BEIJING, Jan. 29 (Xinhua) -- A groundbreaking archaeological discovery at an ancient site in central China's Henan Province is reshaping views of prehistoric innovation, after an international research team uncovered clear evidence that early humans in East Asia were crafting sophisticated handled stone tools as early as 70,000 years ago.

The study, published Wednesday in the journal Nature Communications, focuses on 22 specific stone tools excavated from the Xigou site, nestled in the Qinling Mountains. Detailed technological and microscopic use-wear analysis confirmed these artifacts were hafted, or intentionally modified at the base to be attached to wooden or bone handles, forming composite tools like knives.

"This represents the earliest confirmed evidence of hafting technology in East Asia supported by both technical typology and traceology," said Yang Shixia, corresponding author of the study and a researcher at the Institute of Vertebrate Paleontology and Paleoanthropology (IVPP) of the Chinese Academy of Sciences.

"It significantly pushes back the recorded emergence of this technology in the region," Yang added.

Dated securely to between 160,000 and 72,000 years ago, the Xigou site functioned as a workshop and yielded over 2,600 stone artifacts, primarily crafted from quartz and quartzite, which were once considered unsuitable for refined toolmaking.

The international research team, led by the IVPP, found that the ancient inhabitants of the site had mastered systematic core technologies for producing flake tools. One method involved detaching small flakes from larger ones, while the other entailed efficiently and centripetally striking flakes off a stone core. The toolkit included scrapers, borers and points.

Analysis revealed that the hafted pieces exhibit clear basal modifications for attachment, with some retaining direct evidence of having been mounted onto handles. Much like fitting a blade into a knife handle, these early humans employed two connection methods -- insertion and lateral hafting -- to enhance the effectiveness of their stone tools.

This finding directly challenges the long-standing academic view of a "technologically conservative" East Asia during the period from the late Middle Pleistocene to the early Late Pleistocene (approximately 300,000 to 50,000 years ago), when complex behaviors like hafting technology, formal bone tool production, and the use of personal ornaments and pigments were emerging in both Africa and Europe.

The research team applied multiple luminescence dating techniques, which measure when buried minerals last saw sunlight, on the site's sediments to establish the robust chronological framework.

The discovery at Xigou is not an isolated case. It joins a series of recent findings across China, such as evidence of prepared core technology, bone tool shaping, and pigment use at other sites, that collectively portray early human populations in East Asia as innovative adaptors.

Facing a climate of intense fluctuation, they developed a versatile and flexible technological repertoire, according to Yang.

"This discovery rewrites the traditional narrative of early human behavioral development and adaptation in East Asia," she said. "It underscores that this region played a critical and dynamic role in the global story of human evolution."