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

Detrital zircons from nine river sand samples from the upper, middle and lower streams of the Yangtze River (the world's third largest river) and its two largest tributaries, the Han and Jialing rivers have been analyzed for U–Pb–Lu–Hf–O isotope compositions. Zircons from the upper Yangtze River cluster in age groups at 0–100, 200–300, 400–500, 700–1000, 1800–1900 and 2300–2500 Ma, with a marked peak at 41 Ma diagnostic of magmatism on the Tibetan Plateau. Zircons from the middle and lower Yangtze River and its tributaries exhibit broadly similar age groups at 100–300, 400–500, 700–900, 1800–2000 and 2300–2700 Ma, except for the lack of Cenozoic ages.