Phase Transitions in the Earth's Mantle: Implications for the Nature of the 410-km and 670-km Discontinuities

拟议的研究将通过使用补充高压技术（高温金刚石砧室和多砧装置）来确定与410 km和670 km地震不连续性相关的相位关系。 橄榄石改性的尖晶石和尖晶石=钙钛矿+镁橄榄石过渡系统Mg 2SiO 4-Fe 2SiO 4将确定原位同步辐射X射线测量与高温金刚石电池。 用高温金刚石电池精确测定尖晶石向钙钛矿加镁橄榄石和钛铁矿向钙钛矿转变的斜率。 通过在多砧装置中采用高分辨率和高效率的多室样品室设计，首次考察了α-β转变压力和两相区宽度的组分效应。 预期的结果将用于评估两个间断的性质，410公里间断的尖锐度是否与两相区的宽度一致，以及是否可以根据与670公里间断有关的过渡的斜率发生整个地幔对流。

9418945 Fei The proposed research will determine phase relations relevant to the 410-km and 670-km seismic discontinuities by using complementary high-pressure techniques (high- temperature diamond-anvil cell and multi-anvil apparatus). The olivine-modified spinel and the spinel = perovskite + magnesiowustite transitions in the system Mg2SiO4-Fe2SiO4 will be determined by in situ synchrotron x-ray measurements with a high temperature diamond cell. The slopes of the transformations of spinel to perovskite plus magnesiowustite and of ilmentie to perovskite will be precisely determined with the high temperature diamond cell. The compositional effect of the alpha-beta transition pressure and width of the two-phase region will be examined for the first time by using high-resolution and high-efficiency multi-cell sample chamber design in multi-anvil apparatus. The expected results will be used to evaluate the nature of the two discontinuities,whether the sharpness of the 410-km discontinuity is consistent with the width of the two phase region, and whether whole mantle convection can occur based on the slope of the transitions related to the 670-km discontinuity.