High-resolution records of the mid-Pleistocene Transition in pelagic sediments of the western Pacific

The Mid-Pleistocene Transition (MPT), which occurred approximately 1.25 to 0.85 million years ago, marks a critical geological period characterized by a shift in Earth's glacial cycles from a roughly 41 kyr periodicity to a 100 kyr periodicity. However, the stratigraphic framework is constrained by low sedimentation rates, the absence of high-resolution isotope stratigraphy, and low-resolution or absent biostratigraphic control. In this study, we examined four piston cores collected from the western-central Pacific to more accurately determine the geochronology of the surficial sediments in the deep sea. Through integrated magnetostratigraphy, a proposed chronology since the Pliocene was established, and astronomical tuning was also conducted in one of the four cores. In conjunction with XRF scanning, the geochemical properties were studied to reveal regional changes since the MPT. Our findings indicate the following paleoceanographic evolution: concurrent with global cooling and aridification in Asia, there has been an increase in wind and dust flux in the western Pacific, an enhancement in biological productivity, and a reduction in the degree of seabed redox post the MPT. Additionally, we also found that throughout the MPT (approximately 1.2 to 0.7 Ma), the deep-sea paleoceanographic environment of the Western Pacific has maintained relative stability.