Triassic-Jurassic (Tr-J) Extinction Event (~182 Mya)

A Triassic-Jurassic (Tr-J) Extinction Event (~182 Mya) is an extinction event that marked the period boundary between the Triassic Period and Jurassic Period (resulting in the mass extinction of approximately 76% of all species during the late triassic).

• AKA: End-Triassic Extinction, Tr-J Event, TJME, End-Triasic Extinction.
• Context:
  • It can (typically) mark Geological Boundary through stratigraphic markers and isotope excursions.
  • It can (typically) trigger Ecosystem Change through species extinction and habitat disruption.
  • It can (typically) alter Global Climate through volcanic activity and atmospheric composition.
  • It can (typically) affect Marine Systems through ocean acidification and oxygen depletion.
  • It can (often) demonstrate Extinction Pattern through taxonomic selectivity and survival rates.
  • It can (often) show Environmental Change through sedimentary records and geochemical signatures.
  • It can (often) eliminate Marine Taxa including entire conodont class and 23-34% of marine genera.
  • It can (often) affect Terrestrial Taxa including most archosauromorphs except crocodylomorphs, pterosaurs, and dinosaurs.
  • ...
  • It can range from being a Rapid Extinction to being a Gradual Extinction, depending on its temporal resolution.
  • It can range from being a Local Impact to being a Global Impact, depending on its geographic extent.
  • It can range from being a Selective Extinction to being a Mass Extinction, depending on its taxonomic scope.
  • ...
  • It can be associated with the Central Atlantic Magmatic Province formation.
  • It can coincide with major sea level changes.
  • It can precede the dinosaur dominance in the Jurassic Period.
  • It can demonstrate reduced speciation rates rather than increased extinction rates in marine environments.
  • It can show coral reef community collapse and plant spore turnover.
  • ...
• Examples:
  • CAMP Volcanic Eruption Tr-J Event Scenario causing global warming over 20,000 year interval.
  • Manicouagan Impact Tr-J Event Scenario triggering rapid climate change over 1,000 year interval.
  • Methane Release Tr-J Event Scenario leading to carbon cycle disruption over 50,000 year interval.
  • Sea Level Change Tr-J Event Scenario resulting in habitat loss over 100,000 year interval.
  • Sulfur Emission Tr-J Event Scenario producing ocean acidification over 10,000 year interval.
  • Multiple Impact Tr-J Event Scenario creating combined effects over 5,000 year interval.
  • ...
• Counter-Examples:
  • The Great Oxygenation Event, which lacks mass extinction characteristics.
  • Cretaceous–Paleogene Extinction Event (~66 Mya.), which lacks volcanic cause evidence.
  • Permian-Triassic Extinction Event (~252 Ma), which shows different extinction patterns.
  • Human-due Extinction Period, which has different causal mechanisms.
  • Superintelligences-due Extinction Period, which involves different extinction drivers.
• See: Phanerozoic, Class (Biology), Conodont, Crurotarsi, Archosaur, Therapsid, Amphibia, Mass Extinction, Geological Boundary, Central Atlantic Magmatic Province, Global Climate Change, Ecosystem Recovery.

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References

2023

• (Wikipedia, 2023) ⇒ https://en.wikipedia.org/wiki/Triassic–Jurassic_extinction_event Retrieved:2023-6-5.
  • The Triassic–Jurassic (Tr-J) extinction event (TJME), often called the end-Triassic extinction, marks the boundary between the Triassic and Jurassic periods, , and is one of the top five major extinction events of the Phanerozoic eon, profoundly affecting life on land and in the oceans. In the seas, the entire class of conodonts and 23–34% of marine genera disappeared. On land, all archosauromorphs other than crocodylomorphs, pterosaurs, and dinosaurs became extinct; some of the groups which died out were previously abundant, such as aetosaurs, phytosaurs, and rauisuchids. Some remaining non-mammalian therapsids and many of the large temnospondyl amphibians had become extinct prior to the Jurassic as well. However, there is still much uncertainty regarding a connection between the Tr-J boundary and terrestrial vertebrates, due to a lack of terrestrial fossils from the Rhaetian (latest) stage of the Triassic. What was left fairly untouched were plants, crocodylomorphs, dinosaurs, pterosaurs and mammals; this allowed the dinosaurs, pterosaurs, and crocodylomorphs to become the dominant land animals for the next 135 million years. Statistical analysis of marine losses at this time suggests that the decrease in diversity was caused more by a decrease in speciation than by an increase in extinctions. Nevertheless, a pronounced turnover in plant spores and a collapse of coral reef communities indicates that an ecological catastrophe did occur at the Triassic-Jurassic boundary. Older hypotheses on extinction have proposed that gradual climate or sea level change may be the culprit, or perhaps one or more asteroid strikes. However, the most well-supported and widely-held theory for the cause of the Tr-J extinction places the blame on the start of volcanic eruptions in the Central Atlantic Magmatic Province (CAMP), which was responsible for outputting a high amount of carbon dioxide into Earth's atmosphere, inducing profound global warming, along with ocean acidification.

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