Temporal range

The archaeological object is often held to be the material remains of past human activity up to a certain cut-off point in time – whether taken as the end of the medieval period, the start of the ‘post-medieval’ or ‘modern’, the turn of one century, or the mid-point of another – thereby excluding later evidence from investigation. But Nativ's characterization of the archaeological object as that which is removed from the social through burial, regardless of time, fits much better with the nature of the evidence in the ground. For archaeological strata did not stop forming at some arbitrarily chosen point in the past. On the contrary, the stratigraphic sequences of layers, dumps, cuts and fills kept on forming, are still being formed today, and will continue to form in the foreseeable future. Indeed, never has the stratigraphy of the upper part of the Earth's crust been so radically modified by the actions of humans (and their entourage of domesticated species and machines) as in the last half-century or so. Never have so many artefacts been deposited in the ground, in landfill and other contexts, as now. This material, being buried in stratigraphic formations, is archaeological as surely as more ancient deposits are. William Rathje's innovative studies of rubbish dumped in modern landfills in the USA (Rathje Reference Rathje1992) are just as much about the archaeological object as Gordon Childe's excavation of Neolithic houses at Skara Brae or Heinrich Schliemann's excavation of the ancient citadel of Troy.

As Nativ affirms, the archaeological object comprises recently formed and still-forming as well as ancient material phenomena. Moreover the upper limit of its temporal range is always being extended forward in time, as archaeological strata continue to be produced in the unfolding present.

Spatial scale

This leads on to reconsideration of spatial scale. Nativ puts it like this: ‘If the archaeological is constantly being produced, then the range of relevant occurrences is greatly enlarged’ (p. 16). The fact that the archaeological object is growing rapidly in size might be regarded as one of its fundamental characteristics. There have been massive increases in production of archaeological strata globally in the last five decades, corresponding to a doubling of world human population and associated rises in the numbers of domesticated animals and plants. There has also been increasingly widespread use of petrol-fuelled earth-moving machines, excavating large amounts of material from depth and spreading it around on the surface, filling in basins of deposition and creating new or ‘reclaimed’ land. Archaeological deposits now cover large parts of ice-free terrestrial surfaces of the Earth, spreading inexorably into marine environments too. The millions of tonnes of soil and rock excavated from the ground by Crossrail in the making of the new Elizabeth Underground line in London – transported by barge down the Thames and dumped in the sea to form the mudflats of Wallasea Island – provide a handy illustrative example from close to where I live and work. Those metro tunnels under London and the spoil that was redeposited on the coast are recent extensions of the archaeological object as it continues to expand – in upwards, downwards and lateral directions. Readers from other countries will be able to provide their own close-to-home examples, for such large-scale removals and redepositions of material are going on all over the world. Wherever you are located, you do not have to travel far to observe the archaeological object of the future being created now.

It is not just the archaeological object itself that is expanding and shape-shifting. The perceptual apparatus for apprehending those changes is radically transforming at the same time, enabling it to be studied on multiple scales from the mega to the nano. Space and digital technologies afford archaeologists the capability to view the archaeological evidence from viewpoints in space, by means, for example, of satellite photography and GPS. In this regard, at least, I tend to disagree with Nativ's statement that surface survey does not engage with the archaeological object as such. While excavation is the core method of archaeology, it is important to recognize that study of the surface can reveal much about what lies buried and hidden below. Indeed it is only through the medium of networks of orbiting spacecraft and their surveillance of the planet's surface from above that it has it become possible to get the merest glimpse of the extent of the archaeological object – the sum total of stratigraphic traces of the human presence on Earth – on something like a global scale. This is the archaeosphere (Capelotti Reference Capelotti2010; Edgeworth Reference Edgeworth, Waters, Zalasiewicz, Williams, Ellis and Snelling2014b; Edgeworth et al. Reference Edgeworth, de B. Richter, Waters, Haff, Neal and Price2015), that thin yet extensive layer of humanly modified ground – accumulated over thousands of years but growing and coalescing at unprecedented rates today – now intermeshed with the hydrosphere, biosphere, atmosphere, technosphere and geosphere.

Ecological effectivity

As Nativ intimates, our theoretical conception of the archaeological object is struggling to keep up with recent changes, and needs to be updated. It tends to be framed in terms of models formulated before many of the relevant transformations occurred. For example, the characterization of the object of archaeology as a ‘material record’ configures it as passive rather than active. In terms of the record metaphor, the archaeological object-as-record is understood to be made up of the traces or effects of the actions of numerous entities, yet crucially not itself acting or having effects on other things. It is thus essentially constituted as a non-ecological entity, withdrawn from interaction with other parts of dynamic Earth systems.

This is understandable when archaeological evidence is considered on the relatively small scale of individual features, trenches, sites or landscapes. An archaeological stratum generally only has effects on strata immediately above or below or otherwise contiguous with it. But the accumulation of all those strata and all their local effects, when apprehended on a large enough scale, adds up to an ecological force (or set of forces) of considerable magnitude. Like a giant carpet being rolled out, this substantial body of material – in expanding and coalescing and spreading out over the Earth's terrain – has the power to bury rivers, to smother entire habitats, or indeed to create new ones. The ecological impacts of the accumulating mass – on wider environments, on humans, on climates, on geological processes, on other species – are yet to be even properly considered, let alone fully grasped.

Here I would go further than Nativ, though I am taking the liberty of extending his argument rather than contradicting it. For as well as acknowledging the independent existence of the archaeological object, it is also important to recognize that this object can effectively act independently too, at least in the sense in which it has become an ecological force exerting its own pressures on Earth systems.

Archaeologists are well placed to study large-scale stratigraphic formations of the archaeosphere. No other discipline has acquired such in-depth knowledge and experience of humanly modified ground, or developed the methods to deal with its complexities. Some of the core methods of the discipline are multi-scalar in application and can usefully be scaled up from investigation of pits and postholes to larger features such as landfill quarries and areas of reclaimed land. As Edward Harris (Reference Harris2014) recently argued, the Harris matrix provides a paradigm for understanding the stratigraphy of the Anthropocene.

To maintain that archaeologists have a significant role to play in investigating the archaeological object and its ecological effects on a global scale, in collaboration with other disciplines that are tackling environmental issues of pressing concern, does not in any way challenge the more detailed work that archaeologists carry out on local and regional scales, focusing on the evidence of more ancient deposits. That valuable work should, of course, continue. But traditional renditions of the object of archaeology are now proving too restrictive. These effectively exclude contemporary archaeological deposits from the frame and discourage archaeologists from taking a truly global perspective on the material phenomena they study. Nativ's excellent paper takes important strides in updating and broadening out our understanding of the archaeological object, laying the necessary groundwork for new kinds of research to be undertaken.