Investigating the formation and deformation of the Oman ophiolite(s) through the magmatic record

Description du projet

This transverse project on continental surfaces has the objective to use the polyphased magmatic record within the Oman Mountains to better assess the evolution from the Permian rifting phase to the Cretaceous obduction of oceanic lithosphere above the Arabian margin. Our recent geological observations (submitted for publication) show that rifting, oceanic accretion and obduction stages are all preserved in Oman, with specific structural, sedimentary and igneous records. Our dataset discards former tectonic models of intra-oceanic subduction initiation and rather considers that subduction initiated at the hyper-extended continent-ocean transition zone with exhumed mantle. However, the limited dataset on igneous rocks from rifting, break-up and late-obduction stages still prevents to build a robust tectono-magmatic scenario. We thus collected more than 30 samples of igneous rocks in January 2023 to study the rift-related volcanics and subsequent magmatic phases, which should have recorded the specific mantle rift-inheritance. The BQR fundings will be used for bulk-rock (major and trace elements, Sr-Nd isotope ratios) and mineral analyses, and U/Pb dating on zircons (SEM, and LA-MC-ICP-MS). Results will be used to discuss the evolution of the mantle source of magma through time and build a new generation of models for supra-subduction rifting and obduction