After sorting through, describing and categorising 936 artefacts I can definitely say that my skills in identifying and describing artefacts have improved. With more than 800 of the artefacts comprising flakes and broken flakes, each one had to be studied to identify the features that would enable me to determine how it had been made. Most of these flakes were made of quartz and, owing to the intrinsic properties of that raw material, determining the reduction process proved challenging at times.
After identifying the types, artefacts were then categorised by raw material type, counted and weighed. The total numbers and weight of artefacts from each spit were volumetrically adjusted to account for differences in the amount of sediment removed from each spit. The results are shown in the graphs below. The graphs show total weight of artefacts in grams per kilogram and total count of artefacts per kilogram. Viewing both graphs shows clearly that, when a large artefact substantially affects the weight—such as in Spit 16 which includes a pestle—the artefact count is not affected and we are not misled by the results.
The next phase of the project is to interpret the graphs and other recorded data, which will require consideration of several factors. Firstly, sediment deposition in the shelter is not consistent through time, so the spits do not represent equal periods of time. For example, Spits 20 to 16 represent almost 5000 years of time, meaning the bottom 20% of the excavation represents 50% of the time line. What appears in the graphs as a peaks in artefact counts and weights for the lowest two spits may actually be non-existent when the timeframe of deposition is considered relative to the other spits.
Even when volumetrically adjusted, artefact weights for each spit also need to be carefully considered, as it cannot be assumed that a high weight represents a greater level of activity in the shelter. For example, Spit 16 shows the greatest weight of artefacts for all spits; however, one of the artefacts it contains—a pestle—weighs more than 400g. In contrast, Spit 6 includes 130 flakes that only weigh 174g. The pestle may have only been used once, whilst the flakes may have been used multiple times. So in this case a lower weight could represent greater activity at the site on the basis of the artefact types found.
A stone used for grinding found in Spit 16
Patterns that need to be explained also include changes in time through the raw materials present. In the lower spits (i.e Spits 20 to16) flakes are equally likely to be made of both quartz and quartzite. After this there is a gradual change, with an increase in quartz flakes and a reduction in the number of quartzite flakes. This change reaches a peak in Spit 6, with a ratio of 97:3 of quartz to quartzite flakes. Trying to determine what might have caused people to change their preferred raw material is one of the things I am exploring.
A selection of quartz flakes from Spit 6
Further afield there are different changes seen in the assemblages of other shelters in northwest Queensland that are not seen in Square B0 at GS1. For example, some shelters have shown changes in raw materials used at a specific time, and increases in the use and presence of grinding stones. These changes have not been seen in Square B0.
Once I’ve explored the patterns seen in Square B0 I’ll then consider this in relation to the results from the excavation of the adjacent squares in GS1, other shelters on the Middle Park Station, and other shelters in the northwest Queensland region. This will help to understand whether the patterns observed are specific to the Square B0 assemblage, the GS1 shelter, the Middle Park Station area or whether they are part of a wider sequence of changes occurring in Queensland and beyond at the time.