Lopingian Epoch

What happened during this time?

Biological

Flora, seed-bearing

• Glossopteris dominates in Gondwanaland; Cordaitales are also success groups

  • Both will go extinct at the end of the Permian

• Early Ginkgophytes continue to diversify

• The earliest evidence of the Czekanowskiales found in the early Late Permian (Kustatscher et al. 2019)

• Cycads and Voltzialean conifers, diversify in the expanding desert ecosystems on Pangaea during this time

• Giganopterids were among the most striking and important plants of the Cathaysian flora of Sino-Malaya but will go extinct at the end of the Permian

• New seed ferns such as the Peltasperms and Corystopspermales appear in the Late Permian

  • Some peltasperms show evidence of forming leaf-like stems, called phylloclades (Karasev & Krassilov 2007)

Flora, spore-bearing

• Extant clubmoss groups, such as the Lycopodiales and Selaginellales are found in the understory of some forests

• Marattialean tree ferns are becoming less prominent with the drying of the landscape

• Sphenophyllophytes and zygopterid ferns are found in the understory, and horsetails along rivers and wetlands

• True ferns are becoming more successful as understory plants in gymnosperm forests

• Noeggerathian progymnosperms are still present, but becoming less prominent, eventually going extinct at the end of the Permian

Permian extinction

• Total of all Permo-Triassic events maybe 95% of animal species went extinct

• Some plants species go extinct, but not nearly at the levels as animals

Causes

• The extinction is thought to be gradual (extended over 9 million years), but now appears to be caused by two main pulses

• First pulse of extinction: Between Capitanian Age of the Middle Permian, and the Wuchiapingian Age of this epoch.

• Second pulse of extinction

  • Occurs during the end of the Changhsingian Age of the Lopingian Epoch, was the worst mass extinction in the history of multicellular life

  • This was a relatively fast event, less than 1 Ma, probably much less than 300 Ka

  • Coincides with the largest flood basalt of Phanerozoic (Siberian Traps), which spews a large amount of carbon dioxide into the atmosphere, leading to extreme global warming 

  • "Super eruptions" in eastern Australia occurred repeatedly between 256 and 252 million years ago spewing massive amounts of ash and gasses high into the atmosphere (at least 150,000 km³ of material) over 4 million years (Chapman et al. 2022)

    • The eruptions would have repeatedly covered the entire east coast in ash  – meters thick in some places, and a massive outpouring of greenhouse gases would have triggered global climate change

  • The event is associated with a major anoxic pulse on both land and sea 

  • Extreme global warming may have led to shallow water anoxia 

  • Some evidence suggests a "burp" of hydrogen sulfide, perhaps due to blooms of hydrogen sulfide bacteria in anoxic deep water 

    • If so, would have the additional effect of destroying the ozone layer, adding UV radiation damage to the mix

    • There is evidence of abundant malformed spores and pollen grains that demonstrate an influx of mutagenic UV irradiation (Liu et al. 2023)

  • Possibly associated with a major pulse of hypercapnia (high carbon dioxide levels) in sea

    • Animals with gills for gas exchange were more tolerant, while corals, which have carbonate skeletons, didn't respond that well

    • Groups with the traits more tolerant of CO2, such as clams and snails, largely survived the mass extinction

  • Carbon isotope fluctuations are consistent with the melting of oceanic methane hydrates 

  •  Deep sea ices (clathrates), rich in methane, melted due to warming

  • As the latter rose to the atmosphere, they would greatly increase the greenhouse effect (methane is a stronger greenhouse gas than carbon dioxide) 

  • Through a positive feedback loop, clathrate-driven global warming would melt more clathrates, and so on... 

  • New evidence suggests changes in the physiology of methanogen Archaea, there was a greater release of methane causing global warming

• "...only the end-Permian mass extinction had devastating effects on vegetation on a global scale" (Cascales-Miñana et al. 2015)

  • The impact was greatest among spore-bearing plants and less so with gymnosperms

  • The extinction rate for plant genera is >60% from the Wuchiapingian to the early Middle Triassic (Anisian) (Xiong & Wang 2011)