Step-like growth of the continental crust in South China: evidence from detrital zircons in Yangtze River sediments

Comparison with global crustal growth curves based on detrital zircons highlights the distinct step-like pattern of crustal growth in South China. This emphasizes the potential of comparing regional with global crustal growth curves, and the changes in the rates of crustal growth in South China appear to have been controlled by changes in regional geodynamics. The maximum δ18O values in the zircons analyzed increase markedly at the end of the Archaean, and these increases therefore accompany the estimated increases in atmospheric oxygen at that time. It is therefore suggested the atmospheric O2 levels were associated with increased crustal weathering, the development of more elevated δ18O sediments and their increasing incorporation in the generation of crustally derived magmas from ca. 2.5 Ga.