Anomalous elasticity of talc at high pressures: Implications for subduction systems
نویسندگان
چکیده
• Talc is one of the most elastically anisotropic minerals in subduction zone settings. Talc-bearing lithology can readily explain ultra-slow velocity, high V P / S ratio, and large delay time. Pressure dependence components elastic constant tensor exhibits anomalous behavior. a layered hydrous silicate mineral that plays vital role transporting water into Earth’s interior crucial for explaining geophysical observations In this study, we explored structure, equation state, elasticity both triclinic monoclinic talc under pressures up to 18 GPa using first principles simulations based on density functional theory corrected dispersive forces. Our results indicate principal full C 11 22 , shear 66 several off-diagonal show pressure dependence. This non-monotonic likely related structural changes often manifested polytypic transition from low-pressure polytype talc-I high-pressure talc-II. The occurs at within its thermodynamic stability. However, bulk moduli no softening. study also shows has low extremely anisotropy, anomalously thus making it potential candidate phase could unusually ratio wave splitting delays as observed seismological studies many systems.
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ژورنال
عنوان ژورنال: Geoscience frontiers
سال: 2022
ISSN: ['2588-9192', '1674-9871']
DOI: https://doi.org/10.1016/j.gsf.2022.101381