RIVERAIN: Water availability and Aboriginal prehistory of the Murray River, Lake Victoria area, western New South Wales

Abstract

Lake Victoria lies in the heart of the Murray Darling Basin. During the height of the Last Glacial Maximum (LGM) up to 3 metres of wind-blown sand and dust was deposited along the top of the lunette on the eastern shore of Lake Victoria, creating an unparalleled environment for preserving archaeological remains. Aboriginal shell middens and faunal remains in stratigraphic context provide a record of human adaptation to the extreme climate variability which prevailed between 17,000 and 14,500 BP. Fieldwork at Lake Victoria centred on Gills Gully, a 1 sq km area in the central, highest area of the Lake Victoria lunette. Six LGM dates were obtained from Velesunio shell recovered from middens within this area and a stratigraphic sequence was developed for the upper ten metres of the lunette. Several shell middens were excavated in order to investigate environmental conditions and Aboriginal adaptations during the height of the LGM. LGM middens had been so gently buried by settling dust that ash, tiny bone fragments and delicate dots of scarlet ochre were preserved, and tiny air bubbles can be seen in the dusty grey overburden. Middens were composed of closely packed freshwater mussel shell interspersed with fine ash, charcoal and finely divided ochre. Remains of small macropods (hare wallaby), yabby, lizard, frog and more rarely fish and bird were present - average length of faunal fragments was less than 6 mm. A polished bone point was recovered from a shell lens dated to 16,170+/- 190 (ANU 2876). With the exception of a tiny fragment of sandstone no stone artefacts were recovered from Pleistocene middens. Between 16,000 and 15,000 BP there was a marked change in the pattern of human occupation around Lake Victoria. Chemical and physical analysis of the midden shell and the overburden shows that that the increase in midden density cannot be explained by site preservation factors. By 15,000 years earlier patterns of large, scattered charcoal-rich occupation deposits had been replaced by smaller, more numerous shell middens around 1 metre in diameter, in places so thickly clustered as to form overlapping lenses of well preserved compacted freshwater shells up to 60 cm thick, a much more intense pattern of exploitation. During the last phases of the Last Glacial Maximum Lake Victoria was an oasis an increasingly desiccated late Pleistocene landscape. It is likely that local population increased at this time and that people turned increasingly to freshwater mussels for sustenance.