Post Excavation Analyses
The most common type of archaeological site in New Zealand is shell middens, usually found in coastal locations. Middens are piles of leftover food, whether eaten on the spot or preserved for later consumption off site. For pre-European Māori sites these are mostly made up of shell, and often include fish bone and occasionally bird bone. Early period middens may also contain bone of extinct moa and other birds. For the historic period rubbish pits with cattle, sheep and pig bone are more common. Other items also turn up in middens, such as fishhooks, stone flakes, glass or broken crockery.
Identifying shell and bone to species is a specialist task. The results are primarily used to understand not only what people were eating, but also the season of the year in which they were in occupation, the methods they used to capture and prepare their food and their interactions with the local environment. Understanding these ‘subsistence patterns’ is a basic task of archaeology. We also work with scientific specialists to, for instance, examine soils for microscopic evidence of plant remains, examine the chemistry of otoliths (fish ear bones) which reflects pre-industrial water quality, or extract DNA from otherwise unidentifiable remains. Shell and charcoal from middens can be radiocarbon dated.
Specifically, the extraction and identification of starch grains from both soil samples and residues on artefacts, and charcoal from archaeological contexts. These micro- and macro-botanical remains can be complementary or independent data sets to answer questions surrounding: site environment; artefact, site or feature function; subsistence strategies; and resource preferences for firewood, construction, or other purposes. Comprehensive reference collections of plant cultigens from both the Pacific and New Zealand; and both native and some introduced tree/shrub species from New Zealand have been established to enable identification of each of these archaeobotanical datasets.
Services include the processing of bulk samples using a combination of flotation and wet-sieving for charcoal and proven starch extraction methods, the identification and quantification of extracted archaeobotanical remains using reflected and transmitted light microscopy, and the selection of appropriate material for C14 dating.
Instructions for sample submission:
- Bulk samples can either be submitted for charcoal extraction in the CFG Heritage Ltd lab or processed prior to submission using flotation, wet or dry-sieving.
- Samples need to be accompanied by information including: specific research questions, site number, site name/type, context information (feature or deposit type), stratigraphic relationships between samples, and any information on the prior processing/handling of the sample.
- In order to answer questions surrounding site environment or resource extraction, it is preferable that the sample include at least 50 fragments of charcoal.
- Smaller samples are suitable for the selection of material for AMS C14 dating.
Reports will include:
- Explanation of methodology used for charcoal analysis and sampling strategy.
- Table containing raw data and summary of material from each site.
- Interpretation of the data in light of the specific research questions and summary of information derived from charcoal analysis.
- List of samples appropriate for C14 dating for selection and submission.
Lithic analysis is the study of stone artefacts from archaeological contexts. Stone is one of the most well-preserved artefact types from almost any archaeological site, and as such can provide important information about the relationships people have with their environments and with each other. Consequently, they are one of the most important sources of evidence for human activities and cultural development.
CFG Heritage offers two main types of lithic analysis: technological analysis and geochemical sourcing.
A technological lithic analysis involves examining the life cycle of stone tools and artefacts, beginning with raw material procurement through tool manufacture, use, maintenance, recycling, and disposal. This involves recording various attributes relevant to the size and morphology of the specimens, as well as indicators which can inform on the purpose of the tool, how it was manufactured, what it may have been used for (which can be different from the intended purpose), as well as how these may have changed over the life span of the artefact.
Sourcing studies aim to identify where the raw material used for tool manufacture was precured. New Zealand provides a unique environment for those interested in resource movements, communication networks, and spatial interactions. In a relatively small area, the country plays host to wide geological diversity ranging from rhyolitic volcanism in the North Island, to high quality metamorphism in the South Island. CFG Heritage uses non-destructive X-Ray Fluorescence (XRF) which measures the chemical composition of stone artefacts which can then be matched to a geographical source location. When a distinctive lithic material is found to be widely distributed, this type of analysis can contribute to understanding social communications, means of transport, and spatial interactions which have resulted in the archaeological pattern. The precise results of a modern XRF analysis means that archaeologists are now capable of separating rock types that appear very similar into distinct groups, and assigning these to a source location rapidly, inexpensively and in a way which is non-destructive.
Information obtained from analysing a stone artefact is then viewed in the context of the assemblage, and of the archaeological site itself, and becomes a piece of evidence added to the puzzle which helps develop a picture of past human behaviour.
Historic material analysis
Historic artefacts record the presence and lives of people in historic period New Zealand. These artefacts contain information that written accounts may not contain, particularly for people at the lower end of the social scale. For example, through analysing ceramics we can get an idea about social structures and what was important to these early families in terms of presenting a respectable face to their neighbours and being able to entertain in the latest style. From the alcohol bottles we can track changes in the popularity of a particular tipple, local manufacturing vs. imported or social attitudes towards alcohol in the home by the number of wine glasses recovered. Patent medicines give a glimpse into the health concerns people had at the time. Even the sizes of horse shoes from a rural property gives some idea about what kind of horses they had and from that what kinds of activities were taking place.
While bins of broken ceramics and glass might give us a glimpse into larger social processes, some artefacts raise fascinating questions. How did a Chinese Qianlong tongbao coin, which dates between 1736 and 1795, end up under a rural farm house in Mangere? Why was a whole dinner service thrown away at once? Other items such as boots, pipes and toys connect us with individuals and their lives in a way that historical accounts cannot.
The process starts with bags of artefacts collected or excavated from historic sites. What the assemblage contains depends on the site being excavated, but typically from a domestic house site it will contain a mix of ceramics, glass, metal and other miscellaneous things like toys, items of clothing such as buttons, boots and shoes and personal items such as brushes, pipes, cosmetics and jewellery. Once the artefacts are cleaned they are sorted into categories and then further analysed on the basis of decoration, colour, size etc. Occasionally it’s possible to fit back together entire items but it’s possible to get a lot of information from the smallest fragments at times.