Effect of out-of-equilibrium crystallization and fluid-assisted dynamic recrystallization on Ti-in-quartz thermometry in porphyry-epithermal deposits: Insights from Pagoni Rachi (NE Greece)
Abiven B, Tarantola A, Richard A, Keith M, Melfos V, Voudouris P (2025)
Publication Type: Journal article
Publication year: 2025
Journal
Book Volume: 512-513
Article Number: 108134
DOI: 10.1016/j.lithos.2025.108134
Abstract
Understanding the temperature evolution of magmatic-hydrothermal systems is key to unraveling fluid-rock-deformation reactions and related ore-forming processes. Ti-in-quartz thermometry has been widely used to determine the quartz crystallization temperatures in these systems. However, out-of-equilibrium crystallization and fluid-assisted recrystallization of hydrothermal quartz may significantly influence the temperature estimates; a process that has not sufficiently been studied to date despite its broad implications. Here, we use the Pagoni Rachi Cu-Mo-(Re-Au) deposit (NE Greece) to provide insights into these processes. Typical A-type (ductile, 460–510 °C), B-type (ductile/brittle, 420–440 °C) and E-type (brittle, 220–330 °C) veins are developed in a continuum of deformation, forming from phase-separated fluids followed by cooling and dilution with surface waters. In A-type veins, fluid-assisted recrystallization modified the Ti concentrations (10–60 ppm), yielding Ti-in-quartz temperatures (330–500 °C) lower than the fluid inclusion trapping temperatures, likely due to Ti loss. In later B-type veins, rapid growth under out-of-equilibrium conditions resulted in overestimated Ti-in-quartz temperatures (440–750 °C), i.e., higher than fluid inclusion trapping temperatures. By contrast, effects of recrystallisation are lacking in the late-stage E-type veins, leading to a better agreement between Ti-in-quartz (160–360 °C) and fluid inclusion trapping temperatures. Our results show that out-of-equilibrium crystallization and fluid-assisted dynamic recrystallization processes can shift the Ti concentration in quartz leading to potential misinterpretation of the cooling path of magmatic-hydrothermal systems. This has also important implications on the common classification of vein types in porphyry-epithermal systems based on the Al/Ti and Ge/Ti ratios in quartz. More generally, careful microtextural examinations of quartz veins are crucial for a reliable use of Ti concentrations in quartz as a petrogenetic indicator.
Authors with CRIS profile
Involved external institutions
Université de Lorraine
France (FR)
Aristotle University of Thessaloniki
Greece (GR)
National and Kapodistrian University of Athens
Greece (GR)
France (FR)
Aristotle University of Thessaloniki
Greece (GR)
National and Kapodistrian University of Athens
Greece (GR)
How to cite
APA:
Abiven, B., Tarantola, A., Richard, A., Keith, M., Melfos, V., & Voudouris, P. (2025). Effect of out-of-equilibrium crystallization and fluid-assisted dynamic recrystallization on Ti-in-quartz thermometry in porphyry-epithermal deposits: Insights from Pagoni Rachi (NE Greece). Lithos, 512-513. https://doi.org/10.1016/j.lithos.2025.108134
MLA:
Abiven, Baptiste, et al. "Effect of out-of-equilibrium crystallization and fluid-assisted dynamic recrystallization on Ti-in-quartz thermometry in porphyry-epithermal deposits: Insights from Pagoni Rachi (NE Greece)." Lithos 512-513 (2025).
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