In this article, a cross-disciplinary approach is used to create an overarching theory of how and in what ways plastics are forming an archaeological record. By drawing on foundational archaeological research into those cultural and natural site formation processes that shape the archaeological record, a new theory of site formation in the contemporary ‘Plastic Age’ is presented. This theory is also relevant for predicting future archaeological records. In both cases, the type fossils are not stone, metal, or ceramic, but plastic, creating an archaeological record that is resilient and toxic, as well as ubiquitous. Over time, this contemporary archaeological record is increasing exponentially in overall size, while its component parts (the artefacts) continually break down, eventually to a nanoscale. This presents a contradiction: how society should view an archaeological record that represents a valuable archive documenting activities and behaviours at a crucial time in human history, while at the same time being a dangerous contaminant, threatening planetary health. In conclusion, the article argues the need to reassess what is meant by ‘the archaeological record’ and how it is formed in the Plastic Age—for example, by working more across disciplines to better understand what this archive is telling us about ourselves and about the future.

The archaeological assemblage recovered from the Middle Stone Age (MSA) levels in Blombos Cave, South Africa, is central to our understanding of the development of early modern humans. Here, we demonstrate that the cultural and technological innovations inferred from the Blombos Cave MSA record also correlate with significant shifts in site use and occupational intensity. Through a comprehensive geoarchaeological investigation of three MSA occupation phases, we identified distinct diachronic trends in the frequency of visits and the modes of occupation. During the earliest phases (ca. 88–82 ka), humans inhabited the cave for more extended periods, but cave visits were not frequent. During the later phases (ca. 77–72 ka), the cave was more regularly visited but for shorter periods each time. We argue that these changes in local occupational intensity, which also coincide with shifts in vegetation, sea levels, and subsistence, can best be explained by broader changes in hunter-gatherer mobility strategies and occupation patterns. Fundamental changes in regional settlement dynamics during Marine Oxygen Isotope Stages 5b-4 would have significantly affected the nature and frequency of social interaction within and between prehistoric populations living in the southern Cape, a scenario that ultimately may explain some of the social and technological advances that occurred there during this time frame.

This paper addresses the formation processes at an unparalleled Bronze Age settlement in the Iberian Meseta. The site of El Cerro (Burgos, Spain) presents a series of challenging features: the simultaneous inhumation of three subadults alongside a dwelling quarter and adjacent pits, some of them filled with apparent formality, including such anachronistic elements as Neolithic and Beaker items and several placed deposits, such as a leg of a cow. A critical evaluation of the contextual dataset, a re-fitting operation, and an assessment of the abrasion and size of a ceramic sample were carried out. The archaeological peculiarities of the site are explained as a contextually specific cultural response to a grievous and traumatic episode: the death of three young siblings, which entailed the abandonment of the settlement through prescribed practices. Some depositions are a product of recognizable intentionality, while others are regarded as unintended cumulative outcomes.

The newly identified Paleolithic site Sima de Las Palomas de Teba hosts an almost seven-m-thick sediment profile investigated here to elucidate the rock shelter's chronostratigraphy and formation processes. At its base, the sediment sequence contains rich archeological deposits recording intensive occupation by Neanderthals. Luminescence provides a terminus ante quem of 39.4 ± 2.6 ka or 44.9 ± 4.1 ka (OSL) and 51.4 ± 8.4 ka (TL). This occupation ended with a rockfall event followed by accumulation of archeologically sterile sediments. These were covered by sediments containing few Middle Paleolithic artifacts, which either indicate ephemeral occupation by Neanderthals or reworking as suggested by micromorphological features. Above this unit, scattered lithic artifacts of undiagnostic character may represent undefined Paleolithic occupations. Sediment burial ages between about 23.0 ± 1.5 ka (OSL) and 40.5 ± 3.4 ka (pIRIR) provide an Upper Paleolithic chronology for sediments deposited above the rockfall. Finally, a dung-bearing Holocene layer in the uppermost part of the sequence contains a fragment of a human mandible dated to 4032 ± 39 14C yr BP. Overall, the sequence represents an important new site for studying the end of Neanderthal occupation in southern Spain.

Ploughing is probably the greatest agent of attrition to archaeological sites world-wide. In every country, every year, a bit more is shaved off buried strata and a bit more of the past becomes unreadable. On the other hand, people must eat and crops must be planted. How can the fields be best managed to get the best of both worlds? Perhaps the most pressing need for resource managers is to know how quickly a particular field is eroding: negotiation and protection is then possible. Up to now that has been difficult to measure.

The new procedure presented here, which draws on the unexpected benefits of nuclear weapons testing, shows how variation in the concentration of the radioisotope 137Cs can be used to monitor soil movements over the last 40 years. The measurements allow a site's ‘life expectancy’ to be calculated, and there are some promising dividends for tracking site formation processes.