[M-IS18] Paleoclimatology and paleoceanography

[MIS18-23] Sensitive analysis of carbon dioxide isotopologues using a tunable mid-infrared laser direct absorption spectroscopy and its implication for paleoclimatology

*Akihiro Kano¹, Saburo Sakai² (1.Graduate School of Science, The University of Tokyo, 2.Japan Agency for Marine-Earth Science and Technology)

Keywords:infrared absorption spectroscopy, isotopologue, carbonate, carbon dioxide

Oxygen and carbon stable isotope ratios of CO₂ have contributed to understanding of Earth and planetary systems, especially in field of paleoclimate and paleoceanography. Isotope ratio mass spectrometry (IRMS) is used to measure the stable isotope ratio of carbon dioxide, but recent advances in laser technology enables us to provide a sensitive and accurate measurement by laser spectroscopic technique which is comparable or surpass to IRMS. Here we report a novel method using a tunable mid-infrared laser direct absorption spectroscopy (TILDAS) for measuring the ratios of isotopes from nanomolar CO₂. This method is more sensitive than the conventional IRMS currently available. In addition, our TILDAS system is also potential to analyze ¹⁷O/¹⁶O and carbonate clumped isotopes. Our preliminary results can be a significant mile stone in a number of fields for sensitivity CO₂ isotopic analyses, also for application of rare isotopologues. We will also represent some examples for applying paleoclimatology.