High-pressure on the structure and dynamics of the deep earth's interior.

绘制了Mg_2SiO_4-Fe_2SiO_4系橄榄石改性尖晶石和尖晶石后相变的详细相图。地幔尖晶石在小于4公里的深度范围内分解为钙钛矿(PV)和镁铝尖晶石(MW)，使650公里的不连续变得尖锐。这一特征提供了650公里深度的地幔温度的固定点，并提出了上地幔的标准温度剖面。对下行板的动力特性进行了分析。深源地震的特征可以用相边界的扭曲引起的作用在平板上的下沉和浮力来很好地解释。并指出，700kM深度附近地震活动的突然消失是由于与PV和Mv的击穿组合有关的超塑性。在25 Gpa和2000ﾟC下进行的MgCO_3和MgCO_3-MgSiO_3体系的亚固相线和熔融实验结果表明，…此外，在大于140公里的深度，CO_2不再以挥发性组分的形式存在，而是以菱镁矿的形式固定，CO_2通过火成作用逐渐释放到大气中。通过研究CO2在高P和高T时在H2O流体中的溶解度，讨论了考虑俯冲作用的CO2循环过程。在2 5 0 0ﾟC和2 3 GPa时，硅酸镁PV完全熔化，其dtm/dp斜率约为2 5ﾟ/Gpa。MgO-FeO-SiO_2系的熔融过程表现为PV与MW之间的共晶熔融。值得注意的是，共晶成分在SiO_2中比在过渡带条件下更富，并且随着深度的进一步增加，成分在SiO_2中更富集。熔融实验扩展到了芯材。结果表明，在高于15 Gpa的压力下，SiO_2组分从硅酸盐熔体中溶解到铁水中，且随着压力的增加，溶解作用增强。结果表明，可能作为堆芯热源的钾也溶解于铁水中。这些结果使得建立一个一致地解释外核的轻元素以及与地球冷却有关的核的演化和D^1层的形成的核形成模型成为可能。较少

The detailed phase diagrams of the olivine-modified spinel-spinel and the post spinel transformations, were constructed for the system Mg_2SiO_4-Fe_2SiO_4. The mantle spinel dissociates into perovskite (Pv) and magnesiowustite (Mw) within a depth interval less than 4 km making the 650 km discontinuity be sharp. This feature provide a fixed point of mantle temperature at 650 km depth and a standard temperature profile of the upper mantle was proposed. The dynamic nature of descending slabs was analyzed. The characteristics of deep focused earthquakes are well explained in terms of plunging and buoyant forces acting on the slabs caused by the distortions of phase boundaries. It was also pointed out that the sudden disappearance of seismic activity around 700 km depth would be due to the superplasticity associated with the breakdown assemblage of Pv and Mw.Results of subsolidus and melting experiments on MgCO_3 and the system MgCO_3-MgSiO_3 conducted up to 25 GPa and 2000 ﾟC revealed that … More , in the depths greater than 140 km, CO_2 no longer behaves as a volatile component but is fixed as magnesite, and that CO_2 is progressively released into the atmosphere by the igneous process. Examination of the solubility of CO_2 into H_2O fluid at high P and T made it possible to discuss the recycling process of CO_2 by taking the subduction into consideration.Extensive effort was focused on the melting relations of the lower mantle materials. MgSiO_3 Pv melts congruently at about 2500 ﾟC and 23 GPa with a dTm/dP slope of about 25ﾟ/GPa. The melting reration of the MgO-FeO-SiO_2 system exhibits a eutectic melting between Pv and Mw. It should be noteworthy that the eutectic composition is richer in SiO_2 than that found in the conditions of the transition zone and the composition is enriched in SiO_2 under further increase of depth. Melting experiments were extended to the core materials. It was demonstrated that SiO_2 component dissolves into molten iron from silicate melts at pressures higher than 15 GPa and the dissolution is enhanced by the increasing pressure. It was shown that potassium, a possible candidate as heat source in the core, also dissolves into molten iron. These results make it possible to construct a core formation model which consistently account for the light elements of the outer core, and the evolution of the core and the formation of the D^1 layer associated with cooling of the earth. Less