Explain that the formation mechanism of marine crust is one ofhypothesis, also constitutePlate tectonic theoryOne of the basic ideas of.It believes that there is a split zone (shown as mid ocean ridge or ocean uplift) on the oceanic crust, which is the place where the oceanic crust originates.Mantle materials are constantly gushing out from this and become new oceanic crust after cooling. The original seabed expands to both sides with the generation of new submarine crust.
It is a hypothesis to explain the formation mechanism of the oceanic crust, which is also a component ofPlate tectonic theoryOne of the basic ideas of.It believes that there is a split zone (shown as mid ocean ridge or ocean uplift) on the oceanic crust, which is the place where the oceanic crust originates.Mantle materials are constantly gushing out from this and become new oceanic crust after cooling. The original seabed expands to both sides with the generation of new submarine crust.[1]
Hypothesis principle
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In the 1960s, twobritainMarine geologyhomeH. H. Hess(Harry Hess) andR. S. DietzThe hypothesis of "seafloor spreading" is put forward.According to the measurementthe pacific oceanAt the ocean floor, the crust on both sides of the ridge expands outward at a rate of 5~7 cm per yearAtlanticIt is 1-2 cm per year.It will take about two to three hundred million years for the crust at the bottom of the ocean to undergo a great change of renewal.The theory of seafloor spreading isContinental driftThe new form of doctrine is alsoPlate tectonicsIs an important theoretical pillar.[2]
1. Because of its low density, the oceanic lithosphere floats above the shaped asthenosphere and can drift.
2. The density is uneven due to the uneven temperature of the mantle, which results in convection in the asthenosphere or the whole mantle.The hotter mantle material flows upward, and the colder mantle material flows downward, forming a circulation.
3. The rift zone of the mid ocean ridge is the outlet of the rising mantle material. The continuously upwelling mantle material condenses to form a new ocean floor, and promotes the first formed ocean floor to gradually expand symmetrically on both sides.The old ocean floor formed first subducts downward when it reaches the trench, subducts in the mantle, and becomes part of the asthenosphere.Therefore, the ocean floor is always in the process of continuous production and extinction, and it is always young.[3]
