Deep-Water Dynamics in the Subpolar North Atlantic at the End of the Quaternary

Resumo

In the subpolar North Atlantic, four sediment cores were taken. All of them were suitable for reconstructing the dynamics of the meridional overturning circulation in the late Quaternary. Stratigraphy of the cores was performed by carbonate analyses, study of planktonic foraminifera, and oxygen isotopic composition in Neogloboquadrina pachyderma sin. Study of benthonic foraminifera assemblages has shown significant differences in the deep-water dynamics in the late Quaternary related to water exchange between the North Atlantic and Arctic seas. It has been established that at the end of the middle and most of the late Pleistocene, deep circulation in the subpolar North Atlantic was poor. Its strengthening took place in the time of deglaciations (Termination III and Termination II). During the optimum of the last interglacial (MIS 5e), water flow from the Norwegian Sea into the North Atlantic happened mainly in its western part. The modern deep water in the eastern part of the North Atlantic began to form at the end of the last glaciation.