Abstract
ABSTRACT RISING aims to make a step-change in our understanding of how continental subduction and exhumation develops and evolves by using a multidisciplinary, multi-resolution approach. The proposed study will exploit the full richness of passive-seismic data recently acquired in the area spanning the entire UAE-Oman orogenic belt and its foreland basins, along with cutting-edge imaging techniques, to generate detailed 3-D tomographic models of the lithosphere and underlying upper mantle. RISING will then combine the new seismic observations with new key constraints derived from field, structural, petrological and geochronological analyses along three cross sections. This major effort will be the base for several research avenues, which will allow to: i. Apply advanced transdimensional, Bayesian, hierarchical geophysical inversion methods to passive-seismic data to produce unprecedented quantitative constraints of the lithosphere and underlying upper mantle beneath the study area, which will ultimately point to a set of observables responsible for continental subduction. ii. Define the kinematics, deformation mechanisms and metamorphic conditions of major shear zones, along with the distinctive sequence and duration of tectonic events that led to continental subduction and subsequent exhumation. iii. Develop a model for subduction and exhumation of the continental crust-mantle system beneath an oceanic plate. The tectonic reconstruction of the Oman mountain range holds the key to the understanding of subduction-exhumation processes. RISING will be the first to illuminate the deep structure of the UAE-Oman mountain range and tie the results with crucial new constraints from structural, petrological and geochronological analyses, providing solid constraints on this complex, yet fundamental tectonic process. RESULTS RISING greatly improved our understanding of how continental subduction and exhumation develops and evolves by using a multidisciplinary, multi-resolution approach. RISING combined new key constraints derived from field, structural, petrological and geochronological analyses along three cross sections with the new seismic observations and numerical modelling of subduction zone dynamics. Indeed, RISING produced pressure-temperature-time-deformation constraints for the major shear zones of the subducted continental crust and exploited the full richness of passive-seismic data recently acquired in the area of the Oman orogenic belt and its foreland basins, along with cutting-edge imaging techniques, to generate detailed 3-D tomographic models of the lithosphere and underlying upper mantle. Finally, RISING tested the evolution of the margin by using state-of-the-art geodynamic numerical modelling. RISING results are available in two published articles. Other articles are currently under review. Petroccia A., Giuntoli F., Pilia S., Viola G., Sternai P. & Callegari I. (2025): Sustained strain localisation and coeval brittle-ductile deformation in an exhuming low-grade shear zone: Insights from the Saih Hatat Window (NE Oman). Journal of Structural Geology. https://doi.org/10.1016/j.jsg.2024.105328 This study investigated the Hulw Shear Zone in Oman, which is an exhumation-related shear zone. Decompression-driven fluid-gain reactions facilitated the growth of phyllosilicates, which created a pervasive and interconnected network that promoted strain localisation, causing mechanical weakening as well as the potential compartmentalized fluid cells within the mylonitic foliation. Brittle structures formed due to aqueous fluid release by metamorphic dehydration reactions, transiently increasing pore pressure and triggering brittle failure, resulting in coeval mylonitic foliation and veins. Our findings support sustained shearing promoted by synkinematic K-rich white mica and pyrophyllite growth and cyclic switching between brittle and ductile deformation conditions. The studied structures might represent a record of deep episodic tremors and slow slip events during exhumation-related tectonics in the accretionary wedge of the Oman continental lithosphere. Petroccia A., Giuntoli F.*, Kotowski A., Buono G., Chogani A., Hellebrand E., Pappalardo L., Callegari I. (2026). Tracking dehydration reactions and fossil fluid flux in shear zones using garnet microstructures. Journal of Metamorphic Geology, 44(5), 394–414. https://doi.org/10.1111/jmg.70042 This study investigates fluid flow processes recorded by garnet in quartz-schists from the As Sheik shear zone (Saih Hatat window, NE Oman). We highlight that honeycomb garnet represents a snapshot of the permeability network that allowed the fluids to escape from the shear zone. The internally produced fluid flow and escape from the shear zone occurred through reaction-forming pathways. This study highlights garnet morphology as a tracer of transient fluid pathways during a burial-exhumation cycle of an eclogitic shear zone. The close connection between garnet morphology and fluids calls for a re-evaluation of similar microstructures in different tectonic settings. RISING results were disseminated at numerous international conferences, such as AGU 24, EMC 24, SGI 24 and 25, EGU 2025 and 2026 https://agu.confex.com/agu/agu24/meetingapp.cgi/Paper/1547814 https://www.minersoc.org/wp-content/uploads/2024/09/EMC-Programme-and-Abstracts-FINAL.pdf https://www.socgeol.it/files/download/pubblicazioni/Abstract Book/Abstract Congresso SGI-SIMP 2024.pdf https://www.geoscienze.org/files/download/padova2025/abstract-congresso-2025.pdf https://doi.org/10.5194/egusphere-egu25-7952 https://doi.org/10.5194/egusphere-egu25-16287 https://doi.org/10.5194/egusphere-egu25-16287 https://doi.org/10.5194/egusphere-egu26-6670 https://doi.org/10.5194/egusphere-egu26-17819 https://doi.org/10.5194/egusphere-egu26-331
Dettagli del progetto
Responsabile scientifico: Francesco Giuntoli
Strutture Unibo coinvolte:
Dipartimento di Scienze Biologiche, Geologiche e Ambientali
Coordinatore:
ALMA MATER STUDIORUM - Università di Bologna(Italy)
Contributo totale Unibo: Euro (EUR) 95.520,00
Durata del progetto in mesi: 24
Data di inizio
28/09/2023
Data di fine:
28/02/2026
