کد مقاله کد نشریه سال انتشار مقاله انگلیسی نسخه تمام متن
8915729 1641464 2018 13 صفحه PDF دانلود رایگان
عنوان انگلیسی مقاله ISI
The anisotropic signal of topotaxy during phase transitions in D″
موضوعات مرتبط
مهندسی و علوم پایه علوم زمین و سیارات فیزیک زمین (ژئو فیزیک)
پیش نمایش صفحه اول مقاله
The anisotropic signal of topotaxy during phase transitions in D″
چکیده انگلیسی
While observations and modelling of seismic anisotropy in the lowermost mantle offers the possibility of imaging mantle flow close to the core-mantle boundary, current models do not explain all observations. Here, we seek to explain a long-wavelength pattern of shear wave anisotropy observed in anisotropic tomography where vertically polarised shear waves travel faster than horizontally polarised shear waves in the central Pacific and under Africa but this pattern is reversed elsewhere. In particular, we test an explanation derived from experiments on analogues, which suggest that texture may be inherited during phase transitions between bridgmanite (perovskite structured MgSiO3) and post-perovskite, and that such texture inheritance may yield the long-wavelength pattern of anisotropy. We find that models that include this effect correlate better with tomographic models than those that assume deformation due to a single phase in the lowermost mantle, supporting the idea that texture inheritance is an important factor in understanding lowermost mantle anisotropy. It is possible that anisotropy could be used to map the post-perovskite stability field in the lowermost mantle, and thus place constraints on the temperature structure above the core-mantle boundary.
ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: Physics of the Earth and Planetary Interiors - Volume 276, March 2018, Pages 159-171
نویسندگان
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