Provenance of the Upper Paleozoic Shihezi Formation in the Luonan Region of the Qinling Orogenic Belt and Its Tectonic Implications

This study investigates the provenance of the Permian Shihezi Formation (Fm) siliciclastic sediments in the Luonan area, southern margin of the North China Block, which constrain the sediment sources and tectonic evolution of the basin. Our research investigates the heavy mineral characteristics, geochemical features, detrital zircon U-Pb geochronology, and Lu-Hf isotope tracing the provenance characteristics of the Shihezi Fm in this region. Zircon yielded three distinct U-Pb age groups as follows: 320–300 Ma, 1950–1850 Ma, and 2550–2450 Ma. The εHf(t) values of zircons ranged from −41 to 50, and the two–stage Hf model’s ages (TDM2) values are concentrated between 3940 Ma and 409 Ma, suggesting that magmatic sources likely derive from Early Archaean–Devonian crustal materials. The heavy mineral assemblages are primarily composed of zircon, leucoxene, and magnetite. Further geochemical analyses of the rocks indicate a diverse provenance area and a complex tectonic evolution. Taken together, these results suggest that the provenance of the Shihezi Fm is from the North China Block, with secondary contributions from the Qinling Orogenic Belt and the North Qilian Orogenic Belt. The provenance of Luonan shares similarities with the southern Ordos Basin. Investigating the provenance of the Luonan area along the southern margin of the North China Craton provides critical supplementary constraints for shedding light on the Late Paleozoic tectonothermal events in the Qinling Orogenic Belt.