Coastal sabkha dolomites and calcitised sulphates preserving the Lomagundi-Jatuli carbon isotope signal

A T Brasier* (Corresponding Author), A E Fallick, A R Prave, V A Melezhik, A Lepland, FAR-DEEP Scientists

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

24 Citations (Scopus)


Palaeoproterozoic Tulomozero Formation carbonates of the Onega basin were targeted by ICDP FAR-DEEP Hole 10B. The recovered rocks contain abundant evidence for Palaeoproterozoic gypsum and anhydrite, particularly in the form of pseudomorphs of inclusion-containing nodules, swallow-tail twinned crystals and evaporite dissolution breccias. Similarly, sand-patch fabric indicates the former presence of surface-covering salt crusts in the Palaeoproterozoic. Atmospheric oxygen and seawater sulphate levels at that time must have been sufficient to allow such sulphates to form. Carbonate delta(13)C values are considered sedimentary or early diagenetic, predating greenschist fades metamorphism associated with the Sve-cofennian Orogeny. These carbonate delta(13)C values range from +7.7 to +15.7 parts per thousand, with the highest (and lowest) values found in dolostones. The dolostones as well as calcitised calcium sulphates record the Lomagundi-Jatuli signal. However evidence for activity of sulphate-reducing and/or methanogenic bacteria seems to be lacking. Dolomite precipitation (or dolomitisation), calcium sulphate calcitisation and production of the high (13)C values (processes which typically involve such bacteria in the Phanerozoic) are thus inferred to have proceeded without the direct influence of sulphate reducers and methanogens. The most plausible explanation for the Lomagundi-Jatuli excursion seems to remain significant sequestration of organic carbon in a location yet to be identified. (C) 2011 Elsevier B.V. All rights reserved.

Original languageEnglish
Pages (from-to)193-211
Number of pages19
JournalPrecambrian Research
Issue number1-2
Early online date16 Jun 2011
Publication statusPublished - Aug 2011

Bibliographical note

ATB is supported by NERC grant NE/G00398X/1. VAM is supported by NFR grant 191530/V30 (projects 331000 and 802795). D. Rychanchik and A. Romashkin (Institute of Geoloogy, Petrozavodsk, Russia) provided onsite and archive core documentation. Aivo Lepland (NGU), Ronald Conze (ICDP; Potsdam, Germany) and Melanie Mesli (NGU) developed FAR-DEEP database. Melanie Mesli (NGU) provided essential logistical support. Alcides Sial and another journal reviewer provided helpful comments which improved the manuscript. This is contribution (paper) #3 to the ICDP FAR-DEEP project.


  • palaeoproterozoic
  • lomagundi
  • gypsum
  • carbon isotope
  • methanogenesis
  • sabkha
  • palaeoproterozoic magnesite
  • microbial mediation
  • atmospheric oxygen
  • seawater sulfate
  • rise
  • evaporites
  • water
  • dolomitization
  • environments
  • association


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