Anthropocene recognised as an epoch

Context

The pervasive and persistent signatures of modern human activity on the earth have been so striking that officially, it is being recognised and named as a new geologic epoch (Anthropocene).

About

Recently, the Anthropocene Working Group (AWG) overwhelmingly voted to recognise Anthropocene as an epoch. The vote gives form to the efforts of scientists, notably the Nobel Laureate Paul Crutzen and Eugene F. Stoermer, who coined the term in 2000 to highlight how human activity had changed many facets of the earth.

Geochronology:

  • Eon (largest)
  • Era
  • Period
  • Epoch
  • Age
  • Chron (smallest)

Geological epoch:

  • In geochronology, an epoch is a subdivision of the geologic timescale that is longer than an age but shorter than a period. The current epoch is the Holocene Epoch of the Quaternary Period.
  • Cenozoic (current era)
    • Quaternary (current period)
      • Holocene (current epoch: The start of the Holocene epoch 11,700 years ago marks the end of the transition from the last glacial phase to a period of warming and a rise in sea level.)
      • Pleistocene
    • Neogene
      • Pliocene
      • Miocene
    • Paleogene
      • Oligocene
      • Eocene
      • Paleocene

Anthropocene:

  • It is a proposed epoch dating from the commencement of significant human impact on Earth's geology and ecosystems.
  • Human activity has been drastically changing the earth, with the greatest impacts coming from agriculture, large-scale deforestation, the industrial revolution and increase in atmospheric carbon dioxide, besides the creation of materials such as concrete and plastic.
  • Unlike the others, it will be the first time that the beginning of an epoch would be based on human activity and not the consequences of changes brought about by nature.

Marker for this new epoch:

  • Anthropocene Working group voted to look for unique signatures around the 1950s to define the start of the Anthropocene.
  • To be chosen as a geologic marker, the golden spike must be present globally across most environments and must be a part of deposits for a geologically significant length of time.
  • A decrease in deuterium excess, a proxy for climate change, owing to the reorganisation of North Atlantic Ocean-atmosphere circulation was a definitive geologic marker (or golden spike) to signify the base of Holocene.
  • Now, radionuclides from atomic bomb tests from the early 1950s are emerging as a favourite golden spike candidate to define the base of the Anthropocene.

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