The clumped isotope paleothermometer (Δ47) has been used to reconstruct temperatures from various biogenic carbonate archives. Calibration studies demonstrate that some biogenic carbonates precipitate in Δ47 equilibrium and record growth temperatures accurately (e.g., many bivalve mollusks), while others appear to exhibit disequilibrium, or ‘vital’, effects and yield isotopically reconstructed temperatures that are biased (e.g., shallow-water corals). These studies have largely excluded marine gastropods, so it is not known whether they tend to precipitate their shells in or out of isotopic equilibrium. In this study, we present seasonal-scale δ18O and seasonally targeted Δ47 and Δ48 measurements from modern marine gastropods representing 8 genera and 10 species, reconstructing apparent growth temperatures and screening for equilibrium precipitation. We find that most marine gastropods appear to precipitate in Δ47 and Δ48 equilibrium and faithfully record environmental temperatures, making them suitable for Δ47-paleothermometry. A few gastropods (Caviturritella/Turritella sp., Campanile symbolicum, Megastraea undosa) appear to precipitate out of Δ47 equilibrium, though these disequilibrium signatures may partially be explained by differences between actual growth temperatures and instrumental calibration temperatures (Caviturritella/Turritella sp., M. undosa) or differences between inner and outer layer precipitation (C. symbolicum). We present new Δ47-temperature data for 2 Middle Eocene Campanile giganteum fossils collected from the Paris Basin and discuss how to interpret the results in the context of our modern samples. Finally, in conducting this calibration we demonstrate paired Δ47/Δ48 as an effective tool to screen for disequilibrium precipitation in marine gastropods.
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RBINS Staff Publications 2025 OA
CO2 enhanced oil recovery can play a significant role in stimulating carbon capture and storage because of additional oil revenues generated. However, it also leads to additional greenhouse gas emissions. We estimate the global warming potential of different CO2 capture scenarios with and without enhanced oil recovery. During a 10 year period in which oil and electricity are produced without CO2 being captured, the global warming potential is 11 MtCO2 equivalents. We show that if CO2 is captured and used for 15 years of enhanced oil recovery, the global warming potential decreases to 3.4 MtCO2 equivalents. This level is 100% higher compared to the scenario in which the captured CO2 would be stored in an offshore aquifer instead. If the capture of CO2 is stopped when the oil reservoir is depleted, the global warming potential resulting from 10 years electricity production is 6 MtCO2 equivalents. However, if CO2 is stored in the depleted reservoir, the global warming potential is six times lower during that period. Electricity production and oil refining are the main contributors to the global warming potential. The net present value analysis indicates that for CO2 prices lower than or equal to 15 €/t and oil prices greater than or equal to 115 €/t, it is most profitable to capture CO2 for enhanced oil recovery only. Because of the low CO2 price considered, large incomes from oil production are required to stimulate CO2 capture. The environmental economic trade-off analysis shows that if CO2-enhanced oil recovery is followed by CO2 capture and storage, costs increase, but the net present value remains positive and the global warming potential is reduced. Authorities could use these outcomes to support the development of economic mechanisms for shared investments in CO2 capture installations and to mandate both oil producer and large CO2 emitting firms to store CO2 in depleted oil fields.
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RBINS Staff Publications 2019
