Humans arrived in Asia earlier than thought: Study

Our earliest human ancestors left Africa and colonised Asia over two million years ago, ancient tools and bones discovered in China by archaeologists suggest.

The tools were discovered by a research team led by Professor Zhaoyu Zhu from the Chinese Academy of Sciences at a locality called Shangchen in the southern Chinese Loess Plateau.

The oldest artefacts are 2.12 million years old, and are 270,000 years older than the 1.85 million-year-old skeletal remains and stone tools from Dmanisi, Georgia, which were previously the earliest evidence of humanity outside Africa.

The artefacts include a notch, scrapers, cobble, hammer stones and pointed pieces, according to the study published in the journal Nature.

All show signs of use - the stone had been intentionally flaked. Most were made of quartzite and quartz that probably came from the foothills of the Qinling Mountains 5 to 10 kilometres to the south of the site, and the streams flowing from them.

Fragments of animal bones 2.12 million years old were also found.

"Our discovery means it is necessary now to reconsider the timing of when early humans left Africa," said Professor Robin Dennell from the University of Exeter in the UK, who was also involved in the study.

The Chinese Loess Plateau covers about 270,000 square kilometres, and during the past 2.6 million years between 100 and 300 metres of wind-blown dust - known as loess - has been deposited in the area.

The 80 stone artefacts were found predominantly in 11 different layers of fossil soils which developed in a warm and wet climate.

A further 16 items were found in six layers of loess that developed under colder and drier conditions. These 17 different layers of loess and fossil soils were formed during a period spanning almost a million years.

This shows that early types of humans occupied the Chinese Loess Plateau under different climatic conditions between 1.2 and 2.12 million years ago.

The layers containing these stone tools were dated by linking the magnetic properties of the layers to known and dated changes in the Earth's magnetic field.