Reconstruction of high-resolution paleomagnetic variations in the middle Gauss Chronozone including the upper and lower boundaries of the Mammoth reversed subchronozone

In this study, we provide paleomagnetic records, including the upper and lower boundaries of the Mammoth reversed subchronozone, reconstructed from a continuous outcrop of the upper marine Pliocene in the southernmost part of the Boso Peninsula, which is more than 200 m thick. In this interval, the Mammoth reversed subchronozone was recognized in an interval of approximately 50 m thickness, including a polarity transition zone at its lower boundary of approximately 10 m thickness. Simultaneously, the upper boundary showed no polarity transition zone and a rapid polarity reversal, suggesting a probable lack of strata. Several significant variations were recognized in the paleomagnetic directions in the middle Gauss chronozone, some of which may qualify as new geomagnetic excursions. The relative paleointensity (RPI) around the lower Mammoth boundary was significantly attenuated compared to that of the average of the entire section. Additionally, the Virtual geomagnetic pole (VGP) path of the lower Mammoth boundary exhibits clustering around the North American Continent, moves to the southern hemisphere across the equatorial Pacific region, and clusters again in the eastern Antarctic continent immediately after migration. The new paleomagnetic record obtained in this study is one of the highest temporal resolution continuous paleomagnetic records for the Late Pliocene. Therefore, the results of this study are expected to contribute to clarifying the geodynamic mechanisms and development of Pliocene magnetostratigraphy using RPI records.