Geoscience Reference
In-Depth Information
High-Pressure Studies of Earth Materials
With the advent of dedicated synchrotron beamlines and other modern
technologies, it has become possible to document the properties of Earth
materials in situ, at the high pressures and temperatures of the planet's deep
interior. Measuring the elastic properties that determine seismic wave velocities;
the density, thermal conductivity, and rheological properties that control
geodynamic motions; and the partitioning of minor and trace elements that
produce the geochemical signatures observed in rock samples is now possible at
deep-Earth conditions. First-principles quantum and statistical mechanical
calculations are also offering significant theoretical insights into the chemical and
physical properties of materials throughout the mantle and core. Thus, the seismic
anisotropy of the inner core, the possible chemical and physical interactions at the
core-mantle boundary, the distribution of radioactive heat-producing elements,
and the initiation of melting (or crystallization) throughout the Earth are all
subject to quantitative study over the coming decade. The abundance and
distribution of water and other “volatile” molecules within the planet, as well as
their cycling between the surface and interior over geological history, can be
evaluated for the first time. These are specific examples of the broader question
now being addressed through high-pressure studies; What is the current state of
the Earth's interior, and what are the processes by which it evolved to this state?
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