The Fire Caves of Nanumaga

The Age (Australia), Monday 13 April 1987.
 

Off the northern shore of Nanumaga island in western   Polynesia's Tuvalu island group last year, two scuba divers investigating a local legend of "a large house under the sea" found an underwater cave morethan 40 metres down the wall of a coral cliff. Dark patches on the roof and walls and blackened coral fragments on its floor suggest the use of fire by human occupants.

The last time people could possibly have occupied the cave was during a time of low sea level more than 8000 years ago, a date sharply at odds with the view that the Pacific was settled just 6000 years ago. The evidence of fire may be ambiguous, but the durable cultural memory of the cave's existence is not so easily dismissed.

Pacific archeologists may have got it very wrong. In focusing on archaeological evidence, they have been blind to a vital piece of climatic evidence - a massive and continuous rise in sea level that began l8,000 years ago and stopped 4000 years ago and probably drowned most of the evidence of much earlier human migrations into the Pacific.

In the Journal of Pacific History, Dr. John Gibbons of the University of the South Pacific in Fiji wrote: “…trying to make sense of Pacific prehistory may have been somewhat akin to the efforts of someone who arrives in time for the second act of a play, and then attempts to work out the plot without even realizing that the first act has already taken place.

"Dr Gibbons and his. co-author, Dr. Fergus Clunie, believe  the Pacific was colonised by waves of "boat people”, driven from their ancestral coastal homelands in Indonesia and South-East Asia by rising oceans. The known world of Pacific archaeology ends abruptly at a temporal horizon 6000 years ago, the earliest date of distinctive shards of Lapita, Ppttery. The pottery is found in coastal regions throughout the south-west Pacific, from the Marquesas in the east, to New Caledonia in the south and the Carolines in the north.

The Lapita culture has been thought to trace its origins to coast-dwelling fisher-folk from Indonesia and the Philippines, who mastered the art of sailing and spread rapidly into the Pacific from about 4000 years ago. But the archaeology clashes with linguistic evidence that some of the islands of Polynesia, lying at great distance from Asia, had already been settled at least 5000 years ago.

Dr. Gibbons and Dr. Clunie have offered a radical theory which suggests skilled mariners were navigating around the Pacific perhaps 10,000 years before the flowering of the great civilisations of Sumeria and Egypt.

They point out that, from 100,000 years ago until today's sea levels were established, periods of glaciation locked away huge volumes of water. This caused the sea level to fluctuate between 20 and 45 metres lower than at present. The sea reached its modern level only 4000 years ago, a date corresponding closely to the age of the oldest Lapita pottery -- too closely to be a coincidence.

Tomorow's Pacific archaeology will require scuba gear, or must shift to elevated areas, like the site in Papua New Guinea that recently yielded a stone axe with an indicated age of 40-45,000 years.

What drove the first Pacific colonistst to migrate? The popular view of one is opportunistic migrants, island-hopping when low sea levels created land bridges and reduced inter-island distances.

But Gibbons and Clunie suggest two other driving forces. Periods of very low sea level more than 18,000 years ago disrupted coastal ecosystems and ruined the livelihood of   maritime cultures. Then a period of migration, driven by rising sea levels, crowded retreating coastal peoples into contact with their inland neighbors.  The rising sea levels shrank the ancestral homelands of the Pacific peoples to just a quarter of their former area, placing enormous pressure on coast-dwelling peoples to find new living room.

But, because the ocean rise was slow, some cultures that practised primitive agriculture would have been given time to make the transition to a fishing economy and to develop sailing skills, setting the stage for later eastwards marine migration into the islands of the Pacific.

The preceding period, when disparate coastal and inland cultures were forced together as land became scarce, may account for linguistic evidence of a time of great cultural upheaval and mixing, pre-dating the oldest Lapita pottery shards.

In fact, Clunie and Fergus believe the curiously diverse Lapita culture resulted from a forced fusion of coastal and inland peoples. Its practitioners were fishermen and sailors. Yet their pottery used clay that was brought long distances from inland regions of their islands, suggesting the art originated with earlier inland cultures.

Clunie and Fergus believe the Lapita culture was merely the modern tip of a cultural iceberg and that people who had not yet developed the art of pottey-making were sailing around the Pacific perhaps 10,000 years or more before the Lapita peoples left their pottery shards to posterity.

At first encounter, such a feat of marine technology and navigation stretches credulity. But the colonisation of Australia by the ancestors of the Aborigines is implicit evidence that men were making short sea voyages in the Pacific some 50,000 years ago -- because at no time has the sea gap between Australia and the eastern islands of Indonesia been less than 70 kilometres.

The "big house under the sea” off the island in Tuvalu is not the only hint that the Pacific was colonised much earlier than 4000 years ago. West of Fiji, mysterious humps called  "tumuli" have been found on Ile des Pins in New Caledonia. They appear man-made and have cylindrical ores of a type of lime concrete made of sea shells which yield carbon-dated ages between 3000 and 8000 years.

Did a pre-Lapita people construct tumuli? Or did the rising ocean submerge the roots of a much older Lapita culture one dating back some 10,000 years earlier.

As it turns out, there are there are other lines of evidence, including genetic markers and language, that point to much earlier colonisation of the Pacific. A striking linguistic thread runs through the diverse ethnic groups of Melanesia, Micronesia and Polynesia. They all speak languages that derive from am early language that linguists have dubbed Austronesian, which Clunie and Fergus believe may have been the Lingua franca of communication and trade between early Pacific cultures, just as English is for modern trade and comnmication.

Much simplified, Gibbons and Clunie's new scenario for the colonisation of the Pacific suggests that more than 50,000 years ago, Australian and New Guinea, then a single land mass, were colonised, possibly at a time of low sea level. Sea gaps as large as 50-8O Kilometres still existed between Australia and Indonesia, compelling the conclsion that these first settlers sailed rather than walked, into the new lands. If, on the other hand, the original Australoid peoples were driven from their Asian coastal homes by high sea levels, the migration may have occurred as early as 60-70,000 years ago, when sea levels were very high.

Some 15,000 years ago, waves of Papua-speaking invaders from the flooding lowlands of Indonesia began displacing the original Australoid inhabitants of New Guinea, some of whom retreated into the highlands. Australia had separated from New Guinea, and the Austronesian-speaking Papuans did not reach Australia.

These earliest Papuans probably used their new homeland as a launching point for a further eastward migration into Melanesia -- including the Bismarck Archipelago, the Solomons and Santa Cruz group and beyond -- at least 11,000 years ago, and possibly much earlier.

Subsequently, 8000 years ago, with the oceans still rising, more South-East Asian Austronesian-speaking peoples were displaced from Indonesia into Papua New Guinea. A group which settled the north coast of the island followed the original Papuans into the eastern Pacific, introducing their culture and an Oceanic form of the basic Austronesian language into Melanesia.

The Lapita culture may have arisen from the ensuing cultural mixing, and been sustained by an extensive trading ring in the south-western Pacific. Well over 3,500 years ago, Melanesians had crossed a very large oceanic gap to settle Fiji, taking the Lapita culture with them.

Western Polynesia was settled some centuries later. The origin of the Polynesians is still subject to debate, but by this time, marine technology was presumably more sophisticated and much longer oceanic voyages may have been common.

Despite a romantic view of Polynesians as the descendants of  "high Asians", free of Melanesian blood, the more likely explanation is that they derive from a mixing between later, long-distance emigrants from South-East Asia and Lapita Melanesians. Their settlement of the Cook Islands, the Marquesas and, finally, Hawaii and New Zealand, occurred relatively late in the long history of human colonisation of the Pacific. The impact of the new theory of colonization of the Pacific advanced by Gibbons and Clunie cannot be predicated, but their pointed observations about the likely impact of weld-documented changes in sea levels upon Pacific prehistory will demand a reappraisal of some cherished ideas.