Ore-forming age and tectonic setting of the Linjiasandaogou gold deposit in the Liaodong Peninsula, northeast China: constraints from geochronology and geochemistry

The Linjiasandaogou gold deposit is located in the Qingchengzi Orefield, North China Craton, China, and has not attracted many studies. We present geochronological, whole-rock geochemical, and Sr–Nd–Hf isotopic data to constrain the age and tectonic setting of the mineralization. U–Pb dating of zircon from pre-and post-ore dikes indicates the Linjiasandaogou Au deposit formed at ca.227–226 Ma. The granite porphyry(ca. 227 Ma) and quartz diorite porphyry(ca. 228 Ma), which are slightly older than the mineralization, have(87Sr/86Sr)i-= 0.7127–0.7162, εNd(t)= –13.7 to –17.0, and εHf(t)= –14.6 to –16.9, and display enrichment in light rare earth elements and large ion lithophile elements and depletion in high field strength elements. Two lamprophyres(226 and225 Ma), which are slightly younger than the mineralization, have higher(87Sr/86Sr)i(0.7165–0.7216), negativeεNd(t)(–11.2 to –14.3) and εHf(t)(–15.6 to –18.6) values,and are enriched in light rare earth elements but depleted in high field strength elements(Nb and Ta). The geochemical characteristics of the granitoid and lamprophyres indicate a lower crustal and enriched mantle source, respectively. We infer that the Linjiasandaogou Au deposit formed in a postcollisional tectonic setting, following the collision between the North China, Yangtze craton, and Central Asian Orogeny in Triassic.