The theory of convection (from the Latin to carry with) in the earth's mantle is an attempt to explain how the internal energy, thermal or chemical, can be the cause of dynamic processes of geology and geophysics. The postulated flow is usually supposed to have a cellular pattern of large...
Observational evidence from glacial rebound and gravity anomalies shows that the mantle has a relatively uniform viscosity. Such a structure is consistent with the effects of temperature and pressure on microscopic mechanisms for plastic flow of solids. Thus the asthenosphere may extend to the base of...
This paper demonstrates the feasibility of using numerical calculations to determine the structure of convection cells within the mantle. A temperature and depth-dependent viscosity appropriate for diffusion creep is employed. The upper boundary is a rigid surface moving at constant speed; this boundary...
Geochemical picture of the mantle 1.The mantle is depleted in those elements that are found to be concentrated in crust, hydrosphere and atmosphere, relative to the original composition of the mantle. 2.Some material from crust, hydrosphere and atmosphere is re-injected into the mantle. 3.The ...
The stress field generated by mantle flows, except in the Tian Shan region, also coincide with the stress field of recent tectonic movement in China. The Tarim and Junggar basins are formed by tensional stresses due to divergent mantle convection currents under northwest China. The formation of ...
To investigate dynamical mechanisms that have been proposed to explain the geochemical evidence for the existence of several distinct chemical reservoirs, a recent trend has been towards mantle convection models that track the evolution of specific chemical species, both major and minor. The results of...
Planform of mantle convection beneath the Pacific Ocean, Nature , 288 , 442–446.McKenzie, D. , A. Watts , B. Parsons , M. Roufosse , Platform of mantle convection beneath the Pacific Ocean , Nature , 288 , 442 – 446 , 1980 ....
THE structure of convection in the mantle is still the subject of considerable debate. The now standard modelling of the convective flow as driven in a viscous mantle by density anomalies derived from seismic tomography has successfully explained the longest-wavelength (degree 2 to 8) geoid anomalie...
This chapter describes the models of mantle convection that have been confined to two-dimensional plane layers in Cartesian coordinates. Scientific interest in the subject of thermal convection was stimulated initially by the detailed laboratory experiments of Bénard, who observed steady cellular convection...
Convection Currents and the Mantle OBJECTIVES: Explain how heat is transferred Identify what causes convection currents Radiation The transfer of energy through empty space Example