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Exploration of the mantle is generally conducted at the seabed rather than on land because of the relative thinness of the oceanic crust as compared to the significantly thicker continental crust. The first attempt at mantle exploration, known as Project Mohole, was abandoned in 1966 after repeated failures and cost over-runs. The deepest ...
The silicate mantle of the Earth's moon is approximately 1300–1400 km thick, and is the source of mare basalts. [4] The lunar mantle might be exposed in the South Pole-Aitken basin or the Crisium basin. [4] The lunar mantle contains a seismic discontinuity at ~500 kilometers (310 miles) depth, most likely related to a change in composition. [4]
The pressure at the bottom of the mantle is ≈140 GPa (1.4 Matm). [24] The mantle is composed of silicate rocks richer in iron and magnesium than the overlying crust. [25] Although solid, the mantle's extremely hot silicate material can flow over very long timescales. [26] Convection of the mantle propels the motion of the tectonic plates in the
A diagram of the internal structure of Earth. The lithosphere consists of the crust and upper solid mantle (lithospheric mantle). The green dashed line marks the LAB. The lithosphere–asthenosphere boundary (referred to as the LAB by geophysicists) represents a mechanical difference between layers in Earth's inner structure.
Of particular interest are the so-called "PKiKP" waves—pressure waves (P) that start near the surface, cross the mantle-core boundary, travel through the core (K), are reflected at the inner core boundary (i), cross the liquid core (K) again, cross back into the mantle, and are detected as pressure waves (P) at the surface.
The Nobel Prize winner Patrick Blackett did a series of experiments looking for a fundamental relation between angular momentum and magnetic moment, but found none. [ 5 ] [ 6 ] Walter M. Elsasser , considered a "father" of the presently accepted dynamo theory as an explanation of the Earth's magnetism, proposed that this magnetic field resulted ...
The subcontinental lithospheric mantle (SCLM) is the uppermost solid part of Earth's mantle associated with the continental lithosphere. The modern understanding of the Earth's upper mantle is that there are two distinct components - the lithospheric part and the asthenosphere .
On Earth, the Rayleigh number for convection within Earth's mantle is estimated to be of order 10 7, which indicates vigorous convection. This value corresponds to whole mantle convection (i.e. convection extending from the Earth's surface to the border with the core). On a global scale, surface expression of this convection is the tectonic ...