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The Cenozoic is just as much the age of savannas, the age of co-dependent flowering plants and insects, and the age of birds. [40] Grasses also played a very important role in this era, shaping the evolution of the birds and mammals that fed on them. One group that diversified significantly in the Cenozoic as well were the snakes.
The Late Cenozoic Ice Age falls within the Cenozoic Era which started 66 million years ago. The Cenozoic Era is part of the Phanerozoic Eon which started ~538.8 million years ago. ^ a b In standard nomenclature the Pleistocene Epoch lasts from 2.58 Ma to 11.7 ka and the Holocene epoch lasts from 11.7 ka to present.
During the early Cenozoic, after the extinction of the non-bird dinosaurs, mammals underwent an evolutionary diversification, and some bird groups around the world developed a tendency towards gigantism; this included the Gastornithidae, the Dromornithidae, the Palaeognathae, and the Phorusrhacidae. [36]
The Paleogene (alternatively Palaeogene) Period is a unit of geologic time that began 66 and ended 23.03 Ma [10] and comprises the first part of the Cenozoic Era. This period consists of the Paleocene, Eocene and Oligocene Epochs.
The Quaternary (/ k w ə ˈ t ɜːr n ə r i, ˈ k w ɒ t ər n ɛr i / kwə-TUR-nə-ree, KWOT-ər-nerr-ee) is the current and most recent of the three periods of the Cenozoic Era in the geologic time scale of the International Commission on Stratigraphy (ICS), as well as the current and most recent of the twelve periods of the Phanerozoic eon. [3]
The Late Cenozoic Ice Age began 34 million years ago, its latest phase being the Quaternary glaciation, in progress since 2.58 million years ago. Within ice ages, there exist periods of more severe glacial conditions and more temperate conditions, referred to as glacial periods and interglacial periods , respectively.
c. 4,300 Ma – Nectarian Era begins on Earth. c. 4,250 Ma – Earliest evidence for life, based on unusually high amounts of light isotopes of carbon, a common sign of life, found in Earth's oldest mineral deposits located in the Jack Hills of Western Australia. [4] c. 4,100 Ma – Early Imbrian Era begins on Earth.
Following formal discussions at the 2008 International Geological Congress in Oslo, Norway, [32] the ICS decided in May 2009 to make the Quaternary the youngest period of the Cenozoic Era with its base at 2.58 Mya and including the Gelasian Age, which was formerly considered part of the Neogene Period and Pliocene Epoch. [33]