The chemical and mineral composition of gabbroids of the pre-Jurassic basement of the Syunay-Salin area located in the Arctic part of the West Siberian megabasin on Yamal Peninsula is studied. Borehole 45 has drilled a layered gabbrodiorite intrusion, which was previously considered monotonic diorite one. The gabbroids are metamorphosed under conditions of the lower degree of the greenschist facies of metamorphism and also underwent propylitization, which is resulted in the formation of sulfdes including pyrite, chalcopyrite, also pyrrhotite, pentlandite, cubanite, samaniite and galena. According to mineral geothermometers, sulfde dissemination in Syunay-Salin gabbroids formed at temperature of ~200 °С.

Figures 4. Tables 3. References 22.

Key words: Arctic, South Yamal, Syunay-Salin area, pre-Jurassic basement, gabbro, sulfdes 

Yu.V. Erokhin, Zavaritsky Institute of Geology and Geochemistry, Urals Branch of RAS, ul. Akademika Vonsovskogo, 15, Yekaterinburg, 620016 Russia;
erokhin-yu@yandex.ru

K.S. Ivanov, Zavaritsky Institute of Geology and Geochemistry, Urals Branch of RAS, ul. Akademika Vonsovskogo, 15, Yekaterinburg, 620016 Russia

V.S. Bochkarev,  Zavaritsky Institute of Geology and Geochemistry, Urals Branch of RAS, ul. Akademika Vonsovskogo, 15, Yekaterinburg, 620016 Russia;
Екатеринбург, 620016 Россия; OAO «Siberian Scientifc Analytical Center», ul. Permyakova, 46, Tyumen, 625016 Russia

V.S. Ponomarev, Zavaritsky Institute of Geology and Geochemistry, Urals Branch of RAS, ul. Akademika Vonsovskogo, 15, Yekaterinburg, 620016 Russia

A.V. Zakharov, Zavaritsky Institute of Geology and Geochemistry, Urals Branch of RAS, ul. Akademika Vonsovskogo, 15, Yekaterinburg, 620016 Russia

1. Areshev E.G., Gavrilov V.P., Dong Ch.L., Zao N., Popov O.K., Pospelov V.V., Shan N.T., Shnip O.A. (1997) [Geology and petroleum potential of the basement of the Sunda shelf]. Moscow, Neft i Gas, 288 p. (in Russian)
2. Batt A.P. (1972) Nickel distribution in hexagonal and monoclinic pyrrhotite. Canadian Mineralogist, 11, 892-897.
3. Bochkarev V.S., Brekhuntsov AM., Lukomskaya KG. (2010) [Fold basement of the Yamal Peninsula]. Gornyye vedomosti [Mining Newsletters], (8), 6-35. (in Russian)
4. Bochkarev V.S., Brekhuntsov AM., Nesterov (jn) I.I., Ognev D.A. (2018) [Targeted study of prospects for oil and gas potential of the Paleozoic complexes of the Western Siberia]. Gornyye vedomosti [Mining Newsletters], (5), 6-19. (in Russian)
5. Borishanskaya B.S., Vinogradova R.A, Krutov G.A. (1981) [Ni and Co minerals]. Moscow, MGU, 224 p. (in Russian)
6. Durazzo A., Taylor L.A. (1982) Exsolution in the Mss-Pentlandite system: textural and genetic implications for Ni-sulfde ores. Mineralium Deposita, 17, 313-332.
7. Erokhin Yu.V., Ivanov KS. (2015) [Fayalite from gabbro of the pre-Jurassic basement of Novoportovskaya area (South Yamal, Arctic)]. Trudy IGG UrO RAN [Proceedings of the Institute of Geology and Geochemistry of the Urals Branch of the Russian Academy of Sciences], 162, 159-162. (in Russian)
8. Erokhin Yu.V., Ivanov KS. (2016) [Mineralogy of fayalite gabbro from the pre-Jurassic basement of Novoportovskaya area (South Yamal, Arctic)]. Vestnik Ural’skogo otdeleniya RMO [Bulletin of the Ural Branch of the Russian Mineralogical Society], (13), 43-51. (in Russian)
9. Erokhin Yu.V, Khiller V.V., Ivanov KS., Rilkov S.A, Bochkarev V.S. (2014) [Mineralogy of metamorphic schists from the pre-Jurassic basement of the southern part of the Yamal Peninsula]. Litosfera [Lithosphere], 14(5), 136-140. (in Russian)
10. Fedorov Yu.N., Ivanov KS., Sadykov M.R., Pecherkin M.F., Krinochkin V.G., Zakharov S.G., Krasnobaev A.A., Erokhin Yu.V. (2004) [Structure and oil and gas potential of the pre-Jurassic complex of the territory of the KhMAO: new approaches and methods]. Puti realizatsii neftegazovogo potentsiala KHMAO [Ways of using of oil and gas potential of KhMAO]. Khanty-Mansiysk, 1, 79-90. (in Russian)
11. Ivanov KS., Erokhin Yu.V, Bochkarev VS., Sergeev S.A., Shokal’sky S.P. (2012) [Isotopic U-Pb dating of granites from the Yamal basement]. Gornyye vedomosti [Mining Newsletters], (11), 26-34. (in Russian)
12. Ivanov KS., Erokhin Yu.V, Ponomarev VS., Fedorov Yu.N., Kormil’tsev V.V., Klets A.G., Sazhnova I.A. (2007) [Granitoid complexes of the basement of Western Siberia]. Sostoyaniye, tendentsii i problemy razvitiya neftegazovogo potentsiala Zapadnoy Sibiri [State, trends and problems of the development of oil and gas potential of Western Siberia]. Tyumen, FGUP «ZapSibNIIGG», 49-56. (in Russian)
13. Kitakaze A., Itoh H., Komatsu R. (2011) Horomanite, (Fe,Ni,Co,Cu)9S8, and samaniite Cu2(Fe,Ni)7S8 new mineral species from the Horoman peridotite massif, Hokkaido, Japan. Journal of Mineralogical and Petrological Sciences, 106, 204-210.
14. Kharin N.V, Shelekhov A.P. (2005) [Structural features of the Verkhnorechenskaya fault zone]. Gornyye vedomosti [Mining Newsletters], (12), 64-73. (in Russian)
15. Kostov I., Mincheva-Stefanova Y. (1984) [Sulfde minerals. Crystal chemistry, parageneses, systematics]. Moscow, Mir, 281 p. (in Russian)
16. Melekestseva I.Yu. (2007) [Heterogeneous cobalt-bearing massive sulfde deposits in ultramafc rocks from the paleoisland-arc structures]. Moscow, Nauka, 245 p. (in Russian)
17. Nenasheva S.N., Kravchenko T.A. (2015) Composition features of isocubanite and polymorphous modifcations of CuFeS compound. Geology of Ore 23 Deposits, 57, 626-633.
18. Schwarzenbach E.M., Gazel E., Caddick M.J. (2014) Hydrothermal processes in partially serpentinized peridotites from Costa Rica: evidence from native copper and complex sulfde assemblages. Contributions to Mineralogy and Petrology, 168, 1079.
19. Shishkin N.N., Karpenkov A.M., Kulagov E.A., Mitenkov G.A. (1974) [Classifcation of minerals of the pentlandite group]. Doklady AN SSSR [Doklady Academy of Sciences of the USSR], 217(1), 194-197. (in Russian)
20. Ugryumov A.N. (2014) [Diorites in section 45 of the Syunay-Salin borehole]. Gornyye vedomosti [Mining Newsletters], (9), 44-48. (in Russian)
21. Votyakov S.L., Ivanov K.S., Khiller V.V., Bochkarev V.S., Erokhin Yu.V. (2011) Chemical microprobe Th-U-Pb age dating of monazite and uraninite grains from granites of the Yamal crystalline basement. Doklady Earth Sciences, 439(1), 994-997.
22. Votyakov S.L., Ivanov K.S., Erokhin Yu.V., Khiller V.V., Bochkarev VS., Zakharov A.V., Korotkov S.A. (2013) [Mineral composition and chemical microprobe Th-U-Pb-dating of granites from the basement of the Yamal Peninsula]. Litosfera [Lithosphere], 13(3), 57-66. (in Russian)