Can lower mantle slab-like seismic anomalies be explained by thermal coupling between the upper and lower mantles?

Details Can lower mantle slab-like seismic anomalies be explained by thermal coupling between the upper and lower mantles? Can lower mantle slab-like seismic anomalies be explained by thermal coupling between the upper and lower mantles?

May 1999

adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=1999georl..26.1501c&link_type=abstract

Geophysical Research Letters, Volume 26, Issue 10, p. 1501-1504

Physics

7

Tectonophysics: Dynamics Of Lithosphere And Mantle-General, Tectonophysics: Dynamics, Convection Currents And Mantle Plumes, Tectonophysics: Heat Generation And Transport

Scientific paper

Below subduction zones, high resolution seismic tomographic models resolve fast anomalies that often extend into the deep lower mantle. These anomalies are generally interpreted as slabs penetrating through the 660-km seismic discontinuity, evidence in support of whole-mantle convection. However, thermal coupling between two flow systems separated by an impermeable interface might provide an alternative explanation of the tomographic results. We have tested this hypothesis within the context of an axisymmetric model of mantle convection in which an impermeable boundary is imposed at a depth of 660 km. When an increase in viscosity alone is imposed across the impermeable interface, our results demonstrate the dominant role of mechanical coupling between shells, producing lower mantle upwellings (downwellings) below upper mantle downwellings (upwellings). However, we find that the effect of mechanical coupling can be significantly weakened if a narrow low viscosity zone exists beneath the 660-km discontinuity. In such a case, both thermally induced `slabs' in the lower mantle and thermally activated plumes that rise from the upper/lower mantle boundary are observed even though mass transfer between the shells does not exist.

Affiliated with

Also associated with

No associations

Rating

Can lower mantle slab-like seismic anomalies be explained by thermal coupling between the upper and lower mantles? 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 lower mantle slab-like seismic anomalies be explained by thermal coupling between the upper and lower mantles?, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Can lower mantle slab-like seismic anomalies be explained by thermal coupling between the upper and lower mantles? will most certainly appreciate the feedback.

Rate now

Comments { 0 }

Profile ID: LFWR-SCP-O-1125409