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.
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
Related authors
No articles found.
Alice Taddei, Dan Holtstam, Erik Jonsson, Hans-Jürgen Förster, Stefan S. Andersson, Oona Appelt, and Luca Bindi
Eur. J. Mineral., 37, 937–951, https://doi.org/10.5194/ejm-37-937-2025, https://doi.org/10.5194/ejm-37-937-2025, 2025
Short summary
Short summary
Åsgruvanite-(Ce) is a new rare Earth element (REE) mineral from Åsgruvan in Västmanland, Sweden, linked to Bastnäs-type mineralisation. The chemical formula ideally includes cerium, aluminium, silicon, arsenic, carbonate groups, chlorine, and fluorine. The mineral forms small, grey-green, lustrous grains with distinct cleavage and high density and is associated with carbonates and REE minerals like gadolinite and an allanite-like mineral. It has a unique layered crystal structure.
Dirk Spengler, Monika Koch-Müller, Adam Włodek, Simon J. Cuthbert, and Jarosław Majka
Solid Earth, 16, 233–250, https://doi.org/10.5194/se-16-233-2025, https://doi.org/10.5194/se-16-233-2025, 2025
Short summary
Short summary
Western Norwegian “diamond facies” eclogite contains tiny mineral inclusions of quartz and amphibole lamellae that are not stable in the diamond field. Low trace amounts of water in the lamellae-bearing host minerals suggest that the inclusion microstructure was not formed by fluid infiltration but by dehydration during early exhumation of these rocks. Some samples with higher water content argue that a late fluid overprint was spatially restricted and erased evidence of extreme metamorphism.
Donna L. Whitney, Max Wilke, Sara E. Hanel, Florian Heidelbach, Olivier Mathon, and Angelika D. Rosa
Eur. J. Mineral., 37, 143–149, https://doi.org/10.5194/ejm-37-143-2025, https://doi.org/10.5194/ejm-37-143-2025, 2025
Short summary
Short summary
The Earth recycles water and other elements in a vast system that involves the oceans, minerals, magma, and the atmosphere. We studied the part of the system that involves minerals, specifically, lawsonite and epidote because they contain both water and iron. Iron in these minerals is usually assumed to be Fe3+, but we discovered an unexpected amount of Fe2+. Reactions involving different states of Fe and water in minerals affect many processes related to element cycling in the Earth.
Manuela Borchert, Maria A. Kokh, Marion Louvel, Elena F. Bazarkina, Anselm Loges, Edmund Welter, Denis Testemale, Rami Al Abed, Stephan Klemme, and Max Wilke
Eur. J. Mineral., 37, 111–130, https://doi.org/10.5194/ejm-37-111-2025, https://doi.org/10.5194/ejm-37-111-2025, 2025
Short summary
Short summary
Tungsten (W) concentrations in fluids in equilibrium with crystalline tungsten oxide are used to improve constraints of thermodynamic parameters for W solubility. W species in the hydrothermal fluids are further characterized by X-ray spectroscopy. Improved thermodynamic properties for a set of W fluid species are provided that cover a wide range of fluid compositions, necessary for understanding and describing the complex processes of W enrichment and mineralization in hydrothermal systems.
Monika Koch-Müller, Christian Lathe, Bernd Wunder, Oona Appelt, Shrikant Bhat, Andreas Ebert, Robert Farla, Vladimir Roddatis, Anja Schreiber, and Richard Wirth
Eur. J. Mineral., 36, 1023–1036, https://doi.org/10.5194/ejm-36-1023-2024, https://doi.org/10.5194/ejm-36-1023-2024, 2024
Short summary
Short summary
We examined the influence of Al2O3 and H2O on the position of the coesite–stishovite transition by means of in situ X‑ray diffraction measurements with the large-volume press at the synchrotron PETRA III in Hamburg. The position of the transition was found to be shifted almost in parallel by about 1.5 GPa to lower pressures compared to results for the pure SiO2 system by Ono et al. (2017). Stishovite of this study containing Al and H is only partially quenchable but transforms back to coesite.
Roman Botcharnikov, Max Wilke, Jan Garrevoet, Maxim Portnyagin, Kevin Klimm, Stephan Buhre, Stepan Krasheninnikov, Renat Almeev, Severine Moune, and Gerald Falkenberg
Eur. J. Mineral., 36, 195–208, https://doi.org/10.5194/ejm-36-195-2024, https://doi.org/10.5194/ejm-36-195-2024, 2024
Short summary
Short summary
The new spectroscopic method, based on the syncrotron radiation, allows for determination of Fe oxidation state in tiny objects or in heterogeneous samples. This technique is expected to be an important tool in geosciences unraveling redox conditions in rocks and magmas as well as in material sciences providing constraints on material properties.
Christian Lathe, Monika Koch-Müller, Bernd Wunder, Oona Appelt, Melanie Sieber, Shrikant Bhat, and Robert Farla
Eur. J. Mineral., 35, 1149–1157, https://doi.org/10.5194/ejm-35-1149-2023, https://doi.org/10.5194/ejm-35-1149-2023, 2023
Short summary
Short summary
We examined the reaction phase A plus high-P clinoenstatite to forsterite plus water (Reaction 1) by means of in situ X-ray diffraction measurements with the large volume press at the synchrotron PETRA III, Hamburg. Contrary to other studies, in which all experiments on Reaction (1) were performed at a water activity of 1, the reversed experiments presented in this study were performed at reduced water activity with mole fractions of about XH2O = XCO2 = 0.5.
Christian Lathe, Monika Koch-Müller, Bernd Wunder, Oona Appelt, Shrikant Bhat, and Robert Farla
Eur. J. Mineral., 34, 201–213, https://doi.org/10.5194/ejm-34-201-2022, https://doi.org/10.5194/ejm-34-201-2022, 2022
Short summary
Short summary
The equilibrium phase of A + HP clinoenstatite = forsterite + water was experimentally investigated at aH2O = 1 in situ. In cold subducting slabs, it is of relevance to transport water to large depths, initiating the formation of dense hydrous magnesium silicate (DHMS). At normal gradients, the huge water amount from this reaction induces important processes within the overlying mantle wedge. We additionally discuss the relevance of this reaction for intermediate-depth earthquake formation.
Monika Koch-Müller, Oona Appelt, Bernd Wunder, and Richard Wirth
Eur. J. Mineral., 33, 675–686, https://doi.org/10.5194/ejm-33-675-2021, https://doi.org/10.5194/ejm-33-675-2021, 2021
Short summary
Short summary
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...