Exploring deformation-driven fluid-flow and fluid-rock interactions: insights from the Dinarides orogen, southeastern Europe

Collisional orogens are characterized by complex contractional and extensional deformation, which significantly impact fluid migration and mineralization. These processes are crucial for understanding subsurface fluid flow dynamics, with implications for geothermal energy, hydrogen production, and CO2 storage. The Dinarides orogen in southeastern Europe, formed during the closure of the Neotethys Ocean and subsequent Adria-Europe collision, provides an excellent natural laboratory to investigate fluid-flow and fluid-rock interactions driven by orogenic deformation.

The Dinarides have experienced a sequence of tectonic events in their late evolution, including NE-EW Late Cretaceous-Eocene contraction, NE-SW Oligocene contraction, and bimodal NE-SW/NW-SE Miocene extension. These phases created fracture networks, tension gashes, and fault gouges, facilitating fluid migration and mineral precipitation within the orogen. Field investigations across five tectonic units in Montenegro (Dalmatian, Budva, High Karst, Pre Karst, and East Bosnian-Durmitor) documented structural features associated with these deformation phases.

Petrographic and geochemical analyses of vein-filling cements, including optical microscopy, cathodoluminescence, and stable isotope measurements, reveal that vein formation predominantly occurred under burial conditions with episodic transitions to meteoric environments. These results suggest that deformation-controlled fracture network acted as fluid pathways, driving localized dolomitization and calcite precipitation. The structural timing of these features correlates with major orogenic events, providing insights into the relationship between deformation and fluid flow.

Our findings contribute to understanding how fluid migration is driven by tectonic deformation in collisional orogens. By integrating field observations with petrographic and geochemical data, this study offers a framework for linking mineralization processes to tectonic evolution, with broader implications for fluid flow modelling in similar orogenic systems worldwide.