Geochronological framework of the Damoqujia gold deposit, Jiaodong Peninsula, China: Implications for the timing and geologic setting of gold mineralization

Abstract

The Damoqujia gold deposit in the Jiaodong Peninsula in eastern China contains more than 60 t of gold and is hosted mainly by Mesozoic granitoids. The orebodies comprise pyrite–sericite–silica altered rocks and exhibit Jiaojia‐type mineralization. Although the Damoqujia deposit is an important gold producer in the Zhaoping Fault Zone, the age and tectonic setting of metallogenesis are poorly constrained. Here, we employ precise U–Pb dating of zircon and 40Ar/39Ar dating of hydrothermal sericite from the Damoqujia gold deposit to constrain the age of mineralization, which we integrate with previous studies to understand the tectonic setting of the deposit. The major intrusions exposed in the deposit are the Jurassic monzogranite to the west and the Cretaceous granodiorite to the east. Uranium–Pb dating of zircon from the monzogranite, granodiorite, pre‐ore hydrothermally altered lamprophyre dyke, and post‐ore unaltered gabbro–diorite dyke yield concordia ages of 160 ± 1, 130 ± 1, 125 ± 1, and 120 ± 1 Ma, respectively. Based on these geochronological data, we suggest that the age of gold mineralization at Damuqujia occurred at 124–121 Ma. Sericite from the auriferous quartz–pyrite veinlet in the Damoqujia deposit yields a plateau age of 122.8 ± 0.9 Ma, representing the precise age of gold mineralization. Our geochronological data indicate that gold mineralization occurred at 123 Ma and are consistent with the timing of the main gold mineralization event in the Jiaobei Terrane at 125–120 Ma. The geodynamic setting of the study area during this time is generally considered to have been dominated by subduction of the Palaeo‐Pacific Plate beneath the Eurasian continent, with accompanying lithospheric delamination, asthenospheric upwelling, and intense craton destruction. The gold mineralization at Damoqujia was closely associated with continental extension during the Mesozoic.