All hands on deck for sorting

Microdebris analysis provides a method of evaluating the use of space through the distribution of artifacts.  As its name suggests, microdebris analysis focuses on the study of small artifacts, often less than 5mm in size. These artifacts are retrieved through careful sorting of soil samples. They are informative in several ways. Firstly, they may include small objects like beads and coins or small ecofacts like rodent bones and seeds. Such small things are often missed during excavation, and retrieving them during the sorting process can give us a more complete picture of our artifact assemblages. Secondly, ethnographic studies have shown that small fragments of ceramics and bone are missed during sweeping and get trampled into packed-dirt floors where they fell instead. As such, the distribution of very small fragments can be more indicative of activity areas than large fragments, which are often the result of trash disposal, storage or abandonment processes, rather than primary use. Thirdly, because the volume of the soil samples and the artifacts found are recorded carefully, microdebris analysis allows for a precise quantification of the amount and types of finds, which is difficult to do on a larger scale beyond estimates of “more” and “less”.

Separating the light fraction at the flotation tank

Separating the light fraction at the flotation tank

The microdebris is retrieved, as mentioned above, through sampling deposits. The project has an established sampling protocol which focuses on floor levels but ensures all deposits are sampled for comparative purposes. Each soil sample is washed in a flotation tank for a dual purpose: the process gets rid of sand and silt, and botanical remains and other light material (called the light fraction) float up so they can be collected for specialist analysis. The remainder, called the heavy fraction, will then be sorted and any artifacts or ecofacts collected, counted, and described. Through quantitative analysis we can then start looking at distribution of types of finds and start identifying activity areas.


Further reading:
Rainville, L. 2005. Investigating Upper Mesopotamian Households Using Micro-Archaeological Techniques. Oxford.
Rainville, L. 2012. “Household Matters: Techniques for Understanding Assyrian Houses,” in Parker, B.and Foster, C. (eds.) New Perspectives in Household Archaeology. Winona Lake, IN, 139-164.