Surface precipitation recorded in Neoarchean magmatic-hydrothermal systems of the Kola Craton

• The project involves mapping and measuring the low-δ¹⁸O rocks and minerals from the 2.67 Ga peralkaline granites and host rocks in the Kola Craton

• The lowest d18O value so far measured is -9‰ indicating involvement of meteoric water already in the Neoarchean

• The combined δ¹⁸O-Δ¹⁷O values indicate presence of significantly ¹⁸O-depeleted meteoric waters with δ¹⁸O = -18‰ relative to the hydrosphere. Perhaps, the earliest quantitative reconstruction of meteoric waters

• The magmatic stage of the system is now tightly constrained by low-δ¹⁸O zircon CA-ID-TIMS dates to 2673.5 ±0.3 Ma

• Relevant papers: https://doi.org/10.1016/j.epsl.2021.117322; https://doi.org/10.1130/G050702.1

Paleoproterozoic snowball Earth glaciations, their timing and conditions based on the triple O-isotope systematics of altered rocks

• Surface temperatures and timing of melt-water infiltration during Snowball Earth glaciations based on O-isotope geochemistry of subglacial rocks

• New occurrences of low-δ¹⁸O signatures across cratons, their potential connections in the Paleoproterozoic based on O-isotopes

• Contemporaneous record of seawater (δ¹⁸O and solutes) using submarine altered basalts

• Relevant papers: https://doi.org/10.1130/G38759.1; https://doi.org/10.1016/j.precamres.2019.105431

Modern-day water-rock reactions traced with triple O isotopes

• The systematics of δ¹⁸O-Δ¹⁷O exchange during seawater/meteoric water - basalt reactions in Iceland with measurements of rocks and fluids

• Modern-day seawater-basalt exchange traced with the Δ¹⁷O measurements of submarine vent fluids

• Relevant papers: https://doi.org/10.1016/j.chemgeo.2019.119312; https://doi.org/10.3389/feart.2021.691699

Understanding the O-isotope composition of cherts

• Temperature of terrestrial oceans is poorly constrained for the majority of the geological timescale. Cherts initially precipitate from seawater as amorphous silica and have a potential to preserve the information about ancient oceans.

• We combine high spatial resolution SIMS measurements and high-precision δ¹⁸O-Δ¹⁷O values of cherts across the geological timescale

• Most recent project targets seafloor-drilled cherts that were never exposed to subaerial conditions

• Relevant papers: http://dx.doi.org/10.2138/rmg.2021.86.10; https://doi.org/10.1029/2022GC010741