Thermal Equation Of State Of Magnesite

Recent studies showed that the surface carbon can be transported to the Earth's deep interior via the sinking subduction slabs.Due to the low solubility of carbon in mantle silicates,carbon has been regarded to stored as accessory minerals in the Earth 's mantle,such as carbonates,diamond,carbides,etc.Magnesite(MgCO3)is one of the most important carbonates in the Earth.Experimental studies on the high-pressure physical properties of MgCO3 are thus important of understanding the carbon transportation and storage in the Earth's deep interior.In this study,we performed high pressure-temperature X-ray diffraction measurements on the natural magnesite using laser-heated diamond anvil cells up to 100 GP and xxx K.We noted that MgCO3 stayed in the magnesite structure at the investigated pressure-temperature range.Using the obtained pressure-volume relationships,we have obtained the thermal elastic parameters of MgCO3using the a Mie-Griineisen equation of state.With KT'=4(fixed),Debye temperature ?D0=750 K(fixed),and q=1(fixed),we obtain KT0=1 14.3(4)GPa,?0=1.75,and V0=280.71A3.In order to compare with previous data,we re-calculate the pressure of previous literature using a self-consistent pressure scale to provide more reliable pressure-volume-temperature relationships of magnesite.The obtain thermodynamic parameters enables us to model the density and velocity of the magnesite under the high pressure and high temperature of the lower mantle.