Astronomy

Coastal and marine morphological zones

Coastal and marine morphological zones

Due to the incessant beating of the waves against the emerged lands, certain forms and landscapes typical of the zone of contact between the sea and the emerging land are created. This area is known by coast or coast.

In general, the relief created is related to:

a) The type of rock of the coast (cliffs or beaches),

b) How the currents and waves on the coast affect: if it is directly, the water erodes and breaks (creating cliffs, gulfs and estuaries), if the rock is protected from the waves, sediment accumulation occurs (the isthmus or totems appear, lagoons and capes)

c) The presence of rivers: if the river has less force than the waves, the sea will enter the river course (estuary, for example, the Galician), but if it is the opposite, the river will accumulate the materials transported in the sea ( delta, for example that of the Ebro or that of the Nile). If the forces are the same, there is a mixture of water and sediments (estuary, for example, the Argentine River Plate).

See "Marine erosion: cliffs and beaches" for more detail.

The ocean floor

Once inland and away from the coast, the ocean floor also presents peculiar reliefs that, although we can not see on the surface, are equally beautiful and spectacular.

In general, as seen in the figure, it could be said that the seabed is like a huge river course because as we see in a river, as we enter the sea there is a low slope plain (continental shelf) in which, as the inclination increases (continental slope), more and more pronounced canyons and gorges are developed until finally, in high-rise ravines (abyssal pits) and plains with hardly any slope (ocean floor and abyssal plains). Among them are volcanic mountains (dorsal) that sometimes form islands when emerging from the sea, called arch-islands, or atolls, if they have circular morphology seen from the air and in which corals and other marine organisms are usually installed.

This is explained on the page "Water and the relief of the sea".

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