AGU journal highlights -- March 12, 2009
The following highlights summarize research papers that have been published in Geophysical Research Letters (GRL).
In this release:
- Exploring how corals build their skeletons
- Earth cyclones may help explain Venusian vortices
- Model relates South Polar ozone concentrations and wind patterns
- Laboratory crystals give clues to deep Earth puzzle
- Spacecraft characterize perturbations that can affect orbiting satellites
Anyone may read the scientific abstract for these papers by clicking on the link provided at the end of each Highlight. You can also read the abstract by going to http://www.agu.org/pubs/search_options.shtml and inserting into the search engine the full doi (digital object identifier), e.g. 10.1029/ 2008GL036782. The doi is found at the end of each Highlight below.
Journalists and public information officers (PIOs) at educational or scientific institutions, who are registered with AGU, also may download papers cited in this release by clicking on the links below.
Contact: Maria-Jose Vinas
mjvinas@agu.org
202-777-7530
American Geophysical Union
Source:
- http://www.eurekalert.org/pub_releases/2009-03/agu-ajh031209.php
- http://www.eurekalert.org/bysubject/space.php
==========
Laboratory crystals give clues to deep Earth puzzle
Perovskite is the major mineral phase in the lower mantle—it dominates the seismic properties and viscous deformation of the deep Earth. At high pressures and temperatures, perovskite transforms into an altered crystal-packing form called postperovskite. The region where the transformation occurs, known as the D'' layer, is directly above the core-mantle boundary and is distinguished by large seismic velocity jumps. Using forms of a synthetic, solid compound containing calcium, iridium and oxygen as analogs for perovskite and postperovskite, Walte et al. conduct laboratory experiments to simulate the perovskite transitions under high temperatures and pressures. Expanding on past research that demonstrated that crystal lattice orientations in the analog postperovskite alter when deformed, the authors find that the transformation of the analog perovskite to analog postperovskite itself yields a crystal lattice structure different from postperovskite deformation textures. If the analogue between the compound used in the experiments and the perovskite crystal-packing system holds true, such lattice orientation transitions may explain the observed seismic jumps. On a more local level, the fast spikes in certain seismic velocities may be explained by downwelling material that underwent these observed crystal lattice transformations.
In this release:
- Exploring how corals build their skeletons
- Earth cyclones may help explain Venusian vortices
- Model relates South Polar ozone concentrations and wind patterns
- Laboratory crystals give clues to deep Earth puzzle
- Spacecraft characterize perturbations that can affect orbiting satellites
Anyone may read the scientific abstract for these papers by clicking on the link provided at the end of each Highlight. You can also read the abstract by going to http://www.agu.org/pubs/search_options.shtml and inserting into the search engine the full doi (digital object identifier), e.g. 10.1029/ 2008GL036782. The doi is found at the end of each Highlight below.
Journalists and public information officers (PIOs) at educational or scientific institutions, who are registered with AGU, also may download papers cited in this release by clicking on the links below.
Contact: Maria-Jose Vinas
mjvinas@agu.org
202-777-7530
American Geophysical Union
Source:
- http://www.eurekalert.org/pub_releases/2009-03/agu-ajh031209.php
- http://www.eurekalert.org/bysubject/space.php
==========
Laboratory crystals give clues to deep Earth puzzle
Perovskite is the major mineral phase in the lower mantle—it dominates the seismic properties and viscous deformation of the deep Earth. At high pressures and temperatures, perovskite transforms into an altered crystal-packing form called postperovskite. The region where the transformation occurs, known as the D'' layer, is directly above the core-mantle boundary and is distinguished by large seismic velocity jumps. Using forms of a synthetic, solid compound containing calcium, iridium and oxygen as analogs for perovskite and postperovskite, Walte et al. conduct laboratory experiments to simulate the perovskite transitions under high temperatures and pressures. Expanding on past research that demonstrated that crystal lattice orientations in the analog postperovskite alter when deformed, the authors find that the transformation of the analog perovskite to analog postperovskite itself yields a crystal lattice structure different from postperovskite deformation textures. If the analogue between the compound used in the experiments and the perovskite crystal-packing system holds true, such lattice orientation transitions may explain the observed seismic jumps. On a more local level, the fast spikes in certain seismic velocities may be explained by downwelling material that underwent these observed crystal lattice transformations.
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