Pelagic sediment or
pelagite is a fine-grained
sediment that accumulates as the result of the settling of particles to the floor of the open ocean, far from land. These particles consist primarily of either the microscopic, calcareous or siliceous shells of
phytoplankton or
zooplankton;
clay-size
siliciclastic sediment; or some mixture of these. Trace amounts of meteoric dust and variable amounts of
volcanic ash also occur within pelagic sediments. Based upon the composition of the ooze, there are three main types of pelagic sediments:
siliceous oozes,
calcareous oozes, and
red clays.