“Archaeologists are detectives of the past”

A fellow PhD student once said “archaeologists are detectives of the past”.

He was teaching primary school students about archaeology at The University of Queensland Archaeology Teaching and Research Centre and his expression caught the imagination of many of the young minds present.

Since then, it has been the phrase that I am most likely to deploy on interested parties of all ages when trying to explain my chosen career.

This week an international and multi-disciplinary team led by Associate Professor Chris Clarkson of UQ has rewritten Australian and, indeed, world history by proving that the colonisation of Australia and the first major sea voyage in human history occurred at least 65,000 years ago.

This incredible discovery, and its many implications, is the work of many archaeologists, using small pieces of evidence such as stone tools and grains of sand to understand human behaviour 65 millennia ago.

Another UQ PhD student, Dr Xavier Carah, and I worked on some of the least prepossessing material excavated from this site: small fragments of charcoal.

Through our analyses we began to understand the lives of the first people who inhabited this continent: what they ate, how they stayed warm and how they survived this novel environment.

The only way to describe our work, and that of others at the site, is as ‘detectives of the past’. We used logical inference, scientific techniques (that would not look out of place on CSI) and the expert knowledge of the Mirarr people, living in Western Arnhem Land today, to begin to understand the lives of the first Australians, living 65,000 years ago.

The pieces of charcoal we studied are the remains of past campfires, scattered across the thousands-of-years-old living floors of Madjedbebe rockshelter or found in discrete, still intact domestic hearths.

These pieces of charred plant remains were removed from the sandy sediments that enveloped them using a flotation tank - 44-gallon drums, which, with the help of an electric pump, created a cascading waterfall, separating the sand and heavy artefacts from the light, floating organic remains.

Once floated and dried, Xavier and I studied these pieces of charcoal with both light- and electron-powered microscopes.

Much of our analysis was, therefore, carried out in the archaeology laboratories at UQ.

We identified these ancient plant remains by comparing them to plants present in the region today, looking for unique anatomic features – still visible in charred specimens – that distinguish them from other similar genera and species.

These same pieces of charcoal were then used for radiocarbon dating and isotopic analysis, allowing us to confer the age of the site and the past palaeoenvironmental conditions in which these plants grew.  

To better understand how people used, processed and managed these plant resources we also spent time on Mirarr country.

We worked with the experts, May Nango and Mark Djandjomerr, to both collect plants for our modern reference collection and to discuss and recreate how the plants we found, charred in campfires over 65,000 years ago, could have been used.

May is a Mirarr traditional owner of Madjedbebe, and both she and Mark grew up in this area, and learnt about its flora and fauna from their parents and grandparents.

It is their wealth of knowledge and the generosity with which they shared it, that allowed us to begin to appreciate their ancestors’ relationship with the unique environment.

From my work with the food plants found at site it was clear that the first Australians were able to exploit a wide range of resources at colonisation, including nuts and fruits, roots and tubers.

One of the plants often exploited at the site, and consistently found in ancient campfires, was pandanus, a palm-like tree with large orange fruit, containing edible kernels.

These fruit are very hard to open, even with the metal axes available in this region since Macassan contact in the mid-seventeenth century.

However, the high fat content of these kernels (44-50% fat and 20-34% protein; Low 1991:42), would have made the labour worthwhile for a population surviving on the lean meat of Australian fauna.

This research, as part of my PhD, is ongoing and I hope these pieces of charcoal, in conjunction with the work of other archaeologists at Madjedbebe, and the insight provided by our partnership with the Mirarr, will continue to offer up clues as to life in Australia 65,000 years ago.       

Last updated:
20 July 2017