Electrical conductivity of the Earth's lower mantle

Details Electrical conductivity of the Earth's lower mantle Electrical conductivity of the Earth's lower mantle

Dec 1993

adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=1993natur.366..453s&link_type=abstract

Nature, Volume 366, Issue 6454, pp. 453-455 (1993).

Physics

45

Scientific paper

THE electrical conductivity of the Earth's lower mantle constrains both the propagation to the surface of geomagnetic disturbances in the core and the nature of core-mantle coupling. Extrapolations of laboratory measurements on materials representative of the lower mantle agree weakly1,2 or not at all3,4 with recent geophysical models5-8 of lower-mantle electrical conductivity based on variations of magnetic and electrical fields measured at the Earth's surface. Here we report d.c. conductivity measurements on samples with compositions approximating that of the lower mantle, at pressures of 1.2 to 40 GPa and temperatures in the range 20 to 400 °C. Our results agree with some of those obtained previously1,2. But in contrast to this previous work, we extrapolate the results to lower-mantle conditions by adopting a functional form for the conductivity that incorporates the effect of pressure as well as temperature. The resulting estimates of conductivity are in agreement with the geophysical determinations5-8. We find that, because of a very weak dependence on temperature, pressure and composition, the conductivity is likely to vary by no more than about a factor of five across the entire lower mantle, reaching a maximum value of only 3-10 S m-1. Lateral temperature variations as large as a few hundred degrees will therefore be hard to detect geophysically, and the compositionally distinct D'' layer at the base of the lower mantle remains the only possible location for a highly conducting layer.

Affiliated with

Also associated with

No associations

Rating

Electrical conductivity of the Earth's lower 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 Electrical conductivity of the Earth's lower mantle, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Electrical conductivity of the Earth's lower mantle will most certainly appreciate the feedback.

Rate now

Comments { 0 }

Profile ID: LFWR-SCP-O-1300948