First principles investigation of the elasticity of serpentine minerals

蛇纹石矿物在将水输送到地球深处的过程中起着重要作用。在本研究中，蜥蜴石和反长岩（调制m = 16和17）的结构和弹性已被确定为第一性原理计算高达约12 GPa。结果表明，反长岩的片理面倾斜会使其极化方向发生剧烈变化，且海沟正向极化各向异性随压力增大而增大。结果表明，在弧后区域观测到的约0.2 s的海沟正向极化各向异性也可以用10 ~ 20 km厚的蛇纹化断层来解释。目前的研究还表明，蛇纹石将水输送到100多公里深的地球深处。

Serpenine minerals play important role for the transportation of water into Earth's deep interiors. In this study, the structure and elasticity of lizardite and antigorite (modulation m = 16 and 17) have been determined by first principles calculation up to about 12 GPa. We found that the polarization direction is drastically changed by tilting the foliation plane of antigorite and the trench normal polarization anisotropy increases with pressure. As the result, trench normal polarization anisotropy about 0.2 s observed in the back-arc region can also be explained by the preferably oriented serpentinized fault about 10-20 km thick. The present study also suggests that serpentine transports water more than 100 km depth into the deep earth's interior.