【摘要】 橄榄石在高温高压条件下分解为钙钛矿和方镁石（后尖晶石相变）,这是地幔中最为重要的相变之一,被认为是660KM地震波速间断面的成因。现今所取得的重要进展表现在3个方面:①MG₂SI O₄的后尖晶石相变的原位X射线高温高压实验研究;②水、AL₂O₃以及压力标尺对后尖晶石相变的影响效应;③下地幔条件下地幔岩组分中的后尖晶石相变。在对研究进展进行概述的基础上,对目前存在的问题进行了分析并提出未来可能的研究方向。更多还原

【Abstract】 Ringwoodite, one of the high-pressure and high-temperature forms of olivine, can be decomposed into perovskite and periclase （post-spinel phase transformation）. The process, which seems to be one of the most important transformations in the Earth′s mantle, is believed to be the cause of the 660-km seismic discontinuity dividing the mantle into upper and lower parts. The advances made in the researches are shown in three aspects: ① post-spinel phase transformation of Mg₂SiO₄ at high pressure and high temperature using in situ X-ray diffraction; ② the effects of H₂O, Al₂O₃ and equation of state of gold on the post-spinel phase transformation; ③ the post-spinel phase transformation in peridotite under lower mantle conditions. On the basis of a summary of recent advances, this paper analyzes the existing problems and indicates possible directions for further studies.更多还原