Timing, Provenance, and Tectonic Implications of Ore-Hosting Metasedimentary Rocks in the Giant Liba Gold Deposit, West Qinling Belt, China

The closure time of the Shangdan Ocean is critical for understanding tectonic evolution Proto-Tethys Ocean. However, proposed was prolonged from Ordovician to Devonian. In present study, detrital zircon metasedimentary rocks Liba Group in West Qinling Belt analyzed constrain three youngest grains yield a maximum deposition age 418 ± 13 Ma, indicating Middle Devonian deposition. Detrital show two main U–Pb peaks 810 Ma and 440 with εHf(t) values spanning −24.3 +8.8 −6.3 +4.1, respectively, suggesting that sediments were derived both North South Belts. Lower shows similar provenance Group, whereas are absent Silurian strata Belt. From Late Early Devonian, setting changed subduction collision. This evidence consistently suggests disappearance noticeable decrease magmatism 510–420 420–390 shrinking −15.5–+12.8 −8.4–+4.2 reveal Ocean, as eastmost embranchment closed at ca. 420 Ma.