An assessment of lithostratigraphy for anthropogenic deposits

Abstract

Abstract:The deliberate anthropogenic movement of reworked natural and novel manufactured materials represents a novel sedimentary environment associated with mining, waste disposal, construction and urbanization.

When did the Anthropocene begin? A mid-twentieth century boundary level is stratigraphically optimal

“…However, the anthropogenic acceleration of processes of erosion and sedimentation has led to the physical record of the Anthropocene being substantial (e.g. Price et al, 2011;Hooke et al, 2012;Ford et al, 2014), and large parts of this record are also distinctive, given the geological novelty of many human-driven processes. While the geometrical and temporal complexity of Anthropocene deposits clearly present some unusual challenges, an Anthropocene chronostratigraphical unit may be recognized and this is significant to the choice of a boundary for this unit.…”

“…the global spread of artificial radionuclides from surface A-bomb explosions (Fairchild and Frisia, 2014;Hancock et al, 2014;Wolff, 2014); doubling of the surface reactive nitrogen reservoir (a result of fertilizer manufacture via the HabereBosch process), reflected in nitrogen isotope changes in far-field lacustrine deposits (Holtgrieve et al, 2011;Wolfe et al, 2013); the creation and wide (global) dispersal of new human-made materials (Ford et al, 2014;Zalasiewicz et al, 2014c) and artefacts that may be regarded as technofossils in the environment e almost all the discarded plastic and aluminium waste in surface sediments date from the midtwentieth century, for instance; rapid expansion in the distribution of artificial deposits on land, associated with urbanization (Ford et al, 2014), and of reworked sediment on continental shelves and slopes, associated with deep-sea trawling (see references in Zalasiewicz et al, 2014a); global dispersal of pollutants associated with expansion of industrial activities, including novel organic contaminants that include persistent organic pollutants (POPs) (Muir and Rose, 2007) and increased concentrations of heavy metals that are relatively rare in nature (Leorri et al, 2014;Gałuszka et al, 2014); a significant 'step' in the rate of increase of anthropogenic biotic change (Wolfe et al, 2013;Wilkinson et al, 2014), including accelerated species invasions on land and in the sea that alter species compositions in a wide spectrum of terrestrial and marine communities, in ways that will leave a clear palaeontological signal as we go into the future; a significant signal in polar ice marked by such indicators as lead from gasoline (Wolff, 2014) of different isotopic characteristics than Roman lead from smelting that forms an earlier signal; acceleration in the burning of hydrocarbons that has produced much of the~120 ppm increase in atmospheric carbon dioxide levels since the mid-twentieth century, and hence much of the associated carbon isotope signal (Al-Rousan et al, 2004); the majority of human-created trace fossils derived from sediment and rock drilling. The drilling for petroleum is often particularly deep.…”

Diachronous beginnings of the Anthropocene: The lower bounding surface of anthropogenic deposits

“…This paper examines the stratigraphic evidence for the diachroneity of human impact on the surface of the Earth. It draws from geological literature on artificial ground (McMillan and Powell 1993;Rosenbaum et al 2003;Price et al 2004Price et al , 2011Nirei et al 2012;Ford et al 2010Ford et al , 2014 together with work on archaeological stratigraphy (Barker 1977;Carver 1987Carver , 2009Schiffer 1987;Harris 1989Harris , 2014Roskams 2001) as well as recent articles on the technosphere and technofossils (Haff 2014;Barnosky 2014;Zalasiewicz et al 2014b) and ecological perspectives on human transformations of soils (Richter 2007, Richter andMobley 2009) and the terrestrial biosphere (Ellis 2011). An earlier paper set out to combine aspects of archaeological and geological methodologies and perspectives in its account of anthropogenically modified deposits that now cover large parts of the terrestrial surfaces of the Earth (Edgeworth 2014), and in so doing laid some of the groundwork for the argument presented here.…”

Approaches to inform redevelopment of brownfield sites: An example from the Leeds area of the West Yorkshire coalfield, UK

“…The current artificial ground classification scheme used in Britain divides artificial ground into five classes (Ford et al, 2010), which are listed in Table 1. Although this classification scheme can help inform users of geological map data why artificial ground is present at a particular location, such as distinguishing between a canal or road embankment, a limitation is that the scheme does not describe its composition or thickness (Ford et al, 2014).…”