Record Details

Title:
Pressure-induced amorphization in plagioclase feldspars: A time-resolved powder diffraction study during rapid compression
Affiliation(s):
EuXFEL staff, Other
Author group:
Instrument HED
Keyword(s):
Topic:
Abstract:
The pressure-induced amorphization of the two endmembers of the plagioclase $((Na_{1−x}Ca_{x})Al_{1+x}Si_{3−x}O_{8})$ solid-solution, anorthite $(CaAl_{2}Si_{2}O_{8})$ and albite $(NaAlSi_{3}O_{8})$, has been studied as a function of compression rate by means of time-resolved powder diffraction. Anorthite and albite were compressed in a diamond anvil cell to 80 GPa at multiple rates from 0.05 GPa/s to 80 GPa/s. The amorphization pressure decreases with increasing compression rate. This negative strain rate sensitivity indicates a change in deformation mechanism in the plagioclase solid-solution endmembers from brittle to ductile with increasing compression rate. The presented data support the previously proposed shear deformation mechanism for the amorphization of plagioclase. Furthermore, amorphization progresses over a wide pressure range suggesting heterogeneous amorphization, similar to observations based on recovered material from shock-compression experiments of plagioclase. Our experiments support the contention that amorphization pressures for plagioclase may occur at lower pressures than usually considered.
Imprint:
Elsevier, 2019
Journal Information:
Earth and Planetary Science Letters, 507, 166-174 (2019)
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Language(s):
English
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