Physics – Geophysics
Scientific paper
May 1994
adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=1994rvgeo..32..115m&link_type=abstract
Reviews of Geophysics (ISSN 8755-1209), vol. 32, no. 2, p. 115-137
Physics
Geophysics
65
Convection, Earth Mantle, Earth Planetary Structure, Geotemperature, Plates (Tectonics), Seismology, Tomography, Geophysics, Heat Transfer, Mathematical Models
Scientific paper
The understanding of mantle convection is one of the most puzzling problems of modern geophysics. Among the different approaches used by geophysicists to investigate mantle convection, seismic tomography is the only one able to visualize, at the same time, temperature, petrological anomlalies, and flow directions from seismic velocity and anisotrophy heterogeneities. In order to enable a comparison with other geophysical observables, tomographic models are expanded into spherical harmonics. Most tomographic models agree that down to 300-400 km, deep structure is closely related to plate tectonics and continental distribution. Its corresponding spectral content regularly decreases with decreasing wavelength. At greater depths in the transition zone, degree 2 and (to a lesser extent) degree 6 distributions become predominant. A degree 2 pattern is also present in the lower mantle and is stongly correlated with the geoid but offset with respect to the degree 2 pattern of the transition zone. A simple flow pattern with two upgoing and two downgoing large-scale flows can be invoked to simply explain the predominance of degrees 2 and 6 for seismic velocity and degree 4 for radial anisotropy. Therefore below the apparent complexity of plate tectonics, it turns out that mantle convection is surprisingly simply organized in the transition zone. Generally, the mantle cannot be divided into independent convecting cells but is characterized by imbricated convection, where different scales coexist and where exchange of matter is possible. Therefore seismic tomography is able to provide very strong constraints on possible models of mantle convection, but many features are still unexplained. Only very long spatial wavelengths are well resolved so far, and a complete understanding of mantle dynamics necessitates relating the different scales present in convective processes.
No associations
LandOfFree
Can seismology tell us anything about convection in the mantle? does not yet have a rating. At this time, there are no reviews or comments for this scientific paper.
If you have personal experience with Can seismology tell us anything about convection in the mantle?, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Can seismology tell us anything about convection in the mantle? will most certainly appreciate the feedback.
Profile ID: LFWR-SCP-O-1681064