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Project titleThe origin of ultramafic magmas: komatiites, boninites and meimechites.

AffiliationVernadsky Institute of Geochemistry and Analytical Chemistry of the Russian Academy of Sciences,

Keywordsmantle, magma, peridotite, pyroxenite, eclogite, olivine, chromite, melt inclusions, petrology, geochemistry, geodynamics, temperature, pressure, sulfide

Annotation
The main objective of the proposed project continuation is the determination of the evolution of volatiles (H2O, Cl, F, S) content in the deep mantle source of the komatiite melts. This objective includes determination of the role and origin of water in the deep mantle source as well as resolving the subduction role in this process. This new statement of the problem comes directly from the main result of the first project stage: the discovery of the Neoarchean (2.7 Ga) deep Earth hydrous reservoir- presumably mantle transition zone (Sobolev et al, Nature, 2016). The scale and scientific importance of this objective is related to the unsolved problems of H2O origin on the Earth and the onset of global plate tectonics because the source of H2O in the deciphered Archean deep Earth hydrous reservoir could be either early subduction or Earth accretion or (and) Moon forming event.

Expected results
In this project we plan to determine the contents of volatiles (H2O, Cl, F, S), hydrogen and oxygen isotope compositions and temperatures of the primary melts of komatiites and their mantle sources representing age interval between 3.5 Ga till 93 Ma. Thus we plan to establish temporal evolution of volatile concentrations in the deep mantle sources of komatiites and address the role and origin of H2O in the Earth deep mantle. This information will be used to understand the role of subduction and Earth accretion in H2O enrichment of the mantle transition zone of the Earth. We plan to obtain the mentioned results by the study of melt and spinel inclusions in highly magnesian olivines, experimental development of olivine-spinel-melt geothermometry and modelling of high temperature crystallization and melting processes. The planned results may significantly contribute to understanding of fundamental problems of geochemistry and geodynamics: the origin of water at the Earth and onset of global plate tectonics.

Annotation of the results obtained in 2018
Based on the determination of the contents of the major and trace elements, water and hydrogen isotopes in the olivine hosted melt inclusions from komatiites of Barberton, Belingwe and Abitibi Greenstone belts, a breakthrough result was obtained, accepted for publication in the journal Nature (Sobolev et al, 2018). It has been shown that the deep mantle hydrated reservoir has been present at the Earth at least since the Paleoarchean and was probably formed due to the introduction of water by subducted plates. This means that the recycling of the lithosphere into the deep mantle, possibly through subduction, began more than 3.3 Ga. ago. In order to increase the accuracy of local olivine microanalysis, the olivine standard with certified contents of 27 major and trace elements was created. The standard is based on olivine from mantle xenolith and analyzed in six laboratories around the world by methods of EPMA, LA-ICP-MS, SIMS, Isotope Dilution ICP-MS (for Mg and Fe), XRF, and ICP-MS. Determined the crystallization temperature of olivine Siberian meimechites and formation conditions of their primary melts. It is shown that the meimechites primary melts had elevated concentrations of water (up to 2.5 wt%) and carbon dioxide (up to 7 wt%), started the crystallization in the crust at temperatures 1440оС and formed in the temperature range 1690-1580оС and pressure 65-45 kbar. in a mantle plume with a potential temperature of 1550±50oC. The conditions of formation and crystallization of the most magnesian magmas of Kamchatka - avachites are determined. It is shown that avachites were formed as a result of 15% melting of the enriched peridotite MORB (E-DMM) source at a temperature of 1250 °C, a pressure of 1.5 GPA, contained at least 3.5% H2O and crystallized at a temperature of 1130±40 ° C, oxygen volatility deltaQFM=1.6±0.2 and a pressure of over 3.5 kbar. On the basis of new and published experimental data, a new empirical equation is proposed to predict the ratio of oxide / ferrous iron depending on the oxygen fugacity, temperature and melt composition. In contrast to previous equations, the compositional effect of melts on the Fe3+/Fe2+ ratio is not only modeled by the sum of the molar fraction of the individual oxide components. Additional interactions terms have also been incorporated. The main advantage of the proposed model is its applicability for a wide range of compositions at the content of SiO2<68%. In 2018, 14 papers were published or accepted for publication, including 3 articles in the journals of the first quartile (Q1,WoS). 8 oral presentations were made at international meetings. PhD thesis prepared for defense.

Publications

1. Alexander V. Sobolev, Evgeny V. Asafov, Andrey A. Gurenko, Nicholas T. Arndt, Valentina G. Batanova, Maxim V. Portnyagin, Dieter Garbe-Schönberg, Allan H. Wilson and Gary R. Byerly Deep hydrous mantle reservoir provides evidence for crustal recycling before 3.3 Gyr ago. Nature, - (year - 2018)

2. Batanova V.G., Thompson J.M., Danyushevsky L.V., Portnyagin M.V., Garbe-Schönberg D., Hauri E., Kimura J-I., Chang Q., Senda R., Goemann K., Chauvel C., Campillo S. , Ionov D. and Sobolev A.V. New Olivine reference material for in-situ microanalysis Geostandards and Geoanalytical Research, - (year - 2018)

3. Borisov A, Behrens H, Holtz F Ferric/ferrous ratio in silicate melts: a new model for 1 atm data with special emphasis on the effects of melt composition Contributions to Mineralogy and Petrology, 173:98 p1-15 (year - 2018) https://doi.org/10.1007/s00410-018-1524-8

4. Sobolev A.V., Asafov E.V., Gurenko A.A., Arndt N.T., Batanova V.G., Portnyagin M.V., Garbe-Schönberg D., Wilson A.H., Byerly G.R. Deep hydrous mantle reservoir provides evidence for crustal recycling before 3.3 Gyr ago Nature, v. 571, pp 555-559 (year - 2019) https://doi.org/10.1038/s41586-019-1399-5

5. Asafov E.V., Sobolev A.V., Gurenko А.А., Portnyagin M.V., Arndt N.T., Batanova V.G., Krasheninnikov S.P. Расплавные включения в оливине из древних коматиитов - потенциальный ключ к составу архейской Всероссийский ежегодный семинар по экспериментальной минералогии, петрологии и геохимии 18–19 апреля 2018 г., Тезисы докладов. Москва 2018. ВЕСЭМПГ-2018-013 (year - 2018)

6. Asafov E.V., Sobolev A.V., Gurenko А.А., Portnyagin M.V., Arndt N.T., Batanova V.G., Krasheninnikov S.P. Melt Inclusions In Olivine Provide Constraints On The Water Contents Of Archaean Komatiites AGU-Fall meeting 2018, AGU-Fall meeting (year - 2018)

7. Asafov E.V., Sobolev A.V., Gurenko А.А., Portnyagin M.V., Arndt N.T., Batanova V.G., Krasheninnikov S.P. Water in the Archaean komatiites: results of the melt inclusion studies The problems of magmatic and metamorphic petrology, geodynamics and genesis of diamonds, Abstracts of International Conference dedicated to the 110th anniversary of Academician V.S. Sobolev, Novosibirsk, June 9-14, 2018/Rus. Acad, of Sciences; Sib. Branch, V.S. Sobolev Institute of Geology and Mineralogy. - Novosibirsk. p. 88. (year - 2018)

8. Koshlyakova A.N., Sobolev A.V., Krasheninnikov S.P., Batanova V.G., Borisov A.A Experimental data on Ni partitioning between olivine and highly alkaline silicate melts “Magmatism of the Earth and related strategic metal deposits”. Moscow, 3-7 September 2018. P. 157-160, Proceedings of XXXV International conference “Magmatism of the Earth and related strategic metal deposits”. Moscow, P. 157-160 (year - 2018)

9. Koshlyakova A.N., Sobolev A.V., Krasheninnikov S.P., Batanova V.G., Borisov A.A Высокотемпературные эксперименты по распределению элементов между оливином и расплавом с высоким содержанием щелочей Всероссийский ежегодный семинар по экспериментальной минералогии, петрологии и геохимии 18–19 апреля 2018 г., Тезисы докладов. Москва 2018. ВЕСЭМПГ-2018-078 (year - 2018)

10. Koshlyakova A.N., Sobolev A.V., Krasheninnikov S.P., Batanova V.G., Borisov A.A. The influence of K and Na on Ni partitioning between olivine and silicate melt The problems of magmatic and metamorphic petrology, geodynamics and genesis of diamonds, Abstracts of International Conference dedicated to the 110th anniversary of Academician V.S. Sobolev, Novosibirsk, June 9-14, 2018/Rus. Acad, of Sciences; Sib. Branch, V.S. Sobolev Institute of Geology and Mineralogy. - Novosibirsk. p. 121. (year - 2018)

11. Koshlyakova A.N., Sobolev A.V., Krasheninnikov S.P., Batanova V.G., Borisov A.A. Ni and Mn Partitioning Between Olivine and Highly Alkaline Melts AGU-Fall meeting 2018., - (year - 2018)

12. Krasheninnikov S.P., Sobolev A.V., Asafov E.V., Kargaltsev A.A., Borisov A.A. Рутинная методика гомогенизации расплавных включений в минералах в высокотемпературной печи при атмосферном давлении Всероссийский ежегодный семинар по экспериментальной минералогии, петрологии и геохимии 18–19 апреля 2018 г., Тезисы докладов. Москва 2018. ВЕСЭМПГ-2018-080 (year - 2018)

13. Krasheninnikov S.P., Sobolev A.V., Batanova V.G., Borisov A.A. Экспериментальное изучение равновесия оливин-расплав в области высоких температур и восстановительных условий при атмосферном давлении Всероссийский ежегодный семинар по экспериментальной минералогии, петрологии и геохимии 18–19 апреля 2018 г., Тезисы докладов. Москва 2018. ВЕСЭМПГ-2018-082 (year - 2018)

14. Krasheninnikov S.P., Sobolev A.V., Batanova V.G., Borisov A.A., Kargaltsev A.A High-temperature loop-technique experiments: the new constraints on olivine and silicate melt equilibria at Early Earth and Lunar mantle conditions The problems of magmatic and metamorphic petrology, geodynamics and genesis of diamonds, Abstracts of International Conference dedicated to the 110th anniversary of Academician V.S. Sobolev, Novosibirsk, June 9-14, 2018/Rus. Acad, of Sciences; Sib. Branch, V.S. Sobolev Institute of Geology and Mineralogy. - Novosibirsk. p. 125 (year - 2018)

15. Sobolev, A., Asafov, E., Gurenko, A., Arndt, N., Batanova, V., Portnyagin, M., Garbe-Schönberg, D., Krasheninnikov, S., Wilson, A. and Byerly, G. Deep Mantle H2O Recycling at 3.3 Ga? Goldschmidt Abstracts, 2018, Goldschmidt Abstracts, 2018, 2378 (year - 2018)

Annotation of the results obtained in 2017
The key result of the project (Sobolev et al., Nature 2016) on the presence of a deep-mantle hydrous reservoir in the Archean was confirmed (Asafov et al., 2017, 2018). Excess concentrations of H2O, Cl and, to a lesser extent, F in the primary melts of the komatiites from the Belingwe Greenstone Belt (2.7 Ga, Zimbabwe) and from the Barberton Greenstone Belt, Weltevreden Formation (3.3 Ga, South Africa) were established by the methods of studying olivine-hosted melt inclusions. These results together with the similar data obtained for the first time for the 2.7 Ga Abitibi Greenstone Belt komatiites (Canada, Sobolev et al., 2016) evidence the probable influx of H2O, Cl, and to a lesser extent, F into the mantle transition zone of Earth 3 Ga ago. The unexpected and probably breakthrough result suggests the contemporary deep mantle zones of Earth can be as hot as 2.7 billion years ago (Trela et al., Nature Geoscience 2017). Despite the well-established theory of the Earth’s mantle secular cooling for the last 3 billion years, we, in collaboration with colleagues from the USA, established crystallization temperatures of 1570°C for only 90 million years old Caribbean magmatic province magmas (Trela et al, 2017). Temperature estimates were obtained by applying the two independent methods: Fe-Mg olivine-melt geothermometer accounting for the water contents in olivine-hosted melt inclusions and Al-in-olivine-spinel geothermometer. This result indicates temperatures over 1750°C of the 200 km deep Caribbean mantle flux source and hence the preservation of Archean temperatures in the Earth’s contemporary deep mantle. On the basis of the Al-in-olivine-spinel geothermometer developed at the previous stage the significant crystallization temperature variations for the different geodynamic type magmas were defined. The maximum crystallization temperatures were estimated for the MgO-rich olivines from the ocean islands and large igneous provinces, intermediate temperatures – for the mid ocean ridge basalts and the minimum temperatures – for the Gaussberg volcano ultrapotassic lamproites, Antarctica. These results are the direct evidence of the ideas supporting variable temperature regime of mantle fluxes in the convecting upper mantle and the mantle part of the lithosphere. The second stage melting of the depleted mantle in the absence of subduction zone derived water fluid was indicated (Golowin et al., 2017). Previously, the probability of a considerable second stage mantle melting was intended only for the subduction zones and was associated with the influx of water fluid into the hot mantle material. The second stage melting of mantle may also occur in the intraplate ocean environment in the absence of aqueous fluid as was demonstrated together with the colleagues form Germany based on the comparative study of volcanic rocks forming the 120 million years old Manihika plateau in the Pacific Ocean and suprasubduction boninites of the ophiolite Troodos massif (90 million years, Cyprus ). The generation of Manihika plateau lavas is suggested to result from the recycling of the depleted mantle as a part of a mantle plume and its heating up to temperatures over 1450°C, sufficient for its second stage melting at less than 50 km depth. The important results that promoted the methods used in the project were achieved in 2017. In particular, the new olivine standard for defining of the major, minor and trace elements was developed (Batanova et al., 2017) and the method of the high precision electron probe microanalysis (EPMA) of olivine was significantly improved (Batanova et al., 2018). The new quantitative model separating the effect of temperature and melt composition on the nickel and magnesium distribution between the olivine and the melt was developed (Sobolev et al., 2017). The new data on the reproducibility of the reconstruction of melt inclusion compositions were obtained by studying the artificial olivine hosted melt inclusions (Sobolev et al., 2017). 10 research works including 4 WoS indexed papers were published by the research team of the project in 2017. These include 3 papers published in the First quartile journals (Q1 rank, WoS) with one of them in Nature Geoscience – the top rating geoscience journal. The results of the project were presented in 5 reports at major international conferences, including 2 invited plenary reports.

Publications

1. Asafov E.V., Sobolev A.V., Gurenko A.A., Arndt N.T., Batanova V.G., Portnyagin M.V. Garbe-Schönberg D., Krasheninnikov S.P. Belingwe komatiites (2.7 Ga) originate from a plume with moderate water content, as inferred from inclusions in olivine Chemical Geology, - (year - 2018) https://doi.org/10.1016/j.chemgeo.2017.11.002

2. Batanova V.G., Sobolev A.V., Magnin V Trace element analysis by EPMA in geosciences: detection limit, precision and accuracy Journal of Physics: Conference Series Materials Science and Engineering, - (year - 2018)

3. Golowin R, Portnyagin M, Hoernle K, Sobolev A, Kuzmin D, Werner R The role and conditions of second-stage mantle melting in the generation of low-Ti tholeiites and boninites: The case of the Manihiki Plateau and the Troodos Ophiolite. Contributions to Mineralogy and Petrology, 172:104 (year - 2017) https://doi.org/10.1007/s00410-00017-01424-00413

4. Trela J., Gazel E., Sobolev A.V., Moore L., Bizimis M., Jicha B. and V.G. Batanova The hottest lavas of the Phanerozoic and the survival of deep Archean reservoirs. Nature Geoscience., 10, 451-456 (year - 2017) https://doi.org/10.1038/ngeo2954

5. V.G.Batanova, A.V.Sobolev, Magnin V. Trace element analysis by EPMA in geosciences: current state and perspectives. Book of tutorials and abstracts, EMAS 2017 IUMAS 7,15 th Europian workshop on Modern developments and applications in microbeam analysis, . p 55- 73 (year - 2017)

6. A.V. SOBOLEV, A.W. HOFMANN, S.P. KRASHENINNIKOV, V.G. BATANOVA, E.V.ASAFOV, N.T. ARNDT, A.N. KOSHLYAKOVA AND BORISOV A.A New experiments and komatiites vindicate nickel in magmatic olivine as a monitor of mantle lithology Goldschmidt 2017 Abstracts, p.p.36-38 (year - 2017)

7. Asafov E.V., Sobolev A.V., Gurenko A.A., Arndt N.T., Batanova V.G., Portnyagin M.V., Garbe-Schonberg D., Krasheninnikov S.P. Water in the 2.7 Ga Belingwe komatiite magma inferred from the melt inclusions in olivine Goldschmidt 2017 Abstracts, p.p.27 (year - 2017)

8. Asafov E.V., Sobolev A.V., Gurenko A.A., Arndt N.T., Batanova V.G., Portnyagin M.V., Garbe-Schonberg D., Krasheninnikov S.P., Wilson A.H. and Byerly G.R. Olivine-Hosted Melt Inclusions in the Ancient Komatiites – the Potential Key to the Archean Mantle Composition ECROFI-2017, - (year - 2017)

9. Asafov E.V., Sobolev A.V., Gurenko A.A., Portnyagin M.V., Arndt N.T., Batanova V.G., Krasheninnikov S.P. Состав расплавов коматиитов зеленокаменного пояса Белингве (Зимбабве) по данным изучения расплавных включений в оливине ВЕСЭМПГ-2017-009, с.121 (year - 2017)

10. Batanova V, Sobolev A, Thompson J M, Danyushevsky L V, Goemann K, Portnyagin M V, Garbe-Schonberg D, Hauri E H, Kimura J-I, Chang Q, Senda R, Chauvel C, Campillo S, Ionov D,. Data on new Olivine reference material MongOL Sh11-2 for in-situ microanalysis. Goldschmidt Conf., Paris, 2017, p.p.244-246 (year - 2017)

11. - Тело еще не остыло Чердак: науки, технология, будущее ТАСС, Екатерина Боровикова 23.11.2017 Наука (year - )