Geochronology and petrogenesis of the Neoarchean-Paleoproterozoic Taihua Complex, NE China: Implications for the evolution of the North China Craton

The North China Craton (NCC) preserves important records of Archean-Paleoproterozoic crustal evolution. Here we present results from petrology, geochemistry, zircon U-Pb dating and Lu-Hf isotopes of the Taihua Complex (THC) from the southern part of the NCC. Zircon U-Pb dating of the amphibolite yields the ages of 2776-2771 Ma representing the formation age, marking a major phase of late Archean crustal growth in the NCC. The 1922-1915 Ma ages represent the Paleoproterozoic metamorphism associated with the collisional assembly between the Eastern and Western Blocks. The amphibolites are characterized by low SiO2, Na2O + K2O, and Nb/Y, indicating a sub-alkaline basaltic protolith. These rocks show relatively high LILE/HFSE and LREE/HREE ratios, similar to E-MORB, low [Nb/La](PM), negative Nb-Ta anomalies and positive epsilon(Hf)(t) values indicating partial melting of a metasomatic mantle source. The TTG gneisses are characterized by high SiO2, Sr/Y, (La/Yb)(N), Nb/Ta, Zr/Sm and Zr/Hf ratios, and low MgO, Cr, Ni, Y, Gd/Yb and Dy/Yb ratios, with positive Eu anomalies, indicating partial melting of juvenile lower crust with garnet-amphibolite residue. Our data are consistent with a tectonic setting within a volcanic arc in a convergent margin. Our study on the THC contributes to the Archean-Paleoproterozoic crustal accretion and reworking history along the southern margin of the NCC.