Single crystal elasticity of natural topaz at high-temperatures

Abstract

Topaz is an aluminosilicate mineral phase stable in the hydrothermally altered pegmatitic rocks and also in subducted sedimentary lithologies. In nature, topaz often exhibits solid solution between fluorine and hydrous end members. We investigated elasticity of naturally occurring single crystal topaz (Al2SiO4F1.42(OH)0.58) using Resonant Ultrasound Spectroscopy. We also explored the temperature dependence of the full elastic constant tensor. We find that among the various minerals stable in the Al2O3-SiO2-H2O ternary system, topaz exhibits moderate elastic anisotropy. As a function of temperature, the sound velocity of topaz decreases with and being −3.10 and −2.30 × 10−4 km/s/K. The elasticity and sound velocity of topaz also vary as a function of OH and F content. The effect of composition () on the velocity is equally important as that of the effect of temperature. We also note that the Debye temperature () of topaz at room temperature condition is 910 K and decreases at higher temperature. The Debye temperature shows positive correlation with density of the mineral phases in the Al2O3-SiO2-H2O ternary system.

The Anomalous Seismic Behavior of Aqueous Fluids Released during Dehydration of Chlorite in Subduction Zones

“…Unlike melting, in which mineral phases are [40]. The decrease in Vp and vs. with the incorporation of Fe in chlorite was in agreement with the effect that Fe had on elastic wave velocities of mantle minerals [41][42][43][44][45]. The incorporation of Fe resulted in an increase in density from 2.60 gcm −3 of Fe-free verity [40] to 2.761 gcm −3 in our sample, which represented a 6% increase in density at ambient conditions.…”

First-principles calculations of electronic structure and optical and elastic properties of the novel ABX3-type LaWN3perovskite structure

“…Elasticity is not only related to mechanical stability, but is also closely related to Debye temperature, specic heat, wave velocity and other physical property parameters. [51][52][53] For hexagonal LaWN 3 , there are six independent elastic constants (C 11 , C 33 , C 44 , C 12 , C 13 and C 66 ). Due to the lack of comparable elastic constants for LaWN 3 , other functional materials (CaCO 3 , cubic-SrZrO 3 and a-SrZrO 3 ) are calculated to compare with previous calculation results to judge the correctness of calculation methods used.…”

Topaz, a Potential Volatile-Carrier in Cold Subduction Zone: Constraint from Synchrotron X-ray Diffraction and Raman Spectroscopy at High Temperature and High Pressure

“…Topaz with a chemical formula of Al 2 [SiO 4 ](F,OH) 2 is an important aluminosilicate mineral containing water and fluorine. Furthermore, fluorine-bearing topaz mainly occurs in fluorine-rich pegmatite, while the hydroxyl topaz group mainly occurs in ultra-high-pressure metamorphic rocks [26]. The proportion of F and OH in topaz is above 20 wt.%, while the molar ratio of OH in OH and F (X OH = OH/(OH + F)) is generally less than 0.5 [27][28][29][30].…”