地幔不同深度单斜辉石含水量的高压实验

Experiment study on water contents of clinopyroxene at different depth in the mantle

摘要: 在1.5~5GPa、1100~1200℃条件下开展了含水大陆碱性玄武岩的熔融实验研究。通过红外光谱分析其中单斜辉石的结构水，计算得到其量为1173(153)×10-6～2049(197)×10-6。结果表明：当P＜3GPa时，随着压力增大，单斜辉石的含水量逐渐增加，在3GPa附近达到峰值，之后随着压力的增大单斜辉石含水量又逐渐减少。单斜辉石含水量随压力的这种变化关系可能受单斜辉石中Al含量的影响。该研究为了解上地幔不同深度处水的分布提供了实验证据。

Abstract: The melt experiments using the Continental Alkali Basalt + 6wt.% deionized water were conducted at 1.5-5GPa and1100－1200℃.The Fourier Transform Infrared Spectroscopy was used to analyze the water content of clinopyroxene. The value varied from1173(153)×10-6~2049(197)×10-6. The results indicated that the water content of clinopyroxene increased with pressure below 3.0GPa, while it decreased with pressure above 3.0 GPa. The relationship between the water content and the pressure was probably influenced by Al concentration of clinopyroxene. This study provided some evidences to understand the water distribution at different depth in the upper mantle.