冯华俊;吴耀;金振民;

• 1:中国地质大学地质过程与矿产资源国家重点实验室

摘要(Abstract)：

前人研究表明410km和660km地震不连续面分别由橄榄石向瓦兹利石相变和后尖晶石相变引起。但对520km地震不连续面(简称D520)的研究相对较少,对其成因的解释还存在很大争议。橄榄石中瓦兹利石-林伍德石相变以及CaSiO3钙钛矿的出溶反应被广泛认为是D520的相变成因。辉石相变为尖晶石+斯石英组合也曾被认为是D520的可能成因。1 400℃条件下对MgSiO3辉石相变的实验研究,结合前人对橄榄石相变的研究成果,计算了方辉橄榄岩在1 400℃、18GPa条件下因辉石-瓦兹利石+斯石英和瓦兹利石-林伍德石相变引起的密度增量和波速增量,发现俯冲方辉橄榄岩中辉石的相变对520km深度的密度增量和波速增量有很大的贡献,有助于形成D520。此外,在探讨D520的成因时应综合考虑地幔转换带中温度,水以及矿物间Fe、Mg、Ca等主量元素分配等因素的影响。

关键词(KeyWords)： 地幔转换带;520km地震不连续面;地震观测;高温高压实验

Abstract:

Keywords:

基金项目(Foundation): 中国深部探测项目(Sinoprobe-0801);; 国家自然科学基金项目(41174076)

作者(Author): 冯华俊;吴耀;金振民;

Email:

DOI:

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