The discovery of Early Cretaceous rhyolite interlayer in the Duolong ore concentration area, Tibet

A typical gold-rich porphyry copper ore district with large potential called the Duolong ore concentration area was recently discovered after the discovery of the Gangdise metallogenic belt. It is located in northwest Gerze County in Tibet and lies within the Duobuzha part on the northern margin of the Bangong Co-Nujiang suture zone (BNSZ). 1250000 Wuma regional geological survey was carried out in detail previously, which filled the gap of the study of northern BNSZ. The authors recently found that an Early Cretaceous rhyolite interlayer is exposed in the Quse Formation which was believed to have been formed in the Lower Jurassic. The weighted mean value of zircon U-Pb age measured by LA-ICP-MS from rhyoliteis is 118.8±1.4Ma, which suggests that the sedimentary strata with volcanic rock should have been formed in the Early Cretaceous. The discovery not only complements records of Early Cretaceous magmatic activity in southern Qiangtang block but also provides important clues for the study of the metallogenic geological setting of the Duolong ore concentration area and the evolution of the Bangong Co-Nujiang Ocean. A preliminary study suggests that the strata may represent Early Cretaceous accretionary complexes in Duolong where Mesozoic accretionary complexes are widely distributed. Meanwhile, it might be the contemporaneous product of re-deposition in the environment of regional extension.