Bulletin

Issue: May 2006

Research in Action

Excavating in China for an answer to the great question about our origins

A La Trobe University archaeologist is part of an international team attempting to throw light on the current debate on the origins of the human race.

Did humans spread from Africa to other areas where they replaced local hominid groups – the ‘Out of Africa’ model?

Or did they evolve separately in different localities – the ‘Regional Continuity’ model?

Dr Richard Cosgrove, a senior lecturer in a La Trobe’s Archaeology Program, is part of a team excavating in central China hoping to ‘unearth’ evidence that will contribute significantly to the resolution of the debate.

Dr Cosgrove and his colleagues, Dr Shejiang Wang, a La Trobe postdoctoral fellow, Dr Chen Shen of the Royal Ontario Museum, and Professor Huaya Lu of the Chinese Academy of Sciences in Xian, have received an ARC $368,000 grant over three years to find evidence to help resolve the question.

For the next three years they will excavate into layers up to 300 metres deep of loess – solidified fine wind-borne dust still being blown in from Outer Mongolia – at several sites in the Lounam Basin in central China. This is the geographic divide between north and south China that has been influenced by changing climate many times over millennia.

The team is using stone artefacts plus plant and animal fossils found in the loess to detect evidence of two important factors. One is the climatic changes during the middle and upper Pleistocene Age, between 500,000 and 10,000 years ago, and the other is how people adapted to those changes.

For two reasons, the areas covered in loess in Central China have turned out to be a unique hunting ground for archaeologists.

Firstly, loess, because it contains large amounts of calcium carbonate, preserves vitally important animal and vegetable clues for archaeologists, among them bones, pollen, and other material.

Secondly, this evidence of human settlement over thousands of years has been gradually buried under the loess, leaving behind what was first believed to be an exact ‘chronological’ ordering of human development.

In theory, because of river downing-cutting, the higher up the mountains, the older the loess deposits, but this is has been complicated because wind and water activity have cut through and shifted some loess deposits.

‘Nevertheless we have a great opportunity to see how human behaviour changed through time by examining the artefacts and other material at different levels in the loess,’ says Dr Cosgrove.

‘We use the bones to tell us about climate because the kinds of animals which lived there when the climate was warm were different from those which existed when it was cold. The plant and bone remains tell us about human food, hunting and butchering techniques and past vegetation patterns.’

The team will spend June to August, the spring season, on site for the next three years excavating four cave sites and four river terraces which have been occupied for thousands of years.

‘It is slow painstaking work, using trowels and sieves to collect tiny pieces of material which can be tested by a number of dating techniques,’ Dr Cosgrove said.
‘We would like to be able to gather enough evidence to learn approximately when modern humans became “modern” and whether they evolved in this place.

‘If we can find a sequence of hominid skeletal remains which show gradual evolutionary change, that would tend to support the “Regional Continuity” model of the origin of humans.

‘On the other hand, if we discover evidence of early hominid forms, and then find a large break in time before we find evidence of modern hominids, that would support the ‘Out of Africa’ model.’