How are Earth’s Internal Boundaries Affected by Dynamics, Temperature, and Composition?
How are Earth’s Internal Boundaries Affected by Dynamics, Temperature, and Composition? Figure 1
Maureen D. Long, Yale University/IRIS Consortium
Figure 1. Simplified illustration of the first-order anisotropic structure of the Earth, from Long and Becker (2010). The heavy blue lines in the center show average radial anisotropy in the mantle and core, with a possible mantle flow trajectory for a downwelling slab (blue) displacing a thermo-chemical pile (red) at the CMB shown as a dashed line. Anisotropic structure is most pronounced in the upper and lower boundary layers of the mantle, as well as the inner core. In the upper mantle, flow is primarily horizontal, except beneath upwellings and downwellings, which are associated with primarily vertical flow. At the base of the mantle, possible horizontal flow due to slab material impinging upon the CMB is shown, which may lead to anisotropy.
Long, M. D., Becker, T. W., 2010. Mantle dynamics and seismic anisotropy. Earth Planet. Sci. Lett., in press.
Schmerr, N., and E. Garnero, 2007. Topography on Earth's upper mantle discontinuities from dynamically induced thermal and chemical het- erogeneity, Science, 318, 623-626.
Date Taken: September 29, 2010
Photographer / Contributor: Maureen D. Long