- 1Department of Earth and Environmental Sciences, University of Pavia, Pavia, Italy (stefania.corvo@unipv.it)
- 2Institute of Geosciences and Earth Resources of Pavia, C.N.R., Pavia, Italy
- 3Australian Centre for Microscopy and Microanalysis, The University of Sydney, NSW, Australia
- 4School of Aerospace, Mechanical and Mechatronic Engineering, The University of Sydney, NSW, Australia
- 5The University of Sydney Nano Institute, Faculty of Science, University of Sydney, Sydney, NSW, Australia
- 6Research School of Earth Sciences, Australian National University, Canberra, ACT, Australia
- 7School of Earth and Environment, University of Leeds, Leeds, United Kingdom
In the last decades, titanite has gained popularity in the petro- and micro-structural community due to its advantageous compositional and microstructural properties that make it an important tracer of fluids, chemical reactions and deformation mechanisms in the Earth’s crust. Thanks to its crystal structure, titanite incorporates a wide range of minor and trace elements, including OH, the equivalent chemical component of water. Indeed, although titanite is considered nominally anhydrous, it can incorporate significant amounts of OH (up to 0.1 wt.%). Understandings of hydrogen concentration, which constitutes the water molecule, in titanite is important since it can affect the physical and chemical properties of minerals and rocks of the upper mantle/lower crust, such as deformation mechanisms, rheology and fluid flow. Moreover, these studies could be useful to understand the reservoirs and the water cycle in the Earth system. Nevertheless, advanced studies regarding water content in titanite are still lacking. However, thanks to recent improvements in both petrochronological and microstructural techniques, the investigation of the link between hydrogen mobility and deformation processes at the nanoscale is now possible.
In this study, we combined the Atom Probe Tomography (APT) to obtain 3D maps showing the distribution of OH with Photo-induced Force Microscopy (PiFM) to quantify the amounts of OH in selected deformed and undeformed domains of mylonitic titanite. In particular, we investigate OH variations between titanite domains showing different dislocation densities in rock layers with different composition (amphibolite vs calcsilicate). Preliminary results show interesting OH variations though the titanite grains from the different layers and a positive correlation between OH and dislocation densities, suggesting a heterogeneous distribution of water during deformation strongly dependent by the bulk rock composition. This study highlights the importance of a multi-disciplinary, multi-technique approach to advance our understanding the deformation/chemical processes occurring at the nanoscale ultimately governing the large scale rheological and chemical evolution of rocks during major tectonic events.
How to cite: Corvò, S., Chen, Y.-S., Holmes, N., Förster, M. W., Yaxley, G., Maino, M., Langone, A., Cairney, J., and Piazolo, S.: Deformation control on OH distribution at the nanoscale: a case of mylonitic titanite, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-4781, https://doi.org/10.5194/egusphere-egu25-4781, 2025.
