Challenging the oxygen isotope ratio of calcium carbonate using Raman mass spectrometry.

Abstract

This study focused on developing a method for analysing the oxygen isotope ratio of calcium carbonate in otoliths and other microdomains. The isotope ratios of calcium carbonate varies on the micrometre order even within single crystals. Therefore, we set out to develop a method for analysing oxygen isotope ratios in the micro-region. We focused on microscopic Raman spectroscopy, which has excellent spatial resolution and is non-destructive. There have been no examples of isotope ratio analysis using Raman spectroscopy so far, and most of them have been limited to isotope qualification. In this study, errors in the oxygen isotope ratio of calcium carbonate are investigated from Raman spectra and the potential for natural applications is discussed.