Effects of an endothermic phase transition at 670 km depth in a spherical model of convection in the Earth's mantle
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.
Publication Name: Nature
Subject: Zoology and wildlife conservation
ISSN: 0028-0836
Year: 1993
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Atmospheric cellular convection
Article Abstract:
Clouds in the atmospheres of Venus and Earth are too dissimilar for convection in both to be attributed to the same cause. The hypothesis that the atmospheres are like each other in structure is flawed by the doubtful assumption that cellular formation on Venus can be inferred from the aspect or width/vertical depth ratio. However, the hypothesis that the two atmospheres share similar convective mechanisms justifies further observations to confirm or refute it.
Publication Name: Nature
Subject: Zoology and wildlife conservation
ISSN: 0028-0836
Year: 1992
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A doubling of the post-perovskite phase boundary and structure of the Earth's lowermost mantle
Article Abstract:
The dynamical state and history of planet Earth can be understood by studying the thermal structure of the Earth's lowermost mantle, the D" layer. The study shows that a pair of seismic discontinuities observed in some regions of D" can be explained by the same phase transition as the result of a double-crossing of the phase boundary.
Publication Name: Nature
Subject: Zoology and wildlife conservation
ISSN: 0028-0836
Year: 2005
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