Geology, geochemistry, and geochronology of the Wangjiazhuang porphyry-breccia Cu(-Mo) deposit in the Zouping volcanic basin, eastern North China Block

- Wangjiazhuang quartz monzonite crystallized at 128.3 ± 1.3 Ma.
- Wangjiazhuang porphyry-breccia Cu(-Mo) deposit was formed at 127.8 ± 0.7 Ma.
- Quartz monzonite was derived from subducted oceanic crust and sedimentary components.
- Sulfur and lead in ores are extracted mainly from the quartz monzonite.

The Wangjiazhuang porphyry-breccia Cu(-Mo) deposit is located in the Zouping volcanic basin, western Shandong Province. Seven molybdenite samples yield a Re-Os weighted mean age of 127.8 ± 0.7 Ma (2σ), which is identical within error to the zircon weighted mean 206Pb/238U age of 128.3 ± 1.3 Ma (2σ) determined for quartz monzonite samples. The host rock is characterized by high concentrations of K2O (4.26-4.53 wt.%), Na2O (4.97-5.76 wt.%), LILEs and LREEs, and high Mg# (> 40), and low concentrations of HFSEs and HREEs, with K2O/Na2O ratios of 0.76-0.88. The quartz monzonite also has high Sr/Y (69.9-112.5) and (La/Yb)N (22.0-30.0) ratios, similar to adakitic rocks worldwide. Relatively low initial 87Sr/86Sr ratios (0.70549-0.70556), high εNd(t) values (2.58-3.06), high radiogenic Pb [(206Pb/204Pb)i = 18.3424-18.4606, (207Pb/204Pb)i = 15.5692-15.5985, (208Pb/204Pb)i = 38.1714-38.2734] and high zircon εHf(t) values (− 2.1 to + 4.3) indicate that the magma was likely derived from the partial melting of subducted oceanic crust which then reacted with the peridotitic mantle wedge. Both the breccia and porphyry ores have a narrow range of δ34S (− 4.8 to + 2.1‰) and Pb isotopic compositions (206Pb/204Pb = 18.295-18.402, 207Pb/204Pb = 15.551-15.573, and 208Pb/204Pb = 38.215-38.331), suggesting that the ore metals were extracted primarily from the quartz monzonite or similar source. Subduction of the Paleo-Pacific slab during the Early Cretaceous resulted in the formation of the Wangjiazhuang quartz monzonite and associated Cu(-Mo) deposit in western Shandong Province.