects for Several Lacustrine and Marine Sediment Records Using a Flexible Lock‐In Function Approach

Geomagnetic field models over past millennia rely on two main data sources: archeomagnetic data provide snapshots of the geomagnetic field at specific locations, and sediment records deliver time series of the geomagnetic field at specific locations. The limited temporal and spatial coverage of archeomagnetic data necessitates the incorporation of sediment data especially when models go further back in time. When working with sediment data one should consider the post‐depositional detrital remanent magnetization (pDRM) process, which can cause delayed and smoothed signals. To address the distortion associated with the pDRM process a Bayesian modeling technique incorporating archeomagnetic data and a class of flexible parameterized lock‐in functions has been proposed. In this study, we investigate this method in more detail and apply it to declination and inclination of several lacustrine and marine sediment records. Data‐driven results support the hypothesis that the pDRM process can introduce distortions, including offsets and smoothing, in some lacustrine and marine sediment records. We demonstrate a correction approach to minimize the distortion caused by the pDRM process and its impact on geomagnetic field reconstructions. The variability in the results observed across the nine records points to a potential dependence on sedimentological characteristics. To explore this further, we plan to systematically apply our novel method to a larger number of records in future studies. Plain Language Summary Understanding the Earth's magnetic field changes over the past millennia helps us learn more about the planet's history. We can use the magnetic field information preserved in different materials to reconstruct the past Earth's magnetic field evolution: ancient artifacts (archeomagnetic data), lava flows and sediment records. Archeomagnetic and lava flow data has limited coverage in time and space, so when modeling longer time scales we have to rely more and more on sediment data. When using sediment data, we need to be careful about a process called post‐depositional detrital remanent magnetization (pDRM), which can distort the signals and cause smoothing and delays. To deal with this issue, a new method has been developed using Bayesian modeling, archeomagnetic data and flexible lock‐in functions to correct for the pDRM effect. In this study we explore this method in more detail and test it on several lacustrine and marine sediment records. We found that th