Universal P-V-T Equation of State for Periclase.pdfVIP

Universal P-V-T Equation of State for Periclase Jozsef Garai, Department of Earth Sciences and Department of Mechanical and Materials Engineering, Florida International University, Miami, USA Jiuhua Chen Department of Mechanical and Materials Engineering, Florida International University, Miami, USA Helene Couvy Department of Mechanical and Materials Engineering, Florida International University, Miami, USA Gabor Telekes Ybl Miklós Faculty of Architecture and Civil Engineering, St. István University, Budapest, Hungary [1] Using previous experiments of periclase, covering a pressure and temperature range of 0- 141.8 GPa and 298-3086 K respectively, a universal P-V-T equation of state has been derived for MgO. The root-main-square misfits of the EoS are 0.021 cm3, 0.404 GPa and 66.2 K for the molar volume, pressure and temperature respectively. The presented EoS is valid through the entire pressure and temperature range of the Earth’s mantle and allows calculating any of the variables in a convenient way for any kind of mantle modeling. 1. Introduction [2] Periclase is the end member of the (Mg,Fe)O solid solution series, and Mg-rich ferropericlase is the second most abundant component of the Earth’s lower mantle (Stixrude et al. 1992; Jackson, 1998) its interest in geophysics is then significant. Additionally, MgO has low chemical reactivity and it is stable in large pressure and temperature range which makes an ideal pressure calibrant. Precise description of the pressure, volume and temperature (P-V-T) relationship of MgO is therefore essential. Previous investigations used the conventional definitions of the bulk modulus and the volume coefficient of thermal expansion. Both of these coefficients are pressure and temperature dependent; therefore, it is necessary knowing the derivatives of these parameters. These derivatives are also pressure and temperature dependent which makes the P-V-T description of