Mg/Ca ratios

Our new study delivers the most extensive calibration to date of Patella caerulea (the Mediterranean limpet) as a recorder of sea surface temperatures (SSTs) across the Central and Eastern Mediterranean. The study combined laser-induced breakdown spectroscopy (LIBS) for measuring Mg/Ca ratios with isotope ratio mass spectrometry (IRMS) to analyse oxygen isotope values (δ18O). By analysing 131 modern shells from 22 sites, we explored the relationship between magnesium-to-calcium (Mg/Ca) ratios and oxygen isotope values as palaeotemperature proxies.

Using LIBS to evaluate Mg/Ca ratios in limpet shells from Atlantic and sub-Antarctic regions, this study demonstrates that these ratios can serve as robust palaeotemperature proxies when intra-shell variability is carefully accounted for. The results support the expanded use of LIBS for rapid and high-resolution shell-based climate reconstructions in archaeological and environmental research.