The term Anthropocene, proposed and increasingly employed to denote the current interval of anthropogenic global environmental change, may be discussed on stratigraphic grounds. A case can be made for its consideration as a formal epoch in that, since the start of the Industrial Revolution, Earth has endured changes sufficient to leave a global stratigraphic signature distinct from that of the Holocene or of previous Pleistocene interglacial phases, encompassing novel biotic, sedimentary, and geochemical change. These changes, although likely only in their initial phases, are sufficiently distinct and robustly established for suggestions of a Holocene-Anthropocene boundary in the recent historical past to be geologically reasonable. The boundary may be defined either via Global Stratigraphic Section and Point ("golden spike") locations or by adopting a numerical date. Formal adoption of this term in the near future will largely depend on its utility, particularly to earth scientists working on late Holocene successions. This datum, from the perspective of the far future, will most probably approximate a distinctive stratigraphic boundary.

The Anthropocene, an informal term used to signal the impact of collective human activity on biological, physical and chemical processes on the Earth system, is assessed using stratigraphic criteria. It is complex in time, space and process, and may be considered in terms of the scale, relative timing, duration and novelty of its various phenomena. The lithostratigraphic signal includes both direct components, such as urban constructions and man-made deposits, and indirect ones, such as sediment flux changes. Already widespread, these are producing a significant ‘event layer’, locally with considerable long-term preservation potential. Chemostratigraphic signals include new organic compounds, but are likely to be dominated by the effects of CO 2 release, particularly via acidification in the marine realm, and man-made radionuclides. The sequence stratigraphic signal is negligible to date, but may become geologically significant over centennial/millennial time scales. The rapidly growing biostratigraphic signal includes geologically novel aspects (the scale of globally transferred species) and geologically will have permanent effects.

Procedures used to define an international chronostratigraphic stage boundary and to locate and ratify a Global Boundary Stratotype Section and Point (GSSP) are outlined. A majority of current GSSPs use biostratigraphic data as primary markers with no reference to any physico-chemical markers, despite the International Subcommission on Stratigraphic Classification (ISSC) suggestion that such markers should be included if possible. It is argued that such definitions will not produce the high-precision Phanerozoic time scale necessary to understand such phenomena as pre-Pleistocene ice ages and global climate change. It is strongly recommended that all GSSPs should have physico-chemical markers as an integral part of their guiding criteria, and where such markers cannot be found, the GSSP should be relocated.The methods and approach embodied in oceanic stratigraphy – coring, logging, analysing and archiving of drill sites by numerous experts using a wide range of methods – could usefully serve as a scientific model for the analysis and archiving of GSSPs, all of which are on the present-day continents. The incorporation of many more stratigraphic sections into GSSP studies, the application of physico-chemical methods, and the replacement of old U–Pb dates by newer CA-TIMS U–Pb dates, together with the use of constrained optimization (CONOP) programs that produce a calendar of events from many sections, should lead to much more precise timescales for pre-Cenozoic time than are currently available.

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