Institute of Geology and
Dynamics of the Lithosphere at the
University of
Göttingen
International Conference on
Textures and Physical Properties of
Rocks
October 13 (Wed) to 16 (Sat), 1999 in
Göttingen, Germany
WORKSHOP 2:
Alexander Frischbutter & Kurt Walther (Potsdam), Christian Scheffzük (Dubna):
Diffraction methods for strain measurements on geological samples
A better understanding of the strain-stress-texture behaviour of rocks is
required to improve interpretations of the recent stress field of the earth's crust,
for instance by adding a new quality of data for modelling. Neutron-time-of-flight
diffraction was shown to be a very suitable tool to determine the complete
strain-stress tensor especially for geological samples, because of the high
penetration depth of neutrons and the simultanously measured complete lattice
plane ensemble.
Deepsensitive strain scans may contribute to our knowlegde regarding the effects
of residual stresses in rocks. Results of diffraction experiments under defined
applied load on polymineralic rocks can help to estimate second order stresses,
which are not influenced by any preparation-like processes (even uplift of crustal
blocks). The discussion shall help to formulate the experimental and theoretical
requirements of the method as well as to concrete their possibilities for
geoscientific problems.
Specific topics:
- Experimental procedures and devices (EPSILON and EXSTRESS at beam 7a of the impulsed
reactor IBR-2 JINR Dubna) for strain measurements by diffraction methods (not
excluding others) and how to get measuring time there.
- Strain-stress-texture relations from the theoretical point of view.
- Processing of experimental data
- Results and interpretation of diffraction experiments
without and under applied load as well as on mono- and polymineralic rocks
Oral contributions, posters and software-demonstrations are welcome.
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