Methods in Ecofact Analysis

Although it is beyond the scope of this short definition to discuss the specific analytical methods for these diverse ecofacts, some methodological considerations affect all ecofact studies regardless of the particular material type. These include appropriate methods of material recovery and analysis, a detailed understanding of potential bias caused by differential deposition and preservation, and careful attention to identification and to interpretation through quantification.

1. Recovery and sampling. Ecofactual remains are an intrinsic part of any archaeological site (and of intersite spaces). While these remains are often found dispersed through archaeological deposits, they are sometimes found as dense accumulations (such as shell middens) that hold a wealth of combined palaeoenvironmental and cultural information. Appropriate recovery methods and sampling are essential regardless of the distribution of ecofactual remains in the archaeological context. Appropriate methods determine not only whether remains are found at all, but also whether those remains accurately represent the full range of materials originally deposited. In the science of zooarchaeology, for example, the question of appropriate recovery techniques is vital. The smaller the remains, the more fine-grained the technique of recovery that must be used. Consider, for example, a zooarchaeological study of subsistence that relies on excavation ‘by eye’ (with no screening of the archaeological matrix) compared to one that relies on fine-gauge screening (the most common gauges are 1/4, 1/8, and 1/16 inch) or even microscopic matrix analysis. While the first sample may well provide information on the use of large mammals and birds, the second will provide a more robust sample of all animal remains including fish, small amphibians, and birds, and the smallest of body parts, and the third could provide additional insect casings, parasite ova, and other microzoological remains. However, finer-grained recovery techniques are more labor intensive and costly, so careful consideration must be given to the questions being asked, the likelihood of recovery of some materials, and the type of sampling strategy that would best balance accurate recovery with cost and time effectiveness.

2.  Deposition, preservation, and transportation. Ecofactual materials, often organic, are highly susceptible to degradation under poor preservational conditions and the rate at which they are preserved is variable. Plant remains, for example, are our most fragile ecofacts and the least likely to preserve. However, some plant remains preserve better than others (hard shells, burnt wood, and, one of the most durable organic materials, pollen (see Pollen Analysis), one of the most durable organic materials), and certain conditions are more conducive to the preservation of certain plant remain types (carbonization preserves many macroremains while destroying pollen). Similarly, because ecofactual materials can be deposited naturally or as a result of human subsistence, construction, ritual, and so on, they are differentially deposited into the archaeological record and transported within it. An animal killed or scavenged in the forest, for example, may well have its parts deposited at the kill site, at the butchering site, where the meal is eaten, where the garbage is tossed, or even (as parasitic inclusions) where the animal originally defecated. An understanding of all these variables is essential before an analyst can ensure the distribution of ecofacts reveals clues about ancient environments or behavior, or whether it is simply a result of differential sizes, material types, or preservational conditions.

3.  Identification. Most ecofacts are identified through a process of comparison with known modern counterparts, or comparative collections. Accurate identification depends on the skill of the analyst, good knowledge of the factors controlling variability (genetics, age, moisture regimes, etc.), and the availability of comparative specimens of all known possible species or groups in all possible preservational conditions (consider how different a kernel of corn looks from one that has ‘popped’, and the need for different specimens preserved under different conditions is clear). Here the specialist is necessary. A geoarchaeologist with a speciality in archaeopedology, for example, is trained to recognize the microparticulate variations within soil structure, the morphology and relationship between soil particles, and the chemical signatures that would indicate various land-use practices, and to tie those together to present a clear picture of the life history of the soil sample itself.