Physics
Scientific paper
Apr 1984
adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=1984pepi...34...77r&link_type=abstract
Physics of the Earth and Planetary Interiors, Volume 34, Issue 1-2, p. 77-84.
Physics
15
Scientific paper
Viscosity-depth profiles in the Earth's mantle are estimated on the basis of microrheological equations for ultrabasic silicates, the preliminary reference Earth model (PREM), and two assumed geotherms (one with, and one without, a lower mantle upper thermal boundary layer). The estimation includes assessment of variations of creep parameters with depth.
Both constant-strain rate non-linear viscosity and Newtonian viscosity are in the range 1020-1021 Pa s in the upper mantle. In the lower mantle, there is a moderate increase in viscosity with depth, and upper limit estimates are of the order of 1022 and 1023 Pa s, respectively. As uncertainties are +/-one order of magnitude, the Newtonian-viscosity mantle inferred from geophysical observations cannot be rejected on the strength of rheological considerations.
By the same token, convection should be mantle-wide, as the viscosity layering is not sufficient to prevent it. On the other hand, if the mantle is chemically stratified, and separate convective circulations exist in the upper and lower mantle, the thermal boundary layer below the 670-km discontinuity should have a discernible viscosity signature.
Fischer Baruch
Ranalli Giorgio
No associations
LandOfFree
Diffusion creep, dislocation creep, and mantle rheology 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 Diffusion creep, dislocation creep, and mantle rheology, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Diffusion creep, dislocation creep, and mantle rheology will most certainly appreciate the feedback.
Profile ID: LFWR-SCP-O-1501158