Authigenic rhodochrosite from a gas hydrate-bearing structure in Lake Baikal

Alexey A. Krylov, Akihiro Hachikubo, Hirotsugu Minami, Tatyana V. Pogodaeva, Tamara I. Zemskaya, Mariya G. Krzhizhanovskaya, Jeffrey Poort, Oleg M. Khlystov

Research output: Contribution to journalArticlepeer-review

3 Scopus citations

Abstract

Early diagenetic carbonates are rare in Lake Baikal. Siderite (Fe carbonate) concretions in the sediments were discovered only recently. Here, we discuss the first finding of rhodochrosite concretions (Mn carbonate) discovered in the near-bottom sediments of the gas hydrate-bearing seepage structure St. Petersburg-2 in the deep water environment of the Central Baikal Basin. The crystal lattice of rhodochrosite contains iron and calcium substituting to manganese. Based on pore water geochemistry and of δ 13C values of rhodochrosite (− 23.3 and − 29.4‰), carbon dioxide (+ 3.8 to − 16.1‰) and methane (− 63.2 to − 67.8‰), we show that carbonate crystallization most likely occurred during microbial anaerobic oxidation of organic matter, and that part of the oxygen making up the rhodochrosite seems to be derived from the 18O-rich water released from dissociating gas hydrates.

Original languageEnglish
Pages (from-to)2011-2022
Number of pages12
JournalInternational Journal of Earth Sciences
Volume107
Issue number6
DOIs
StatePublished - 1 Sep 2018

Scopus subject areas

  • Earth and Planetary Sciences(all)

Keywords

  • Authigenic carbonates
  • Gas hydrates
  • Lake Baikal
  • Methane
  • Rhodochrosite

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