The 5th International Conference of Geobiology

Biominerals serve as critical archives for deciphering life-environment interactions throughout geological history (Pérez-Huerta et al., 2018). As exemplary products of biologically controlled mineralization, the structural-compositional signatures of biological apatite preserve key records of metabolic processes. However, geological alteration often obscures these biogenic features, posing significant challenges for identifying the primary biological signals in paleontological and archaeological materials. While nanoscale heterogeneity in mineral structure and composition may retain primary biogenic information, resolving such features requires cutting-edge analytical methodologies. Atom probe tomography (APT), currently the highest-resolution characterization technique, offers unprecedented three-dimensional elemental mapping at sub-nanometer resolution, demonstrating exceptional potential for decoding structural-compositional information within biominerals.
Our APT comparative analysis of modern human enamel and Qin Dynasty ancient enamel (~2200 BP) reveals distinct mineralization patterns. Modern enamel exhibits Mg-Na-F enrichment in hydroxyapatite crystal core with depletion in shell and slight enrichment at intergranular phase, consistent with previous findings (DeRocher et al., 2020). In contrast, Qin specimens retain Mg-rich cores but display inverted Na-F distribution patterns: depletion in core and intergranular phase regions versus significant enrichment in shell, suggesting dietary influences on mechanical property evolution. Further investigation of Early Triassic conodont phosphate fossils reveals residual organic components (C-N co-enrichment) despite extensive biogenic degradation and diagenetic alteration. Most regions show dispersed C-N distribution, documenting dynamic organic degradation processes (Gao et al., 2024).

References
Pérez-Huerta A., Coronado I., Hegna T. A., 2018. Understanding biomineralization in the fossil record. Earth-Science Reviews, 179, 95-122.
DeRocher K.A., Smeets P.J.M., Goodge B.H., Zachman M.J., Balachandran P.V., Stegbauer L., Cohen M.J., Gordon L.M., Rondinelli J.M., Kourkoutis L.F., Joester D., 2020. Chemical gradients in human enamel crystallites. Nature, 583, 66-71.
Gao F., Xue J., Li X-H., Hu R., Li Q-L., 2024. Atom Probe Tomography Reveals Nano-scale Organic Remaining in Conodont. Atomic Spectroscopy, 45, 1-8.

Acknowledgements
This research was funded by the National Natural Science Foundation of China (42225301).

APT,Apatite,Dental enamel,Conodont