At ocean ridges or mid-ocean ridges they are features of the underwater relief that present abrupt elevations at altitudes much higher than their surrounding relief, forming true submerged mountain ranges. Not by chance, the oceanic ridges are also called oceanic or mid-ocean ranges.
THE formation of oceanic ridges is linked to the expulsion of magma existing in the Earth's mantle from fractures caused by the spacing between the tectonic plates, so the magma quickly turns into igneous rocks. These rocks can remain in this state or gradually transform into metamorphic rocks, depending on the pressure conditions of the environment.
Area of formation of oceanic ridges in regions of tectonic separation
At the extremities of mid-ocean ridges, scarps are formed, the incidence of which depends on the rate of tectonic propagation of underwater relief forms, since this environment is predominantly conditioned by endogenous relief transformation agents. Therefore, in some locations, very steep elevations form and even
ocean trenches, where the depth is greater and the water pressure reaches very high values.The areas where the ocean ridges form are obviously geologically younger and constitute the points of rock renewal, as the magma solidifies in these areas. In the localities of collision and meeting between two tectonic plates, at the opposite end of the dorsal plates, the heavier plate submerges and the rocks are gradually converted into magma again, constituting the cyclical renewal process of the rocks.
One of the best known and most studied dorsal fins by scientists is the mid-Atlantic ridge, formed during continental separation and with the consequent constitution of the Atlantic Ocean during the cretaceous period, about 140 million years ago. This dorsal, in fact, has been up to question theme for Enem. As the plates that are submerged by this ocean are in the process of moving away, the continental areas bathed by it have a marked geological stability, with few earthquakes and virtually no volcanism, which includes the territory Brazilian.
By Me. Rodolfo Alves Pena
Source: Brazil School - https://brasilescola.uol.com.br/geografia/dorsais-oceanicas.htm
