Bischofite movies
  The bischofite and carnallite experiments were described in detail in Urai (1987). These experiments were carried out using samples cut from coarse grained natural samples. The experiments were done with a pore fluid of saturated aqeous solution, in a closed system with a moving seal between the glass plates. These movies were recorded in 1982 at the Institute for Earth Sciences, Utrecht University.

1 Twinning in dry Bischofite single crystal

This experiment starts with a single crystal of bischofite, without a pore fluid. It is shortened horizontally, and develops a set of twin lamellae. With further shortening the twin lamellae widen and coalesce into a completely twinned crystal, except in the right side of the sample where the early formation of a second twin set prevents twinning to go to completion. Field of view is approximately 3 mm.

 

2 Deformation of wet Bischofite

In the presence of a saturated solution, bischofite recrystallizes readily at room temperature. This movie was taken from a deformation experiment using wet bischofite, at 80 degrees C and 5x10-5 s-1 strain rate. It was described in detail in Urai (1987).

Several interesting features can be seen, such as the large changes in migration rate of the grain boundaries (fast and slow migration), twinning of newly grown grains, and the oscillatory motion of grain boundaries.

The figure shown corresponds to the second frame of fig. 5 in Urai (1987). Old grains (C and D for example) and a string of finer recrystallized grains formed during sample preparation (B) are features of the starting material. Grain A is a recrystallized grain studied in detail in fig. 6 of Urai (1987).

 
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