Pelagic Sediment

Pelagic sediment is fine-grained deep-sea deposit that settles slowly through the water column far from continental sources, distinct from terrigenous and hemipelagic sediment near margins. It splits into biogenic oozes, calcareous above the CCD and siliceous in high-productivity belts, and abyssal red clay where both dissolve. Accumulation is slow, on the order of 1 to 10 mm per thousand years, so a centimeter of red clay can represent thousands of years. The grain population is mostly clay-size particles, microfossil tests, wind-blown dust, and authigenic minerals. It covers the abyssal plains across most of the deep ocean floor.