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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 ...
The asthenosphere in relation to the other layers of Earth's structure. The asthenosphere is a part of the upper mantle just below the lithosphere that is involved in plate tectonic movement and isostatic adjustments. It is composed of peridotite, a rock containing mostly the minerals olivine and pyroxene. [2]
The asthenosphere is the ductile region of the upper mantle. Mantle processes which operate across mountain belts include those related to subduction (e.g., slab break-off, flat-slab subduction, subduction of a triple junction). Volcanism is driven by mantle processes such as partial melting and thermal convection currents.
The secondary mechanisms view plate motion driven by friction between the convection currents in the asthenosphere and the more rigid overlying lithosphere. This is due to the inflow of mantle material related to the downward pull on plates in subduction zones at ocean trenches.
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.
This process creates convection currents in the outer core, which are thought to be the prime driver for the currents that create the Earth's magnetic field. [5] The existence of the inner core also affects the dynamic motions of liquid in the outer core, and thus may help fix the magnetic field. [citation needed]
In this framework, the LAB separates the two heat transport regimes [conduction vs. convection]. [5] However, the transition from a domain that transports heat primarily through convection in the asthenosphere to the conducting lithosphere is not necessarily abrupt and instead encompasses a broad zone of mixed or temporally variable heat transport.
Earth heat transport occurs by conduction, mantle convection, hydrothermal convection, and volcanic advection. [15] Earth's internal heat flow to the surface is thought to be 80% due to mantle convection, with the remaining heat mostly originating in the Earth's crust, [16] with about 1% due to volcanic activity, earthquakes, and mountain ...