Cenozoic
| Phanerozoic eon (542 mya - present) | ||
|---|---|---|
| Paleozoic era | Mesozoic era | Cenozoic era |
| Cenozoic era 65 - 0 million years ago | |
The Cenozoic (sen-oh-ZOH-ik; sometimes the British English Caenozoic) meaning "new life" (Greek kainos = new + zoe = life) is the most recent of the three classic geological eras of the geologic time scale. It covers the 65.5 million years since the Cretaceous-Tertiary extinction event at the end of the Cretaceous that marked the demise of the last dinosaurs and the end of the Mesozoic era. The Cenozoic era is ongoing.
The fauna and geology that we see today is vastly different than what was the case in the Mesozoic era, but comes on the foundation of the earlier time periods. The Mesozoic was the "Age of Dinosaurs," but the present era is sometimes referred to as the "Age of Mammals."
The Cenozoic is divided into two periods, the Paleogene and Neogene, and they are in turn divided into epochs. The Paleogene consists of the Paleocene, Eocene, and Oligocene epochs, and the Neogene consists of the Miocene, Pliocene, Pleistocene, and Holocene epochs, the last of which is ongoing.
Historically, the Cenozoic has been divided into periods (or sub-eras) named the Tertiary (Paleocene to Pliocene) and Quaternary (Pleistocene and Holocene), as well as the Neogene and Paleogene periods. However, the International Commission on Stratigraphy has decided to stop endorsing the terms Quaternary and Tertiary as part of the formal nomenclature.
Geology of the Cenozoic
Geologically, the Cenozoic is the era when continents moved into their current positions. Australia-New Guinea split from Gondwana to drift north and, eventually, abut South-east Asia. Antarctica moved into its current position over the South Pole. The Atlantic Ocean widened and, later in the era, South America became attached to North America.
Life in the Cenozoic era
| Cenozoic era (65-0 mya) | |
|---|---|
| Paleogene | Neogene Quaternary |
The Cretaceous-Tertiary extinction event, known also as the K-T extinction event, occurred about 65.5 million years ago. Approximately 50 percent of all plant and animal families disappeared during this mass extinction, including the non-avian dinosaurs. The most widely accepted current theory for this extinction is that an object from space produced an impact event on Earth.
The K-T extinction event marked the boundary between the Mesozoic era and the Cenozoic era—and between the last period of the Mesozoic (the Cretaceous) and the first period of the Cenozoic (the Paleogeneera, or the Tertiary sub-era traditionally). The Cenozoic is the “age of mammals.” 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.
See also
References and further reading
- Natural History Museum, London. British Caenozoic Fossils (Tertiary and Quaternary). 5th Edition. Intercept, Ltd., 1975. ISBN 1898298777
- Raymond, A., and C. Metz. “Ice and its consequences: Glaciation in the Ordovician, Late Devonian, Pennsylvanian-Permian and Cenozoic compared.” Journal of Geology 112:655-670, 2004.
- Redfern, R. Origins: The Evolution of Continents, Oceans and Life. Norman, OK: University of Oklahoma Press, 2001. ISBN 0806133597
Credits
New World Encyclopedia writers and editors rewrote and completed the Wikipedia article in accordance with New World Encyclopedia standards. This article abides by terms of the Creative Commons CC-by-sa 3.0 License (CC-by-sa), which may be used and disseminated with proper attribution. Credit is due under the terms of this license that can reference both the New World Encyclopedia contributors and the selfless volunteer contributors of the Wikimedia Foundation. To cite this article click here for a list of acceptable citing formats.The history of earlier contributions by wikipedians is accessible to researchers here:
The history of this article since it was imported to New World Encyclopedia:
Note: Some restrictions may apply to use of individual images which are separately licensed.
- ↑ Retallack, G.J. (1997). Neogene Expansion of the North American Prairie. PALAIOS 12 (4): 380-390.
- ↑ Zachos, J.C. and Kump, L.R. (2005). Carbon cycle feedbacks and the initiation of Antarctic glaciation in the earliest Oligocene. Global and Planetary Change 47 (1): 51-66.
- ↑ Krijgsman, W. and Garcés, M.; Langereis, C.G.; Daams, R.; Van Dam, J.; Van Der Meulen, A.J.; Agustí, J.; Cabrera, L. (1996). A new chronology for the middle to late Miocene continental record in Spain. Earth and Planetary Science Letters 142 (3-4): 367-380.
