Mean element and biogenic silica concentrations in Arctic Ocean sediments (Table 1)

The timing of polar upwelling coincides with periods of a weakened meridional thermal gradient, suggesting that heat transport to the poles by oceanic circulation may have been important. The timing of biogenic silica deposition in the Arctic precedes its deposition in both the Norwegian-Greenland Sea of the North Atlantic and the Bering Sea of the North Pacific.

Tectonic events may be responsible for the timing and siting of sites of deposition of biogenic silica in high northern latitudes, particularly the tectonic evolution of sites of deep-water exchange between the Arctic and the world ocean. We outline three phases in the post-mid-Cretaceous history of silica deposition in high northern latitudes. During Phase I, the Arctic is a silica sink, with deep-water formation but with no deep-water outflow.