Accumulation of biogenie silica and opal dissolution in upper quaternary skagerrak sediments

In a core from the outer Skagerrak, the content of biogenic opal is higher in Late Pleistocene (Younger Dryas) than in Holocene deposits. In terms of opal accumulation, rates are 1 g/cm2/1,000 y during the Holocene and five to ten times larger during the Younger Dryas. Intensive dissolution has greatly reduced the Holocene opal content and does not allow calculation of paleoproductivity. The intensity of opal dissolution is reflected by dissolution stages of both the diatomParalia sulcata and sponge spicules. The intensity of dissolution is negatively correlated to the sedimentation rate and appears to be controlled by silica-undersaturated environment on the sea floor and the uppermost sediment layer