Seeing the mantle in the round

Article Abstract:

Several long-standing puzzles concerning the structure of the Earth's mantle may be resolved by using three-dimensional geometry combined with the hypothesis of an endothermic phase transformation at a depth of 670 kilometer (km). Experiments showed that the observed seismic velocity variation at the depth of 670 km is consistent with a phase transformation of the gamma-spinel phase of olivine to perovskite. Three-dimensional calculations predict 'flushing events' to the lower mantle following accumulation of downwelling material. These accumulations could result in observed seismic anomalies.

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Probing Earth's dynamo

Article Abstract:

The Earth, like most planets in the Solar System, has a magnetic field originating from a self-sustaining dynamo. However, the inner workings of planetary magnetism remain obscured by the inability to build laboratory-scale dynamos because they require large volumes of conducting fluids. A new numerical dynamo model successfully imitates many of the characteristics observed in the Earth's magnetic field. It is shown that the earth's solid iron inner core is crucial in the dynamics of the whole core.

Geomagnetism, Geomagnetic fields

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Deep thoughts on the mantle

Article Abstract:

A new report links mantle temperature and composition theories, finding that two diverse methods for calculating the temperature agree. Some problems remain, although they may be due to inadequate tomographic resolution. Temperature anomalies should persist beyond 110 km deep, where they seem to peter out. Two different inversions, used in tandem, may best explain these results, giving a correlation down to 400 km.

Research, Earth temperature, Earth's temperature

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