کد مقاله | کد نشریه | سال انتشار | مقاله انگلیسی | نسخه تمام متن |
---|---|---|---|---|
8915738 | 1641465 | 2018 | 8 صفحه PDF | دانلود رایگان |
عنوان انگلیسی مقاله ISI
Negative activation volume of oxygen self-diffusion in forsterite
ترجمه فارسی عنوان
حجم فعال سازی منفی خود-نفوذ اکسیژن در فورستریت
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کلمات کلیدی
موضوعات مرتبط
مهندسی و علوم پایه
علوم زمین و سیارات
فیزیک زمین (ژئو فیزیک)
چکیده انگلیسی
Oxygen self-diffusion coefficients (DOx) were measured in single crystals of dry synthetic iron-free olivine (forsterite, Mg2SiO4) at a temperature of 1600â¯K and under pressures in the range 10â4 to 13â¯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 â3.9â¯Â±â¯1.2â¯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 â¼10â¯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, DOxâ¯+â¯DMg in forsterite decreases with increasing pressure, and then increases slightly at pressures greater than 10â¯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 â¼300â¯km depth to the bottom of the asthenosphere.
ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: Physics of the Earth and Planetary Interiors - Volume 275, February 2018, Pages 1-8
Journal: Physics of the Earth and Planetary Interiors - Volume 275, February 2018, Pages 1-8
نویسندگان
Hongzhan Fei, Michael Wiedenbeck, Naoya Sakamoto, Hisayoshi Yurimoto, Takashi Yoshino, Daisuke Yamazaki, Tomoo Katsura,