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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.
Pelagic clay accumulates in the deepest and most remote areas of the ocean. It covers 38% of the ocean floor and accumulates more slowly than any other sediment type, at only 0.1–0.5 cm/1000 yr. Containing less than 30% biogenic material, it consists of sediment that remains after the dissolution of both calcareous and siliceous biogenic ...
The theory of plate tectonics did, indeed, arise from the revelations discovered on sea floor features. The theory of plate tectonics incorporates Wegener's theory of continental drift but also a more modern theory called "Seafloor Spreading."
As we discussed in Chapter 10, oceanic crust is formed at sea-floor spreading ridges from magma generated by decompression melting of hot upward-moving mantle rock (Figure 10.18). About 10% of the mantle rock melts under these conditions, producing mafic magma.
- Steven Earle
- 2015
The floor of the Pacific, like those of the other oceans, is actually very flat, even in areas with seamounts or deep trenches. The vast sediment-covered abyssal plains of the oceans are much flatter than any similar-sized areas on the continents.
- Steven Earle
- 2015
Apr 24, 2024 · Pelagic carbonate sediment is derived from organisms (e.g., foraminifera) living in the ocean water (at various depths, but mostly near surface) that make their shells (a.k.a. tests) out of carbonate minerals such as calcite.
Feb 15, 2021 · Neritic sediments cover about ¼ of sea floor and are near landmasses. The term pelagic means "of or relating to the open sea" particularly the upper layers of the ocean away from shore. Pelagic sediments are generally deep-water deposits mostly oozes (see below) and windblown clays.
