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| Titel |
Techniques of Elastic Properties Measurements under Simulated Earth's Mantle Conditions |
| VerfasserIn |
Hans J. Mueller, Joern Lauterjung, Frank R. Schilling, Christian Lathe, Michael Wehber |
| Konferenz |
EGU General Assembly 2010
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| Medientyp |
Artikel
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| Sprache |
Englisch
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 12 (2010) |
| Datensatznummer |
250037794
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| Zusammenfassung |
| The Earth’s mantle has a mass of about 4.08 . 1021 tons and represents 68 % of the total mass
of the Earth. It is only accessible by indirect methods, above all seismological studies. The
interpretation of seismic data from the Earth’s deep interior requires measurements of the
physical properties of Earth materials under experimental simulated mantle conditions. The
simulation of these in situ conditions require high pressure techniques - diamond
anvil cells (DAC), multi-anvil devices (MAD) and mostly synthetical samples.
MADs are more limited in pressure, but provide sample volumes 3 to 7 orders of
magnitude bigger. They also offer small and even adjustable temperature gradients over
the whole sample. The bigger samples make anisotropy and structural effects in
complex systems accessible for measurements in principle. The measurement of both
elastic wave velocities have also no limits for opaque and encapsulated samples.The
ultrasonic interferometry allows the highly precise travel time measurement at a sample
enclosed in a high-pressure multi-anvil device. Under high pressure conditions
the influence of sample deformation is so important that ultrasonic interferometry
requires the exact sample deformation measurement under in situ conditions using
synchrotron radiation. There is a promising way to increase the maximum pressure of
multi-anvil devices by multi-staging, i.e. implementation of additional sub-anvil
set-ups resulting in a better distribution and limitation of the stress inside the anvils.
Contrary to the common opinion of overshooting the maximum crushing strength
most of the anvils fail in high pressure experiments due to the exceeding of the
maximum tensile stress as a result of the lateral deformation. We present recent
techniques and results of elastic properties measurements performed at different
multi-anvil devices. That comprises standard-free pressure measurements, transient
experiments, multi-cycle and multi-staging experiments as well as melt studies. |
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