Recovering Macrobotanical Remains from East Timor Cave Deposits

( through bucket flotation and wet-sieving )

Nuno Vasco Oliveira

Department of Archaeology and Natural History, Research School of Pacific and Asian Studies,
The Australian National University

Introduction

Bucket flotation and wet-sieving were used as methods to recover macrobotanical remains from Bui Ceri Uato Mane rock shelter, in Baucau (East Timor).

After previous archaeological work in the region (Glover 1986, Spriggs and O'Connor 2002), where recover was not specifically aimed at the macrobotanical evidence, this practice was regarded as the most suited for assessment or early plant use and environmental reconstruction within the timeframe of site occupation (Fairbairn in press).

Materials and methods

The method of flotation involved the use of fine chiffon cloth (< 25 mm), a few buckets and pegs. All excavated spits were transported from the excavation site to the village in woven plastic sacks, where they were processed.

The soil samples were weighted, poured into buckets (1/3 of soil and 2/3 of water) and stirred. After a few minutes to allow the soil to settle, the water and floating material were

poured into the chiffon cloth sieve, labeled and hung to dry.

The heavy residue left in the bucket was then poured into a 1mm sieve, where the rest of the sediment was removed. This was again weighted, labeled and put in the sun to dry. All recovered material (small stone tools, shells, animal bones and other plant remains) was sorted, labeled and stored.

Results

After a preliminary field season in 2004 where a few archaeological sites were located and tested (including Bui Ceri Uato Mane rock shelter), a new field season was carried out in 2005.

Although some macrobotanical collections are known from previous excavations in East Timor (Glover 1986, Spriggs and O'Connor 2002), we know this specific method of recovering has never been used before in the country.

As seen in figure 6, floating and sieving archaeological sediment in water clearly affects the size of charcoal samples (few fragments are bigger than 4 mm). Despite this, it enables systematically recollection of specimens otherwise too small to be seen and collected during excavation, resulting in a a less biased sample due to poor recovery techniques

Charcoal samples have been recovered from nearly every excavated spit. Squares B and D contain the most significant amounts as most fire episodes (fireplaces or similar structures) were located in those areas.

The top spits probably correspond to a moment when the rock shelter was used as an animal pen, with sequential episodes of fire mixed with goat dung and layers of consolidated ashes.

The last spits (bottom orange layer) contain fewer charcoal and otherwise any other materials, as they probably represent a moment when Bui Ceri Uato Mane was not being occupied by humans.

Conclusions and Future Prospects

• Although as yet no identifications have been made, the recovery method used in Bui Ceri Uato Mane, aimed specifically at the macrobotanical evidence, proved very efficient. Preliminary analysis indicate significative amounts of charred remains in most excavated units, mostly wood charcoal
• Separation and identification of the fruits and nuts, using both binocular and scanning electron microscopes, are planned. Together with a detailed dating program of the occupational sequence of the shelter, will enable to assess the history of plant use in the region, helping distinguish local from introduced crops
• While in the field, plant specimens with current economical use in the area were also collected. This was done under technical advice from the Australian National Herbarium, where the specimens were deposited and will later be analyzed

Literature cited

• Fairbairn, A. 2005. Simple bucket flotation and wet sieving in the wet tropics. Canberra: RSPAS, ANU (Palaeoworks Technical Report 4 )
• Fairbairn, A. in press. An archaeobotanical perspective on Holocene plant use practices in lowland northern New Guinea. World Archaeology
• Glover, I. 1986. Archaeology in Eastern Timor, 1966-67. Canberra: RSPAS, Australian National University
• Spriggs, M. and S. O'Connor. 2002. Vestiges of Early Pre-agricultural Economy in the Landscape of East Timor. Recent Research. In Fishbones and Glittering Emblems (eds A. Karlström and A. Källén). Stockholm: pp. 49-58

Acknowledgments

Andy Fairbairn for technical advice, Sue O'Connor for help in the field and supervision, Matthew Spriggs for supervision, Peter Bellwood for advice, Mattiu Prebble, Gillian Atkin and Janelle Stevenson for laboratory assistance, Lyn Craven (Australian National Herbarium) for help with collecting plant specimens. GERTiL has produced the maps and given assistance while in East Timor. Funding for this project was provided by Fundação para a Ciência e a Tecnologia (Portugal) and the Department of Archaeology and Natural History, RSPAS, Australian National University.

For further information

Please contact Nuno Oliveira

More information on this project available here