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Updated: Jul 29, 2026

Simulation of the Planetary Interior Differentiation Processes in the Laboratory
Published on: November 16, 2013
Deep mantle structure and the postperovskite phase transition
1Seismological Laboratory, California Institute of Technology, Pasadena, CA 91125, USA. helm@gps.caltech.edu
Abstract:
Seismologists have known for many years that the lowermost mantle of the Earth is complex. Models based on observed seismic phases sampling this region include relatively sharp horizontal discontinuities with strong zones of anisotropy, nearly vertical contrasts in structure, and small pockets of ultralow velocity zones (ULVZs). This diversity of structures is beginning to be understood in terms of geodynamics and mineral physics, with dense partial melts causing the ULVZs and a postperovskite solid-solid phase transition producing regional layering, with the possibility of large-scale variations in chemistry. This strong heterogeneity has significant implications on heat transport out of core, the evolution of the magnetic field, and magnetic field polarity reversals.
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