Origin and evolution of the Qiangtang block, northern Tibetan Plateau: New insights from detrital zircon U-Pb geochronology and Lu-Hf isotopic compositions

Abstract

Detrital zircon age spectra analysis offers insights into tectonic and sedimentary environments. In the Paleozoic sedimentary rocks of the Qiangtang block, northern Tibetan Plateau, we measured U-Pb ages of detrital zircons to elucidate the blocks tectonic-sedimentary evolution and its relationship to the Tethyan regime. Our findings reveal zircon age peaks at approximately ca. 2500, ca. 1600, ca. 970, and ca. 550 Ma, closely resembling the Cimmerian continent and exhibiting paleogeographic affinities with the northern margin of Gondwanan India. Our new data, alongside existing geological data, indicate distinct tectonic pathways for the North and South Qiangtang blocks since the Neoproterozoic as a result of Rodinia breakup. Our sedimentological and geochronological evidence implies that the Longmu Co-Shuanghu suture zone is an in situ ophiolite mélange formed by the closure of the Paleo-Tethyan Ocean.