Offshore Islands and Maritime Explorations in Australian Prehistory

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There are several aspects of islands which interest us archaeologically. One is the obvious relationship between islands and maritime technology. It is now well known that Australia was colonized at least 40,000, and possibly 60,000, years ago, and that colonization must have involved sea crossings. It might be assumed therefore that the use of watercraft would have a long tradition in Australia and we would expect a long continuous history of exploitation of offshore islands. This is not however borne out by the evidence.

Another reason why islands are of interest is because their defined geographical parameters allow them to be perceived as laboratories which permit the examination of various theoretical propositions. Biogeographers in particular have developed general "propositions about animal ecology in island settings, and have extrapolated these to the human use of islands (Keegan & Diamond 1987). Again, however, the Australian evidence confounds expectations in this area.

Several Australian offshore islands have archaeological evidence of occupation which dates to the Pleistocene. In every such case, however, they were not then islands but part of die continental land mass, and tell us nothing about early use of islands or watercraft. These islands came into being with the post-glacial eustatic sea level rise. In some cases, it is possible to consider the effect of their separation from the mainland, that is, the phenomenon of islands becoming islands and how this affected their human populations. Some modem offshore islands seem to have been unoccupied in the ethnographic present but have archaeological evidence of prehistoric occupation. Others were exploited on a regular basis by Aboriginal people in recent pre-European times. There is a question as to whether any islands other than Tasmania were occupied by human groups on a permanent year-round basis. The distinction between occupation and exploitation, where total isolation is not assumed, is not easy to make.

Islands abandoned or isolated (Figure 1,

Tables 1,2)

Many Australian offshore islands appear to have been occupied during the late Pleistocene or early Holocene, and then abandoned, or at least left unoccupied or unvisited. The usual interpretation is that when they became islands, they were too small to support a permanent occupation, and `relict' populations thus stranded sooner or later died out. Tasmania alone was large enough to sustain a human population in isolation from the mainland. The less explicit assumption in this reasoning is that the people on the near-by mainland in all these cases either did not possess the appropriate maritime technology, or did not have an economic interest in the resources of these islands, or both.

Kangaroo Island

Kangaroo Island, 14.5 km off the coast near modern Adelaide, is a comparatively large (4400 sq. km) island which has been a subject of archaeological interest and speculation for many years now. It lies 14.5 km from the South Australian mainland, and was not occupied nor visited by Aborigines at the time of European contact. The oldest archaeological date for human occupation is 16,000 b.p., (1) which of course reflects a time when Kangaroo Island was part of Greater Australia. Separation would have occurred about 9500 b.p., but occupation of the island continued until at least 4300 b.p., on the evidence of the archaeological site with the most recent date. There has been considerable debate as to whether the population then died off or migrated to the mainland, and what the reasons or mechanisms involved may have been. Lampert (1981:184-5) favours the extinction of a small continuing population at risk due to demographic and biogeographic considerations: too few people, not enough land, environmental deterioration and no evidence of watercraft during the critical period.

Tasmania

Tasmania, some 15 times the size of Kangaroo Island (67,900 sq. …