Knowra Siliceous ooze Siliceous ooze Siliceous ooze is deep-sea sediment composed mainly of microscopic silica-rich remains, especially the skeletons of diatoms and radiolarians. It accumulates where silica production exceeds dissolution and dilution by other sediment.
Diatom : A photosynthetic, mostly unicellular alga whose cell wall is made of hydrated silica. Diatom frustules supply much of the silica preserved in productive surface waters.
Diatomaceous earth : A porous sedimentary material formed mainly from accumulated diatom remains, commonly preserved on land. It is a diatom-rich deposit, unlike the deep-sea sediment defined by siliceous ooze.
Paleoceanography : The study of past ocean conditions using geological, chemical, and biological evidence. Siliceous ooze preserves evidence used to reconstruct ancient ocean environments.
Calcareous ooze : Deep-sea sediment composed mainly of calcium carbonate remains from marine organisms. It is the principal biogenic ooze counterpart, with carbonate rather than silica tests.
Radiolaria : A group of planktonic protists that build intricate skeletons from silica. Radiolarian skeletons sink from surface waters and contribute silica tests to deep-sea deposits.
Diatom frustule : The porous silica cell wall of a diatom, typically formed from two interlocking halves. Frustules are a distinctive microscopic particle that can accumulate in the ooze.
Marine sediment core : A cylindrical sample of layered sediment recovered from the seafloor. Cores reveal the changing abundance and composition of siliceous deposits through time.
Pelagic clay : Fine-grained deep-sea sediment dominated by slowly accumulating clay minerals and windblown particles. It accumulates where biogenic material is scarce or dissolves, unlike silica-rich ooze.
Biogenic silica : Silica produced by organisms, commonly as shells, skeletons, or other structural material. Siliceous ooze is a seafloor accumulation of this biologically produced material.
Radiolarian skeleton : A silica-based internal skeleton produced by a radiolarian protist. These skeletons are another major identifiable component of siliceous deposits.
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