Australia: The Land Where Time Began

A biography of the Australian continent 

The available material at the Stud Creek site, dating to the Late Holocene, that was nearby, about 12 km south of Gorge Quarry, was dominated by medium-grained silcrete, with a lower proportion of microcrystalline silcrete and a small amount of  fine-grained silcrete (Doelman et al., 2001; Holdaway et al., 2004). According to the authors, microcrystalline silcrete was the preferred material for the manufacture of blades and tools requiring a high degree of fine retouch, such as thumbnail scrapers and high edge-holding properties, such as tula and burren adzes, based on the stone artefacts scattered on the surface at Stud Creek. Microcrystalline silcrete was flaked more intensively than medium-grained silcrete, as indicated by the completed flakes being of a smaller size, a higher flake to core ratio and mean core volume of the cores that was smaller. For core and flake tools requiring less retouch, the medium-grained silcrete, that was of lower quality, were generally used. The differences in the mechanical properties of the 2 types of silcrete are reflected in this usage pattern. The low to moderate fracture toughness of the medium-grained silcrete compared to that of the microcrystalline silcrete result in it having flaking properties that are relatively poor, as in the case of the Lake Mungo silcrete, with less resistance to edge fracturing when the tool is used, making it less suitable for blade manufacture and less able to be sharpened repeatedly, as well as having a relatively high frequency of step-fracture terminations, especially during fine retouching, as a result of the larger quartz clasts present.

For more detailed information and illustrations see Source 1

Sources & Further reading

1. Webb, J.A. & Domanski, M, The Relationship Between Lithology, Flaking Properties & Artefact Manufacture for Australian Silcretes, Archaeometry, Oxford University, Archaeometry, 50, 4 (2008) 555-575

Stone tools