CRYSTALLOGRAPHIC INFLUENCE ON ELEMENTAL UPTAKE BY CALCITE FROM ARTIFICIAL SEAWATER

Understanding mechanisms of trace or minor elements (impurities) incorporation into calcite is fundamental in deciphering paleoceanographic proxies. Calcite, a widespread carbonate mineral, features a unique rhombohedral crystallography, segmented into 'a', 'b', and 'c' axes. As atomic configuration can be different on the surface of these crystallographic planes.

This study explored an uptake of impurities across these axes from artificial seawater, simulating a natural marine environment. New layer of calcite was precipitated on the differently oriented cleavage fragments of Iceland spar and examined with LA-ICP-MS depth profiling technique. Experimental results revealed a noticeable difference in the incorporation of Sr and Mg. The 'a' axis demonstrated the greatest uptake, while the 'b' axis exhibited the lowest.

The obtained data highlight the significant role of crystallographic control in the incorporation of impurities into calcite, shedding light on the complex dynamics of elemental uptake in marine carbonates. This research paves the way for more refined geochemical modeling, strengthens the interpretive power of paleoceanographic proxies, and emphasizes the need for continued research into this complex interplay between crystallographic, kinetic, and thermodynamic effects.