Clay-mineral flux in the Fram Strait and Norwegian Sea

Abstract

Since 1983 time-series traps have been deployed in the Fram Strait and the Norwegian Sea to study sedimentation processes in open ocean and ice-covered areas. The seasonal and regional variability of clay minerals is used to decipher the effect of current systems on particle flux and particle producing processes. Toward this end the occurrence of the clay mineral kaolinite can be used to identify transported material. High koalinite/illite ratios are related to distinct sedimentation events caused by particularly high plankton productivity. In the various current systems, the following types of sedimentation can be distinguished: a “polar” type, characterized by low total flux, high lithogenic content and a kaolinite/illite-ratio of <0.3, in the region of the predominantly ice-covered East Greenland Current (EGC), and an “arctic-atlantic” type, characterized by very high total flux, high lithogenic content and a kaolinite/illite-ratio of >0.3, in the area of the West Spitsbergen Current. The type of sedimentation in the region of the drift-ice margin is referred to as “ice-margin” type, characterized by medium total flux, medium lithogenic content and a kaolinite/illite-ratio of >0.3. Additionally, in the near-shore sediments of the Norwegian Sea, a “continental” influence from resuspended material with high contents of terrigenous material in the otherwise characteristically pelagic sediments is apparent.