Fig. 4: Compositional profile through the APT reconstruction across the nacre tablet.
From: Growth dynamics and amorphous-to-crystalline phase transformation in natural nacre
The qualitative profile across the APT reconstruction shown in Fig. 3. The plot is divided by black dashed lines into three sections: Sr-poor aragonite, Sr-rich aragonite and interlamellar sheet. The transition from Sr-poor to Sr-rich aragonite is defined by a significant increase in Sr, while the transition from Sr-rich aragonite to the organic interlamellar sheet is defined as the point of intersection between the Ca (grey) and the C (magenta) signals (see methods). The Sr-poor aragonite is characterised by high Ca concentrations indicative of CaCO3, while the Sr-rich area is defined by high Sr (red) at intermediate Ca and the interlamellar sheet by high C and H (yellow) counts. The Sr-enriched area appears within 4 nm of the mineralised nacre tablet adjacent to the organic sheet. The abundance of Na (green) increases steadily from the tablet into the organic sheet. Shaded envelopes depict the first standard deviations.
