The geochemistry of modern calcareous barnacle shells and applications for palaeoenvironmental studies

Strong systematic fluctuations in Mg/Ca ratios over length scales of ca. 5-15 µm are exhibited by the scalpelliform species Capitulum mitella, the only studied species which consistently forms high Mg calcite, and are tentatively linked to tidal control on the shell secretion pattern. Cathodoluminescence images for this species suggest that additionally a seasonal pattern of Mn distribution in its shell plates is recorded, pointing to a potential use for reconstruction of seasonal changes in terrestrial element supply.