Journal article
Crystallization pathways, fabrics and the capture of climate proxies in speleothems: Examples from the tropics
S Frisia, A Borsato, A Hartland, M Faraji, A Demeny, RN Drysdale, CE Marjo
Quaternary Science Reviews | Published : 2022
Abstract
The quality of climate proxy data from speleothem archives depends to varying degrees on crystallization processes, which result in diverse fabrics. Here, we document shifts in calcite growth mechanisms, from ion-by-ion to nanoparticle/nanocrystal attachment, in stalagmites from the tropical island of Atiu (South Pacific). Changes in solution stoichiometry and organic matter content result in the development of two columnar fabrics that are common elsewhere in settings characterized by seasonal contrast. A porous columnar fabric, characterized by intracrystalline micro and nanoporosity grows via a non-classical pathway through amorphous calcium carbonate (ACC) nanoparticles (∼2–4 nm in diame..
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Awarded by Australian Research Council
Funding Acknowledgements
This study was supported by the Australian Research Council Discovery Project grant DP160101058. Special thanks to thelandowners, people and Island Council, and to the National Research Committee of the Cook Islands for sampling permission. We are grateful to Roger Malcom who collected monthly rainwater samples, and to Tura Koronui and George Mateariki, who intro-duced us to the caves in Atiu. We are indebted to Sergey Rubanov at the Bio 21 Melbourne Advanced Microscopy Unit and Huiming Zhang at the EM-X-Ray Unit of University of Newcastle for assis-tance at FIB and HRTEM, and to Martin Dietzel (University of Graz) for discussion about the kinetics of oxygen isotope incorporation in calcite. Four anonymous reviewers have condiderably helped in improving the clarity of the manuscript.