Scientists on Tuesday completed the first drilling task of an expedition to the South China Sea.

Workers working on the drilling ship JOIDES Resolution.[Photo: Xinhua]

The hole, identified as U1499A, has reached 3,770 meters below sea level, for collection of sediment samples.

According to Sun Zhen of the Chinese Academy of Sciences South China Sea Institute of Oceanology, a preliminary lithologic study was conducted on sediment believed to have been formed eight million years ago.

A second hole, U1499B, will be close to the first.

A total of 33 scientists from China, the United States, France and other countries boarded the U.S. drilling ship JOIDES Resolution on February 8, and arrived at the drilling site last Tuesday.

As part of the International Ocean Discovery Program (IODP), they will explore the lithosphere extension during the continental breakup, by drilling at four sites in the northern area of the South China Sea to a depth of up to 4,000 meters. The study will contribute to understanding of how marginal basins grow.

Since joining the IODP, China has played a major role in expeditions to the South China Sea in 1999 and 2014, collecting samples for studying climate change and basin formation.