Nature and origin of the Wenquan granite: Implications for the provenance of Proterozoic A-type granites in the North China craton

The Proterozoic Wenquan granite occurs at the northern margin of the North China craton. New U–Pb zircon ages reveal that the Wenquan granite was emplaced at 1697 ± 7 Ma, and is thus approximately coeval with the 1753 ± 23 Ma Changsaoying granite and the 1683 ± 4 Ma Shachang granite found in the area. The ubiquitous occurrence of titanite and magnetite demonstrates that the granites are oxidized. Geochemically, they show most of the characteristics of typical A-type granites, such as high contents of alkalis (i.e., high K2O + Na2O, with K2O/Na2O > 1), Rb, Y, Nb and rare earth elements (REE, except for Eu), high FeOt/MgO and Ga/Al ratios and low contents of CaO, Al2O3, and Sr. Their negative bulk rock initial Nd and zircon initial Hf isotopic ratios suggest that they were most likely derived from the late Archean lower crust. The three Proterozoic A-type granites are believed to be genetically related to the breakup of the Columbia supercontinent.

► U–Pb zircon ages reveal that the Wenquan granite intrusion was emplaced at 1697 ± 7 Ma.
► Geochemically, the Wenquan granites show characteristics of typical A-type granites.
► The Wenquan granites were probably derived from an oxidized late Archean lower crust source.
► The Wenquan granites are probably related to breakup of the Columbia supercontinent.