Abstract

  Lake cores that were recovered from Elson Lagoon at Barrow Point in Alaska provide carbon-14-dated Arctic records and extend to the Last Glacial Maximum. P, Pb, Ni, Cu, Zn, and Cr of the Arctic Ocean inferred from lagoon-lake sediment provide an environmental record. The data shows in detail that many of the rapid environmental shifts were between 0 and 5000 years before the present which were not observed in central Greenland ice cores between 16,000 and 5000 years before the present. P of the core decreased 400 ug/g between 16000 and 4800 years before the present, which is consistent with curves from Ni, Cu, Zn, and Pb. The abrupt onset and termination from 5,400 years suggest ocean processes were the probable drivers. Regional accumulation increased at 3,700, 2,500, and 1,000 years which is concurrent with higher value. Unlike these elements, Cr was found to be about 350 ug/g at 11,200 years before the present but decreased to 200 ug/g over the past 9,200 years reflecting new conditions. Thus, these results imply that environmental forcing acted in different fashion for Cr and other element and that ocean circulation played an important role in the development of these events. These records likely reflect short weakening of the thermohaline circulation caused by episodic discharges of continental freshwater into Arctic. Deviating millennial-scale trends, however, indicate that environmental change between Barrow and Greenland progressed systematically reflecting a gradual rearrangement of Arctic circulation during de-glaciation period.