Permian period

Permian period
Scotese, Christopher R.; Vérard, Christian; Burgener, Landon; Elling, Reece P.; · CC BY 4.0 · source
Name	Permian
Time start	298.9
Time end	251.902
Color	#ff7f50
Caption	Extent of Pangaea during the Permian
Former supercontinents	Pangaea
Epoch or period	Period
Preceded by	Carboniferous
Followed by	Triassic

Permian period The Permian period marks the final interval of the Paleozoic Era and precedes the Mesozoic. It witnessed major transitions in plate tectonics and paleoclimate that reshaped life before the Triassic–Jurassic extinction event. Well-studied in regions such as the Ural Mountains, Siberia, and Zechstein Basin, the period is central to understanding deep-time shifts documented in formations like the Cisuralian and Lopingian.

Overview

The Permian is subdivided into epochs including the Cisuralian, Guadalupian, and Lopingian, with biostratigraphic markers tied to taxa from the GSSP network and indexed by zones used at institutions such as the Geological Society of America and International Commission on Stratigraphy. Global correlations use fossil groups recorded in the Beetley Formation, Kaibab Limestone, Guadalupian Reef sequences, and sections in the South China Block and Karoo Basin. Major research programs at the Smithsonian Institution, Natural History Museum, London, and Russian Academy of Sciences have advanced isotope stratigraphy and magnetostratigraphy for Permian sequences.

Stratigraphy and Geology

Permian stratigraphy integrates lithostratigraphic units such as the Cutler Formation, Beekmantown Group, and Wuchiapingian limestones with chronostratigraphic frameworks used by the International Chronostratigraphic Chart. Sedimentary environments include the Zechstein Sea evaporites, the continental red beds of the Permo-Carboniferous basins, and the carbonate platforms documented in the Guadalupian. Volcaniclastic deposits related to the Siberian Traps flood basalts and associated intrusive suites impacted local lithologies and are correlated with anomalies in the Capitan Reef Complex and the Ob Basin sequences.

Paleoclimate and Oceanography

Permian climate shifted from glacial conditions inherited from the late Carboniferous to aridification associated with the assembly of Pangaea and the influence of monsoonal systems affecting the Tethys Ocean and the Panthalassa. Proxy records from δ13C and δ18O isotopes in marine carbonates, analyses by teams at Lamont–Doherty Earth Observatory, and sedimentary evidence from the Permian Basin indicate episodes of warming, ocean stratification, and anoxia. Sea-level fluctuations documented in the Hettangian-correlative shorelines and the Sakmarian–Kungurian successions influenced reef distribution and the spread of euxinic conditions documented in black shales from the Antrim Shale-type deposits.

Flora and Fauna

Terrestrial ecosystems hosted diverse synapsids such as taxa comparable to genera studied in the Karoo Supergroup and the Moscow Basin collections, while marine faunas included brachiopods, ammonoids, and the reef-building sponges and corals recorded in the Capitan Reef. Plant assemblages transitioned from the coal-forming lycopsids of the Westphalian to gymnosperm-dominated floras including ginkgoaleans and glossopterids found in Gondwanan outcrops examined by teams at the University of Cape Town and the Australian National University. Vertebrate paleontology advanced through fieldwork in the Red Beds of Texas, Gansu, and the Cis-Uralian localities, with museum collections at the Field Museum and Museo Argentino de Ciencias Naturales preserving key specimens.

Tectonics and Paleogeography

Tectonic reconfiguration culminated in the assembly of Pangaea, with suturing events along the Uralian orogeny, Alleghany orogeny, and interactions between the Laurentia and Siberia plates. Paleogeographic reconstructions by teams at Caltech and ETH Zurich show interior aridity, extensive continental interiors like the Central Pangean Mountains, and shoreline systems along the Tethys margin. Mantle plume activity linked to the Siberian Traps and basin development in the Karoo Basin and Paraná Basin influenced sedimentary architecture and magmatic episodes recorded in the Juvenile crust terranes.

End-Permian Extinction

The end-Permian extinction, recorded in sections such as the Meishan GSSP and studied by researchers at Peking University and University of Edinburgh, represents the most severe Phanerozoic biotic crisis. Multiproxy evidence implicates massive volcanism from the Siberian Traps, rapid greenhouse gas release, widespread anoxia, and ocean acidification, with chain reactions affecting ecosystems from the Panthalassa to Gondwana. Geochemical anomalies in mercury and carbon isotopes, paleontological turnovers documented in the Guadalupian–Lopingian boundary strata, and sedimentological signatures across the Nanxiong Basin support a complex, multiphase extinction model.

Legacy and Geological Significance

Permian successions provide crucial records for petroleum geology in the Permian Basin of West Texas and the North Sea petroleum provinces, influence mining in the Zechstein evaporite belts, and underpin stratigraphic frameworks used by the United States Geological Survey and British Geological Survey. The period’s diachronous faunal turnovers inform macroevolutionary models used in comparative studies at the University of Chicago and Stanford University, while Permian rocks continue to be key targets for field training at institutions such as the University of California, Berkeley and the University of Sydney.

Category:Geological periods Category:Paleozoic