Anthony D. Barnosky, 2014. "Palaeontological evidence for defining the Anthropocene", A Stratigraphical Basis for the Anthropocene, C. N. Waters, J. A. Zalasiewicz, M. Williams, M. Ellis, A. M. Snelling
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Palaeontology formed the basis for defining most of the geological eras, periods, epochs and ages that are commonly recognized. By the same token, the Anthropocene can be defined by diverse palaeontological criteria, in accordance with commonly accepted biostratigraphic practice. The most useful Anthropocene biostratigraphic zones will be assemblage and abundance zones based on mixes of native and non-native species in both the marine and terrestrial realms, although lineage zones based on evolution of crop plants may also have utility. Also useful are human-produced trace fossils, which have resulted in prominent biohorizons that can mark the onset of the Anthropocene, especially the paved road system, widespread through terrestrial regions, and microplastics, ubiquitous in near-shore and deep-water marine sediments. Most of these palaeontological criteria support placing the Holocene–Anthropocene boundary near 1950. Continuation of current extinction rates would produce an extinction biohorizon on the scale of the Big Five mass extinctions within a few centuries, but enhanced conservation measures could prevent making mass extinction an Anthropocene signature. A grand challenge for palaeontologists now is to define Anthropocene biostratigraphic zones rigorously, not only as a necessary precursor to formalizing the epoch, but also to more fully understand how humans have restructured the biosphere.
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A Stratigraphical Basis for the Anthropocene
Humankind has pervasively influenced the Earth’s atmosphere, biosphere, geosphere, hydrosphere and cryosphere, arguably to the point of fashioning a new geological epoch, the Anthropocene. To constrain the Anthropocene as a potential formal unit within the Geological Time Scale, a spectrum of indicators of anthropogenically-induced environmental change is considered, and shown as stratigraphical signals that may be used to characterize an Anthropocene unit, and to recognize its base. This volume describes a range of evidence that may help to define this potential new time unit and details key signatures that could be used in its definition. These signatures include lithostratigraphical (novel deposits, minerals and mineral magnetism), biostratigraphical (macro- and micro-palaeontological successions and human-induced trace fossils) and chemostratigraphical (organic, inorganic and radiogenic signatures in deposits, speleothems and ice and volcanic eruptions). We include, finally, the suggestion that humans have created a further sphere, the technosphere, that drives global change.