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

• Published in: Ore geology reviews Vol. 67; pp. 336 - 353
• Main Authors: Wang, Hao, Fu, Bin, Xu, Zhaowen, Lu, Xiancai, Lu, Jianjun, Li, Haiyong, Qu, Wenjun, Yang, Xiaonan, Chen, Wei, Zhang, Jun
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 01.06.2015
• Subjects: Geochemistry; Geochronology; Isotopes; North China Block; Porphyry–breccia Cu(–Mo) deposit; Geochemistry; Geochronology; Isotopes; North China Block; Porphyry–breccia Cu(–Mo) deposit
• ISSN: 0169-1368; 1872-7360
• DOI: 10.1016/j.oregeorev.2014.12.010

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±0.7Ma (2σ), which is identical within error to the zircon weighted mean 206Pb/238U age of 128.3±1.3Ma (2σ) determined for quartz monzonite samples. The host rock is characterized by high concentrations of K2O (4.26–4.53wt.%), Na2O (4.97–5.76wt.%), 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. •Wangjiazhuang quartz monzonite crystallized at 128.3±1.3Ma.•Wangjiazhuang porphyry–breccia Cu(–Mo) deposit was formed at 127.8±0.7Ma.•Quartz monzonite was derived from subducted oceanic crust and sedimentary components.•Sulfur and lead in ores are extracted mainly from the quartz monzonite.