Structure and Dynamics of Earth's Lower Mantle
2008; American Association for the Advancement of Science; Volume: 320; Issue: 5876 Linguagem: Inglês
10.1126/science.1148028
ISSN1095-9203
AutoresEdward J. Garnero, A. K. McNamara,
Tópico(s)earthquake and tectonic studies
ResumoProcesses within the lowest several hundred kilometers of Earth's rocky mantle play a critical role in the evolution of the planet. Understanding Earth's lower mantle requires putting recent seismic and mineral physics discoveries into a self-consistent, geodynamically feasible context. Two nearly antipodal large low-shear-velocity provinces in the deep mantle likely represent chemically distinct and denser material. High-resolution seismological studies have revealed laterally varying seismic velocity discontinuities in the deepest few hundred kilometers, consistent with a phase transition from perovskite to post-perovskite. In the deepest tens of kilometers of the mantle, isolated pockets of ultralow seismic velocities may denote Earth's deepest magma chamber.
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