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

Abstract

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 εHf(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.