Devonian sedimentation in the Xiqingshan Mountains: Implications for paleogeographic reconstructions of the SW Qinling Orogen

• Devonian sediments in the Xiqingshan Mountains were deposited in a foreland basin.
• Sedimentation occurred in non-marine to shallow-marine environments.
• Lower Devonian sandstones are dominated by feldspathic litharenite.
• Ages of the sources of detritus in the Early and Middle Devonian are ca. 770 Ma and 400 Ma, respectively
• Sediments were eroded from an uplifted Neoproterozoic arc fragment.

The Qinling Orogen between the North China and Yangtze plates comprises various accreted and collisional terranes, recording the evolution of the Proto-Tethyan Ocean and the formation of east Asia. Knowledge of the provenance and tectonic setting of a thick succession of E–W striking Devonian sedimentary rocks sandwiched tectonically between the Shangdan and Mianlue ophiolitic suture zones in this belt is essential to understanding the evolution of the Qinling Orogen and the assembly of the North China and Yangtze plates during the Late Paleozoic. Systematic studies of the Devonian sedimentary facies in the Xiqingshan Mountains indicate the northern margin of the South Qinling belt was uplifted prior to the Early Devonian. Lower Devonian sandstones are dominated by feldspathic litharenite (Q12–31F18–37L40–65), indicative of a continental arc derivation. Detrital zircon U–Pb data demonstrate that the Lower and Middle Devonian sandstones were derived respectively from ca. 770 Ma and ca. 400 Ma felsic arc-related magmatic sources. Devonian sedimentation in the Xiqingshan Mountains is interpreted to have occurred in a foreland basin between the Yangtze plate and the North Qinling continental arc.