Depositional age, provenance and tectonic setting of the Proterozoic Ruyang Group, southern margin of the North China Craton

Detrital zircons from three sandstone samples of the Ruyang Group yield 207Pb/206Pb ages ranging from 1.70 Ga to 2.70 Ga with two pronounced peaks at ca. 2.10 Ga and 1.86 Ga. A weighted mean age at 1744 ± 22 Ma from nine young zircon ages between 1.80 Ga and 1.70 Ga can constrain the maximum depositional age of the Ruyang Group. Most detrital zircons exhibit negative ɛHf(t) values ranging from −15.6 to 0 and old TDMC ages ranging from 2.50 Ga to 3.60 Ga, implying reworking of Archean crust. A close match between the U-Pb ages and TDMC(Hf) ages, as well as the positive ɛHf(t) values for some detrital zircons, indicate a contribution of juvenile materials. The detrital zircon grains have TDMC(Hf) ages clustering between 3.00 Ga and 2.60 Ga with a peak at around 2.80-2.70 Ga, indicating a major period of crustal growth at this time.