Geodynamic setting of Upper Miocene to Quaternary alkaline basalts from Harrat al ‘Uwayrid (NW Saudi Arabia): Constraints from K Ar dating, chemical and Sr-Nd-Pb isotope compositions, and petrological modeling

Highlights • Volcanic activity of Harrat Uwayrid (NW Arabia) lasted from 8.2 to 0.3 Ma. • Alkali olivine basalts are followed by basanites, tephrites and tephriphonolites. • Sr-Nd-Pb isotopic ratios of all volcanic rocks suggest a PREMA source. • Different degrees of partial melting of amphibole-garnet-spinel lherzolite • Lithospheric mantle source rather than asthenosphere or plume-type mantle Abstract The volcanic field of Harrat ar Rahah-’Uwayrid (NW Saudi Arabia) consists of an older plateau basalt sequence that overlies Cambrian sandstone and younger cinder cones with smaller flows that are concentrated in the central part of this field. Petrographic and whole rock geochemical data ind…