Diagenesis in Abiotic Calcite: A Biomineralization Approach
Calcite containing marine shells that encode vital paleoclimate information (relating to global warming) can get compromised by isotopic exchange with ambient water. This can lead to overestimation of paleo-temperatures.1 The mechanism of alteration is often attributed to grain-boundary diffusion and mineral dissolution-reprecipitation process. However, the coexistence of multiple factors such as (i) organic inclusions in minerals, (ii) amorphous phase and (iii) the calcitic shell’s ultrastructure make it difficult to study the individual effect of each factor, that is necessary for creating models for accurate paleoclimate prediction.
In this project, we plan to synthesize abiotic calcite where the above three factors could be independently studied in connection with isotopic exchange. Our multidisciplinary approach combines biomineralization,2 nanofabrication3 and NanoSIMS experiments4 to create a variety of biomimetic calcite ultrastructure and quantitatively study the isotope distribution in them. We will also determine analytical parameters such as rate constants relating to diffusion and dissolution/reprecipitation reactions and compare them with those obtained from biogenic counterparts to accordingly quantify the temperature bias in the paleotemperature records pertaining to the latter.
This project has received funding from the European Research Council (ERC) under the European Union’s Advanced Grant (AdG), PE10, ERC-2017-ADG (Grant agreement No. 788752).
- Bernard, S.; Daval, D.; Ackerer, P.; Pont, S.; Meibom, A., Burial-induced oxygen-isotope re-equilibration of fossil foraminifera explains ocean paleotemperature paradoxes. Nature Communications 2017, 8 (1), 1134.
- Raut, H. K.; Schwartzman, A. F.; Das, R.; Liu, F.; Wang, L.; Ross, C. A.; Fernandez, J. G., Tough and Strong: Cross-Lamella Design Imparts Multifunctionality to Biomimetic Nacre. ACS Nano 2020, 14 (8), 9771-9779.
- Raut, H. K.; Wang, H.; Ruan, Q.; Wang, H.; Fernandez, J. G.; Yang, J. K. W., Hierarchical Colorful Structures by Three-Dimensional Printing of Inverse Opals. Nano Letters 2021, 21 (20), 8602-8608.
- Cisneros-Lazaro, D.; Adams, A.; Guo, J.; Bernard, S.; Baumgartner, L. P.; Daval, D.; Baronnet, A.; Grauby, O.; Vennemann, T.; Stolarski, J.; Escrig, S.; Meibom, A., Fast and pervasive diagenetic isotope exchange in foraminifera tests is species-dependent. Nature Communications 2022, 13 (1), 113.