| The possibility of retrieving relative intensity variations of the Earth's magnetic field from sediments allows the documentation of continuous geomagnetic paleointensity variations back in time, and these records show a mutual good agreement to the global scale field. At present, RPI curves have been increasingly used as global, millennial-scale correlation and stratigraphic tool. Despite such importance, data constraining the past intensity of the planetary body remain relatively scarce, especially in the Pacific Ocean. In this study, we present the details of a paleomagnetic and rock magnetic study carried out on the sediments from the West Pacific Ocean. The aim of this study is to document the relative paleointensity data by normalizing the natural remanent magnetization, which would provide a new approach for regional stratigraphic division and correlation.A detailed rock magnetic analysis has been conducted on core Ph05 from the West Philippine Sea. Rock magnetic results demonstrate that the core preserve a strong, stable remanent magnetization and meet the magnetic mineral criteria for relative paleointensity (RPI) analyses. The magnetic minerals in the sequence are dominated by pseudosingle-domain magnetite, and the concentration of magnetic minerals are at the same scale. Both the conventional normalizing method as well as the pseudo-Thellier method were used in conjunction with the examination of the rock magnetic properties and natural remanent magnetization. Susceptibility (χ), anhysteretic remnant magnetization (ARM) and saturation isothermal remnant magnetization (SIRM) were used as the natural remanent magnetization normalizer. However, coherence analysis results indicate that only ARM is more suitable for paleointensity construction .The age model of core is established based on oxygen isotope data and AMS14C data, which is consistent with the age model estimated from RPI records. The relative paleointensity data provide a continuous record of the intensity variation during the last 200 ka, which correlates well with the global references RPI stacks. Several prominent low paleointensity values are identified and correlate to the main RPI minima in the SINT-200 record, it suggests that the sediments have recorded the real changes of geomagnetic field.The rock magnetic measurements of core F090102 suggested that the cores preserve a strong, stable remanent magnetization and meet the magnetic mineral criteria for reliable paleointensity analyses.χ, ARM and SIRM were used as the natural remanent magnetization normalizer. The relative paleomagnetic intensity record over the past about 2 Ma was obtained and was further compared to previously published stack records, SINT-800 and SINT-2000. Our new RPI record exhibits asymmetrical saw-tooth pattern of the geomagnetic field intensity and some major declines in paleointensity (DIP) at reversal boundaries as well as geomagnetic excursions. The Brunhes/Matuyama polarity transition was characterized by a single-DIP but not a double-DIP, it may be due to the low sedimentation accumulation rates. The record can be used to refine the chronological framework of the sediment in this region.The results of core EC2005, located in the mud area in the inner shelf of the East China Sea, demonstrate that the upper 110 cm sediments are little affected by reductive diagenesis; The 110-600 cm sediments are within the stage of iron oxide reduction, PSD magnetite mainly contributes to sediments of this section, with less abundant and coarser grains downcore. The magnetic parameters vary along with the fluctuation of the content of hard magnetic phases; The 600-2800 cm sediments are within the stage of sulphate reduction. Values of magnetic parameters, such as x, SIRM, and HIRM, drop sharply in this section, with little fluctuation. Paramagnetic minerals contribute to sediments of this section, including pyrites. The reductive diagenesis and post-depositonal alteration have weaken and destroyed the original magnetic signals.
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