Articles | Volume 34, issue 5
https://doi.org/10.5194/ejm-34-411-2022
© Author(s) 2022. This work is distributed under
the Creative Commons Attribution 4.0 License.
the Creative Commons Attribution 4.0 License.
https://doi.org/10.5194/ejm-34-411-2022
© Author(s) 2022. This work is distributed under
the Creative Commons Attribution 4.0 License.
the Creative Commons Attribution 4.0 License.
Research article
| 
06 Oct 2022
Research article |
| 06 Oct 2022
| 06 Oct 2022
Melting relations of Ca–Mg carbonates and trace element signature of carbonate melts up to 9 GPa – a proxy for melting of carbonated mantle lithologies
Section 3.6 and 3.1, GFZ German Research Centre for Geosciences,
Telegrafenberg, 14473 Potsdam, Germany
present address: Mineralogy, Institute of Geosciences, University of Potsdam, Karl-Liebknecht-Straße 24–25, 14476 Potsdam, Germany
Max Wilke
Mineralogy, Institute of Geosciences, University of Potsdam, Karl-Liebknecht-Straße 24–25, 14476 Potsdam, Germany
Oona Appelt
Section 3.6 and 3.1, GFZ German Research Centre for Geosciences,
Telegrafenberg, 14473 Potsdam, Germany
Marcus Oelze
Section 3.6 and 3.1, GFZ German Research Centre for Geosciences,
Telegrafenberg, 14473 Potsdam, Germany
present address: Bundesanstalt für Materialforschung und -prüfung
(BAM), Richard-Willstätter-Straße 11, 12489 Berlin, Germany
Monika Koch-Müller
Section 3.6 and 3.1, GFZ German Research Centre for Geosciences,
Telegrafenberg, 14473 Potsdam, Germany
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Dense hydrous magnesium silicates, like the 3.65 Å phase, are thought to cause deep earthquakes. We investigated the dehydration of the 3.65 Å phase at P and T. In both directions of the investigated simple reaction, additional metastable water-rich phases occur. The observed extreme reduction in grain size in the dehydration experiments might cause mechanical instabilities in the Earth’s mantle and, finally, induce earthquakes.
Cited articles
Barker, D. S.: Calculated silica activities in carbonatite liquids,
Contrib. Mineral. Petr., 141, 704–709,
https://doi.org/10.1007/s004100100281, 2001.
Beattie, P.: Systematics and energetics of trace-element partitioning
between olivine and silicate melts: Implications for the nature of
mineral/melt partitioning, Chem. Geol., 117, 57–71, https://doi.org/10.1016/0009-2541(94)90121-x, 1994.
Becker, M. and Le Roex, A. P. L.: Geochemistry of South African on-and
off-craton, Group I and Group II kimberlites: petrogenesis and source region
evolution, J. Petrol., 47, 673–703, https://doi.org/10.1093/petrology/egi089, 2006.
Biedermann, N.: Carbonate-silicate reactions at conditions of the Earth's
mantle and the role of carbonates as possible trace-element carriers, PhD thesis, 2020.
Blundy, J. and Wood, B.: Partitioning of trace elements between crystals and
melts, Earth Planet. Sci. Lett., 210, 383–397, https://doi.org/10.1016/s0012-821x(03)00129-8, 2003.
Brenker, F. E., Vollmer, C., Vincze, L., Vekemans, B., Szymanski, A.,
Janssens, K., Szaloki, I., Nasdala, L., Joswig, W., and Kaminsky, F.:
Carbonates from the lower part of transition zone or even the lower mantle,
Earth Planet. Sc. Lett., 260, 1–9, 2007.
Brey, G. P., Bulatov, V. K., Girnis, A. V., and Lahaye, Y.: Experimental
Melting of Carbonated Peridotite at 6–10 GPa, J. Petrol., 49,
797–821, https://doi.org/10.1093/petrology/egn002, 2007.
Brey, G. P., Bulatov, V. K., and Girnis, A. V.: Influence of water and
fluorine on melting of carbonated peridotite at 6 and 10 GPa, Lithos, 112,
249–259, https://doi.org/10.1016/j.lithos.2009.04.037, 2009.
Brey, G. P., Bulatov, V. K., and Girnis, A. V.: Melting of K-rich carbonated
peridotite at 6–10 GPa and the stability of K-phases in the upper mantle,
Chem. Geol., 281, 333–342, https://doi.org/10.1016/j.chemgeo.2010.12.019, 2011.
Buob, A.: Experiments on CaCO3-MgCO3 solid solutions at high pressure and
temperature, Am. Mineral., 91, 435–440, https://doi.org/10.2138/am.2006.1910, 2006.
Byrnes, A. P. and Wyllie, P. J.: Subsolidus and melting relations for the
join CaCO3-MgCO3 at 10 kbar, Geochim. Cosmochim. Ac., 45, 321–328,
https://doi.org/10.1016/0016-7037(81)90242-8, 1981.
Chakhmouradian, A. R., Reguir, E. P., and Zaitsev, A. N.: Calcite and
dolomite in intrusive carbonatites. I. Textural variations, Mineral.
Petrol., 110, 333–360, 2016.
Dalton, J. A. and Presnall, D. C.: The Continuum of Primary
Carbonatitic-Kimberlitic Melt Compositions in Equilibrium with Lherzolite:
Data from the System CaO-MgO-Al2O3-SiO2-CO2 at 6 GPa, J. Petrol.,
39, 1953–1964, https://doi.org/10.1093/petroj/39.11-12.1953,
1998.
Dasgupta, R. and Hirschmann, M. M.: Melting in the Earth's deep upper mantle
caused by carbon dioxide, Nature, 440, 659–662, https://doi.org/10.1038/nature04612, 2006.
Dasgupta, R. and Hirschmann, M. M.: The deep carbon cycle and melting in
Earth's interior, Earth Planet. Sci. Lett., 298, 1–13, https://doi.org/10.1016/j.epsl.2010.06.039, 2010.
Dasgupta, R., Hirschmann, M. M., McDonough, W. F., Spiegelman, M., and
Withers, A. C.: Trace element partitioning between garnet lherzolite and
carbonatite at 6.6 and 8.6 GPa with applications to the geochemistry of the
mantle and of mantle-derived melts, Chem. Geol., 262, 57–77, https://doi.org/10.1016/j.chemgeo.2009.02.004, 2009.
Effenberger, H., Mereiter, K., and Zemann, J.: Crystal structure refinements of magnesite, calcite, rhodochrosite, siderite, smithonite, and dolomite, with discussion of some aspects of the stereochemistry of calcite type carbonates, Z. Krist.-Cryst. Mater., 156, 233–243, https://doi.org/10.1524/zkri.1981.156.14.233, 1981.
Elzinga, E., Reeder, R., Withers, S., Peale, R. E., Mason, R., Beck, K. M.,
and Hess, W. P.: EXAFS study of rare-earth element coordination in calcite,
Geochim. Cosmochim. Ac., 66, 2875–2885, https://doi.org/10.1016/S0016-7037(02)00888-8, 2002.
Falloon, T. J. and Green, D. H.: The solidus of carbonated, fertile
peridotite, Earth Planet. Sc. Lett., 94, 364–370, https://doi.org/10.1016/0012-821X(89)90153-2, 1989.
Ghosh, S., Ohtani, E., Litasov, K. D., and Terasaki, H.: Solidus of
carbonated peridotite from 10 to 20 GPa and origin of magnesiocarbonatite
melt in the Earth's deep mantle, Chem. Geol., 262, 17–28, https://doi.org/10.1016/j.chemgeo.2008.12.030, 2009.
Girnis, A. V., Bulatov, V. K., Brey, G. P., Gerdes, A., and Höfer, H.
E.: Trace element partitioning between mantle minerals and silico-carbonate
melts at 6–12 GPa and applications to mantle metasomatism and kimberlite
genesis, Lithos, 160–161, 183–200, https://doi.org/10.1016/j.lithos.2012.11.027, 2013.
Hammouda, T. and Keshav, S.: Melting in the mantle in the presence of
carbon: Review of experiments and discussion on the origin of carbonatites,
Chem. Geol., 418, 171–188, https://doi.org/10.1016/j.chemgeo.2015.05.018, 2015.
Hermann, J., Troitzsch, U., and Scott, D.: Experimental subsolidus phase
relations in the system CaCO3–CaMg(CO3)2 up to 6.5 GPa and implications for
subducted marbles, Contrib. Mineral. Petr., 171, 84,
https://doi.org/10.1007/s00410-016-1296-y, 2016.
Huang, W.-L. and Wyllie, P. J.: Melting relationships in the systems CaO-CO2
and MgO-CO2 to 33 kilobars, Geochim. Cosmochim. Ac., 40, 129–132,
https://doi.org/10.1016/0016-7037(76)90169-1, 1976.
Humphreys, E. R., Bailey, K., Hawkesworth, C. J., Wall, F., Najorka, J., and
Rankin, A. H.: Aragonite in olivine from Calatrava, Spain—Evidence for
mantle carbonatite melts from >100 km depth, Geology, 38,
911–914, https://doi.org/10.1130/g31199.1, 2010.
Hunter, R. H. and McKenzie, D.: The equilibrium geometry of carbonate melts
in rocks of mantle composition, Earth Planet. Sc. Lett., 92,
347–356, https://doi.org/10.1016/0012-821x(89)90059-9, 1989.
Ionov, D. A., Dupuy, C., O'Reilly, S. Y., Kopylova, M. G., and Genshaft, Y.
S.: Carbonated peridotite xenoliths from Spitsbergen: implications for trace
element signature of mantle carbonate metasomatism, Earth Planet.
Sc. Lett., 119, 283–297, https://doi.org/10.1016/0012-821X(93)90139-Z, 1993.
Irving, A. J. and Wyllie, P. J.: Subsolidus and melting relationships for
calcite, magnesite and the join CaCO3-MgCO3 36 kb, Geochim.
Cosmochim. Ac., 39, 35–53, https://doi.org/10.1016/0016-7037(75)90183-0, 1975.
Johnson, M. C. and Walker, D.: Brucite [MG(OH)2] dehydration and the molar
volume of H2O to 15 GPa, Am. Mineral., 78, 271–284, 1993.
Jones, A. P., Genge, M., and Carmody, L.: Carbonate Melts and Carbonatites,
Rev. Mineral. Geochem., 75, 289–322, https://doi.org/10.2138/rmg.2013.75.10, 2013.
Katsura, T. and Ito, E.: Melting and subsolidus phase relations in the
MgSiO3MgCO3 system at high pressures: implications to evolution of the
Earth's atmosphere, Earth Planet. Sc. Lett., 99, 110–117,
https://doi.org/10.1016/0012-821x(90)90074-8, 1990.
Korsakov, A. V. and Hermann, J.: Silicate and carbonate melt inclusions
associated with diamonds in deeply subducted carbonate rocks, Earth
Planet. Sc. Lett., 241, 104–118, https://doi.org/10.1016/j.epsl.2005.10.037, 2006.
Lakshtanov, L. and Stipp, S.: Experimental study of europium (III)
coprecipitation with calcite, Geochim. Cosmochim. Ac., 68, 819–827,
https://doi.org/10.1016/j.gca.2003.07.010, 2004.
Li, Z., Li, J., Lange, R., Liu, J., and Militzer, B.: Determination of
calcium carbonate and sodium carbonate melting curves up to Earth's
transition zone pressures with implications for the deep carbon cycle, Earth
Planet. Sc. Lett., 457, 395–402, https://doi.org/10.1016/j.epsl.2016.10.027, 2017.
Litasov, K. D.: Physicochemical conditions for melting in the Earth's mantle
containing a C–O–H fluid (from experimental data), Russ. Geol.
Geophys., 52, 475–492, https://doi.org/10.1016/j.rgg.2011.04.001, 2011.
Müller, J., Koch-Müller, M., Rhede, D., Wilke, F. D. H., and Wirth,
R.: Melting relations in the system CaCO3-MgCO3 at 6 GPa, Am.
Mineral., 102, 2440–2449, https://doi.org/10.2138/am-2017-5831, 2017.
Nagasawa, H.: Trace element partition coefficient in ionic crystals,
Science, 152, 767–769, https://doi.org/10.1126/science.152.3723.767, 1966.
Onuma, N., Higuchi, H., Wakita, H., and Nagasawa, H.: Trace element
partition between two pyroxenes and the host lava, Earth Planet.
Sc. Lett., 5, 47–51, https://doi.org/10.1016/S0012-821X(68)80010-X, 1968.
Palme, H. and O' Neill, H.: Cosmochemical Estimates of Mantle Composition,
Treatise on Geochemistry, 2nd Edn., 3, 1–39, https://doi.org/10.1016/B978-0-08-095975-7.00201-1, 2014.
Podborodnikov, I. V., Shatskiy, A., Arefiev, A. V., Chanyshev, A. D., and
Litasov, K. D.: The system Na2CO3–MgCO3 at 3 GPa, High Pressure Res.,
38, 281–292, https://doi.org/10.1080/08957959.2018.1488972,
2018.
Reguir, E. P., Chakhmouradian, A. R., Halden, N. M., Yang, P., and Zaitsev,
A. N.: Early magmatic and reaction-induced trends in magnetite from the
carbonatites of Kerimasi, Tanzania, Can. Mineral., 46, 879–900,
https://doi.org/10.3749/canmin.46.4.879, 2008.
Schmidt, M. W. and Ulmer, P.: A rocking multianvil: elimination of chemical
segregation in fluid-saturated high-pressure experiments, Geochim.
Cosmochim. Ac., 68, 1889–1899, https://doi.org/10.1016/j.gca.2003.10.031, 2004.
Shannon, R. and Prewitt, C.: Revised values of effective ionic radii, Acta Crystallogr. B, 26, 1046–1048, https://doi.org/10.1107/S0567740870003576, 1970.
Shatskiy, A., Sharygin, I. S., Gavryushkin, P. N., Litasov, K. D., Borzdov,
Y. M., Shcherbakova, A. V., Higo, Y., Funakoshi, K.-I., Palyanov, Y. N., and
Ohtani, E.: The system K2CO3-MgCO3 at 6 GPa and 900–1450 ∘C,
Am. Mineral., 98, 1593–1603, https://doi.org/10.2138/am.2013.4407, 2013.
Shatskiy, A., Litasov, K. D., Sharygin, I. S., Egonin, I. A., Mironov, A.
M., Palyanov, Y. N., and Ohtani, E.: The system Na2CO3–CaCO3–MgCO3 at 6 GPa
and 900–1250 ∘C and its relation to the partial melting of
carbonated mantle, High Pressure Research, 36, 23–41, https://doi.org/10.1080/08957959.2015.1135916, 2016.
Shatskiy, A., Podborodnikov, I. V., Arefiev, A. V., Minin, D. A., Chanyshev,
A. D., and Litasov, K. D.: Revision of the CaCO3–MgCO3 phase diagram at 3
and 6 GPa, Am. Mineral., 103, 441–452, https://doi.org/10.2138/am-2018-6277, 2018.
Shatsky, V., Ragozin, A., and Sobolev, N.: Some aspects of metamorphic
evolution of ultrahigh-pressure calc-silicate rocks of the Kokchetav Massif,
Russ. Geol. Geophys., 47, 105–119, 2006.
Sieber, M. J., Wilke, F., and Koch-Müller, M.: Partition coefficients of
trace elements between carbonates and melt and suprasolidus phase relation
of Ca-Mg-carbonates at 6 GPa, Am. Mineral., 105, 922–931,
https://doi.org/10.2138/am-2020-7098, 2020.
Sieber, M. J., Wilke, F. D. H., Appel, O., Oelze, M., and Koch-Müller, M.: Major and trace element analysis of Ca-Mg-carbonates and carbonate melt at 6 and 9 GPa, V.1, GFZ Data Services [data set], https://doi.org/10.5880/GFZ.3.6.2022.001, 2022.
Stipp, S. L. S., Christensen, J. T., Lakshtanov, L. Z., Baker, J. A., and
Waight, T. E.: Rare Earth element (REE) incorporation in natural calcite:
Upper limits for actinide uptake in a secondary phase, Radiochim. Acta,
94, 523–528, https://doi.org/10.1524/ract.2006.94.9-11.523,
2006.
Stoppa, F., Schiazza, M., Rosatelli, G., Castorina, F., Sharygin, V. V.,
Ambrosio, F. A., and Vicentini, N.: Italian carbonatite system: From mantle
to ore-deposit, Ore Geol. Rev., 114, 103041, https://doi.org/10.1016/j.oregeorev.2019.103041, 2019.
Suito, K., Namba, J., Horikawa, T., Taniguchi, Y., Sakurai, N., Kobayashi,
M., Onodera, A., Shimomura, O., and Kikegawa, T.: Phase relations of CaCO3at
high pressure and high temperature, Am. Mineral., 86, 997–1002,
https://doi.org/10.2138/am-2001-8-906, 2001.
Syracuse, E. M., van Keken, P. E., and Abers, G. A.: The global range of
subduction zone thermal models, Phys. Earth Planet.
In., 183, 73–90, https://doi.org/10.1016/j.pepi.2010.02.004, 2010.
Wallace, M. E. and Green, D. H.: An experimental determination of primary
carbonatite magma composition, Nature, 335, 343–346, https://doi.org/10.1038/335343a0, 1988.
Wang, A., Pasteris, J. D., Meyer, H. O. A., and Dele-Duboi, M. L.:
Magnesite-bearing inclusion assemblage in natural diamond, Earth
Planet. Sc. Lett., 141, 293–306, https://doi.org/10.1016/0012-821x(96)00053-2, 1996.
Watenphul, A., Wunder, B., and Heinrich, W.: High-pressure ammonium-bearing
silicates: Implications for nitrogen and hydrogen storage in the Earth's
mantle, Am. Mineral., 94, 283–292, https://doi.org/10.2138/am.2009.2995, 2009.
Wirth, R.: Focused Ion Beam (FIB): A novel technology for advanced
application of micro- and nanoanalysis in geosciences and applied
mineralogy, Eur. J. Mineral., 16, 863–876,
https://doi.org/10.1127/0935-1221/2004/0016-0863, 2004.
Yaxley, G. M. and Brey, G. P.: Phase relations of carbonate-bearing eclogite
assemblages from 2.5 to 5.5 GPa: implications for petrogenesis of
carbonatites, Contrib. Mineral. Petr., 146, 606–619,
https://doi.org/10.1007/s00410-003-0517-3, 2004.
Yaxley, G. M. and Green, D. H.: Experimental demonstration of refractory
carbonate-bearing eclogite and siliceous melt in the subduction regime,
Earth Planet. Sc. Lett., 128, 313–325, https://doi.org/10.1016/0012-821x(94)90153-8, 1994.
Yaxley, G. M., Ghosh, S., Kiseeva, E. S., Mallik, A., Spandler, C., Thomson,
A. R., and Walter, M. J.: CO2-Rich Melts in Earth, in: Deep Carbon: Past to
Present, edited by: Orcutt, B. N., Daniel, I., and Dasgupta, R., Cambridge
University Press, Cambridge, 129–162, https://doi.org/10.1017/9781108677950, 2019.
Zedgenizov, D. A., Kagi, H., Shatsky, V. S., and Ragozin, A. L.: Local
variations of carbon isotope composition in diamonds from São-Luis
(Brazil): Evidence for heterogenous carbon reservoir in sublithospheric
mantle, Chem. Geol., 363, 114–124, https://doi.org/10.1016/j.chemgeo.2013.10.033, 2014.
Zhong, S. and Mucci, A.: Partitioning of rare earth elements (REEs) between
calcite and seawater solutions at 25 ∘C and 1 atm, and high dissolved REE
concentrations, Geochim. Cosmochim. Ac., 59, 443–453, https://doi.org/10.1016/0016-7037(94)00381-U, 1995.
Short summary
Carbonates reduce the melting point of the mantle, and carbonate melts produced in low-degree melting of a carbonated mantle are considered the precursor of CO2-rich magmas. We established experimentally the melting relations of carbonates up to 9 GPa, showing that Mg-carbonates melt incongruently to periclase and carbonate melt. The trace element signature of carbonate melts parental to kimberlites is approached by melting of Mg-rich carbonates.
Carbonates reduce the melting point of the mantle, and carbonate melts produced in low-degree...
