The Guadalupian is the second and middle series/

epoch In chronology and periodization, an epoch or reference epoch is an instant in time chosen as the origin of a particular calendar era. The "epoch" serves as a reference point from which time is measured. The moment of epoch is usually decided b ...

of the

Permian The Permian ( ) is a geologic period and System (stratigraphy), stratigraphic system which spans 47 million years, from the end of the Carboniferous Period million years ago (Mya), to the beginning of the Triassic Period 251.902 Mya. It is the s ...

. The Guadalupian was preceded by the Cisuralian and followed by the

Lopingian The Lopingian is the uppermost series/last epoch of the Permian. It is the last epoch of the Paleozoic. The Lopingian was preceded by the Guadalupian and followed by the Early Triassic. The Lopingian is often synonymous with the informal te ...

. It is named after the Guadalupe Mountains of

New Mexico New Mexico is a state in the Southwestern United States, Southwestern region of the United States. It is one of the Mountain States of the southern Rocky Mountains, sharing the Four Corners region with Utah, Colorado, and Arizona. It also ...

and

Texas Texas ( , ; or ) is the most populous U.S. state, state in the South Central United States, South Central region of the United States. It borders Louisiana to the east, Arkansas to the northeast, Oklahoma to the north, New Mexico to the we ...

, and dates between 272.95 ± 0.5 – 259.1 ± 0.4 Mya. The series saw the rise of the therapsids, a minor

extinction Extinction is the termination of an organism by the death of its Endling, last member. A taxon may become Functional extinction, functionally extinct before the death of its last member if it loses the capacity to Reproduction, reproduce and ...

event called Olson's Extinction and a significant mass extinction called the

end-Capitanian extinction event The Capitanian mass extinction event (also known as the end-Guadalupian extinction event, the Guadalupian-Lopingian boundary mass extinction, the pre-Lopingian crisis, or the Middle Permian extinction) was a major mass extinction event that occu ...

. The Guadalupian is also known as the Middle Permian.

Name and background

The Guadalupian is the second and middle series or epoch of the Permian. Previously called Middle Permian, the name of this epoch is part of a revision of Permian stratigraphy for standard global correlation. The name "Guadalupian" was first proposed in the early 1900s, and approved by the International Subcommission on Permian Stratigraphy in 1996. References to the Middle Permian still exist. The Guadalupian was preceded by the Cisuralian and followed by the Lopingian. It is named after the Guadalupe Mountains in New Mexico. The International Chronostratigraphic Chart V2021/07 provides a numerical age of 273.01 ± 0.14 – 259.51 ± 0.21 mya.

Biodiversity

Therapsids became the dominant land animals in Guadalupian, displacing the pelycosaurs. Therapsids evolved from a group of pelycosaurs called sphenacodonts. Therapsida consists of four major clades: the dinocephalians, the herbivorous anomodonts, the carnivorous biarmosuchians, and the mostly carnivorous theriodonts. After a brief burst of evolutionary diversity, the dinocephalians died out in the later Guadalupian. Titanophoneus chart2 DB15

A mass extinction occurred in the early Guadalupian before the larger Permian–Triassic extinction event. This extinction was originally called Olson's Gap because it was thought to be a problem in preservation of fossils. Since the 1990s it has been renamed Olson's Extinction. This extinction event occurred near the beginning of the epoch and led to an extended period of low diversity when two-thirds of terrestrial vertebrate life was lost worldwide. Global diversity rose dramatically by the end probably the result of disaster taxa filling empty guilds, only to fall again when the end-Guadalupian event caused a diversity drop in the

Wuchiapingian In the geologic timescale, the Wuchiapingian or Wujiapingian (from in the Liangshan area of Hanzhong, Shaanxi Province ) is an age or stage of the Permian. It is also the lower or earlier of two subdivisions of the Lopingian Epoch or S ...

. There is no agreed cause for the Olson's Extinction.

Climate change Present-day climate change includes both global warming—the ongoing increase in Global surface temperature, global average temperature—and its wider effects on Earth's climate system. Climate variability and change, Climate change in ...

may be a possible cause. Extreme environments were observed from the Permian of Kansas which resulted from a combination of hot climate and acidic waters particularly coincident with Olson's Extinction. Whether this climate change was a result of Earth's natural processes or exacerbated by another event is unknown.

Climate

The climate resembled that of much of central Asia today. Pangea was a supercontinent and had very hot dry summers and cold bitter winters. At this time on the equator there was a desert that reached 74 degrees Celsius. The coasts were tropical and had monsoons. The first two-thirds of the epoch were the continuation of a temperate and tropical climate. This started to dry out and the coal forming of the previous epoch stopped. The change in climate also provided a new environment for new tetrapods, reptiles, fish, plants, and invertebrates. In the last third the temperature started to drop and many coral reefs died out. If that was not enough, increased volcano activity brought a reduction in oxygen, a greenhouse and mass extinction.

Subdivisions

There are three stages in the guadalupian, they are the Roadian, Wordian, and Capitanian.

Roadian

The Roadian Stage was between 272.3 ± 0.5 – 268.8 ± 0.5 Mya. Olson's Extinction was a worldwide loss of terrestrial vertebrate life that occurred during the Roadian and Wordian. Fauna did not recover fully from Olson's Extinction before the impact of the Permian-Triassic extinction event. Estimates of recovery time vary, where some authors indicated recovery was prolonged, lasting 30 million years into the Triassic. Several important events took place during Olson's Extinction, most notably the origin of

therapsids Therapsida is a clade comprising a major group of eupelycosaurian synapsids that includes mammals and their ancestors and close relatives. Many of the traits today seen as unique to mammals had their origin within early therapsids, including li ...

, a group that includes the evolutionary ancestors of mammals. Further research on the recently identified primitive therapsid of the Xidagou Formation (Dashankou locality) in China of Roadian age may provide more information on this topic.

Wordian

The Wordian Stage was between 268.8 ± 0.5 – 265.1 ± 0.4 Mya. The base of the Wordian Stage is defined as the place in the stratigraphic record where fossils of conodont species '' Jinogondolella aserrata'' first appear. The global reference profile for this stratigraphic boundary is located at Getaway Ledge in the Guadalupe Mountains of

. The top of the Wordian (the base of the Capitanian Stage) is defined as the place in the stratigraphic record where the conodont species ''Jinogondolella postserrata'' first appears.

Capitanian

The Capitanian Stage was between 265.1 ± 0.4 – 259.8 ± 0.4 Mya. The Guadalupian ended with a deteriorating environment, Greenhouse conditions, and several series of mass-extinctions; both the great dinocephalians, other taxa on land and various invertebrates in the sea. They would be succeeded by new types of therapsids, especially the

gorgonopsia Gorgonopsia (from the Greek Gorgon, a mythological beast, and 'aspect') is an extinct clade of Saber-toothed predator, sabre-toothed therapsids from the Middle Permian, Middle to the Upper Permian, roughly between 270 and 252 million years ago. ...

ns among others. A significant mass extinction event (the

End-Capitanian extinction event The Capitanian mass extinction event (also known as the end-Guadalupian extinction event, the Guadalupian-Lopingian boundary mass extinction, the pre-Lopingian crisis, or the Middle Permian extinction) was a major mass extinction event that occu ...

) occurred at the end of this epoch, which was associated with anoxia and acidification in the oceans and possibly caused by the volcanic eruptions that produced the Emeishan Traps. This extinction event may be related to the much larger Permian–Triassic extinction event that followed about 10 million years later. Carbon isotopes in marine

limestone Limestone is a type of carbonate rock, carbonate sedimentary rock which is the main source of the material Lime (material), lime. It is composed mostly of the minerals calcite and aragonite, which are different Polymorphism (materials science) ...

from the Capitanian Age show an increase in δ¹³C values. The change in carbon isotopes in the sea water reflects cooling of global climates. This climatic cooling may have caused the end-Capitanian extinction event among species that lived in warm water, like larger fusulinids (Verbeekninidae), large

bivalve Bivalvia () or bivalves, in previous centuries referred to as the Lamellibranchiata and Pelecypoda, is a class (biology), class of aquatic animal, aquatic molluscs (marine and freshwater) that have laterally compressed soft bodies enclosed b ...

s ( Alatoconchidae) and rugose corals, and Waagenophyllidae.

Other subdivisions

Subdivisions that are sometimes used are, :* Kazanian or Maokovian (in Europe) 70.6 ± 0.7 – 260.4 ± 0.7 Myaref> :* Braxtonian (in

New Zealand New Zealand () is an island country in the southwestern Pacific Ocean. It consists of two main landmasses—the North Island () and the South Island ()—and List of islands of New Zealand, over 600 smaller islands. It is the List of isla ...

) 70.6 ± 0.7 – 260.4 ± 0.7 Mya

References

{{Geological history of Earth, p, m Geological epochs *02