The problem of diamond formation, despite the huge amount of accumulated information, has not been finally resolved. Currently, the most well-established hypothesis is that the diamond will be formed as a result of metasomatosis. According to this theory, the source of carbon were fluids of C-H-O-N-S composition. There are still questions concerning the environment for diamond crystallization. One of the most common inclusions in diamonds from kimberlite tubes are sulfides. They are also represented in diamondiferous xenoliths of peridotite and eclogite from diamondiferous tubes, but their quantity in diamonds is still higher in comparison with xenoliths. Modern scientific researches allow to assert that large diamonds, such as Kullinan (3106 carats), Koh-i-Noor, etc., were formed at great depths of about 360 – 750 km. Inclusions in these diamonds are, along with silicate minerals, iron-nickel alloy, iron-nickel carbide and sulfide (pyrrhotite). The present study is devoted to studying the model growth environment of a diamond in the Fe-C-S system with a sulfur content of 3 wt. % in relation to iron. The experiments of 0.5 hours duration were carried out at 6 GPa and 1450 С on a high-pressure apparatus of “cutting sphere” type. As a result, diamond synthesis was obtained. The following phases were recorded during the analysis of growth medium composition (metal-sulfide sintering): solid solution of carbon in iron, iron sulfide, iron carbide. Iron sulfide is represented by pyrrhotite. Thus, the phases established in solid products of the experiments fully correspond to the phases isolated from inclusions of natural diamonds.

Karpovich Zakhar Alekseevich, Postgraduate, Sobolev Institute of Geology and Mineralogy SB RAS, 3, Akademik Koptyug av., Novosibirsk, 630090, Russian Federation, e-mail: zkarpovich@yandex.ru 

Zhimulev Egor Igorevich, Doctor of Sciences (Geological and Mineralogical), Senior Researcher, Sobolev Institute of Geology and Mineralogy SB RAS, 3, Akademik Koptyug av., Novosibirsk, 630090, Russian Federation, e-mail: ezhimulev@igm.nsc.ru

Karpovich Z.A., Zhimulev E.I. Experimental Modeling of Diamond Formation Processes in Fe-C-S System at High P-T Parameters. The Bulletin of Irkutsk State University. Series Earth Sciences, 2020, vol. 34, pp. 67-81. https://doi.org/10.26516/2073-3402.2020.34.67 (in Russian)

Bulanova G.P., Specius Z.V., Leskova N.V. Sul'fidy v almazah i ksenolitah iz kimberlitovyh trubok Jakutii [Sulphides in diamonds and xenoliths from kimberlite pipes of Yakutia]. Novosibirsk, Nauka Publ., 1990. 120 p. (in Russian) 

Chepurov A.I. O roli sulfidnogo rasplava v processe prirodnogo almazoobrazovanija [On the role of sulfide melt in the natural diamond formation process]. Geol. i geofizika, 1988, no. 8, рр.119-124. (in Russian)

Chepurov A.I., Fedorov I.I., Sonin V.M. Jeksperimentalnoe modelirovanie processov almazoobrazovanija [Experimental simulation of diamond formation processes]. Novosibirsk, Nauka Publ., 1997, 196 p. (in Russian)

Chepurov A.I., Fedorov I.I., Sonin V.M. Jeksperimental'nye issledovanija obrazovanija almaza pri vysokih RT-parametrah [Experimental studies of diamond formation at high PT parameters]. Geol. i geofizika, 1998, vol. 39, no. 2, рр. 234-244. (in Russian) 

Chepurov A.I., Fedorov I.I., Sonin V.M., Sobolev N.V. Obrazovanie almaza v sisteme (Fe,Ni)-S-C-H pri vysokih RT-parametrah [Diamond formation in the system (Fe,Ni)-S-C-H at high PT parameters]. Doklady Earth Sciences, 1994, vol. 336, no. 2, pp. 238-240. (in Russian)

Sobolev N.V. Glubinie vklyuchenia v kimberlitah i problema sostava verhney mantii [Deep inclusions in kimberlites and the problem of upper mantle composition]. Novosibirsk, Nauka Publ., 1974, 264 p. (in Russian) 

Sobolev N.V. Paragenezisy almaza I problema glubinogo mineraloobrazovania [Parageneses of diamond and the problem of deep mineral formation]. Zapiski WMO, 1983, H SH, vol. 4, pp. 389-397. (in Russian)

Shushkanova A.V., Litvin Ju.A. Osobennosti obrazovanija almaza v sulfidnyh pirrotin-uglerodnyh rasplavah po dannym jeksperimentov pri 6.0-7.1 GPa: prilozhenie k prirodnym uslovijam [Features of diamond formation in sulfide pyrrhotite-carbon melts according to the experiments at 6.0-7.1 GPa: application to natural conditions]. Geohimija, 2008, no. 1, pp. 37-47. (in Russian)

Tonkov E.Y. Fazovie diagrammi elementov pri visokom davlenii [Phase diagrams of elements at high pressure]. Moscow, Nauka Publ., 1979, 192 p. (in Russian) 

Boyd F.R., Finnerty A.A. Conditions of Origin of Natural Diamonds of Peridotite Affinity. J. Geophys. Res., 1980, vol. 85, pp. 6911-6918. 

Bulanova G.P., Griffin W.L., Ryan C.G., Shestakova O.V., Barnes S.J. Trace elements in sulfide inclusions from Yakutian diamonds. Contrib. Mineral. Petrol., 1996, vol. 124, pp. 111-125. 

Buono A.S., Dasgupta R., Lee C-T.A., Walker D. Siderophile element partitioning between cohenite and liquid in the Fe-Ni-S-C system and implications for geochemistry of planetary cores and mantles. Geochim. Cosmochim. Acta, 2013, vol. 120, pp. 239-250. https://doi.org/10.1016/j.gca.2013.06.024

Chen B., Li J., Hauck II S.A. Non-ideal liquidus curve in the Fe-S system and Mercury’s snowing core. Geophys. res. lett., 2008, vol. 35, L07201. https://doi.org/10.1029/2008GL033311 

Chepurov A.I., Sonin V.M., Zhimulev E.I., Chepurov A.A., Tomilenko A.A. On the formation of element carbon during decomposition of CaCO 3 at high P-T parameters under reducing conditions. Doklady Earth Sciences, 2011, vol. 441, iss. 2, P.1738-1741. 

Corgne A., Wood B. J., Fei Y. C- and S-rich molten alloy immiscibility and core formation of planetesimals. Geochimica et Cosmochimica Acta, 2008, vol.72, pp. 2409-2416. https://doi.org/10.1016/j.gca.2008.03.001 

Dasgupta R., Buono A., Whelan G., Walker D. High-pressure melting relations in Fe-C-S systems: Implications for formation, evolution, and structure of metallic cores in planetary bodies. Geochim. Cosmochim. Acta, 2009, vol. 73, pp. 6678-6691. https://doi.org/10.1016/j.gca.2009.08.001

Gunn S.C., Luth R.W. Carbonate reduction by Fe-S-O melts at high pressure and high temperature. Amer. Mineral., 2006, vol. 91, pp. 1110-1116. https://doi.org/10.2138/am.2006.2009

Gurney J.J., Helmstaedt H. H., Richardson S. H., Shirey S. B. Diamond through Time // Soc. of Econ. Geolog., inc. Economic Geology. 2010. Vol.105. pp.689-712. https://doi.org/10.2113/gsecongeo.105.3.689 

Haggerty S.E. A diamond trilogy: superplumes, supercontinents and supernovae. Science, 1999, vol. 285, pp. 851-860. 

Harris J.W. Diamond geology. The properties of natural and synthetic diamond. Ed. by Field J.E. London, Acad. Press., 1992, pp. 345-393. 

Meyer H.O.A. Inclusions in diamond. Mantle xenoliths. New York, John Wiley&Sons, 1987, pp. 501-533. 

Nishida K., Kono Y., Terasaki H., Takahashi S., Ishii M., Shimoyama Y., Higo Y., Funakoshi K., Irifune T., Ohtani E. Sound velocity measurements in liquid Fe-S at high pressure: Implications for Earth’s and lunar cores. Earth and Planet. Sci. Lett., 2013, vol. 362, pp. 182-186. https://doi.org/10.1016/j.epsl.2012.11.042

Pal’yanov Yu.N., BorzdovYu.M., Bataleva Yu.V., Sokol A.G., Pal’yanova G.A., Kupriyanov I. N. Reducing role of sulfides and diamond formation in the Eath’s mantle. Earth and Planet. Sci. Lett., 2007, vol. 260, pp. 242-256. https://doi.org/10.1016/j.epsl.2007.05.033 

Palot M., Pearson D.G., Stern R.A., Stachel T., Harris J.W. Multiple growth events, processes and fluid sources involved in diamond genesis: A micro-analytical study of sulphide-bearing diamonds from Finsch mine, RSA. Geochim. Cosmochim. Acta, 2013, vol .106, pp. 51-70. https://doi.org/10.1016/j.gca.2012.12.024

Sharp W.E. Pyrrhotite: a common inclusion in the South African diamonds. Nature, 1966, vol. 211, no. 5047, pp. 402-403.

Shirey S.B., Cartigny P., Frost D.J., Keshav S., Nimis F.N.P., Pearson D.G., Sobolev N.V., Walter M.J. Diamonds and the Geology of Mantle Carbon. Revie. Mineral. Geochem., 2013, vol. 75, pp. 355-421. https://doi.org/10.2138/rmg.2013.75.12 

Smit K.V., Shirey S.B., Richardson S.H., le Roex A.P., Gurney J.J. Re-Os isotopic composition of peridotitic sulphide inclusions in diamonds from Ellendale, Australia: Age constrains on Kimberley cratonic lithosphere. Geochim.Cosmochim. Acta, 2010, vol.74, pp. 3292-3306. 

Smith E.M., Shirey S.B., Nestola F., Bullock E.S., Wang J., Richardson S.H., Wang W. Large gem diamonds from metallic liquid in Earth’s deep mantle. Science, 2016, vol. 354 (6318), pp.1403-1405. https://doi.org/10.1126/science.aal1303

Stachel T., Brey G.P., Harris J.W. Inclusions in sublithospheric diamonds: Glimpses of Deep Earh. Elements, 2005, vol. 1, pp. 73-78. https://doi.org/10.2113/gselements.1.2.73

Stachel T., Harris J. W. Syngenetic inclusions in diamond from the Birim field (Ghana) – a deep peridotitic profile with a history of depletion and re-enrichment. Contrib. Mineral. and Petrol., 1997, vol. 127, pp. 336-352. 

Strong H.M., Wentorf R.H. Growth of large, high-quality diamond crystals at General Electric. Am. J. Phys., 1991, vol. 59, no. 11, pp. 1005-1008.

Thomassot E., Cartighy P., Harris J.W., Lorand J.P., Rollion-Bard C., Chaussidon M. Metasomatic diamond growth: A multi-isotope study (¹³C, ¹⁵N, ³³S, ³⁴S) of sulphide inclusions and their host diamonds from Jwaneng (Botswana). Earth and Planet. Sci. Lett., 2009, vol. 282, pp. 79-90. https://doi.org/10.1016/J.EPSL.2009.03.001

Tomilenko A.A., Zhimulev E.I., Bul'bak T.A., Sonin V.M., Chepurov A.I., Pokhilenko N.P. Peculiarities of the Composition of Volatiles of Diamonds Synthesized in the Fe-S-C System: Data on Gas Chromatography-Mass Spectrometry. Doklady Earth Sciences, 2018, vol. 482, iss. 1, pp. 1207-1211. https://doi.org/10.1134/S1028334X18090180

Tsuno K., Dasgupta R., Fe-Ni-Cu-C-S phase relations at high pressures and temperatures – the role of sulfur in carbon storage and diamond stability at mid- to deep- upper mantle. Earth and Planet. Sci. Lett., 2015, vol. 412, pp. 132-142. https://doi.org/10.1016/j.epsl.2014.12.018

Tsymbulov L.B., Tsemekhman L.Sh. Solubility of carbon in sulfide melts of the system Fe-Ni-S. Rus. J. Appl.Chem., 2001, vol. 74, pp. 925-929. 

Wentorf R.H. Diamond formation at high pressures. Advance in High-Pressure Research, 1974, no. 4, pp. 249-281. 

Zedgenizov D.A., Shatskiy A., Ragozin A.L., Kagi H., Shatsky V.S. Merwinite in diamond from Sao Luiz, Brazil: A new mineral of the Ca-rich mantle environment. Amer. Mineral., 2014, vol. 99, pp. 547-550. 

Zhimulev E.I., Babich Yu.V., Karpovich Z.A., Chepurov A.I., Pokhilenko N.P. Low-Nitrogen Diamond Growth in the Fe–C–S System. Doklady Earth Sciences, 2020, vol. 494, part 1. pp. 696-698. https://doi.org/10.1134/S1028334X20090226 

Zhimulev E.I., Chepurov A.I., Sinyakova E.F., Sonin V.M., Chepurov A.A., Pokhilenko N.P. Diamond Crystallization in the Fe–Co–S–C and Fe–Ni–S–C Systems and the Role of Sulfide–Metal Melts in the Genesis of Diamond. Geochemistry International, 2012, Vol. 50, no. 3, pp. 205-216. https://doi.org/10.1134/S0016702912030111 

Zhimulev E.I., Shein M.A., Pokhilenko N.P. Diamond Crystallization in the Fe–S–C System. Doklady Earth Sciences, 2013, vol. 451, part 1, pp. 729-731. https://doi.org/10.1134/S1028334X1307009X 

Zhimulev E.I., Sonin V.M., Bul’bak T.A., Chepurov A.I., Tomilenko A.A., Pokhilenko N.P. Volatile Compounds of Sulfur in the Fe–C–S System at 5.3 GPa and 1300°C. Doklady Earth Sciences. 2015, vol. 462, part 1, pp. 528-533. https://doi.org/10.1134/S1028334X15050219