کد مقاله | کد نشریه | سال انتشار | مقاله انگلیسی | نسخه تمام متن |
---|---|---|---|---|
4678398 | 1634845 | 2010 | 9 صفحه PDF | دانلود رایگان |
عنوان انگلیسی مقاله ISI
High-temperature compression of ferropericlase and the effect of temperature on iron spin transition
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کلمات کلیدی
موضوعات مرتبط
مهندسی و علوم پایه
علوم زمین و سیارات
علوم زمین و سیاره ای (عمومی)
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چکیده انگلیسی
High-temperature compression experiments with in situ X-ray diffraction of ferropericlase (Fp) with a composition of (Mg0.81Fe0.19)O were made in a laser-heated diamond anvil cell to pressures (P) of 116Â GPa at a constant temperature (T) of 1600-1900Â K. Room-temperature experiments with a laser annealing technique were also carried out on the same material. Anomalous unit-cell volume reductions that can be explained by the spin transition of ferrous iron were observed at PÂ =Â 63-96Â GPa and 45-63Â GPa at TÂ =Â 1600-1900Â K and 300Â K, respectively, indicating that the spin transition pressure interval expands with increasing temperature. The observed density changes across this spin transition at TÂ =Â 1600-1900Â K and 300Â K are about 1.6% and 1.0%, respectively, indicating that the spin transition pressure interval expands with increasing temperature. The thermal expansivity of Fp is large in the mid-lower mantle due to the effect of the spin transition. In a peridotitic composition, the spin transition in Fp increases the rock density by 0.35% at the lowermost mantle conditions. Calculated densities show that both perovskitic and peridotitic mantle models may explain the PREM lower mantle density. However, the peridotitic lower mantle model requires less assumption to satisfy the PREM density and is more self-consistent.
ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: Earth and Planetary Science Letters - Volume 297, Issues 3â4, 1 September 2010, Pages 691-699
Journal: Earth and Planetary Science Letters - Volume 297, Issues 3â4, 1 September 2010, Pages 691-699
نویسندگان
Tetsuya Komabayashi, Kei Hirose, Yukio Nagaya, Emiko Sugimura, Yasuo Ohishi,