Two-stage crustal growth in the Arabian-Nubian shield: Initial arc accretion followed by plume-induced crustal reworking

Island-arc accretion during the assembly of Gondwana has been widely regarded as main mechanism for Neoproterozoic crustal growth in Arabian-Nubian Shield (ANS). However, processes involved to transform newly accreted juvenile terranes into a typical continental crust remain unclear. Here, we present geochemical, isotopic, and U-Pb geochronological data from El-Shadli volcanic province (80 km × 35 > 10 thick) Eastern Desert Egypt, which lies north-western part ANS, overlies strongly deformed, previously arc terranes. The consists mainly mafic-felsic bimodal suite subordinate intermediate rocks that intrude mafic suite. are tholeiitic, whereas have calc-alkaline affinity. both yield zircon ages ~ 700 Ma implying they coeval. High ?Hf(t) values (average = +11.46) well +9.76) indicate were either magmatic extractions derived directly depleted mantle source, or products remelting crust. Oxygen isotope similar ?18O 4.94‰) 4.79‰). These lower than indicating parental magma cases interacted with hydrothermal fluids. Based on petrological, isotopic data, suggest produced by reworking MORB-like arc-like oceanic lithosphere, respectively, most likely driven plume break-up Rodinia. recognition plume-induced post-kinematic magmatism provides transformation chemically stratified normal In addition, such events may result new converted