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Hemipelagic sediment, or hemipelagite, is a type of marine sediment that consists of clay and silt-sized grains that are terrigenous and some biogenic material derived from the landmass nearest the deposits or from organisms living in the water.
Altogether, the pelagic zone occupies 1,330 million km 3 (320 million mi 3) with a mean depth of 3.68 km (2.29 mi) and maximum depth of 11 km (6.8 mi). [2] [3] [4] Pelagic life decreases as depth increases. The pelagic zone contrasts with the benthic and demersal zones at the bottom of the sea. The benthic zone is the ecological region at the ...
Marine sediment, or ocean sediment, or seafloor sediment, are deposits of insoluble particles that have accumulated on the seafloor.These particles either have their origins in soil and rocks and have been transported from the land to the sea, mainly by rivers but also by dust carried by wind and by the flow of glaciers into the sea, or they are biogenic deposits from marine organisms or from ...
The mesopelagic zone has some unique acoustic features. The Sound Fixing and Ranging (SOFAR) channel, where sound travels the slowest due to salinity and temperature variations, is located at the base of the mesopelagic zone at about 600–1,200m. [6] It is a wave-guided zone where sound waves refract within the layer and propagate long ...
The formation of this harbour has occurred due to active erosional processes on an extinct shield volcano, whereby the sea has flooded the caldera, creating an inlet 16 km in length, with an average width of 2 km and a depth of −13 m relative to mean sea level at the 9 km point down the transect of the central axis. [5]
Also called Indianite. A mineral from the lime-rich end of the plagioclase group of minerals. Anorthites are usually silicates of calcium and aluminium occurring in some basic igneous rocks, typically those produced by the contact metamorphism of impure calcareous sediments. anticline An arched fold in which the layers usually dip away from the fold axis. Contrast syncline. aphanic Having the ...
The oceanic zone is typically defined as the area of the ocean lying beyond the continental shelf (e.g. the neritic zone), but operationally is often referred to as beginning where the water depths drop to below 200 metres (660 ft), seaward from the coast into the open ocean with its pelagic zone.
This wedge incorporates sediment eroded from the continental margin and marine sediments carried into the subduction zone on the Pacific plate. [18] The Franciscan Formation of California – Franciscan rocks in the Bay Area range in age from about 200 million to 80 million years old. The Franciscan Complex is composed of a complex amalgamation ...