Secondary (biogenic and abiogenic) carbonates as paleoenvironmental proxies
Contact person:
Dr. Gábor Újvári
Secondary carbonates – primarily pedogenic (soil-formed) carbonates and biogenic carbonates of terrestrial snails – are important paleoenvironmental proxies, as their formation is directly linked to changes in climate, hydrological conditions, and soil formation processes.
The stable isotope composition (δ13C, δ18O) of pedogenic carbonates sensitively reflects the sources of CO2 in the soil, the vegetation composition (C3/C4), as well as evaporation and temperature conditions. These carbonates are particularly well suited to the reconstruction of terrestrial paleoenvironments from loess–paleosol sequences or even certain fluvial sedimentary sequences, as their isotopic composition accurately reflects climate and environmental conditions.
Biogenic carbonates from terrestrial snail shells also constitute a valuable archive, as the δ18O values of the shells primarily reflect precipitation isotope ratios, as well as local relative humidity and temperature conditions. Furthermore, the analysis of the clumped isotope (Δ47) in snail shells allows for a direct estimation of the carbonate formation temperature, which is an important quantitative paleoclimatological tool. Furthermore, analysis of clumped isotopes (Δ47) in snail shells allows for direct estimation of the carbonate formation temperature, which is an important quantitative paleoclimatological tool. Snail shells are well suited to the quantitative reconstruction of past precipitation isotopic composition and temperature. They are reliable supplementary proxies for other terrestrial archives.