Stability of magnesite and its high-pressure form in the lowermost mantle

  title={Stability of magnesite and its high-pressure form in the lowermost mantle},
  author={Maiko Isshiki and Tetsuo Irifune and Kei Hirose and Shigeaki Ono and Yasuo Ohishi and Tetsu Watanuki and Eiji Nishibori and Masaki Takata and Makoto Sakata},
Carbonates are important constituents of marine sediments and play a fundamental role in the recycling of carbon into the Earth's deep interior via subduction of oceanic crust and sediments. Study of the stability of carbonates under high pressure and temperature is thus important for modelling the carbon budget in the entire Earth system. Such studies, however, have rarely been performed under appropriate lower-mantle conditions and no experimental data exist at pressures greater than 80 GPa… 
Fate of carbonates within oceanic plates subducted to the lower mantle, and a possible mechanism of diamond formation
We report on high-pressure and high-temperature experiments involving carbonates and silicates at 30–80 GPa and 1,600–3,200 K, corresponding to depths within the Earth of approximately 800–2,200 km.
Experimental investigation of the stability of Fe‐rich carbonates in the lower mantle
The fate of carbonates in the Earth's mantle plays a key role in the geodynamical carbon cycle. Although iron is a major component of the Earth's lower mantle, the stability of Fe-bearing carbonates
Fate of Carbonates in the Earth’s Mantle (10-136 GPa)
Earth carbon cycle shapes the evolution of our planet and our habitats. As a key region of carbon cycle, subduction zone acts as a sole channel transporting supracrustal carbonate rocks down to the
Magnesite formation from MgO and CO2 at the pressures and temperatures of Earth’s mantle
Abstract Magnesite (MgCO3) is an important phase for the carbon cycle in and out of the Earth’s mantle. Its comparably large P-T stability has been inferred for several years based on the absence of
Structures of dolomite at ultrahigh pressure and their influence on the deep carbon cycle
Dolomite-III does not decompose up to the melting point and its thermodynamic stability demonstrates that this complex phase can transport carbon to depths of at least up to 1,700 km, and is a likely occurring phase in areas containing recycled crustal slabs, which are more oxidized and Ca-enriched than the primitive lower mantle.
Stability of iron-bearing carbonates in the deep Earth’s interior
Fe4C4O13 is stable at conditions along the entire geotherm to depths of at least 2,500 km, thus demonstrating that self-oxidation-reduction reactions can preserve carbonates in the Earth’s lower mantle.
Reversal of carbonate-silicate cation exchange in cold slabs in Earth’s lower mantle
Experiments in this study demonstrate that at deep mantle conditions MgCO3 reacts with silicates to form CaCO3, and allow us to predict that the signature of surface carbon reaching Earth’s lowermost mantle may include Ca CO3.
The fate of carbonate in oceanic crust subducted into earth's lower mantle


Evidence from ultra-high-pressure marbles for recycling of sediments into the mantle
ROCKS of crustal origin metamorphosed at ultra-high pressures (P>2.5 GPa) have been described from several orogenic belts1–5. In the western Alps, for example, ultra-high pressure rocks originally
Lower Mantle Mineral Associations Preserved in Diamonds
The composition of the Earth's mantle inferred from carbonaceous chondrites and also from solar energetic particles and spectroscopy, is hugely dominated by SiO2 and MgO, with subordinate but
Genesis of diamonds in the lower mantle
Abstract The “forbidden” assemblage (ferropericlase + enstatite) as inclusions in diamonds has been taken as evidence to imply that these inclusions and their host diamonds formed initially in the
Stability of Magnesite under the Lower Mantle Conditions
High-pressure and high-temperature stability of MgCO3 magnesite was investigated using a lever and spring type of diamond anvil cell up to 55GPa at about 1300°C. No phase transformation was observed
Stability Of Magnesite (MgCO3) At Mantle Pressure And Temperature Conditions - A Raman-Spectroscopic Study
The stability of magnesite (MgCO3) has been studied by Raman spectroscopy at high pressure and high temperature using a diamond-anvil cell heated by a CO2 laser. Raman spectra up to 32 GPa at room
Stability and equation of state of Fe3C to 73 GPa: Implications for carbon in the Earth's core
We have measured the volume and lattice parameters of Fe3C‐cementite as a function of pressure to 73 GPa using synchrotron‐based x‐ray diffraction. Several samples were laser heated and
Carbonation and melting reactions in the system CaO–MgO–SiO2–CO2 at mantle pressures with geophysical and petrological applications
Bowen's petrogenetic grid was based initially on a series of decarbonation reactions in the system CaO-MgO-SiO2-CO2 with starting assemblages including calcite, dolomite, magnesite and quartz, and