BEIJING -- Researchers from Chinese and American institutions studying sedimentary records from the northern South China Sea recently determined that the modern-scale Pearl River was formed 30 million years ago.

Scientists have done a lot of research on the evolution history of the Pearl River. Due to the lack of continuous and high-resolution sedimentary records over a long geological time, its evolution history had been poorly understood.

Researchers from the Institute of Oceanology under the Chinese Academy of Sciences, Louisiana State University and other Chinese and American institutions used sediments from the latest deep sea drilling core in the northern South China Sea in this study.

They reconstructed the evolutionary history of the Pearl River by tracing changes in clay mineral assemblages and Strontium-Neodymium isotopic compositions of the sediments.

The study, which was published in the journal Earth and Planetary Science Letters, found that the modern-scale Pearl River drainage system was formed 30 million years ago and began to play an important role in the evolution of the sedimentary environment of the northern South China Sea.

Tectonic deformation, mainly the elevated southeastern Tibetan Plateau, contributed to the topographic reversal in the South China Block, thus promoting the westward expansion and formation of the main body of the Pearl River, according to the study.