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Mantle convection is the very slow creep of Earth's solid silicate mantle as convection currents carry heat from the interior to the planet's surface. [2] [3] Mantle convection causes tectonic plates to move around the Earth's surface. [4] The Earth's lithosphere rides atop the asthenosphere, and the two form the components of the upper mantle ...
Subduction slabs drive plate tectonics by pulling along the lithosphere to which they attach in a process known as slab pull and by inducing currents in the mantle via slab suction. [2] The slab affects the convection and evolution of the Earth's mantle due to the insertion of the hydrous oceanic lithosphere. [3]
Mantle convection occurs at rates of centimeters per year, and it takes on the order of hundreds of millions of years to complete a cycle of convection. Neutrino flux measurements from the Earth's core (see kamLAND ) show the source of about two-thirds of the heat in the inner core is the radioactive decay of 40 K , uranium and thorium.
This thickening occurs by conductive cooling, which converts hot asthenosphere into lithospheric mantle and causes the oceanic lithosphere to become increasingly thick and dense with age. In fact, oceanic lithosphere is a thermal boundary layer for the convection [10] in the mantle. The thickness of the mantle part of the oceanic lithosphere ...
Earth's tectonic evolution over time from a molten state at 4.5 Ga, [11] to a single-plate lithosphere, [24] to modern plate tectonics sometime between 3.2 Ga [25] and 1.0 Ga [26] Primordial heat energy comes from the potential energy released by collapsing a large amount of matter into a gravity well, and the kinetic energy of accreted matter.
Lateral density variations in the mantle result in convection currents, the slow creeping motion of Earth's solid mantle. At a seafloor spreading ridge , plates move away from the ridge, which is a topographic high, and the newly formed crust cools as it moves away, increasing its density and contributing to the motion.
Sinking lithosphere at subduction zones are a part of convection cells in the underlying ductile mantle. This process of convection allows heat generated by radioactive decay to escape from the Earth's interior. [6] The lithosphere consists of the outermost light crust plus the uppermost rigid portion of the mantle.
The structure of Earth can be defined in two ways: by mechanical properties such as rheology, or chemically. Mechanically, it can be divided into lithosphere, asthenosphere, mesospheric mantle, outer core, and the inner core. Chemically, Earth can be divided into the crust, upper mantle, lower mantle, outer core, and inner core. [6]