Abstract:The detrital zircon dating of the modern river sands from the tributaries and mainstream of the Pearl River reveals age spectra with eight major age groups: 2 800—2 300 Ma, 2 000—1 800 Ma, 1 800—1 300 Ma, 1 100—700 Ma, 600—400 Ma, 380—230 Ma, 200—80 Ma and <65 Ma, corresponding to tectonic events within the drainage e.g. crustal growth, Lüliangian, Jinningian, Caledonian, Indosinian and Yanshanian. The tributaries are characterized with different age spectra and can be classified by their location. The Beipanjiang River, the Nanpanjiang River, the Hongshuihe River, the Youjiang River, the Zuojiang River and the mainstream of Xijiang River from the upstream feature a 380—230 Ma age peak, indicating that these zircons were mainly from the Youjiang Orogenic Belt. The 2 000—1 800 Ma age peak only occurs in the Youjiang River and the Zuojiang River, suggesting that those zircons probably come from an ancient basement. The Liujiang River from the middle stream is characterized with a 1 000—800 Ma age peak, which represents zircons from the Yangtze Block. Besides this 1 000—800 Ma age peak, another two age peaks of 660—400 Ma and 2 800—2 300 Ma are found in the Guijiang River, suggesting provenances from the Jiangnan Orogenic Belt and the Cathaysia Block. The detrital zircons from the North River, the East River and the Pearl River delta of the downstream are mainly deprived from the granite belt along the southeast coast. This result shows that the peaks of the detrital zircon ages can be used to identify the sediment from the tributaries, which may be helpful for studying the provenance of the northern South China Sea sediment and its relationship with the evolution of the Pear River.
