Geochemistry and Geochronology of the Huangcha Pluton and Tectonic Significance

The Zanhuang Complex is situated on the eastern margin of the Trans-North China Orogen, with the Huangcha Pluton being a constituent of this complex. To ascertain the nature of the approximately 2.5-billion-year-old Huangcha Pluton, crucial evidence for understanding its extensional setting was sought through petrogenesis and dating investigations. LA-ICP-MS dating of zircon from the granite yielded an age of (2488 +/- 6) Ma. Primarily composed of porphyritic monzonite with sporadic melanocratic enclaves, the Pluton's phenocrysts are predominantly feldspar with minor quartz. The granite exhibits high SiO2 content (72.64%-74.16%) and alkali levels, with Na2O + K2O ranging from 7.59% to 9.07%, classifying it as a shoshonitic series with a slightly peraluminous feature. Enrichment in large-ion lithophile (LIL) elements (Rb, Th, and U) and depletion in Sr, V, Cr, Co, and Ni were observed, with high Rb/Sr and Ga/Al ratios ranging from 0.73 to 2.72 and 2.75 x 10(-4) to 3.11 x 10(-4), respectively. The rock exhibits high epsilon Nd(t) values, ranging from -0.06 to 0.88, with TDM2 ages falling between 2.79 and 2.87 billion years. Zircon grains display Hf-176/Hf-177 ratios ranging from 0.281266 to 0.281412 and epsilon Hf(t) values spanning from 0.96 to 6.18, calculated using the Pb-207/Pb-206 age. It is suggested that the Huangcha Pluton represents A-type granite formed via anatexis of the Neoarchean TTG in an extensional setting following orogenic processes. The formation of the Huangcha Pluton further corroborates the stabilization of the North China Craton towards the end of the Neoarchean. This finding supports the hypothesis that the North China Craton may belong to the Rae-family cratons, sharing similar magmatic and tectono-metamorphic records around similar to 2.5 billion years ago.