Geology, geochronology and geochemistry of the Saishitang Cu deposit, East Kunlun Mountains, NW China: Constraints on ore genesis and tectonic setting

摘要: Abstract The Saishitang Cu deposit, located on the eastern area of Eastern Kunlun Orogenic Belt (EKOB), and northern margin Tibetan Plateau, is one most important copper deposits in Qinghai Province, China. Skarn orebodies mainly occur as stratoids or lenses along contact zone between quartz diorite Lower to Middle Triassic metamorphosed tuff marble. In this study, we use new zircon U–Pb ages, molybdenite Re–Os granitoid geochemical compositions, Hf isotope data constrain ore genesis tectonic setting deposit. composed inner medium- fine-grained phase an outer porphyritic phase. dating zircons by laser ablation–inductively coupled plasma–mass spectrometry (LA–ICP–MS) yield ages 222.7 ± 2.3 Ma 222.6 ± 2.4 Ma for diorite, respectively. Molybdenite separated from ore-bearing veins yields a isochron age 223.4 ± 1.5 Ma, indicating close temporal link magmatism mineralization. Geochemically, shows high contents SiO 2 (59.63–68.21 wt.%), Al O 3 (15.57–18.13 wt.%) Na (3.07–3.56 wt.%), with A/CNK values 0.90 1.01 Mg# 46 52, classified calc-alkaline I-type granite. trace element patterns are characterized LREE (LREE/HREE = 7.36–13.03), weak negative Eu anomalies (δEu = 0.69–0.86), relative enrichment Rb, Th, K, Pb, depletion Nb, Ta, P, Ti. has variable e (t) (− 2.5 4.87) Mesoproterozoic two-stage model (997 1387 Ma). Based petrological features, infer that derived partial melting thickened lower crust additional input mantle components. According geological, geochemical, mineralogical propose deposit skarn minor porphyry-type mineralization porphyry–skarn mineral system related crust–mantle interaction. evolution Paleo-Tethys Ocean during Late Triassic, intrusions associated were regional extension EKOB post-collision environment. results also show have similar (240–220 Ma) granitoids present significant potential prospecting deposits.