Other biogenic deposits include those that are siliceous, which
are rich in silica dioxide. Organisms that are siliceous include
diatoms, radiolarians, and some sponges. Siliceous sediments are
usually found in colder water.
These deposits reflect the biological life above the ocean basins. If
you look at the productivity of the areas that contain the siliceous and
calcareous component it is much higher than the rest of the basins.
If you look at the currents and nutrients available these areas
usually have an increase of upwelling. Upwelling is when water,
rich in nutrients comes up toward the surface due to physical conditions
of the water masses.