Polarity reversals of remanent magnetization in a sedimentary core from Northwind Ridge, western Arctic Ocean

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We studied the remanent magnetization of a sedimentary core PC2 (6.48m length) drilled during the MR99-K05 cruise of JAMSTEC in the western Arctic Ocean. Discrete specimens and u-channel samples were used in the study. In the discrete specimens, the change of remanent magnetization with depth show many clear polarity reversals in both inclination and declination. Furthermore, most reversals in discrete specimens correlated well with those in the u-channel samples. Core PC2 is characterized by distinct alternations of dark gray and brownish layers. Through comparison of lithostratigraphic cycles with glacial-interglacial cycles (referring to R.L. Phillips and A. Grantz, Geol. Soc. Am. Bull., 109, 1101, 1997), sedimentary cycles of core PC2 are correlated to marine isotope stages up to MIS-8. This indicates that polarity reversals of remanent magnetization in core PC2 are geomagnetic excursions in the Brunhes epoch. Comparison with the previously known geomagnetic excursions shows that the polarity reversals are clear and have long duration in core PC2. This feature may be related to characteristic geomagnetism around the western Arctic Ocean.
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