Mohorovicic discontinuity

Figure 3.1 A cross section of the crusts, rigid upper mantle, and plastic mantle asthenosphere of the Earth. The Mohorovicic Discontinuity is the boundary between the crust and upper mantle. The lithosphere includes the crusts and the upper mantle.

Mohorovicic Discontinuity The boundary between the lower crust and the upper mantle. 

Crust - The outer layer of the solid earth, above the Mohorovicic discontinuity. Its thickness averages about 35 km on the continents and about 7 km below the ocean floor. 

This table gives the density p, pressure p, and acceleration due to gravity as a function of depth below the earth s surface, as calculated from the model of the structure of the earth in Reference 1. The model assumes a radius of 6371 km for the earth. The boundary between the crust and mantle (the Mohorovicic discontinuity) is taken as 21 km, while in reality it varies considerable with location. 

Present technology permits experimentation at steady-state pressures of up to about 400,000 atm [ ]. By such techniques, workers have converted graphite into diamond, studied the miscibility of quartz and water, produced metallic sulfur, and performed many other just as exciting experiments. The solid state phase transition of feldspar into jade, which occurs at very near the temperature and pressure conditions at the Mohorovicic Discontinuity, has been cited in discussions of the famous Mohole Project. 

Fig. 15.11 This cross-section of the crust of West and East Antarctica was drawn along line A-B in Fig. 15.10 using the contours of crustal thickness of a diagram by Bentley (1983). The profile of crustal thickness indicates the depth to the Mohorovicic Discontinuity (Moho) which separates the continental crust of Antarctica from the lithospheric mantle below. This cross-section demonstrates that the crust of West Antarctica is thinner than the crust of East Antarctica and that the transition is abrupt which suggests the presence of a fault zone or suture. The vertical exaggeration is 40x. The crustal thicknesses were derived from gravity anomalies by Groushinsky and Sazhina (1982)...

The profile of the crustal thickness of parts of West and East Antarctica in Fig. 15.11 indicates the complementary depth to the Mohorovicic Discontinuity (Moho) and illustrates the increase of the crustal thickness at the boundary between West and East Antarctica. The structure of the crust of Antarctica was also investigated by Dewart and Toksoz (1965), Jankowski and Drewry (1981), Kurinin and Grikurov (1982), and by... 

The sharp boundary existing between the bottom of the Earth s crust and the upper mantle that was first identified in 1909 by the Croatian seismologist Andriaja Mohorovicic by a clear change in the velocity of P seismic waves is called the Mohorovicic discontinuity or simply Moho. 

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