Paleocene

Paleocene
Name	Paleocene
Time start	66.0
Time end	56.0
Time unit	million years ago
Major subdivisions	Danian, Selandian, Thanetian
Preceded by	Cretaceous
Followed by	Eocene

Paleocene The Paleocene epoch marks the earliest interval of the Cenozoic Era and follows the Cretaceous–Paleogene extinction event. It spans roughly from 66 to 56 million years ago and features recovery and diversification of life, major tectonic reorganizations, and climatic trends that set the stage for modern ecosystems.

Etymology and Definition

The name derives from classical roots introduced in stratigraphic literature and adopted by stratigraphic bodies such as the International Commission on Stratigraphy and discussed in works associated with Charles Lyell, Adam Sedgwick, and later authors like Sir Archibald Geikie. Early usage appears in 19th-century European geological surveys conducted by institutions such as the British Geological Survey and museums including the Natural History Museum, London and the Smithsonian Institution. Definitions were refined through contributions from stratigraphers connected to the Geological Society of London and the United States Geological Survey and codified in chronostratigraphic charts drawn up by panels convened under the auspices of the International Union of Geological Sciences.

Stratigraphy and Geologic Boundaries

Paleocene stratigraphy is subdivided into the Danian Stage, Selandian Stage, and Thanetian Stage and correlated globally via type sections and reference profiles defined in basins such as the Demerara Rise, the Maastrichtian-overlying sequences in the Paris Basin, and sections in the Hanna Basin and Williston Basin. The base is formally placed above the K-Pg boundary marked by iridium anomalies and microtektites recognized in studies involving investigators from institutions like the Geological Survey of Canada and laboratories at Caltech and Harvard University. Boundaries rely on biostratigraphic markers such as planktic foraminiferal turnovers examined by researchers affiliated with the Geological Society of America and magnetostratigraphic correlation performed by teams from ETH Zurich and Columbia University.

Paleogeography and Climate

Paleocene paleogeography reflects the rifting of continents driven by tectonic forces recorded in reconstructions by groups at the Paleomap Project and plate models advanced by scientists from Scripps Institution of Oceanography and the Woods Hole Oceanographic Institution. Continents like Laurasia and Gondwana continued fragmenting with seaways such as the Tethys Ocean reshaped by motions between North America, Greenland, Eurasia, and Africa. Climate during the epoch featured a warm greenhouse trend interrupted by hyperthermal events analyzed in publications from Max Planck Institute for Chemistry and climate modeling by researchers at IPCC-affiliated centers and universities including Oxford University and Princeton University. Carbon cycle perturbations were investigated via isotope studies conducted at Lamont–Doherty Earth Observatory and cores recovered by the Integrated Ocean Drilling Program and its successor, the International Ocean Discovery Program.

Flora and Fauna

Plant recovery and diversification are documented in floras curated at institutions like the Royal Botanic Gardens, Kew and the New York Botanical Garden where angiosperm lineages expanded after disturbances recorded by paleobotanists from University of California, Berkeley and Yale University. Terrestrial faunas saw rapid mammalian diversification among groups studied by paleontologists at the American Museum of Natural History and the Natural History Museum of Los Angeles County, with early orders such as Plesiadapiformes and primitive Eutheria radiating in ecosystems sampled in basins including Williston Basin and Raton Basin. Marine recovery featured proliferation of bivalves, gastropods, and foraminifera cataloged in collections at the Smithsonian Institution and the Muséum national d'Histoire naturelle. Avian groups evolved rapidly with fossils described by teams from University of Kansas and University of Cambridge. Paleocene insect assemblages and plant–insect interactions were examined by researchers at University of Florida and University of Michigan using compression fossils from localities such as the Paskapoo Formation and the Willwood Formation.

Major Events and Extinctions

The epoch begins in the aftermath of the mass extinction tied to impact structures like the Chicxulub crater and volcanic episodes associated with the Deccan Traps, topics examined by consortiums including investigators from MIT, University of Copenhagen, and the Geological Survey of India. Subsequent biotic turnovers and regional extinctions, including marine foraminiferal crises, were documented in studies by the Royal Society-affiliated researchers and teams from the British Antarctic Survey. Hyperthermal events such as the Paleocene-Eocene Thermal Maximum are linked to carbon injections explored by scientists at Lamont–Doherty Earth Observatory, ETH Zurich, and University of Arizona. Sea-level changes and anoxic events recorded in sedimentary archives were interpreted by groups from University of Texas at Austin and the Ohio State University.

Human Discovery and Research History

Discovery and interpretation of Paleocene strata have been products of fieldwork by geologists and paleontologists associated with institutions such as the Geological Survey of Canada, United States Geological Survey, British Museum (Natural History), and universities including University of Chicago and Columbia University. Key fossil discoveries and taxonomic descriptions were published in journals linked to the Paleontological Society, the Journal of Vertebrate Paleontology, and the New Phytologist with major monographs produced by scholars from Harvard University, Yale University, University of Oxford, and the Natural History Museum, London. International collaboration through programs like the International Geosphere-Biosphere Programme and archives maintained by the British Library and Library of Congress have shaped modern syntheses; ongoing research continues at centers such as Smithsonian Tropical Research Institute and the California Academy of Sciences.

Category:Paleogene