Abstract
The structure and isothermal equation of state of aragonite were determined to 40 GPa using synchrotron single-crystal X ray techniques. In addition, powder diffraction techniques were used to determine thermal expansion between 298–673 K. At room temperature, aragonite has orthorhombic Pnma structure to 40 GPa, with an isothermal bulk modulus of 66.5(7) GPa and K′ = 5.0(1). Between 25–30 GPa the aragonite unit cell begins to distort due to a stiffening of the c-axis compressibility, which is controlled by the orientation and distortion of the carbonate groups. The ambient pressure thermal expansion measurements yielded thermal expansion coefficients a0 = 4.9(2) × 10–5 and a1 = 3.7(5) × 10–8. The combined results allow the derivation of a thermal equation of state. The new data provide constraints on the behavior of carbonates and carbon cycling in the Earth’s crust and mantle.
Acknowledgments
Thanks to the Deep Carbon Observatory for providing travel assistance for S. Palaich. This work was funded in part by NSF EAR-0969033 and DOE NNSA Stewardship Science Graduate Fellowship to S. Palaich, DOE DE-FG02-10ER16136. ESRF and Elettra facilities are acknowledged for provision of beamtime. Paolo Lotti is acknowledged for help in the experimental activity.
References Cited
Angel, R.J., Gonzalez-Platas, J., and Alvaro, M. (2014) EosFit7c and a Fortran module (library) for equation of state calculations. Zeitschrift für Kristallographie, 30, 405–419.10.1515/zkri-2013-1711Search in Google Scholar
Antao, S.M., and Hassan, I. (2010) Temperature dependence of the structural parameters in the transformation of aragonite to calcite, as determined from in situ synchrotron powder X ray-diffraction data. Canadian Mineralogist, 48, 1225–1236.10.3749/canmin.48.5.1225Search in Google Scholar
Arapan, S., and Ahuja, R. (2010) High-pressure phase transformations in carbonates. Physical Review B, 82, 184115.10.1103/PhysRevB.82.184115Search in Google Scholar
Arapan, S., Souza de Almeida, J., and Ahuja, R. (2007) Formation of sp3 hybridized bonds and stability of CaCO3 at very high pressure. Physical Review Letters, 98, 268501.10.1103/PhysRevLett.98.268501Search in Google Scholar PubMed
Boulard, E., Menguy, N., Auzende, A.L., Benzerara, K., Bureau, H., Antonangeli, D., Corgne, A., Morard, G., Siebert, J., Perrillat, J.P., Guyot, F., and Fiquet, G. (2012) Experimental investigation of the stability of Fe-rich carbonates in the lower mantle. Journal of Geophysical Research, 117, B02208.10.1029/2011JB008733Search in Google Scholar
Boulard, E., Pan, D., Galli, G., Liu, Z., and Mao, W.L. (2015) Tetrahedrally coordinated carbonates in Earth’s lower mantle. Nature Communications, 6, 6311.10.1038/ncomms7311Search in Google Scholar PubMed
Dasgupta, R., and Hirschmann, M.M. (2010) The deep carbon cycle and melting in Earth’s interior. Earth and Planetary Science Letters, 298, 1–13.10.1016/j.epsl.2010.06.039Search in Google Scholar
Fei, Y. (1995) Thermal Expansion. In T.J. Ahrens, Ed., Mineral Physics and Crystallography: A handbook of physical constants, p. 29–45. American Geophysical Union, Washington, D.C.10.1029/RF002p0029Search in Google Scholar
Johannes, W., and Puhan, D. (1971) The calcite-aragonite transition, reinvestigated. Contributions to Mineralogy and Petrology, 31, 26–38.10.1007/BF00373389Search in Google Scholar
Kelemen, P.B., and Manning, C.E. (2015) Reevaluating carbon fluxes in subduction zones, what goes down, mostly comes up. Proceedings of the National Academy of Sciences, 112, E3997–E4006.10.1073/pnas.1507889112Search in Google Scholar PubMed PubMed Central
Kraft, S., Knittle, E., and Williams, Q. (1991) Carbonate stability in the Earth’s mantle: A vibrational spectroscopic study of aragonite and dolomite at high pressures and temperatures. Journal of Geophysical Research, 96, 17,997–18,009.10.1029/91JB01749Search in Google Scholar
Liu, L.-G., Chen, C.-C., Lin, C.-C., and Yang, Y.-J. (2005) Elasticity of single-crystal aragonite by Brillouin spectroscopy. Physics and Chemistry of Minerals, 32, 97–102.10.1007/s00269-005-0454-ySearch in Google Scholar
Mao, H.-K.K., Xu, J.-A., and Bell, P.M. (1986) Calibration of the ruby pressure gauge to 800 kbar. Journal of Geophysical Research, 91, 4673–4676.10.1029/JB091iB05p04673Search in Google Scholar
Martinez, I., Zhang, J., and Reeder, R.J. (1996) In situ X-ray diffraction of aragonite and dolomite at high pressure and high temperature; evidence for dolomite breakdown to aragonite and magnesite. American Mineralogist, 81, 611–624.10.2138/am-1996-5-608Search in Google Scholar
Merlini, M., and Hanfland, M. (2013) Single-crystal diffraction at megabar conditions by synchrotron radiation. High Pressure Research, 33, 511–522.10.1080/08957959.2013.831088Search in Google Scholar
Merlini, M., Hanfland, M., Salamat, A., Petitgirard, S., and Mueller H. (2015) The crystal structures of Mg2Fe2C4O13, with tetrahedrally coordinated carbon, and Fe13O19, synthesized at deep mantle conditions. American Mineralogist, 100, 2001–2004.10.2138/am-2015-5369Search in Google Scholar
Oganov, A.R., Glass, C.W., and Ono, S. (2006) High-pressure phases of CaCO3: Crystal structure prediction and experiment. Earth and Planetary Science Letters, 241, 95–103.10.1016/j.epsl.2005.10.014Search in Google Scholar
Oganov, A.R., Ono, S., Ma, Y., Glass, C.W., and Garcia, A. (2008) Novel high-pressure structures of MgCO3, CaCO3 and CO2 and their role in Earth’s lower mantle. Earth and Planetary Science Letters, 273, 38–47.10.1016/j.epsl.2008.06.005Search in Google Scholar
Ono, S., Kikegawa, T., Ohishi, Y., and Tsuchiya, J. (2005) Post-aragonite phase transformation in CaCO3 at 40 GPa. American Mineralogist, 90, 667–671.10.2138/am.2005.1610Search in Google Scholar
Ono, S., Kikegawa, T., and Ohishi, Y. (2007) High-pressure transition of CaCO3. American Mineralogist, 92, 1246–1249.10.2138/am.2007.2649Search in Google Scholar
Oxford Diffraction (2006) CrysAlis. Oxford Diffraction, Abingdon, U.K.Search in Google Scholar
Palatinus, L., and Chapuis, G. (2007) SUPERFLIP—a computer program for the solution of crystal structures by charge flipping in arbitrary directions. Journal of Applied Crystallography, 40, 786–790.10.1107/S0021889807029238Search in Google Scholar
Petricek, V., Dusek, M., and Palatinus, L. (2006) Jana2006: The crystallographic computing system. Institute of Physics, Praha, Czech Republic, http://jana.fzu.cz/.Search in Google Scholar
Pickard, C.J., and Needs, R.J. (2015) Structures and stability of calcium and magnesium carbonates at mantle pressures. Physical Review B, 91, 104101.10.1103/PhysRevB.91.104101Search in Google Scholar
Rebuffi, L., Plaisier, J.R., Abdellatief, M., Lausi, A., and Scardi, P. (2014) MCX: A synchrotron radiation beamline for X-ray diffraction line profile analysis. Zeitschrift für anorganische and allgemeine Chemie, 640, 3100–3106.10.1002/zaac.201400163Search in Google Scholar
Ross, N.L., and Reader, R.J. (1992) High-pressure structural study of dolomite and ankerite. American Mineralogist, 77, 412–421.Search in Google Scholar
Santillán, J., and Williams, Q. (2004) A high pressure X-ray diffraction study of aragonite and the post-aragonite phase transition in CaCO3. American Mineralogist, 89, 1348–1352.10.2138/am-2004-8-925Search in Google Scholar
Shcheka, S.S., Wiedenbeck, M., Frost, D.J., and Keppler, H. (2006) Carbon solubility in mantle minerals. Earth and Planetary Science Letters, 245, 730–742.10.1016/j.epsl.2006.03.036Search in Google Scholar
Vizgirda, J., and Ahrens, T.J. (1982) Shock compression of aragonite and implications for the equation of state of carbonates. Journal of Geophysical Research: Solid Earth, 87, 4747–4758.10.1029/JB087iB06p04747Search in Google Scholar
Ye, Y., Smyth, J.R., and Boni, P. (2012) Crystal structure and thermal expansion of aragonite-group carbonates by single-crystal X ray diffraction. American Mineralogist, 97, 707–712.10.2138/am.2012.3923Search in Google Scholar
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