Melt “pockets” and sulfide inclusions: evidence for the garnet megacrysts transformation in alkali basalts (Shavaryn-Tsaram, Tariat Plateau, Mongolia)

Authors

  • Anna V. Aseeva Far East Geological Institute, FEB RAS, Vladivostok, Russia
  • Aleksandr A. Karabtsov Far East Geological Institute, FEB RAS, Vladivostok, Russia
  • Sergey V. Vysotskiy Far East Geological Institute, FEB RAS, Vladivostok, Russia
  • Tatyana A. Velivetskaya Far East Geological Institute, FEB RAS, Vladivostok, Russia
  • Maria A. Ushkova Far East Geological Institute, FEB RAS, Vladivostok, Russia
  • Konstantin P. Kosukhin Far East Geological Institute, FEB RAS, Vladivostok, Russia
  • Aleksey V. Ruslan Far East Geological Institute, FEB RAS, Vladivostok, Russia
  • Viktoriya V. Yakovenko Far East Geological Institute, FEB RAS, Vladivostok, Russia
  • Anton Yu. Sinyov Far East Geological Institute, FEB RAS, Vladivostok, Russia

Keywords:

alkali basaltoids, megacrysts, garnet, melt “pockets”, sulfides inclusions, deep nodules, Win TWQ 2.32, Shavaryn-Tsaram, Mongolia

Abstract

This paper studies sulfide inclusions and melt “pockets” in garnet megacrysts collected from the Shavaryn-Tsaram Cenozoic basaltic cone (Tariat plateau, Mongolia). Syngenetic sulfide inclusions confined to growth zones of garnet megacrysts were formed in garnets due to the presence of two immiscible melts: strongly fluidized silicate and sulfide melts. Isotopic data indicate a mantle source for sulfides (δ34S 0.1–0.4 ‰, δ33S 0.1–0.2 ‰, Δ33S 0.00–0.03 ‰) and host garnets (δ18OVSMOW 5.4 to 5.8 ‰). Formation of garnet megacrysts was caused by hetero- geneous nucleation (epitaxial growth). Silicate inclusions (melt and multi-phase) witnessed garnet megacrysts evolution in alkali basaltic magma. The Win TWQ 2.32 modelling revealed that garnets were captured from the lower horizons of the Earth’s crust at P = 0.8–1 GPa and T = 1120–1160 °C and multi-phase silicate inclusion was crystallized at same pressure but lower temperatures: P = 0.85–1.1GPa and T = 790–950 °C.

Author Biographies

Anna V. Aseeva, Far East Geological Institute, FEB RAS, Vladivostok, Russia

Candidate of Sciences in Geology and Mineralogy, Senior Researcher

https://orcid.org/0000-0001-5809-8125

Aleksandr A. Karabtsov, Far East Geological Institute, FEB RAS, Vladivostok, Russia

Candidate of Sciences in Geology and Mineralogy, Leading Researcher, Head of Laboratory

Sergey V. Vysotskiy, Far East Geological Institute, FEB RAS, Vladivostok, Russia


Doctor of Sciences in Geology and Mineralogy Chief Researcher, Head of Laboratory 

http://orcid.org/0000-0002-5194-5616

Tatyana A. Velivetskaya, Far East Geological Institute, FEB RAS, Vladivostok, Russia

Candidate of Sciences in Geology and Mineralogy, Leading Researcher, Head of Laboratory  

https://orcid.org/0000-0002-2833-1026

Maria A. Ushkova, Far East Geological Institute, FEB RAS, Vladivostok, Russia

Engineer 

Konstantin P. Kosukhin, Far East Geological Institute, FEB RAS, Vladivostok, Russia

Engineer

Aleksey V. Ruslan, Far East Geological Institute, FEB RAS, Vladivostok, Russia

Candidate of Sciences in Geology and Mineralogy, Junior Researcher

Viktoriya V. Yakovenko, Far East Geological Institute, FEB RAS, Vladivostok, Russia

Candidate of Sciences in Geology and Mineralogy, Senior Researcher

http://orcid.org/0000-0003-3834-3626

Anton Yu. Sinyov, Far East Geological Institute, FEB RAS, Vladivostok, Russia

Engineer 

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Published

2023-10-16

How to Cite

Aseeva А. В., Karabtsov А. А., Vysotskiy С. В., Velivetskaya Т. А., Ushkova М. А., Kosukhin К. П., Ruslan А. В., Yakovenko В. В., & Sinyov А. Ю. . (2023). Melt “pockets” and sulfide inclusions: evidence for the garnet megacrysts transformation in alkali basalts (Shavaryn-Tsaram, Tariat Plateau, Mongolia). Vestnik of the Far East Branch of the Russian Academy of Sciences, (5), 82–100. Retrieved from http://vestnikdvo.ru/index.php/vestnikdvo/article/view/1123

Issue

No. 5 (2023)

Section

Earth and environment sciences