Table 1: Potential start dates for a formal Anthropocene Epoch

From: Defining the Anthropocene

EventDateGeographical extentPrimary stratigraphic markerPotential GSSP date*Potential auxiliary stratotypes
Megafauna extinction50,000–10,000 yr bpNear-globalFossil megafaunaNone, diachronous over 40,000 yrCharcoal in lacustrine deposits
Origin of farming11,000 yr bpSouthwest Asia, becoming globalFossil pollen or phytolithsNone, diachronous over 5,000 yrFossil crop pollen, phytoliths, charcoal
Extensive farming8,000 yr bp to presentEurasian event, global impactCO2 inflection in glacier iceNone, inflection too diffuseFossil crop pollen, phytoliths, charcoal, ceramic minerals
Rice production6,500 yr bp to presentSoutheast Asian event, global impactCH4 inflection in glacier ice5,020 yr bp CH4 minimaStone axes, fossil domesticated ruminant remains
Anthropogenic soils3,000–500 yr bpLocal event, local impact, but widespreadDark high organic matter soilNone, diachronous, not well preservedFossil crop pollen
New–Old World collision1492–1800Eurasian–Americas event, global impactLow point of CO2 in glacier ice1610 CO2 minimaFossil pollen, phytoliths, charcoal, CH4, speleothem δ18O, tephra
Industrial Revolution1760 to presentNorthwest Europe event, local impact, becoming globalFly ash from coal burning1900 (ref. 94); diachronous over 200 yr14N:15N ratio and diatom composition in lake sediments
Nuclear weapon detonation1945 to presentLocal events, global impactRadionuclides (14C) in tree-rings1964 14C peak§240Pu: 239Pu ratio, compounds from cement, plastic, lead and other metals
Persistent industrial chemicals1950 to presentLocal events, global impactFor example, SF6 peak in glacier icePeaks 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.