Clumped Isotope Data Uncovers Concealed CO2 Sink in Ocean Transform Faults

The international research, led by scientists at the Woods Hole Oceanographic Institution (WHOI), analysed rocks from the St. Paul’s transform fault, a remote location 500km off the coast of Brazil. Professor John’s team’s contribution was crucial, providing clumped isotope data that was instrumental in establishing the model presented in the study. 

Transform faults, where tectonic plates slide past each other, have long been considered geologically uneventful due to low volcanic activity. This new research, however, suggests they may act as significant sinks for CO2, as it reveals that mantle rocks exposed along these faults react with CO2-rich hydrothermal fluids, locking away the carbon and potentially impacting global geological CO2 fluxes. 

Professor John’s team’s clumped isotope data provided critical insights into the origin and behaviour of carbon within the rocks. This data, alongside other analyses, helped build the model explaining the carbon capture process within the transform fault. 

Understanding the geological carbon cycle is essential for modelling past and future climate change. This study highlights a previously overlooked mechanism that may have played a significant role in regulating Earth’s climate over millions of years. 

While the amount of CO2 currently emitted by transform faults is negligible compared to human activity, the discovery underscores the importance of considering all aspects of the carbon cycle for accurate climate modelling. 

Professor John comments: “I am delighted that my team and I were able to contribute to this pioneering research in collaboration with our colleagues at WHOI. Our team’s expertise in analysing clumped isotopes in magnesium carbonates played a critical role in this study. Our findings have significant implications for not only our understanding of tectonic carbon cycling but also for the potential to safely sequester carbon in similar rocks at ambient water temperatures. This research could pave the way for new approaches in carbon capture and storage, thereby contributing to the reduction of greenhouse gases in the atmosphere.”