The Permian period, spanning 299 to 252 million years ago, marked the end of the Paleozoic Era. It saw the formation of Pangaea, the dominance of the Panthalassic Ocean, and diverse marine and terrestrial life.

The period concluded with Earth's most severe mass extinction, wiping out 96% of marine species and 70% of land vertebrates. This event reshaped life's evolution, setting the stage for the Mesozoic Era.

Permian period overview

• The Permian period, lasting from 299 to 252 million years ago, was the final period of the Paleozoic Era and witnessed significant changes in Earth's climate, geography, and biosphere
• It is characterized by the formation of the supercontinent Pangaea, the dominance of the Panthalassic Ocean, and the evolution of diverse marine and terrestrial life forms
• The end of the Permian is marked by the most severe mass extinction event in Earth's history, which had profound impacts on the course of life's evolution

Temporal range of Permian

• The Permian period extends from 299 to 252 million years ago
• It follows the Carboniferous period and precedes the Triassic period of the Mesozoic Era
• The Permian is divided into three epochs: the Cisuralian (299-272 Ma), the Guadalupian (272-259 Ma), and the Lopingian (259-252 Ma)

Paleoclimate in Permian

• The Permian climate was generally warm and dry, with extensive deserts and seasonally wet areas
• Early Permian glaciations occurred in the southern hemisphere, particularly in Australia and Antarctica, as evidenced by glacial deposits
• The late Permian saw a gradual warming trend, with the disappearance of glaciers and the expansion of arid regions
• Atmospheric CO2 levels were high, possibly due to increased volcanic activity and reduced weathering rates

Permian paleogeography

• The Permian witnessed the assembly of the supercontinent Pangaea, which dominated the global landscape
• The Panthalassic Ocean surrounded Pangaea, while the Tethys Sea separated the northern and southern portions of the supercontinent
• The formation of Pangaea had significant implications for ocean circulation patterns, climate, and biogeography

Pangaea supercontinent formation

• Pangaea formed through the collision and suturing of several earlier continents, including Laurussia, Gondwana, and Siberia
• The Alleghenian orogeny, resulting from the collision of Gondwana and Laurussia, contributed to the formation of the Appalachian Mountains in North America and the Mauritanide Belt in Africa
• The Uralian orogeny, caused by the collision of Siberia and Baltica, led to the formation of the Ural Mountains

Panthalassic ocean dominance

• The Panthalassic Ocean, also known as the Paleo-Pacific Ocean, was the largest ocean basin during the Permian
• It surrounded the supercontinent Pangaea and covered approximately 70% of the Earth's surface
• The Panthalassic Ocean played a crucial role in global ocean circulation and heat transport

Permian stratigraphy

• Permian stratigraphy encompasses the rock layers and formations deposited during the Permian period
• These strata provide valuable insights into the paleogeography, paleoclimate, and paleoenvironments of the Permian
• Permian strata are well-represented in many regions worldwide, including North America, Europe, Asia, and Australia

Major Permian rock formations

• The Permian Basin in the southwestern United States contains extensive Permian sedimentary deposits, including the Wolfcamp, Leonard, Guadalupe, and Ochoa series
• The Zechstein Formation in Europe represents a series of evaporite deposits formed in a shallow marine setting
• The Emeishan Traps in China are a large igneous province that formed during the late Permian, possibly contributing to the end-Permian mass extinction

Permian stratotypes

• The Global Stratotype Section and Point (GSSP) for the base of the Permian is located in the Aidaralash section in Kazakhstan
• The GSSP for the base of the Guadalupian series is defined at Stratotype Canyon in the Guadalupe Mountains of Texas, USA
• The GSSP for the base of the Lopingian series is located in the Penglaitan section in Guangxi, China

Permian marine life

• Permian oceans hosted a diverse array of marine organisms, including reef-building organisms, brachiopods, bryozoans, ammonoids, and fusulinids
• The Permian saw the emergence of rudist bivalves, which would become important reef-builders in the Mesozoic Era
• The end-Permian mass extinction had a profound impact on marine biodiversity, with many groups suffering significant losses

Permian reef ecosystems

• Permian reefs were built primarily by calcareous sponges, bryozoans, and algae
• Reefs were widespread in shallow marine environments, particularly during the Guadalupian epoch
• The Capitan Reef Complex in the Guadalupe Mountains of Texas and New Mexico is a well-studied example of a Permian reef system

Abundance of brachiopods and bryozoans

• Brachiopods and bryozoans were among the most abundant and diverse marine invertebrates during the Permian
• Brachiopods, such as Productida and Spiriferida, were common in a variety of marine habitats
• Bryozoans, including fenestrate and trepostome forms, were important components of reef and shallow marine communities

Ammonoid and fusulinid diversity

• Ammonoids, a group of cephalopods, experienced a significant diversification during the Permian
• Permian ammonoids exhibited a wide range of shell morphologies and ornamentation, reflecting adaptations to different environments and lifestyles
• Fusulinids, a group of large benthic foraminifera, reached their peak diversity during the Permian and were important indicators of shallow marine environments

Emergence of rudist bivalves

• Rudist bivalves, characterized by their unusual shell morphology and adaptation to reef environments, first appeared in the late Permian
• While rudists were relatively rare in the Permian, they would go on to become dominant reef-builders in the Mesozoic Era, particularly during the Cretaceous period

Permian terrestrial life

• Permian terrestrial ecosystems were dominated by synapsids, early reptiles, and a diverse array of insects and plants
• The Permian saw the evolution of important plant groups, such as cycads and conifers, as well as the widespread distribution of the Glossopteris flora in the southern hemisphere
• The end-Permian extinction had a significant impact on terrestrial life, with many groups of synapsids and plants experiencing major losses

Dominance of synapsids

• Synapsids, which include the ancestors of mammals, were the dominant terrestrial vertebrates during the Permian
• Permian synapsids included both herbivorous and carnivorous forms, such as the large predatory Dimetrodon and the herbivorous Edaphosaurus
• The Permian saw the evolution of more advanced synapsid groups, such as the therapsids, which would give rise to mammals in the Mesozoic Era

Early reptile diversification

• The Permian witnessed the early diversification of reptiles, including the appearance of the first archosaurs, the group that would later include dinosaurs and crocodilians
• Notable Permian reptiles include the aquatic mesosaurs, the herbivorous pareiasaurs, and the small insectivorous procolophonids
• The Permian also saw the evolution of the first turtles, such as Eunotosaurus, which exhibited early adaptations to a shelled body plan

Insect evolution in Permian

• Insects underwent significant diversification during the Permian, with the appearance of many modern insect orders
• Permian insects included early representatives of Coleoptera (beetles), Hemiptera (true bugs), and Diptera (true flies)
• The Permian also saw the evolution of the first social insects, such as termites, as evidenced by the presence of fossilized termite nests

Glossopteris flora in Gondwana

• The Glossopteris flora, characterized by the distinctive Glossopteris leaf morphology, was widespread across the southern hemisphere landmass of Gondwana during the Permian
• Glossopteris plants were adapted to cool temperate climates and formed extensive coal deposits in many regions, including Australia, Antarctica, and South America
• The disappearance of the Glossopteris flora at the end of the Permian is considered a significant floral turnover and may have been linked to the end-Permian mass extinction

End-Permian mass extinction

• The end-Permian mass extinction, also known as the Permian-Triassic extinction event, was the most severe biodiversity crisis in Earth's history
• The extinction event occurred approximately 252 million years ago and resulted in the loss of an estimated 96% of marine species and 70% of terrestrial vertebrate species
• The causes of the end-Permian extinction are still debated, but likely involved a combination of factors, including volcanic eruptions, climate change, and ocean anoxia

Permian-Triassic extinction event

• The Permian-Triassic extinction event marks the boundary between the Paleozoic and Mesozoic eras
• The extinction was rapid in geological terms, occurring over a period of approximately 60,000 years
• The event is characterized by a sharp decline in biodiversity, as evidenced by the disappearance of many characteristic Permian fossil groups in the rock record

Causes of end-Permian extinction

• The formation of the Siberian Traps, a large igneous province in Russia, is considered a likely contributor to the end-Permian extinction
• Volcanic eruptions associated with the Siberian Traps released large amounts of greenhouse gases, such as CO2 and methane, leading to rapid global warming
• Other proposed causes include ocean acidification, reduced oxygen levels in the oceans (anoxia), and the release of toxic hydrogen sulfide from the deep ocean

Marine vs terrestrial extinction patterns

• The end-Permian extinction had a more severe impact on marine ecosystems compared to terrestrial ones
• In the oceans, entire groups of organisms, such as trilobites, rugose and tabulate corals, and most crinoids, went extinct
• On land, the extinction was less severe but still significant, with the disappearance of many synapsid and amphibian groups

Recovery from end-Permian extinction

• The recovery of life after the end-Permian extinction was prolonged, lasting several million years into the Early Triassic
• The Early Triassic is characterized by low diversity ecosystems, often dominated by opportunistic and generalist species
• The recovery was punctuated by several smaller extinction events, such as the Smithian-Spathian boundary event, which may have delayed the full recovery of ecosystems
• The post-extinction world set the stage for the rise of new groups, such as archosaurs and mammals, which would go on to dominate the Mesozoic Era