WATER COLUMN ANOMALIES IN DISSOLVED SILICA OVER OPALINE PELAGIC SEDIMENTS AND THE ORIGIN OF THE DEEP SILICA MAXIMUM

Recent estimates based on pore water studies and mass balance considerations put the average flux of dissolved silica from the sediments into the deep water at c.3 micromol cm-2 yr-1. This flux, if mixed uniformly in a bottom layer 100m thick, results in an anomaly increment of 0.3 micromol kg-1 yr-1. In basins of restricted circulation containing opaline sediments the residence time of the bottom waters should be long enough that the resulting anomaly be easily resolvable using existing data. Examination of the many hundreds of detailed, precise silica profiles presently available in unpublished reports shows that this is indeed the case. -from Authors