The Dynamics of Ophiolite Emplacement: Insights from Thermomechanical Modeling and Tethyan-Type Ophiolites

In this work we investigate the complex processes involved in the emplacement of ophiolites—rock assemblages typically found at tectonic plate boundaries and orogenic zones. Ophiolite sequences, comprising sediments, mafic dykes, pillow lavas, crustal cumulates, and peridotites, present significant challenges in understanding their obduction onto continental margins. The study focuses on key aspects of obduction, including its mechanisms, petrological and geodynamic processes, and unresolved questions regarding timescales, obduction rates, and the formation of metamorphic soles.

Our results integrate geological, geochemical, geophysical, and geochronological data, with particular emphasis on small oceanic basins and classic Tethyan ophiolite examples. Using thermomechanical numerical models, our results show that young, hot oceanic basins are necessary for successful overthrusting onto continental regions, with critical factors being convergence velocity and the asymmetric structure of the oceanic plate. Interestingly, only strong lower-continental-crust rheologies lead to successful obduction scenarios. Additionally, we utilized 1-D, high-resolution, thermomechanical modeling to explore the role of shear heating during obduction. The results of the 1-D model provided explanations for the incorporation of metamorphosed crustal rocks into the ophiolitic complex and reveal how metamorphic gradients can develop, as observed in Oman ophiolites. In particular, the structural incorporation of the metamorphic sole, its metamorphic gradient, and more importantly, its isotopic age signature can be explained with the influence of shear heating.

Our geodynamic modelling approach allows that our results can be further coupled to thermochronological modelling to quantify the influence of erosion, convergence velocity, and dissipative heating on isotopic age resetting in deeper crustal rocks. This work enhances the understanding of ophiolite emplacement processes and offers new insights into the evolution of Tethyan-type ophiolites, with broader implications for global ophiolite studies.