Table 1 Potential start dates for a formal Anthropocene Epoch

From: Defining the Anthropocene

Event Date Geographical extent Primary stratigraphic marker Potential GSSP date* Potential auxiliary stratotypes
Megafauna extinction 50,000–10,000 yr bp Near-global Fossil megafauna None, diachronous over 40,000 yr Charcoal in lacustrine deposits
Origin of farming 11,000 yr bp Southwest Asia, becoming global Fossil pollen or phytoliths None, diachronous over 5,000 yr Fossil crop pollen, phytoliths, charcoal
Extensive farming 8,000 yr bp to present Eurasian event, global impact CO2 inflection in glacier ice None, inflection too diffuse Fossil crop pollen, phytoliths, charcoal, ceramic minerals
Rice production 6,500 yr bp to present Southeast Asian event, global impact CH4 inflection in glacier ice 5,020 yr bp CH4 minima Stone axes, fossil domesticated ruminant remains
Anthropogenic soils 3,000–500 yr bp Local event, local impact, but widespread Dark high organic matter soil None, diachronous, not well preserved Fossil crop pollen
New–Old World collision 1492–1800 Eurasian–Americas event, global impact Low point of CO2 in glacier ice 1610 CO2 minima Fossil pollen, phytoliths, charcoal, CH4, speleothem δ18O, tephra†
Industrial Revolution 1760 to present Northwest Europe event, local impact, becoming global Fly ash from coal burning 1900 (ref. 94); diachronous over 200 yr 14N:15N ratio and diatom composition in lake sediments
Nuclear weapon detonation 1945 to present Local events, global impact Radionuclides (14C) in tree-rings 1964 14C peak§ 240Pu: 239Pu ratio, compounds from cement, plastic, lead and other metals
Persistent industrial chemicals 1950 to present Local events, global impact For example, SF6 peak in glacier ice Peaks often very recent so difficult to accurately date§ Compounds from cement, plastic, lead and other metals
  1. For compliance with a Global Stratotype Section and Point (GSSP) definition, a clearly dated global marker is required, backed by correlated auxiliary markers that collectively indicate global and other widespread and long-term changes to the Earth system. bp, before present, where present is defined as calendar date 1950.
  2. *Requires a specific date for a GSSP primary marker. †From Huaynaputina eruption in 1600 (refs 78, 79).
  3. §Peak, rather than earliest date of detection selected, because earliest dates reflect available detection technology, are more likely influenced by natural background geochemical levels101, and will be more affected by the future decay of the signal, than peak values.