Resistance to mantle flow inferred from the electromagnetic strike of the Australian upper mantle

摘要: Seismic anisotropy is thought to result from the strain-induced lattice-preferred orientation of mantle minerals, especially olivine1,2, owing shear waves propagating faster along a-axis olivine crystals than other axes. This results in birefringence, or ‘shear-wave splitting’3, which has been investigated numerous studies1,4. Although also anisotropic with respect electrical conductivity5 (with being most conductive), few studies upper have undertaken, and these limited relatively shallow depths lithospheric mantle6,7. Theoretical models flow used infer that, for progressive simple imparted by motion an overriding tectonic plate, a-axes should align themselves parallel direction plate motion8,9. Here, however, we show that a significant discrepancy exists between electromagnetic strike below Australia present-day absolute motion10. We this are not aligned Australia, indicating resistance deformation motion.