Sound Velocities in Shock‐Synthesized Stishovite to 72 GPa
Sound Velocities in Shock‐Synthesized Stishovite to 72 GPa
复制标题
冲击合成 Stishovite 中的声速可达 72 GPa
DOI：
10.1029/2019gl085301
复制
发表时间：
2019
影响因子：
5.2
通讯作者：
T. Duffy
中科院分区：
文献类型：
--
作者：
Eleanor J. Berryman;J. M. Winey;Y. Gupta;T. Duffy
斯季肖维特（金红石型SiO2）是致密硅酸盐的原型，可能出现在下地幔条件下的后石榴石榴辉岩中。在stishovite声速是了解其在高压和高温下的力学和热力学行为的基础。在这里，我们使用平板冲击实验结合速度干涉测量法来确定应力，密度和纵向声速在石英在44 GPa及以上的冲击压缩过程中形成。测得的声速范围从43.8（8）GPa时的12.3（8）km/s到72.7（11）GPa时的9.8（4）km/s。在64 GPa下观察到的减少反映了stishovite的剪切模量的减少，可能是由于熔融的开始。到72 GPa时，测得的声速与理论体声速一致，表明由于完全熔化而损失了所有剪切刚度。我们的声速结果为冲击诱导熔化提供了直接证据，与以前的高温测量数据一致。
Stishovite (rutile‐type SiO2) is the archetype of dense silicates and may occur in postgarnet eclogitic rocks at lower‐mantle conditions. Sound velocities in stishovite are fundamental to understanding its mechanical and thermodynamic behavior at high pressure and temperature. Here, we use plate‐impact experiments combined with velocity interferometry to determine the stress, density, and longitudinal sound speed in stishovite formed during shock compression of fused silica at 44 GPa and above. The measured sound speeds range from 12.3(8) km/s at 43.8(8) GPa to 9.8(4) km/s at 72.7(11) GPa. The decrease observed at 64 GPa reflects a decrease in the shear modulus of stishovite, likely due to the onset of melting. By 72 GPa, the measured sound speed agrees with the theoretical bulk sound speed indicating loss of all shear stiffness due to complete melting. Our sound velocity results provide direct evidence for shock‐induced melting, in agreement with previous pyrometry data.
影响因子：
8.6
作者：
S. Tracy;S. Turneaure;T. Duffy
通讯作者：
S. Tracy;S. Turneaure;T. Duffy
影响因子：
56.9
作者：
Millot, M.;Dubrovinskaia, N.;Jeanloz, R.
通讯作者：
Jeanloz, R.