Abrupt intensification of North Atlantic Deep Water formation at the Nordic Seas during the late Pliocene climate transition

作者：Sato Masahiko^*; Makio Masato; Hayashi Tatsuya; Ohno Masao

来源：Geophysical Research Letters, 2015, 42(12): 4949-4955.

DOI：10.1002/2015GL063307

• North Atlantic Deep Water
• Iceland-Scotland Overflow Water
• Nordic Seas
• Integrated Ocean Drilling Program Expedition 306
• late Pliocene transition

Knowledge of the evolution of North Atlantic Deep Water (NADW) is key to understanding the past evolution of the climatic system. Here we developed a new rock-magnetic method to determine the constituent magnetic minerals of sediments and report on the evolution of NADW during 2.2-2.9Ma. We measured isothermal remanence acquisition curves of North Atlantic deep-sea sediments drilled at the Gardar Drift and decomposed the first derivatives of these curves into high-coercivity and low-coercivity components. Residuals of the decomposition were sufficiently small throughout the study interval, confirming that the Gardar Drift sediments represent a mixing of the two end-members. Fractional changes of the high-coercivity component represent variation of the Iceland-Scotland Overflow Water, a branch of NADW formed at the Nordic Seas. The high-coercivity component increased significantly during an interglacial period just after similar to 2.68Ma, which suggests that NADW formation in the Nordic Seas abruptly intensified at this time.

• 出版日期2015-6-28