Chronostratigraphy of sediment cores from the Bering Sea and the subarctic Pacific based on paleomagnetic and oxygen isotopic analyses

The chronostratigraphy of six piston cores collected from the Bering Sea and one piston core from the subarctic Pacific is reported. Age models are primarily based on oxygen isotope data from Cores BOW-8A and ES in conjuction with relative paleointensity proxy records, biogenic opal data, and a radiolarian datum from other cores whose sediments mainly consist of diatom microfossils and poorly preserved calcium carbonate. The records, the first paleointensity proxy reported from the Bering Sea, show that characteristic paleointensity lows at ∼40, ∼60 and ∼100 ka, which have been well documented in other paleointensity records. Those features can be correlated to standard paleointensity curves with the aid of biogenic opal data and a radiolarian datum. The mean sedimentation rates of the diatom-rich cores collected in the eastern Bering Sea range from 10 to 20 cm kyr−1. In contrast, the mean sedimentation rate of Core BOW-8A, from the western edge of the Bowers Ridge, is only ∼3 cm kyr−1, which is comparable to Core ES from the pelagic realm in the subarctic Pacific. These results suggest that biological productivity has been quite high during the late Pleistocene in the eastern part of the Bering Sea, but low over the western edge of the Bowers Ridge.