Dating North Pacific Abyssal Sediments by Geomagnetic Paleointensity: Implications of Magnetization Carriers, Plio-Pleistocene Climate Change, and Benthic Redox Conditions

Non-carbonaceous abyssal fine-grained sediments cover vast parts of the North Pacific’s deep oceanic basins and gain increasing interests as glacial carbon traps. They are, however, difficult to date at an orbital-scale temporal resolution still rarely used for paleoceanographic reconstructions. Here, we show that sedimentary records past geomagnetic field intensity have high potential improve reversal-based magnetostratigraphic age models. Five sediment cores from Central Pacific mid-latitudes (39–47°N) water depths ranging 3,900 6,100 m were cube-sampled 23 mm analyzed by automated standard paleo- rock magnetic methods, XRF scanning, electron microscopy. Relative Paleointensity (RPI) determined comparing natural vs. anhysteretic remanent magnetization losses during alternating demagnetization using a slope method within optimized coercivity windows. The paleomagnetic record delivered well interpretable reversal sequences back 3 Ma. This span covers climate-induced transition biogenic magnetite prevalence in Late Pliocene Early Pleistocene dust-dominated detrital mineral assemblage since Mid-Pleistocene. Volcaniclastic materials concurrent eruptions gravitational or contouritic re-deposition along extinct seamount flanks provide further important source fine- coarse-grained carriers. Surprisingly, higher proportions late correlate with systematically lowered RPI values, which seems be consequence magnetofossil oxidation rather than reductive depletion. Our match astronomically tuned stack mostly bathyal records. While stratigraphic correlation element ratio logs oxygen isotope was sporadically possible, minima allowed establish tie points ∼50 kyr intervals. Thus, this RPI-enhanced magnetostratigraphy appears major step forward reliably unaltered close resolution.