Topaz was previously considered as a typical hydrothermal mineral, and topaz greisen a typically altered rock. However, the geological and geochemical evidence in recent years has made it clear that the layer-like top...Topaz was previously considered as a typical hydrothermal mineral, and topaz greisen a typically altered rock. However, the geological and geochemical evidence in recent years has made it clear that the layer-like topaz greisen at the top of Ta- and Nb-bearing展开更多
Subducting oceanic sediments and crusts,originating from the Earth's surface and descending into its deep interior,are important carriers of volatiles.The volatiles have significant effects on materials cycling an...Subducting oceanic sediments and crusts,originating from the Earth's surface and descending into its deep interior,are important carriers of volatiles.The volatiles have significant effects on materials cycling and the dynamic evolution of the subduction zones.A simplified Al_(2)O_(3)-SiO_(2)-H_(2)O(ASH)ternary system models the relationship of minerals in the hydrated and alumina-silica rich sedimentary layer.Topaz Al_(2)SiO_(4)(F,OH)_(2)is an important mineral in the ASH system and comprises two volatiles:H_(2)O and fluorine(F).In this study,the thermoelasticity of a natural F-rich topaz was investigated using synchrotron-based single-crystal X-ray diffraction combined with diamond anvil cells up to 29.1 GPa and 750 K.The pressure-volume-temperature data were fitted to a third-order Birch-Murnaghan Equation of state with V_(0)=343.15(7)Å3,K_(0)=166(1)GPa,K_(0)'=3.0(1),(∂K_(0)/∂T)P=-0.015(9)GPa/K andα_(0)=3.9(5)×10^(-5)K^(-1).The isothermal bulk modulus increases with the F content in topaz,and the various F contents present significant effects on its anisotropic compressibility.Our results further reveal that the isothermal bulk modulus K_(0)of the minerals in ASH system increases with density.F and H contents in hydrous minerals might greatly affect their properties(e.g.,compressibility and stability),providing more comprehensive constraints on the subduction zones.展开更多
Blue colored topaz is one of the most recognized gemstones worldwide.However,it is rarely found in the field and the products have been made mostly in laboratory using gamma,neutron and electron irradiation or combina...Blue colored topaz is one of the most recognized gemstones worldwide.However,it is rarely found in the field and the products have been made mostly in laboratory using gamma,neutron and electron irradiation or combinations of these devices.Origin of the blue color in topaz remains not well understood, largely due to a lack of nondestructive way in idnetifying the blue topaz.Here we report a compari-展开更多
基金National Natural Science Foundation of ChinaState Key Laboratory on Mineral Deposit Research,Nanjing University.
文摘Topaz was previously considered as a typical hydrothermal mineral, and topaz greisen a typically altered rock. However, the geological and geochemical evidence in recent years has made it clear that the layer-like topaz greisen at the top of Ta- and Nb-bearing
基金financial support from the National Science Foundation of China(No.41827802)supported by the National Science Foundation-Earth Sciences(No.EAR-1634415)+2 种基金the Department of Energy,Geosciences(No.DE-FG0294ER14466)supported by DOE-BES(No.DE-AC0206CH11357)supported in part by COMPRES under NSF Cooperative Agreement EAR-1661511。
文摘Subducting oceanic sediments and crusts,originating from the Earth's surface and descending into its deep interior,are important carriers of volatiles.The volatiles have significant effects on materials cycling and the dynamic evolution of the subduction zones.A simplified Al_(2)O_(3)-SiO_(2)-H_(2)O(ASH)ternary system models the relationship of minerals in the hydrated and alumina-silica rich sedimentary layer.Topaz Al_(2)SiO_(4)(F,OH)_(2)is an important mineral in the ASH system and comprises two volatiles:H_(2)O and fluorine(F).In this study,the thermoelasticity of a natural F-rich topaz was investigated using synchrotron-based single-crystal X-ray diffraction combined with diamond anvil cells up to 29.1 GPa and 750 K.The pressure-volume-temperature data were fitted to a third-order Birch-Murnaghan Equation of state with V_(0)=343.15(7)Å3,K_(0)=166(1)GPa,K_(0)'=3.0(1),(∂K_(0)/∂T)P=-0.015(9)GPa/K andα_(0)=3.9(5)×10^(-5)K^(-1).The isothermal bulk modulus increases with the F content in topaz,and the various F contents present significant effects on its anisotropic compressibility.Our results further reveal that the isothermal bulk modulus K_(0)of the minerals in ASH system increases with density.F and H contents in hydrous minerals might greatly affect their properties(e.g.,compressibility and stability),providing more comprehensive constraints on the subduction zones.
文摘Blue colored topaz is one of the most recognized gemstones worldwide.However,it is rarely found in the field and the products have been made mostly in laboratory using gamma,neutron and electron irradiation or combinations of these devices.Origin of the blue color in topaz remains not well understood, largely due to a lack of nondestructive way in idnetifying the blue topaz.Here we report a compari-
