Motupore Island continued

The following is a slightly edited version of a report I originally wrote for PAST, the newsletter of the Prehistoric Society, which provided me with some funding to attend the Motupore Island excavation in Papua New Guinea in 2016. This did not end up appearing in PAST, so I thought I would post it here.

In June 2016 the University of Papua New Guinea (UPNG) ran an archaeological field school on Motupore Island, Papua New Guinea (PNG). Because my research as a graduate student at the University of Otago had looked at the archaeology of sites and regions thought to be linked to Motupore Island, I was invited to attend as an overseas student. A short report on the excavation follows. 

Motupore Island in Bootless Bay is a small, waterless island located some 16km east of Port Moresby, the national capital of PNG. The island is about 800m long, 275m wide at its widest point, and rising to a maximum 61.4m above sea level. On the protected northern (shoreward) end of the island, a cuspate sand spit of approximately 1.5ha has formed and been consolidated with grass cover. In front of this is a white sandy beach and tidal spit. It is this formation that gives the island its name in the local language, Motu (motu = island; pore = gravel or sand bank). Archaeological materials (pottery sherds, stone, shell and bone) can be recovered from the sand spit, beach and tidal spit, with the densest concentrations along the base of the hill. In 1970 the island was purchased by the UPNG, primarily as an archaeological training site, but also as a field station for other disciplines at the university.

Left: Location of Papua New Guinea (PNG) in the Western Pacific. The yellow star indicates the rough location of Bootless Bay and Motupore Island. Right: aerial view of Motupore Island. The yellow star indicates the location of the 2016 excavation unit. Images from Google Earth.

 

Photo taken by the author looking south towards the island along the tidal spit indicated in Figure 1 above.

During the 1970s, archaeological investigations were undertaken on Motupore Island by  archaeologists from the UPNG. The principal archaeologist was Jim Allen (now Emeritus Professor at La Trobe University in Australia), who was invited back to take part in the 2016 excavation. Earlier this year Jim published his long awaited report on the 1970s investigations, which is available free to download here. I have been asked to write a review of the report for the research journal Archaeology in Oceania - this will be coming out early next year. (EDIT: The review is now up on my ResearchGate profile). 

Radiocarbon dates obtained in the 1970s indicated continuous occupation of the island for almost 500 years from around 1200 AD to almost 1700 AD. Motupore Island was interpreted by Allen as a specialist trading site operating in a prehistoric exchange network that was a forerunner to that described in later ethnographic accounts. As detailed in these accounts, the Western Motu were involved in multiple interlinked trading relationships. Most famously, they undertook annual long distance hiri trading voyages by sea to the Gulf of Papua, a journey of almost 400km to the west, where they traded specially manufactured pottery for sago.

Pots laid out prior to loading on canoes (lakatoi) for the hiri trading voyage. This photo, which is attributed to J. W. Lindt, was obtained by the author from Jim Allen.

A hiri trading canoe (lakatoi). Image sourced from here.

 

In light of a surge in archaeological research elsewhere along the PNG south coast over the past decade, fresh excavations on Motupore Island were considered necessary given the methodological and technological limitations of the investigations in the 1970s. A key objective was to refine the chronology of site occupation by obtaining new samples suitable for AMS radiocarbon dating. The new excavations also provided a rare opportunity for current UPNG students to take part in an archaeological excavation. 

A 2m by 1m unit was opened up at the base of the hill. The unit was excavated down to the original beach - a sterile white coral sand about 1.9m below the present surface. Analysis of the excavated material is on-going at the UPNG laboratory. However, material identified at the sieving station consisted of numerous pottery sherds (a low-fired, hand-made earthenware), faunal material consisting of shell and bone (fish, dugong, turtle and wallaby), flaked stone tools, and worked shell. Of particular note were finds of small circular drilled shell beads in various stages of manufacture and small elongated stone flakes, heavily reshaped along the margins and pointed at one end. Jim Allen interprets these artefacts as points for pump drills, as described in the ethnographic literature, used principally and perhaps exclusively for the manufacture of the shell beads, a product for trade. 

Shell beads from Motupore at various stages of the manufacturing process. Finished bead on the right is 8.5mm wide. Photo appears as Plate 7 in Allen et al. (1997).

Dorsal and side views of a drillpoint, with snapped tip (artefact is 30mm long). Photo appears as Plate 5 in Allen et al. (1997).

Another point of interest was the massive increase in the density of pottery sherds in the upper layers of the site. This pottery horizon could well mark the beginning of the hiri trade voyages previously noted. In the ethnographic accounts masses of pots were produced at great speed by the Motuan women prior to the hiri each year (and no doubt many broke, particularly during firing!). A recent large-scale radiocarbon dating programme in the Gulf of Papua suggests a start to the large-scale importation of ceramics into the region at around 500 years ago, so the new dates from Motupore Island are awaited with great interest. Previous petrographic and chemical analysis of archaeological samples of pottery recovered from late prehistoric sites in the Gulf of Papua has indicated a likely source in the Bootless Bay area (see Jim Allen's recent report, freely available to download from here).

 

The excavation unit (2m x 1m). The hill discernible to the right of the unit is actually a large rubbish dump, mostly built up during the last 150 years of the Motupore sequence. Photo taken by the author.

At the wet sieving station, excavation unit in the background (Photo: Anne Ford).

Recording the stratigraphy (layers) of our excavation unit (photos taken by the author):

  

Acknowledgements

In addition to the author, the 2016 Motupore team consisted of Dr Matthew Leavesley, Vincent Kewibu, Jason Kariwiga, Teppsy Beni, Andrew Sarar, Auvita Kilori, Benardine Mandui Mirio, Ellen Bruno, Roxanne Tsang and Tony Ikosi (UPNG); Professor Glenn Summerhayes and Dr Anne Ford (University of Otago); and Professor Jim Allen and his wife Jill. At various times we were assisted by staff from the PNG National Museum and Art Gallery. And, of course, to John and Bryony Coles and the Prehistoric Society for the Coles Bursary. Tenkyu tru!