Abstract
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. The experiments are intended to represent the decomposition process of carbonates contained within oceanic plates subducted into the lower mantle. In basaltic composition, CaCO3 (calcite and aragonite), the major carbonate phase in marine sediments, is altered into MgCO3 (magnesite) via reactions with Mg-bearing silicates under conditions that are 200–300°C colder than the mantle geotherm. With increasing temperature and pressure, the magnesite decomposes into an assemblage of CO2 + perovskite via reactions with SiO2. Magnesite is not the only host phase for subducted carbon—solid CO2 also carries carbon in the lower mantle. Furthermore, CO2 itself breaks down to diamond and oxygen under geotherm conditions over 70 GPa, which might imply a possible mechanism for diamond formation in the lower mantle.
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Akahama Y, Kawamura H (2004) High-pressure Raman spectroscopy of diamond anvil to 250 Gpa: method for pressure determination in the multimegabar pressure range. J Appl Phys 96:3748–3751
Akahama Y, Kawamura H, Hausermann D, Hanfland M, Shimomura O (1995) New high-pressure structural transition of oxygen at 96 GPa associated with metallization in a molecular-solid. Phys Rev Lett 74:4690–4693
Andrault D, Angel RJ, Mosenfelder JL, Le Bihan T (2000) Equation of state of stishovite to lower mantle pressures. Am Mineral 88:301–307
Biellmann C, Gillet P, Guyot F, Peyronneau J, Reynard B (1993) Experimental evidence for carbonate stability in the Earth’s lower mantle. Earth Planet Sci Lett 118:31–41
Dasgupta R, Hirschmann MM, Dellas N (2005) The effect of composition on the solidus of carbonated eclogite from partial melting experiments at 3 GPa. Contrib Mineral Petrol 149:288–305
Fiquet G, Guyot F, Kunz M, Matas J, Andrault D, Hanfland M (2002) Structural refinements of magnesite at very high-pressure. Am Mineral 87:1261–1265
Hammouda T (2003) High-pressure melting of carbonated eclogite and experimental constraints on carbon recycling and storage in the mantle. Earth Planet Sci Lett 214:357–368
Hirose K, Fei Y, Ma Y, Mao H (1999) The fate of subducted basaltic crust in the Earth’s lower mantle. Nature 397:53–56
Hirose K, Takafuji N, Sata N, Ohishi Y (2005) Phase transition and density of subducted MORB crust in the lower mantle. Earth Planet Sci Lett 237:239–251
Iota V, Yoo CS (2001) Phase diagram of carbon dioxide: evidence for new associated phase. Phys Rev Lett 86:5922–5925
Isshiki M, Irifune T, Hirose K, Ono S, Ohishi Y, Watanuki T, Nishibori E, Takata M, Sakata M (2003) Stability of magnesite and its high-pressure form in the lowermost mantle. Nature 427:60–63
Kaminsky FV, Zakharchenko OD, Davies R, Griffin WL, Khachatryan-Blinova GK, Shiryaev A (2001) Superdeep diamonds from the Juina area, Mato Grosso State, Brazil. Contrib Mineral Petrol 140:734–753
Liu L-G (1999) Genesis of diamonds in the lower mantle. Contrib Mineral Petrol 134:170–173
Luth RW (2001) Experimental determination of the reaction aragonite + magnesite = dolomite at 5–9 GPa. Contrib Mineral Petrol 141:222–232
Morlidge M, Pawley A, Droop G (2006) Double carbonate breakdown reactions at high-pressures: an experimental study in the system CaO–MgO–FeO–MnO–CO2. Contrib Mineral Petrol 152:365–373
McCammon C (2001) Deep diamond mysteries. Science 293:813–814
McCammon C (2006) Microscopic properties to macroscopic behavior: the influence of iron electronic state. J Mineral Petrol Sci 101:130–144
Nishio-Hamane D, Nagai T, Fujino K, Seto Y, Takafuji N (2005) Fe3+ and Al solubilities in MgSiO3 perovskite: implication of the Fe3+AlO3 substitution in MgSiO3 perovskite at the lower mantle condition. Geophys Res Lett 32:L16306. doi :10.1029/2005GL023529
Occelli F, Loubeyre P, Letoullec R (2003) Properties of diamond under hydrostatic pressures up to 140 GPa. Nat Mater 2:151–154
Perterrmann M, Hirschmann MM (2003) Partial melting experiments on a MORB-like pyroxenite between 2 and 3 GPa: constraints on the presence of pyroxenite in basalt source regions from solidus location and melting rate. J Geophys Res 108(B2):10. doi :1029/2000JB000118
Ringwood AE, Irifune T (1988) Nature of the 650-km seismic discontinuity: implications for mantle dynamics and differentiation. Nature 331:131–136
Sano Y, Williams NS (1996) Fluxes of mantle and subducted carbon along convergent plate boundaries. Geophys Res Lett 23:2749–2752
Sato K, Katsura T (2001) Experimental investigation on dolomite dissociation into aragonite plus magnesite up to 8.5 Pa. Earth Planet Sci Lett 184:529–534
Shim S-H, Duffy TS (2000) Constraints on the P–V–T equation of state of MgSiO3 perovskite. Am Mineral 85:354–363
Stacey FD (1992) Physics of the Earth. (3rd edn.) Brookfield Press, Brisbane
Stachel T, Harris JW, Brey GP, Joswig W (2000) Kankan diamonds (Guinea) II: lower mantle inclusion parageneses. Contrib Mineral Petrol 140:16–27
Takafuji N, Nagai T, Fujino K, Seto Y, Hamane D (2006) Decarbonation reaction of magnesite in subducting slabs at the lower mantle. Phys Chem Mineral 33:651–654
Tschauner O, Mao H, Hemley R (2001) New transformations of CO2 at high-pressures and temperatures. Phys Rev Lett 87:75701-1–75701-4
Yaxley GM, Brey GP (2004) Phase relations of carbonate-bearing eclogite assemblages from 2.5–5.5 GPa: implications for petrogenesis of carbonatites. Contrib Mineral Petrol 146:606–619
Yoo CS, Cynn H, Gygi F, Galli G, Iota V, Nicol M, Carlson S, Hausermann D, Mailhiot C (1999) Crystal structure of carbon dioxide at high-pressure: “superhard” polymeric carbon dioxide. Phys Rev Lett 83:5527–5530
Acknowledgments
X-ray observations were conducted at SPring-8 (BL10XU, proposal No. 2006B1184, 2007A1510) and KEK-PF (BL13A, proposal No. 2005G143). This research was supported by a MEXT Grant-in-Aid for the 21st century COE Program on “Neo-Science of Natural History” at Hokkaido University, Japan. Y.S. and D.H. are also supported by JSPS research fellowship.
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Seto, Y., Hamane, D., Nagai, T. et al. Fate of carbonates within oceanic plates subducted to the lower mantle, and a possible mechanism of diamond formation. Phys Chem Minerals 35, 223–229 (2008). https://doi.org/10.1007/s00269-008-0215-9
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DOI: https://doi.org/10.1007/s00269-008-0215-9