Palaeozoic

Palaeozoic
Name	Palaeozoic
Time start	541
Time end	252.17

Palaeozoic

Overview and Definition

The Palaeozoic era is a major interval of the Geological time scale associated with the assembly and fragmentation of Pangea and marked by innovations tied to the fossil record studied by institutions such as the Smithsonian Institution, the Natural History Museum, London, and the American Museum of Natural History; paleontologists including Charles Doolittle Walcott, Edward Drinker Cope, Othniel Charles Marsh, Mary Anning and Georg Friedrich von Walther contributed to its interpretation. This era features sedimentary successions exposed in regions like the Appalachian Mountains, the Ural Mountains, the Caledonian orogeny area and the Siberian Platform, and has been dated through methods developed at laboratories such as the US Geological Survey, the British Geological Survey, and the Geological Survey of Canada.

Chronostratigraphy and Geologic Time Scale

Chronostratigraphic subdivisions of the era are formalized by the International Commission on Stratigraphy and correlate with global stages recognized in publications from the Geological Society of America, the Palaeontological Association, and the Royal Society. Absolute ages for boundaries have been refined through radiometric techniques developed at institutions like the California Institute of Technology, Massachusetts Institute of Technology, and the Berkeley Geochronology Center using isotope systems such as uranium-lead employed by researchers affiliated with Yale University, ETH Zurich, and the Max Planck Society. Stratotypes and Global Boundary Stratotype Sections and Points (GSSPs) for many intervals were ratified following proposals discussed at meetings of the International Union of Geological Sciences, the European Geosciences Union, and national academies including the National Academy of Sciences.

Major Periods and Subdivisions

The era comprises traditionally recognized periods often taught in curricula at the University of Oxford, Harvard University, University of Cambridge, and the University of Chicago: the Cambrian, Ordovician, Silurian, Devonian, Carboniferous, and Permian, with regional subdivisions such as the Mississippian and Pennsylvanian used in North America by the United States Geological Survey and the Canadian Geological Survey. Each period is characterized by type sections described in monographs from publishers like Cambridge University Press, Springer, and Elsevier and by fossils curated at museums such as the Field Museum and the Royal Belgian Institute of Natural Sciences.

Paleoenvironments and Climate Changes

Palaeozoic paleoenvironments shifted from greenhouse conditions recorded in carbonate platforms of the Burgess Shale and the Chengjiang biota to glaciations interpreted from deposits in the Gondwana margin, studied by teams from Columbia University, University of Adelaide, and University of Cape Town. Atmospheric and oceanic changes inferred from isotopic records by researchers at the Scripps Institution of Oceanography, the Woods Hole Oceanographic Institution, and the Lamont–Doherty Earth Observatory document events such as Cambrian warming, Ordovician cooling, Devonian anoxia, and Permian aridification that impacted faunas known from sites like Mazon Creek and Joggins Fossil Cliffs.

Biodiversity and Major Evolutionary Events

Major evolutionary events include the Cambrian Explosion documented in collections of Royal Ontario Museum, the Ordovician Radiation examined by scholars affiliated with Princeton University and University of California, Berkeley, the rise of vascular plants linked to work at the Royal Botanic Gardens, Kew, and vertebrate transitions to land studied via fossils in holdings at the Natural History Museum, London and the National Museum of Natural History (Smithsonian). Key clades such as trilobites, brachiopods, cephalopods, eurypterids, placoderms, temnospondyls, lycophytes, sphenopsids, and early amniotes are central to monographs published by the Palaeontological Association, the Society for Sedimentary Geology, and universities including University of Edinburgh and University of Toronto.

Paleogeography and Plate Tectonics

Plate tectonic reconstructions for the era are produced by research groups at University College London, the University of Sydney, and the GEOMAR Helmholtz Centre for Ocean Research Kiel, integrating paleomagnetic data from the British Antarctic Survey, the Geological Survey of India, and the Russian Academy of Sciences to illustrate the drifting of terranes, the opening of the Iapetus Ocean, closure of the Panthalassa, suturing at the Variscan Belt, and the culmination of continental collision in the formation of Pangea.

Extinction Events and Biotic Turnovers

The era experienced several major extinction events including the Late Ordovician extinction examined by teams at University of California, Santa Cruz and Ohio State University, Devonian pulses analyzed by researchers at University of Kansas and University of Calgary, and the end-Permian mass extinction—the largest crisis studied intensively at institutions such as the Max Planck Institute for Chemistry, Chinese Academy of Sciences, and the Australian National University—with mechanisms debated in literature from journals associated with the American Geophysical Union, Elsevier, and the Royal Society of London.

Category:Geologic eras