¡¡¡¡LHASA, May 29 (Xinhuanet) -- A group of Chinese archeologists have discovered 13 sites of prehistoric stone tools during a field survey on the Qinghai-Tibet Plateau.

¡¡¡¡They indicate that human activity had reached the plateau area at an average altitude of 4,000 meters, an environment of low temperatures, harsh weather conditions, and an acute shortage of oxygen.

¡¡¡¡Some of the uncovered stone implements could be used for hunting or farming, said the experts, who belong to an excavation team organized for the on-going Qinghai-Tibet Railway Project.

¡¡¡¡It is the first time that Tibet Autonomous Region has sent archeologists to join major projects.

¡¡¡¡The 16-member team, composed of professionals from Tibet as well as experts from prestigious Sichuan University and archeologists from northwestern Shaanxi province, has been workingon the 700-km Tibet section of the railway since May 10. Enditem