Geochemistry and U-Pb zircon dating constraints of some plutonic rocks along Bir Tawilah shear zone, central Saudi Arabia: Implication for magma peterogenesis and age of gold mineralization

The study area covered by this work is located along the Bir Tawilah fault zone which encompasses the Arabian Shield between Afif terrane and western oceanic terranes. The rocks are dominantly ophiolite assemblages, island arc metavolcanic and metasedimentary rocks, and dioritic to granitic intrusions. The diorite and granodiorite rocks are I-type granitoids, calk-alkaline, metaluminous to peraluminous, formed in a volcanic arc setting, whereas the monzogranite is classified as A-type granite, alkaline and highly fractionated calc-alkaline, generated in within-plate tectonic setting. Nb and Y relationships indicated that the diorites and granodiorites were generated by a mafic parental magma contaminated with crustal materials, and controlled by fractional crystallization, whereas the monzogranites were generated from a magma characterized by an enriched mantle (EM) source.Mineralization including gold is hosted by the carbonatized serpentinite (listvenite) and the syn-tectonic granodiorite along Bir Tawilah thrust zone. U-Pb zircon geochronology indicates that the granodiorite at Jabal Ghadarah is emplaced at ca. 630 ± 12 Ma, probably suggests that the metallic minerals associated with the granodiorite along Bir Tawilah thurst zone are the result of remobilization of pre-existing gold mineralization associated with listevenite that is related to arc accretion.