Australian Archaeology

Organic material, unless preserved in anaerobic (oxygen reduced) conditions deteriorates rapidly leaving no trace for the archaeologist. The oldest surviving wooden artefacts in Australia come from Wyrie swamp in south-east Australia and are about 10 000 years old. While there is one site with wooden implements from the terminal Pleistocene, there are billions of stone artefacts scattered around Australia, stretching back to the period of initial colonisation. Undoubtedly, stone artefacts are important, but they only represent a fraction of cultural material and wooden implements were heavily utilised.

We know this because many of the stone tools found are woodworking tools, whether they are hatchets, adzes or wood-shaving implements. The abundance of stone artefacts, can present a lop-sided view of an ancient culture, especially when stone artefacts abound. This makes stone appear to be the only form of material culture. However, stone is a permeable record and much can be gleaned from the study of lithics. For instance, Peter Hiscock in a paper titled, Technological Responses To Risk in Holocene Australia, considers the development of new stone technologies as a response to environmental changes.

In Australian archaeology, as in other parts of the world, stone artefacts also contribute to developing a broad chronology for occupation, simply because they span the total period of occupation. In an excavation, stone artefacts are often found in association with fireplaces. Fragments of charcoal in hearths associated with stone artefacts are dated, and this provides a radiocarbon date for each stratified layer. By using the Law of Superposition, a premise stating that the bottom layer is the oldest, with each succeeding layer above being younger, a site chronology can be developed. This in turn is combined with information from other sites and a general chronology at local, regional, and continent levels can be created.

Australian Archaeology Raw Materials
The function of a stone tool often decides what raw material is to be used, although if a particular material is not available, a second choice may be necessary. Stone implements form two broad groups, those that are used for cutting or scraping (flaked tools) and those that are used to grind or pound. Flaked Tools: When making a flaked tool, the raw material or core stone must have certain inherent properties, otherwise the flakes will not flake off properly, or the flakes may be malformed and useless. The first criterion is the hardness of the raw material and the second is how isotropic the material is. Essentially this means the piece (core) selected to make the flake should be hard and brittle to provide a sharp working edge, and homogenous enough not to fracture into pieces when struck by the hammer stone (Figure 1).

Obsidian is found in parts of northern Australia, and was traded over long distances. Flakes from obsidian were highly valued and renowned for an extremely fine cutting edge. Tektite nodules originate from meteorite showers and are generally only found in small quantities. Small fragments of Darwin glass are scattered over a localised area in southern Tasmania, originating from the impact of a single meteorite. In manufacturing a flake, a knapper must decide which raw material to use. Often this dictated by the proximity, availability and suitability of the material to the task. Most raw materials are sourced from outcrops occurring in hills, ranges, or from large pebbles along river courses.

Silcrete is abundant throughout the arid region, being the remnants of Tertiary duricrust, now eroded into boulders of various sizes. The silcrete boulder pictured below (Figure 2) is from the Merton Escarpment in western Queensland. The boulder has been broken apart, creating smaller manageable pieces, and a suitable piece would be selected to serve as a core. A discarded flake is shown in the inset, possibly a result of knapper sampling.

Grindstones.
Most grinding stones in Australian archaeology are slabs of sandstone (Figure 3), often rounded at the edges for ease of handling. Seeds were placed on the grindstone and another stone (muller) was used to grind seeds into flour. Sandstone is granular, relatively soft, containing quartz grains that provide sharp edges to shred the seeds. The surface of the grindstone is continually being renewed, as grains are ground off the slab, exposing more sharp edges. The resultant flour would have grains of quartz mixed in, contributing to a high rate of dental wear. The muller stone is generally a hard granite-like material, and after years of use a muller develops a flat working surface and becomes polished. You can see how flat and polished a stone becomes in the broken muller below (Figure 4.).

However, evidence for widespread use of seed grinding in Australian archaeology only dates to the Holocene. At Malakunanja II an ochre-stained grindstone fragment, dating to 18 000 BP was excavated, confirming Pleistocene use of grindstones for ochre preparation. Ochre was ground to provide pigments for rock art and body decorations.

Hatchets
Some of the earliest dated stone artefacts in Australia are edge ground hatchet heads. Whilst some people refer to these artefacts as axes , the size and weight means they were used with one hand like a hatchet, and not two hands like contemporary axes. Figure 5.1 shows a waisted edge ground hatchet head, excavated from Nawamoyn rockshelter dating back 20 thousand years. The similarity is striking to a hatchet head from the 1900s made in southern Australia (Figure 5.2)

In other places knapping floors (places where people knapped flakes) occur in what appears to be unlikely surrounds. For instance Figure 7.2 shows an exposed campsite perhaps thousands of years old. Whilst it initially appears an unlikely camp area, it is within a few kilometres of an extensive quarry where high quality raw materials were quarried to make stone artefacts. The small flags dotted through Figure 6.2 denote the position of surveyed flakes.

Flakes found in stratigraphic sequences within a rockshelter (Fig 7.3) provide a better opportunity to securely date a site. This is because a rockshelter offers less chance of disturbance than does an open-air site, permitting artefacts to remain in situ while the sands of time slowly cover the deposit.

The core was found within a few kilometres of a chert outcrop, and no doubt a better piece could easily be acquired. However, in other areas where this high quality raw material is not so readily available, heavily reduced cores are more likely to be found. Studies have been conducted to show a correlation between core sizes and distance to raw material. Many core stones are one-tenth this size, presenting no cortex, with every possible flake removed. Sometimes a core is found along with flakes and other debitage, and this constitutes a knapping floor . It is possible to refit the flakes, a process called conjoining which gives insight into the reduction sequence. By studying a reduction sequence archaeologists can retrace the steps of an ancient knapper, understanding something about their approach to stone tool manufacture.

Bipolar reduction: If a core becomes so small that contact with the hammerstone results in the core moving rather than detachment of a flake, its reduction can be continued by bipolar reduction. Bipolar is also a useful technique for the knapping of rounded pebbles which were either too small, or did not present angles suitable for freehand percussion.. In bipolar reduction the core is placed on an anvil, generally with its longest axis perpendicular to the anvil. The core is then struck at an angle of 90 degrees. The Term bipolar is derived from the fact that each core reduced by this method will have two polarised (directly opposite) striking platforms or zones of percussion (Binford 1972b:356) . One of these zones is the point where the hammerstone comes into contact with the core, the other is formed by the core coming into contact with the anvil.

Indirect percussion: Indirect percussion involved the use of an intermediate percussor, such as a piece of stone with a rounded point, bone, wood or antler, between the hammerstone and the core. Indirect percussion is often termed the punch technique. The flakes removed by indirect percussion frequently have very small platforms.

Pressure flaking: When the knapper requires precise control over the location of flake removal, flake size and shape, this was achieved by pressure flaking. In the pressure flaking technique a pointed instrument of stone, copper, bone, wood, or antler was used to exert pressure to push the flakes from the implement being produced. In Australia, pressure flaking was still being undertaken by Aboriginal groups this century.

The Rolling Pressure Technique: In the rolling pressure technique the flake is held in the palm of the hand with ventral surface uppermost and the edge to be worked resting on the pad at the base of the thumb. A rounded, generally smooth flat pebble is laid on the bulbar surface, rolled towards the margin and pressure exerted. This removed very small, semi-circular, equal sized flakes.

The Chimbling Pressure Technique: Chimbling was first described by Dickson (1973:12-13) as a method used to retouch the edge of blades or flakes to produce Bondi Points. In chimbling the flake is not held in the hand but placed on a piece of bark or wood, which will give a little under pressure. This allows the full force of the arm to be used to remove the flake rather than just the fingers, as in the rolling technique discussed above.

Anvil Technique: In the anvil technique the core is brought down directly on the anvil with enough force to initiate fracture. The result of this action will depend on the type and size of the core and the amount of force with which it contacts the anvil.