LANZHOU, Oct. 22 (Xinhua) -- The Lancang River, the world's twelfth longest river and seventh longest in Asia, was formed around 17 million years ago, according to the latest study conducted by the Department of Resources and Environment at Lanzhou University, which is based in northwestern China's Gansu Province.
Recently published in the Nature Geoscience journal, the study also indicates that climate change is closely related to the river's formation.
Slopes are mainly responsible for the formation of rivers, so the age of Lancang River's valleys can provide a major clue in determining when the river was formed, said She Junsheng, a professor at Lanzhou University who led the research. He added that determining the approximate age of the valleys has been a years-long battle for scientists.
Professor She and his team members determined the age of Lancang River's valleys using thermochronometry, which involves collecting rock samples and studying their thermal evolution. From this, they concluded that steep slopes formed at the upper, middle and lower parts of the river's valleys around 17 million years ago, contributing to the formation of the Lancang River.
The study also shows that increasing rainfalls and erratic weather brought about by stronger East Asian monsoons steepened the slopes of the valleys, indicating that climate change also led to the river's formation.
Starting on the Tibetan Plateau in western China's Qinghai Province, the Lancang River runs through Laos, Myanmar, Thailand, Cambodia and Vietnam. It is also an important trade route between western China and Southeast Asia.