The Cenozoic (also Caenozoic or Cainozoic) Era (pronEng|ˌsiːnəˈzoʊ
ɪk/, /ˌsɛn-) (meaning "new life" (Greek Polytonic|καινός ("kainos"), "new", and Polytonic|ζωή ("zoe"), "life"), is the most recent of the three classic geological eras and covers the period from 65.5 million years ago to the present. It is marked by the Cretaceous–Tertiary extinction eventat the end of the Cretaceousthat saw the demise of the last non-avian dinosaurs and the end of the MesozoicEra. The Cenozoic era is ongoing.
The Cenozoic Era is divided into two periods, the
Paleogeneand Neogene, and they are in turn divided into epochs. The Paleogene consists of the Paleocene, Eocene, and Oligoceneepochs, and the Neogene consists of the Miocene, Pliocene, Pleistocene, and Holoceneepochs, the last of which is ongoing. Historically, the Cenozoic has been divided into periods (or sub-eras) named the Tertiary(Paleocene through Pliocene) and Quaternary(Pleistocene and Holocene).
Geologically, the Cenozoic is the era when the
continents moved into their current positions.Clarifyme|the continents have been moving to their current position since their formation...|date=March 2008 Australia-New Guinea split from Gondwanaand drifted north and, eventually, adjacent to South-east Asia; Antarcticamoved into its current position over the South Pole; the Atlantic Oceanwidened and, later in the era, South Americabecame attached to North America.
India collided with Asia between 55 and 45 million years ago; Arabia collided with Eurasia, closing the
Tethys ocean, around Ma|35.cite doi|10.1016/j.palaeo.2008.04.021 ]
The Cenozoic Era has been a period of long-term cooling. In the early Cenozoic, particulate ejecta from the
K-T boundaryimpact blocked incoming solar radiation Fact|date=December 2007. After the tectonic creation of Drake Passage, when Australia fully detached from Antarctica during the Oligocene, the climate cooled significantly due to the advent of the Antarctic Circumpolar Currentwhich brought cool deep Antarctic water to the surface. Warm conditions returned in the Miocenedue to uncovered gas hydrates releasing carbon dioxide.Fact|date=November 2007 When South America became attached to North America creating the Isthmus of Panama, the Arctic region cooled due to the strengthening of the Humboldt and Gulf StreamcurrentsFact|date=December 2007, eventually leading to the Last Glacial Maximum.
The Cenozoic Era is the age of new life. During the Cenozoic, mammals diverged from a few small, simple, generalized forms into a diverse collection of terrestrial, marine, and flying animals. The Cenozoic is just as much the age of
savannas, or the age of co-dependent flowering plants and insects. Birds also evolved substantially in the Cenozoic.
Bolcais an important lagerstättenear Verona, Italy, containing excellently preserved fish and other fossils of Eoceneage.
Geologic Time Scale
*"British Caenozoic Fossils", 1975, The Natural History Museum, London.
*"Geologic Time", by Henry Roberts.
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