Permo-Carboniferous

Permo-Carboniferous
Name	Permo-Carboniferous
Color	#B0C4DE
Time start	298.9
Time end	298.9
Time unit	million years ago
Caption	Composite stratigraphy and paleogeography

Permo-Carboniferous is a compound chronostratigraphic concept used in some regional syntheses to denote the contiguous interval spanning the late Carboniferous and early Permian around the Paleozoic transition, emphasizing continuity in sedimentary regimes, biotic turnover, and tectonic reorganization. It frames the interval in which deposits, faunal assemblages, and tectonic events that are traditionally split between the Carboniferous and the Permian are treated as a single evolutionary and stratigraphic continuum for comparison across cratons like the Laurentia, Gondwana, and Pangea.

Definition and Chronostratigraphy

The term collates stages conventionally recognized as the late Pennsylvanian and early Cisuralian in global chronostratigraphy, and aligns with type sections and stage boundaries defined by bodies such as the International Commission on Stratigraphy and regional stratigraphers from institutions like the United States Geological Survey and the British Geological Survey. Correlation hinges on datable ash beds tied to the U-Pb zircon timescale, magnetostratigraphy correlated with the Geomagnetic Polarity Time Scale, and biostratigraphic markers including key conodont and fusulinid taxa used by researchers at the Smithsonian Institution and the Natural History Museum, London.

Geological and Paleogeographic Setting

During this interval continental configurations reflect the assembly and suturing episodes that produced Pangea, with collision zones such as the Alleghanian orogeny and the Hercynian (Variscan) orogeny active along margins. Marine basins persisted in regions later represented by the Zealandia reconstructions and the Tethys Ocean margin, while intracratonic basins on Laurentia and Siberia accumulated thick coal-bearing strata. Plate-boundary interactions recorded in terranes studied by teams at the Geological Survey of Canada and the Russian Academy of Sciences controlled subsidence patterns that produced stratigraphic wedges documented in the Permo-Triassic Basin successions.

Climate and Atmospheric Changes

Global climates shifted from the humid, equatorial-wet regimes of the late Carboniferous to more arid and seasonal conditions in the early Permian, a transition constrained by isotopic datasets produced at the Lamont–Doherty Earth Observatory and climate modeling groups at the Max Planck Institute for Meteorology. Atmospheric oxygen peaked and then declined, as inferred from charcoal frequency and geochemical records analyzed by scientists at the University of California, Berkeley and the University of Oxford, while carbon dioxide concentrations evolved in concert with glacial-interglacial cycles tied to the Late Paleozoic Ice Age documented in Gondwanan outcrops sampled by teams from the Australian National University.

Flora and Fauna

Vegetation in the interval shows persistence of lycopsids and sphenopsids in coal swamps studied by botanists affiliated with the Royal Botanic Gardens, Kew and the Missouri Botanical Garden, alongside diversification of gymnosperms including early conifers recorded in floras curated at the Field Museum of Natural History and the National Museum of Natural History (France). Terrestrial vertebrates record the rise of synapsid lineages and diverse amphibian clades described in collections at the American Museum of Natural History and the Natural History Museum, London, while marine faunas include ammonoids and brachiopods used for correlation by paleontologists at the Smithsonian Institution and the Museum für Naturkunde, Berlin.

Tectonics, Sedimentation, and Depositional Environments

Sedimentary facies range from coal-bearing cyclothems of equatorial basins to red-bed continental deposits recording monsoonal regimes, deposited in fluvial systems mapped by the United States Geological Survey and the Geological Survey of Brazil. Orogenic loading and flexural basins produced subsidence patterns investigated in studies by the University of Edinburgh and the Massachusetts Institute of Technology, while synorogenic foreland basins preserved terrestrial vertebrate assemblages documented by the Denver Museum of Nature & Science. Carbonate platforms on passive margins gave way to siliciclastic influx during uplift episodes tied to collisions such as the Alleghanian orogeny.

Mass Extinctions and Biotic Transitions

The interval encompasses the protracted biotic turnover that culminated at the end-Permian extinction but includes earlier pulses of extinction and faunal replacement documented in vertebrate and invertebrate records curated at the Smithsonian Institution and the Natural History Museum, London. Patterns include reductions in marine diversity among brachiopods and fusulinids and restructuring of terrestrial ecosystems with synapsid dominance, interpreted through quantitative paleobiological methods developed at the Paleobiology Database and research groups at the University of Chicago.

Economic Significance and Natural Resources

Rocks of this interval host major coal seams exploited in basins once mapped by the British Geological Survey and the Interstate Oil and Gas Compact Commission, as well as hydrocarbon source and reservoir rocks targeted by energy companies and national surveys such as the Petroleum Exploration and Production Association of New Zealand and the Norwegian Petroleum Directorate. Permo-Carboniferous strata also contain economically important evaporite deposits and mineralization studied by geologists at the USGS and the Geological Survey of India, and they remain key targets for carbon sequestration assessments undertaken by research consortia including the European Commission-funded projects.

Category:Paleozoic geology