Zircon U-Pb dating of rhyolite of the Lapeiquan Formation in north Altyn Tagh, Xinjiang and its geological implications

The Kaladawan area in the northern margin of Altyn Tagh is the most important and famous Fe-Cu-Pb-Zn-Ag polymetallic ore cluster field in Altyn Tagh. The Lapeiquan Formation, as the ore-bearing stratum in the ore cluster area, consists of one set of volcanic-sedimentary rock assemblage, but its formation age has not been restricted. This study carried out LA-ICP-MS zircon U-Pb dating for rhyolite from the third member of the Lapeiquan Formation. A weighted ²⁰⁶Pb/²³⁸U age of 488±2 Ma was obtained for the Lapeiquan Formation, indicating that the Lapeiquan Formation belongs to upper Cambrian, not Ordovician, Sinian or Jixian System. This finding, together with previous work, suggests that the Lapeiquan Formation formed in the continental arc setting. This study is of important scientific significance for understanding the metallogenetic and geological setting of the Kaladawan ore cluster area.