Abstract
One of the principal means of understanding upper mantle dynamics involves inferring mantle flow directions from seismic anisotropy under the assumption that the seismic fast direction (olivine a axis) parallels the regional flow direction. We demonstrate that (i) the presence of melt weakens the alignment of a axes and (ii) when melt segregates and forms networks of weak shear zones, strain partitions between weak and strong zones, resulting in an alignment of a axes 90° from the shear direction in three-dimensional deformation. This orientation of a axes provides a new means of interpreting mantle flow from seismic anisotropy in partially molten deforming regions of Earth.
Original language | English (US) |
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Pages (from-to) | 1227-1230 |
Number of pages | 4 |
Journal | Science |
Volume | 301 |
Issue number | 5637 |
DOIs | |
State | Published - Aug 29 2003 |