Cenozoic

Cenozoic
Emanuele Petrachi (Petrescu) · CC BY 3.0 · source
Name	Cenozoic
Start	66 Ma
End	Present

Cenozoic The Cenozoic marks the most recent interval of Earth's history, beginning about 66 million years ago and extending to the present; it follows the Mesozoic and precedes the Anthropocene discussions. This era witnessed the rise of modern continental configurations including the Himalayas, the establishment of contemporary climates such as those of the Arctic, the development of modern faunas tied to refugia like Madagascar, and the eventual emergence of anatomically modern Homo sapiens. Paleontologists, geochronologists, and stratigraphers use a combination of fossil biostratigraphy, radiometric dating, and magnetostratigraphy developed in institutions like the Smithsonian Institution and the British Geological Survey to subdivide and interpret the era.

Definition and Nomenclature

The term derives from Greek roots used in early 19th-century stratigraphy debates involving figures at the Royal Society and in correspondence between scholars at the University of Cambridge and the Muséum national d'Histoire naturelle. International standardization occurred under bodies such as the International Commission on Stratigraphy and the International Union of Geological Sciences, which approved chronostratigraphic nomenclature parallel to schemes applied in the Permian and Jurassic. Regional usage differs in literature from the Rocky Mountains to the Great Dividing Range and in repositories like the Natural History Museum, London where exhibition labels reflect global stratigraphic charts.

Geological Subdivisions and Timescale

Stratigraphic subdivisions follow global stages and epochs ratified by the ICS and employed by organizations including the United States Geological Survey and the Geological Survey of Canada. Major epochs include the Paleocene, Eocene, Oligocene, Miocene, Pliocene, Pleistocene, and Holocene, which are correlated against magnetostratigraphic records associated with specific sites such as the Blake Nose and the Walvis Ridge. Radiometric calibration employs techniques refined at laboratories like those at Caltech and the Max Planck Society, using isotopes first exploited by researchers at the University of Chicago and cross-checked with records from the Vostok Station ice cores and the Greenland Ice Sheet Project. Global sea-level curves and oxygen isotope excursions recorded in cores from the Deep Sea Drilling Project and the Integrated Ocean Drilling Program anchor subdivisions relative to events like the Paleocene–Eocene Thermal Maximum.

Major Tectonic and Climatic Events

Tectonic reorganizations include collision of the Indian subcontinent with Eurasia forming the Himalayan orogeny, rifting at the East African Rift, and closure of ocean gateways like the Isthmus of Panama, each affecting ocean circulation studied by researchers at the Scripps Institution of Oceanography and the Woods Hole Oceanographic Institution. Climate events include the PETM, the Middle Miocene Climatic Optimum, and the Quaternary glaciations, recorded at sites tied to the Antarctic Treaty research stations and the Royal Society climate symposia. These events reshaped atmospheric composition measured by projects at the National Oceanic and Atmospheric Administration and led to biogeographic shifts documented in records curated by the Natural History Museum, London and the American Museum of Natural History.

Evolution of Life and Biotic Radiations

The era saw mammalian radiations yielding groups such as primates linked to fossil finds from the Siwalik Hills, perissodactyls and artiodactyls from the Messel Pit, and proboscideans with material in the Fayum Depression. Avian diversification appears in beds studied by teams at the Field Museum and the Smithsonian Institution. Marine faunas record transitions in cetaceans preserved along the Atlanticcoast and in formations found by expeditions from the Natural History Museum of Los Angeles County. Island radiations on Galápagos Islands and Hawaiian Islands paralleled adaptive radiations described in works by researchers associated with the University of California, Berkeley and the University of Oxford. Floral shifts, including grassland expansion and C4 photosynthesis, are recorded in isotopic studies from the Lamont–Doherty Earth Observatory and in palynological archives housed in the Royal Botanic Gardens, Kew.

Paleoenvironments and Ecosystem Changes

Paleoenvironmental reconstructions derive from sedimentology at basin studies in the Paris Basin, Williston Basin, and North Sea, and from proxy records preserved in the Greenland Ice Core Project, pelagic sequences from the Atlantic Ocean, and lacustrine deposits in the Ebro Basin. Forest-to-grassland transitions, faunal turnover, and coastal transgressions affected biodiversity in regions such as the Sahara, the Andes, and the Great Plains, with vertebrate assemblages curated in collections at the Natural History Museum, London and the Museo Nacional de Ciencias Naturales. Human-driven transformations during the Holocene intersect with archaeological records from sites like Çatalhöyük and Göbekli Tepe, linking environmental change to cultural developments studied by teams at the University of Cambridge and the Max Planck Institute for Evolutionary Anthropology.

Economic Geology and Human Impact

Cenozoic strata host hydrocarbons exploited in basins such as the Gulf of Mexico, the North Sea, and the Persian Gulf, developed by firms like ExxonMobil, Shell, and national companies of Norway and Saudi Arabia. Mineral deposits including bauxite in Guinea, phosphate in Morocco, and orogenic gold associated with the Andean orogeny underpin extractive industries regulated by agencies such as the United States Environmental Protection Agency and the European Environment Agency. Human impacts include land-use change traced through pollen records in archives at the British Library and greenhouse gas increases measured by the Intergovernmental Panel on Climate Change and monitored by satellites from the European Space Agency.

Research History and Methods

Historical research ranges from 19th-century stratigraphers at the Geological Society of London and field campaigns led by the U.S. Geological Survey to modern multidisciplinary programs like the International Ocean Discovery Program and consortia at universities such as Harvard University, Stanford University, and the University of Tokyo. Methods combine paleontology, geochronology, geochemistry, and remote sensing developed at laboratories like Lawrence Berkeley National Laboratory and analytic facilities at the Natural Environment Research Council. Ongoing work integrates data repositories hosted by the PANGAEA data publisher and the Global Biodiversity Information Facility with open-science platforms associated with the European Research Council.

Category:Geologic eras