Petrogenesis of Early Paleozoic high Sr/Y intrusive rocks from the North Qilian orogen: Implication for diachronous continental collision

A combination of U-Pb zircon ages and geochemical and Sr-Nd-Hf isotopic data are presented for the Early Paleozoic granodiorites from the Haoquangou and Baimawa plutons in order to probe the crustal thickness variation of the eastern North Qilian and the diachronous evolution of the North Qilian orogen. The granodiorites formed at 436–435 Ma and have high Sr/Y ratios (63–117). Elemental and isotopic data combined with geochemical modeling and...