کد مقاله | کد نشریه | سال انتشار | مقاله انگلیسی | نسخه تمام متن |
---|---|---|---|---|
6447460 | 1641484 | 2016 | 10 صفحه PDF | دانلود رایگان |
عنوان انگلیسی مقاله ISI
Phase relations in the system MgSiO3-Al2O3 up to 52Â GPa and 2000Â K
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کلمات کلیدی
موضوعات مرتبط
مهندسی و علوم پایه
علوم زمین و سیارات
فیزیک زمین (ژئو فیزیک)
پیش نمایش صفحه اول مقاله
چکیده انگلیسی
Phase relations in the system MgSiO3-Al2O3 have been determined for pressures from 15 to 52Â GPa and at a temperature of 2000Â K from in situ synchrotron X-ray diffraction measurements obtained using sintered diamond anvils in a multi-anvil apparatus. A wide two-phase region of garnet and corundum is found to exist up to 27Â GPa; at higher pressures, a phase assemblage of aluminous bridgmanite and corundum is stabilized. The solubility of Al2O3 in bridgmanite and that of MgSiO3 in corundum are highly dependent on pressure; the Al2O3 content in bridgmanite increases from 12Â mol% at 27Â GPa to 29Â mol% at 52Â GPa, forming bridgmanite with the pyrope composition (25Â mol% Al2O3) at about 45Â GPa. In contrast, the MgSiO3 content in corundum decreases from 24Â mol% at 27Â GPa to 9Â mol% at 52Â GPa. The minimum pressure where the pyropic bridgmanite is formed is significantly higher than the result of the earlier study (â¼37Â GPa) on the pyrope composition. These results suggest the Al2O3 content in bridgmanite and the MgSiO3 content in corundum are good pressure indicators in the mixed-phase region at pressures above 30Â GPa, where virtually no pressure references are available for quench experiments. The new phase diagram in the system MgSiO3-Al2O3 confirms that bridgmanite is the dominant host mineral for Al2O3 in the pyrolitic or peridotitic compositions under the pressure and temperature conditions of the Earth's lower mantle.
ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: Physics of the Earth and Planetary Interiors - Volume 257, August 2016, Pages 18-27
Journal: Physics of the Earth and Planetary Interiors - Volume 257, August 2016, Pages 18-27
نویسندگان
Zhaodong Liu, Tetsuo Irifune, Masayuki Nishi, Yoshinori Tange, Takeshi Arimoto, Toru Shinmei,