Negative activation volume of oxygen self-diffusion in forsterite

Fei, Hongzhan; Wiedenbeck, Michael; Sakamoto, Naoya; Yurimoto, Hisayoshi; Yoshino, Takashi; Yamazaki, Daisuke; Katsura, Tomoo

doi:10.1016/j.pepi.2017.12.005

Item

ITEM ACTIONSEXPORT

Add to Basket

Local TagsRelease HistoryDetailsSummary

Released

Journal Article

Negative activation volume of oxygen self-diffusion in forsterite

Authors

Fei, Hongzhan
External Organizations;

/persons/resource/michawi

Wiedenbeck, Michael
3.1 Inorganic and Isotope Geochemistry, 3.0 Geochemistry, Departments, GFZ Publication Database, Deutsches GeoForschungsZentrum;

Sakamoto, Naoya
External Organizations;

Yurimoto, Hisayoshi
External Organizations;

Yoshino, Takashi
External Organizations;

Yamazaki, Daisuke
External Organizations;

Katsura, Tomoo
External Organizations;

External Ressource

No external resources are shared

Fulltext (public)

There are no public fulltexts stored in GFZpublic

Supplementary Material (public)

There is no public supplementary material available

Citation

Fei, H., Wiedenbeck, M., Sakamoto, N., Yurimoto, H., Yoshino, T., Yamazaki, D., Katsura, T. (2018): Negative activation volume of oxygen self-diffusion in forsterite. - Physics of the Earth and Planetary Interiors, 275, 1-8.
https://doi.org/10.1016/j.pepi.2017.12.005

Cite as: https://gfzpublic.gfz-potsdam.de/pubman/item/item_2956909

Abstract

Oxygen self-diffusion coefficients (DOx) were measured in single crystals of dry synthetic iron-free olivine (forsterite, Mg2SiO4) at a temperature of 1600 K and under pressures in the range 10−4 to 13 GPa, using a Kawai-type multi-anvil apparatus and an ambient pressure furnace. Diffusion profiles were obtained by secondary ion mass spectrometry operating in depth profiling mode. DOx in forsterite increases with increasing pressure with an activation volume of −3.9 ± 1.2 cm3/mol. Although Mg is the fastest diffusing species in forsterite under low-pressure conditions, O is the fastest diffusing species at pressures greater than ∼10 GPa. Si is the slowest throughout the stable pressure range of forsterite. Based on the observed positive and negative pressure dependence of DOx and DMg (Mg self-diffusion coefficient), respectively, DOx + DMg in forsterite decreases with increasing pressure, and then increases slightly at pressures greater than 10 GPa. This behavior is in agreement with the pressure dependence of ionic conductivity in forsterite based on conductivity measurements (Yoshino et al., 2017), and can be used to explain the conductivity increase from ∼300 km depth to the bottom of the asthenosphere.