The tectonic setting during ophiolite formation and emplacement are debated. The Samail ophiolite in Oman and the United Arab Emirates is the largest and one of the best-studied ophiolites in the world, and is an ideal place to study these processes. This research project uses high precision U-Pb zircon geochronology and radiogenic isotope, major and trace element geochemistry to study the evolution from formation of the ophiolite crust to development of thrusting below the ophiolite. The work will focus on late magmatic series that intruded the ophiolite mantle and crust, and metamorphic rocks and associated leucocratic pods within the metamorphic sole. The late magmatic series in the crust and mantle have isotopic and trace element signatures that have been attributed to thrusting or subduction below the ophiolite, and the combined dating and geochemical analyses will determine the timing of thrusting or subduction relative to crustal growth. Similar analyses from the metamorphic sole will provide a complimentary record within the under-thrust plate. The complete dataset will provide a detailed temporal record of the tectonic development of the ophiolite and help to differentiate between existing models of ophiolite formation.
Ophiolites are thin slices of crust that formed at oceanic spreading centers and subsequently thrust onto the continents. Because ophiolites are easier to access than in-situ oceanic crust, and often expose cross sections through the crust and upper mantle, research on ophiolites has played a major role in the development of current models for the structure of the oceanic crust and the processes that form it. However, there are chemical differences between ophiolites and in-situ oceanic crust, which suggest ophiolites may form in more complex tectonic environments. To understand how observations from ophiolites can be applied to the formation of the oceanic crust, it is necessary to understand the tectonic setting during formation and emplacement of ophiolites. Several authors have proposed that ophiolites may form during the initial development of new subduction zones, and as a result, research on ophiolites may also provide insight into the processes of subduction initiation. The proposed research will generate a temporal and chemical record of the formation of the Semail ophiolite, providing insight into both the origin of ophiolites and potentially the processes of subduction initiation.
