Periodic Reporting for period 4 - PROMOTING (PROgrade metamorphism MOdeling: a new petrochronological and compuTING framework)
Período documentado: 2024-12-01 hasta 2025-11-30
The main goal of PROMOTING was to quantify the fluxes of aqueous fluids and silicate melts released during prograde metamorphism within the Earth's interior, and to model fluid pathways. Understanding the behaviour of these liquids is crucial, as they play a significant role in earthquake generation, arc magmatism, continental crust growth, and global geochemical cycles. However, direct observation in a metamorphic environment is impossible, and indirect geophysical observations lack the required spatial resolution. Additionally, fluid presence in the grain boundary network of a metamorphic rock is important, as it acts as a catalyst, reducing the kinetic barriers to mineral dissolution and growth. However, the presence of fluid often remains invisible once the rock has been dried and brought to the surface.
The PROMOTING project aimed to develop new analytical tools, modelling frameworks and computer programmes to track and simulate fluid-rock interaction processes and fluid flows in the lithosphere. The project focused on quantifying: (1) aqueous fluid fluxes during oceanic subduction, using natural examples from the Alps and the Cyclades, as well as rock composition databases; and (2) silicate melt fluxes during the partial melting of continental crust, using the El Oro massif in Ecuador as a natural case study. Estimates from the natural record were essential for quantifying key model parameters such as permeability for conditions that could not be estimated experimentally. Advanced surface analysis and three-dimensional characterisation of grain shapes and textures are required to investigate the collected samples. To this end, the PROMOTING project has developed several data analysis and data reduction techniques and new computer models.
The PROMOTING project aimed to develop new analytical tools, modelling frameworks and computer programmes to track and simulate fluid-rock interaction processes and fluid flows in the lithosphere. The project focused on quantifying: (1) aqueous fluid fluxes during oceanic subduction, using natural examples from the Alps and the Cyclades, as well as rock composition databases; and (2) silicate melt fluxes during the partial melting of continental crust, using the El Oro massif in Ecuador as a natural case study. Estimates from the natural record were essential for quantifying key model parameters such as permeability for conditions that could not be estimated experimentally. Advanced surface analysis and three-dimensional characterisation of grain shapes and textures are required to investigate the collected samples. To this end, the PROMOTING project has developed several data analysis and data reduction techniques and new computer models.
1) Analytical developments:
An advanced analytical technique for multi-phase quantitative compositional mapping using LA-ICPMS has been developed in the open-source XMapTools software (Markmann et al. 2024). New tools that use a combination of chemical and machine vision strategies to classify complex datasets have also been developed and implemented (Lanari & Tedeschi 2025). A machine learning strategy for mineral shape classification in 3D and a program garNET were developed (Hartmeier et al. 2024).
2) Modelling programs:
A multi-phase flow model has been developed with a new advection algorithm (Dominguez et al., 2024). A multi-rock coupled mechanical-petrochemical model (ThorPT) for simulating the production and extraction of aqueous fluids has been developed. (Markmann 2024). A diffusion model has been developed to simulate element transport in 3D within microCT-derived natural crystal geometries (Dominguez et al 2026). Two new modelling strategies of PROMOTING are still in the process of being developed: a thermodynamic model for aqueous speciation calculations within a Gibbs energy minimiser and a programme for simulating metastable systems.
3) Main applications:
In-situ oxygen isotope analyses were used to quantify critical parameters of fluid flow during high-pressure metamorphism in the Alps and Cyclades (Bovay et al. 2001; Rubatto et al. 2023; Markmann 2024). These applications are based on petrochemical modelling developments from the project. The key finding is that pervasive fluid flow plays a significant part in the transport of fluids in subduction zones, and its activation is closely linked to metamorphic reactions. The investigation of the possible consequences of element redistribution by aqueous fluid during metamorphism was investigated using databases of whole-rock compositions (Forshaw & Pattison, 2022; Forshaw et al. 2024). These studies demonstrate that, overall, aqueous fluids traveling and interacting with rocks have a limited impact. The distribution of garnet crystal shapes in a metabasalt from the Alps enabled the development of a kinetic model of garnet dissolution (Hartmeier et al., 2024). There are very few published quantitative kinetic models of reaction rates, and this new original approach was made possible by the micro-CT developments from the project.
Secondly, several studies focused on petrochronology and modelling melt production in the El Oro Massif in Ecuador and the Fuping Terrane in China (Dominguez, 2024; Liu et al., 2025). The results encompass the refinement of melt production duration in the El Oro complex using zircon geochronology, as well as the production of crustal-scale melt models. In the Fuping Terrane, the analytical developments of the project were employed alongside diffusion modelling. This is the first paper in the literature to demonstrate that mineral growth rates in nature can be as fast as those observed in a laboratory setting (Liu et al. 2025).
4) Other stimulated applications:
The multi-rock petrochemical model developed by the PROMOTING team has shown from the outset that robust pressure-temperature estimates and robust thermodynamic models are critical for the simulation of natural rocks. A complementary study was performed using low-grade condition samples to identify the most suitable thermodynamic database for these conditions in crustal-scale models (Petroccia et al., 2025). A new hybrid method was developed for thermobarometry to estimate robust pressure-temperature conditions in partially equilibrated samples (Nerone et al., 2025). Finally, a machine learning model based on transfer learning was used to calibrate a biotite deep-learning model for improved single-mineral thermometry (Hartmeier et al., 2025).
The project's microCT developments have been used to study the porosity of sandstone (Zhou et al., 2022) and to characterise a historical artefact made from a meteorite (Hofmann et al., 2023). This demonstrates how the technical developments of the project can be applied to other areas of research.
An advanced analytical technique for multi-phase quantitative compositional mapping using LA-ICPMS has been developed in the open-source XMapTools software (Markmann et al. 2024). New tools that use a combination of chemical and machine vision strategies to classify complex datasets have also been developed and implemented (Lanari & Tedeschi 2025). A machine learning strategy for mineral shape classification in 3D and a program garNET were developed (Hartmeier et al. 2024).
2) Modelling programs:
A multi-phase flow model has been developed with a new advection algorithm (Dominguez et al., 2024). A multi-rock coupled mechanical-petrochemical model (ThorPT) for simulating the production and extraction of aqueous fluids has been developed. (Markmann 2024). A diffusion model has been developed to simulate element transport in 3D within microCT-derived natural crystal geometries (Dominguez et al 2026). Two new modelling strategies of PROMOTING are still in the process of being developed: a thermodynamic model for aqueous speciation calculations within a Gibbs energy minimiser and a programme for simulating metastable systems.
3) Main applications:
In-situ oxygen isotope analyses were used to quantify critical parameters of fluid flow during high-pressure metamorphism in the Alps and Cyclades (Bovay et al. 2001; Rubatto et al. 2023; Markmann 2024). These applications are based on petrochemical modelling developments from the project. The key finding is that pervasive fluid flow plays a significant part in the transport of fluids in subduction zones, and its activation is closely linked to metamorphic reactions. The investigation of the possible consequences of element redistribution by aqueous fluid during metamorphism was investigated using databases of whole-rock compositions (Forshaw & Pattison, 2022; Forshaw et al. 2024). These studies demonstrate that, overall, aqueous fluids traveling and interacting with rocks have a limited impact. The distribution of garnet crystal shapes in a metabasalt from the Alps enabled the development of a kinetic model of garnet dissolution (Hartmeier et al., 2024). There are very few published quantitative kinetic models of reaction rates, and this new original approach was made possible by the micro-CT developments from the project.
Secondly, several studies focused on petrochronology and modelling melt production in the El Oro Massif in Ecuador and the Fuping Terrane in China (Dominguez, 2024; Liu et al., 2025). The results encompass the refinement of melt production duration in the El Oro complex using zircon geochronology, as well as the production of crustal-scale melt models. In the Fuping Terrane, the analytical developments of the project were employed alongside diffusion modelling. This is the first paper in the literature to demonstrate that mineral growth rates in nature can be as fast as those observed in a laboratory setting (Liu et al. 2025).
4) Other stimulated applications:
The multi-rock petrochemical model developed by the PROMOTING team has shown from the outset that robust pressure-temperature estimates and robust thermodynamic models are critical for the simulation of natural rocks. A complementary study was performed using low-grade condition samples to identify the most suitable thermodynamic database for these conditions in crustal-scale models (Petroccia et al., 2025). A new hybrid method was developed for thermobarometry to estimate robust pressure-temperature conditions in partially equilibrated samples (Nerone et al., 2025). Finally, a machine learning model based on transfer learning was used to calibrate a biotite deep-learning model for improved single-mineral thermometry (Hartmeier et al., 2025).
The project's microCT developments have been used to study the porosity of sandstone (Zhou et al., 2022) and to characterise a historical artefact made from a meteorite (Hofmann et al., 2023). This demonstrates how the technical developments of the project can be applied to other areas of research.
The new methodologies developed in the PROMOTING project have been crucial in achieving results that go beyond what is currently possible.
To improve our understanding of fluid transfer in subduction zones, we have demonstrated that oxygen isotopes can be used to trace and quantify pervasive fluid flows which are invisible in major and minor elemental and textural records. The new multi-rock coupled mechanical-petrochemical model is a key tool for simulating these processes in several different scenarios. We have also developed a kinetic model that uses innovative, AI-driven 3D imaging capabilities to analyse rock samples and estimate relative reaction rates. This model can also be used to demonstrate the pressure and temperature conditions that favour these reactions.
To improve our understanding of melt production, we developed an innovative petrochronological approach to estimate mineral growth rates in metamorphic rocks. This approach is the first to use multi-element, multi-profile diffusion inversion modelling, stemming from the development of an analytical technique for multi-phase quantitative compositional mapping. Another study is currently using the combination of analytical and new modelling techniques for element diffusion in 3D from, to quantify the trace element budget during crustal partial melting. These results exceed the project's initial objectives.
Finally, the multi-rock modelling approach developed by the team has been an inspiration to the community, and a research project has been funded to further our understanding of the early Earth environment based on a similar strategy.
To improve our understanding of fluid transfer in subduction zones, we have demonstrated that oxygen isotopes can be used to trace and quantify pervasive fluid flows which are invisible in major and minor elemental and textural records. The new multi-rock coupled mechanical-petrochemical model is a key tool for simulating these processes in several different scenarios. We have also developed a kinetic model that uses innovative, AI-driven 3D imaging capabilities to analyse rock samples and estimate relative reaction rates. This model can also be used to demonstrate the pressure and temperature conditions that favour these reactions.
To improve our understanding of melt production, we developed an innovative petrochronological approach to estimate mineral growth rates in metamorphic rocks. This approach is the first to use multi-element, multi-profile diffusion inversion modelling, stemming from the development of an analytical technique for multi-phase quantitative compositional mapping. Another study is currently using the combination of analytical and new modelling techniques for element diffusion in 3D from, to quantify the trace element budget during crustal partial melting. These results exceed the project's initial objectives.
Finally, the multi-rock modelling approach developed by the team has been an inspiration to the community, and a research project has been funded to further our understanding of the early Earth environment based on a similar strategy.