The stratigraphic status of the Anthropocene

The term Anthropocene was coined to describe the present geological epoch, in which human activity dominates many of the processes acting on the surface of the Earth. The expression has been widely adopted, but remains informal and lacks precise definition. There have been several attempts to establish formal stratigraphic markers to define the start of the Anthropocene. Most recently, Certini and Scalenghe (Certini G and Scalenghe R (2011) Anthropogenic soils are the golden spikes for the Anthropocene. The Holocene 21: 1269-1274) have argued that the best markers are anthropogenic soils and that these may be used to identify the base of the Anthropocene in stratigraphic sequences. Unfortunately, soils fail to meet many of the criteria required for the establishment of stratigraphic 'golden spikes'. Their preservation potential is poor, many stratigraphically important environments do not experience pedogenesis and anthrosols do not always provide the stratigraphically lowest marker of human impact. In addition, there are practical and theoretical difficulties in defining the base of anthrosols and thus in identifying the start of the Anthropocene. More generally, the worldwide diachroneity of human impact makes it impossible to establish a single chronological datum for the epoch, raising questions about the value of stratigraphic methods in defining the base of the Anthropocene. More significantly, much of the work undertaken on the Anthropocene lies beyond stratigraphy, and a stratigraphic definition of this epoch may be unnecessary, constraining and arbitrary. It is not clear for practical purposes whether there is any real need for a golden spike at the base of the Anthropocene. The global stratigraphic approach may prove of limited utility in studies of human environmental impact.