Biogenic Magnetite Indicating the Evolution of Bottom Water Oxygenation in the Northern South China Sea Since the Last Glacial Maximum

This dataset includes rock magnetic and sedimentological data from sediment core SCS5 (118.0401°E, 21.21478°N; water depth: 1600 m) retrieved from the northern South China Sea (NSCS) near the Luzon Strait. The core is 929 cm long, with samples collected at 2 cm intervals for magnetic analysis. The main goal of this data collection was to reconstruct bottom-water oxygenation (BWO) variations over the past ~28,000 years using biogenic magnetite as a proxy.<br>Magnetic susceptibility (κ), anhysteretic remanent magnetization (ARM), hysteresis loops, first-order reversal curves (FORC), and low-temperature magnetic properties were measured to characterize magnetofossil abundance and mineralogy. The dataset includes 457 samples, which were analyzed using a variety of techniques: ARM and κ were measured on all samples, while 196 subsamples were selected for FORC and hysteresis analysis, and 51 for low-temperature experiments. The δ-ratio, which reflects the magnetic transitions of nanoscale biogenic magnetite, was derived from low-temperature measurements between 110 K and 85 K. The dataset provides a robust record of BWO variations, highlighting a four-stage oxygenation history: low oxygenation during the Last Glacial Maximum, rapid increase during deglaciation, maximum oxygenation during the early to mid-Holocene, and gradual decline thereafter.<br>The data were collected from the sediment core using standard environmental magnetism protocols and analyzed at the Paleomagnetism Laboratory, Sun Yat-sen University, and the Institute of Geology and Geophysics, Chinese Academy of Sciences.