By Kelsie

On the 26th May 2016 I attended the launch of the Geoarchaeology Research Group (GRG) which is headed by Associate Professor Tim Denham (ANU College of Arts and Social Sciences). The launch consisted of a series of short talks presenting the range of topics the group has been working on as well as some input from geoarchaeological researchers from the University of Wollongong. I am definitely not an expert in geoarchaeology and so I encourage anyone who wants to know more about it to check out the GRG website. I just think that the stuff they do is really cool and interesting. It’s also quite important.

But first a definition from the recently launched GRG website:

“Geoarchaeology is ‘the application of concepts and methods of the geosciences to archaeological research’ (Waters, 1992, p.3). Geoarchaeology provides a framework for understanding the relationships between humans and their environments. Our approach to geoarchaeology centres on devising ways to move fluidly between different analytical scales of understanding human and environmental relations, from landscape-wide  geomorphological and  environmental reconstructions to studying the interaction between human and natural processes which create deposits at the micro-scale.”

Researchers in GRG have been working closely with research and technical staff of RSES to further develop their sample preparation and analytical techniques.

top left clockwise: Ulrike Troitzch, x-ray diffraction lab, RSES; John Vickers and Shane paxton, sample preparation of ceramic petrographic thin sections and QEMSCAN billets, RSES; Rachel Wood, radicoarbon lab, RSES.
Top left clockwise: Ulrike Troitzch, x-ray diffraction lab; John Vickers and Shane paxton, sample preparation of ceramic petrographic thin sections and QEMSCAN billets,; Rachel Wood, radicoarbon lab.

At many archaeological sites geoarchaeologists play an integral role in contextualising materials and better establishing site chronology, which can have a huge impact when you’re dealing with site withe early hominins for example. They look at site formation and post-depositional processes (things that happened to the sediment and archaeology after they were first laid down in a site) and examine multiple scales of information from the micro, to the macro to the wider landscape. As shown in the image below, geoarchaeologists typically take large samples of sediment called “monoliths” from excavations, and then embed these with a plastic resin and make thin sections.

The different scales of analysis used by Emily Dillion in her geoarchaeology 2014 Honours thesis
The different scales of analysis used by Emily Dillion in her 2014 Honours thesis.

I thought all the talks were wonderful but some of the most interesting in my opinion were the following.

For Emily Dillon’s honours thesis she examined the stratigraphy of a location at Lake Mungo at different scales in order to better establish the site chronology (see image above). Her presentation at the GRG launch questioned the obsession of Australian archaeologists with the oldest and rarest archaeological sites/materials. Basically there just hasn’t been enough work done on establishing the stratigraphic integrity of many of these earliest sites or materials at a fine enough level of detail to ensure that the site has remained undisturbed. This is something that geoarchaeologists like Emily could help to improve.

Emily holding sitting at the top of her site at Lake Mungo, holding one of her monolith samples.
Emily sitting at the top of her site at Lake Mungo, holding one of her plastered monolith samples.

Masters student, Aleese Barron spoke about her work on identifying rice imprints in ancient pottery shards using 3D tomography. From the 3D images she could identify whether the rice was domesticated or wild. This method is a non destructive approach to identifying rice husks within pottery and can be applied to tracking the spread of domesticated rice across southeast Asia.

rice temper SEAsia
3D tomographic images of some of Aleese’s pot shards. These are the images she can manipulate to pick out the individual rice husks within the samples.

Elle Grono spoke about her PhD work on identifying constructed floors within thin section slides of excavated stratigraphies from two sites in Vietnam. Constructed floors are those that were intentionally made by past occupants and are identified as areas of highly compacted sediments.

Elle extracting a stratigraphic sample from one of the Neolithis sites in Vietnam
Elle extracting a stratigraphic sample from one of the Neolithis sites in Vietnam

They are easily distinguished from compression caused by trampling as they are much more compact. She is using the identification of these floors within her excavated sites to examine theories about waste compaction, sedentism and occupation cycles of sites as well as the effects of bioturbation on such structures. This year she is heading back to Vietnam to take samples of modern constructed floors to compare with those from her ancient excavated sites.

Some of Elle's thin sections which contain pottery, bone and floor surfaces.
Some of Elle’s thin sections which contain pottery, bone and floor surfaces.

Dr Mike Morley and students from the University of Wollongong drove down to visit ANU specifically for the GRG launch. Dr Morley reported on the work going on at Liang Bua Cave in Flores, which some of you may recognize as the site where the new species of early hominin, Homo floresiensis nicknamed the Hobbit, was discovered in 2003. The current focus of Mike and his team is on filling the chronological gap at the site between ~50-20ka which relates to the period of time between the dated homo floresiensis remains (~60-50ka) and modern human arrival. They will be closely examining the complex stratigraphy at the back of the cave which includes volcanic tephras (fragmental material produced by a volcanic eruption), coarse limestone gravel and speleothems (mineral deposits formed from groundwater within underground caverns, eg stalagmites, stalactites).
The Liang Bua cave excavations on the island of Flores, Indonesia (credit to Smithsonian / Liang Bua Team)

Vida Kumartono gave a talk introducing her PhD research. She is investigating the evidence behind the idea that in the past people couldn’t live in the rainforest without help from farmers. Her site is situated in the deep interior equatorial rainforest of Borneo and took her 3 days travel (mostly via boat over some serious looking rocky rapids!) to reach.

Excavations in the deep rainforest in Borneo
Vida (top right) at her excavation site in the deep rainforests of Borneo

Vida is using  petrographic analysis of ceramics (pot sherds) to compare to the geology of the region to figure out where the raw materials came from. This can give insights into human mobility, settlement patterns and trade networks. All towards answering questions like: “Was the interior rainforest occupied by humans prior to 3000BP?” and “How intensive was environmental exploitation by humans?”.

Thin section slides of some of Vida’s pottery sherds

There were so many brilliant projects presented at the opening and I wish I could go into each and every one of them here but I hope I have given you a taste of some of the complex and detailed work, combining geological techniques with archaeological problems, being undertaken just down the hill from RSES.

Follow the Geoarchaeology Research Group on twitter: @geoarchaeology1

Check out their website: