Diffusion Creep in Perovskite: Implications for the Rheology of the Lower Mantle
Diffusion Creep in Perovskite: Implications for the Rheology of the Lower Mantle
复制标题
DOI：
10.1126/science.255.5049.1238
复制
发表时间：
1992-03
期刊：
影响因子：
56.9
通讯作者：
S. Karato;Ping Li
中科院分区：
文献类型：
--
作者：
S. Karato;Ping Li
高温蠕变实验的多晶钙钛矿（CaTiO 3），（Mg，Fe）SiO3钙钛矿的下地幔的类似物，表明（晶粒尺寸敏感）扩散蠕变是重要的下地幔，并显示蠕变速率提高的正交四斜晶系结构的转变。这些观察结果表明，俯冲板片通过670公里的不连续性或钙钛矿从斜方晶系到四方晶系的相变后，晶粒尺寸减小将导致下地幔顶部的流变软化。
High-temperature creep experiments on polycrystalline perovskite (CaTiO3), an analog of (Mg,Fe)SiO3 perovskite of the lower mantle, suggest that (grain size-sensitive) diffusion creep is important in the lower mantle and show that creep rate is enhanced by the transformation from the orthorhombic to the tetragonal structure. These observations suggest that grain-size reduction after a subducting slab passes through the 670-kilometer discontinuity or after a phase transformation from orthorhombic to tetragonal in perovskite will result in rheological softening in the top portions of the lower mantle.