下地幔深部压力条件下顽火辉石Perovskite(MgSiO3)的冲击诱导相变

最近的计算机模拟分析和静高压实验结果都证实了钙钛矿顽火辉石Perovsk ite(M g-S iO3)在下地幔条件下发生了后钙钛矿相变(post—perovsk ite)。通过对顽火辉石动态高压实验Hugon iot数据进行分析,结果发现Perovsk ite(M gS iO3)在冲击压力为120G pa时(相当于下地幔压力)密度发生了系统性跳跃,增大了1.5%,于是我们推测顽火辉石在冲击波实验中也可能出现后钙钛矿相变,进一步的分析得到在2500K和109GPa条件下的C lapeyron斜率为4.0±0.4M Pa/k,其值和最近所得到的静高压实验、分子动力学模拟以及地球物理观测所得到的数据有很好的一致性。

Shock-induced Transition of Perovskite(MgSiO3) under the Pressure of the Low Mantle

Recently,it has been proved that Perovskite(MgSiO_3)was transited into post—perovskite under the pressure of the earth's low mantle by the experiments of static high—pressure and MD(molecular dynamics simulation).Through the analysis of Hugonint data from shock experiments of Perovskite(MgSiO_3),a systematic jump of the density was observed and increased(1.5%) when shock—pressure was 120Gpa(consistent with the pressure of the low mantle).So we presume there is post—perovskite phase transition in shock experiments too.More detailed study showed a Clapeyron slope-4.0±4.0MPa/k at 2500k and 109GPa,the datum of which is consistent with that of static high—pressure experiment,MD and Geophysics observations.