Archaeologists often use the term ‘palimpsest’ to describe many archaeological deposits. By my reckoning, very few disciplines use the term more than archaeology, which may be keeping us from being invited to parties. By definition, a palimpsest is a piece of parchment from which previously inscriptions have been scraped away in order to add new inscriptions, leaving marks or evidence of older inscriptions. But clearly we’re not talking about parchment, so when we call the record a ‘palimpsest’, what do we mean?
Often, it seems as though the term gets used very broadly to refer to archaeological deposits that are messy or lacking clear stratigraphic relationships, and this is used to dismiss their interpretive value. However, some argue that all archaeological deposits are palimpsests of one form or another. In a recent publication, Lucas suggests that it might be fruitful to consider different parts of the archaeological record as sitting between two extremes: a true stratigraphy, where are all archaeological deposits occur in separable geological contexts, and a true palimpsest, where each depositional event erases the one that came before.
Recently, I put out a paper with colleagues Simon Holdaway and Patricia Fanning that explores this idea as a model for the formation of surface scatters in a region of arid Australia. The model uses a simple agent-based structure to look at how the temporal distribution of datable features visible on the surface might be affected by localized sequences of sediment erosion and deposition. Among other things, we find that organized patterns such as increasing frequencies of dates and chronological gaps that are often explained through demographic changes, could also be explained as resulting from a sufficiently dynamic landscape. Expectations from the model are borne out in additional patterns in the archaeological record, suggesting that, rather than dismiss palimpsests, archaeologists would do well to consider what kinds of palimpsests their records come from.