Geochemistry of the paleoproterozonic Nanying granitic gneisses in the Fuping complex: implications for the tectonic evolution of the Central Zone, North China Craton

The Nanying granitic gneisses are geochemically similar to the CCA and CCL groups of granitoids, except for a few samples, which plot in the HLO group. The Nanying granitic gneisses exhibit depletion in Rb, Sr, Ba, Ti and U, and enrichment in Th, Nb, Zr, Hf and REE, similar to those of syn-shear, high-potassium calc-alkaline granitoids and late-shear alkaline granitoids; they therefore represent the product of a syn-collisional to post- collisional magmatic event. This collisional event, which is significantly older than the ∼1.84-1.80 Ga event that has been proposed for the juxtaposition of the Eastern and Western Archean continental blocks in the final stabilization of the North China Craton, supports a tectonic model involving multiple collisional events for the amalgamation of the internal lithotectonic domains within the Central Zone and the assembly of the North China Craton as a whole.