Mai The Trung, deputy director of Quang Tri Museum, said the museum had received two of the axes from the British expedition team, which recently surveyed the cave under the leadership of Dr Howard Limbert.
The axes were found among layers of soil and rock eroded by floodwaters inside Hang En Cave, located in the core zone of the national park.
Preliminary assessments by museum experts indicate the tools date to the Neolithic period.
Made from siliceous stone, the artefacts include shouldered and transverse-shouldered axes, with polished blades, chipping marks and wear indicating repeated use in prehistoric daily life.
Dr Limbert and his wife donated the axes to Quang Tri Museum and Hanoi Museum.
“This is a highly significant archaeological discovery, demonstrating that prehistoric humans once lived in caves within Phong Nha-Ke Bang National Park,” Trung said.
Limbert has spent nearly 35 years surveying caves in the area and has helped identify cultural and palaeontological remains in several systems, including Cham relics in Phong Nha Cave and fossilised flora in Hang Toi and Son Doong.
Hang En is one of the world’s largest caves and serves as the gateway to Son Doong, the world’s largest known cave. It stretches more than 1.6 km and has an estimated volume of 6.7 million cubic metres.
Opened to adventure tourism in 2012, the cave has three entrances and features a vast interior chamber with ceilings reaching 145 metres.
During an expedition from March 21 to April 11, cave specialists surveyed 26 newly identified caves in the national park, many featuring underground rivers and extensive stalactite formations.
