Primeval 13 – Triassic Period

 

Whatever the cause of the Permian-Triassic Extinction Event, recovery was protracted; on land ecosystems took 30 million years to recover.(1)Sarda Sahney and Michael J. Benton (2008) “Recovery from the most profound mass extinction of all time,” Proceedings of the Royal Society B, Volume 275, Number 1636, Pages 759–65 The Triassic was a geologic period and system that extended from about 252 to 201 million years ago. It was the first period of the Mesozoic Era which ran from around 252 to 66 million years ago. This was the Age of Reptiles; the new species on the planet were largely reptilians similar to the earlier Permian species, although during this period the first dinosaurs, mammals and flying vertebrates appeared. The dinosaurs at the time were small creatures that competed with reptiles and mammals; they would not become dominant until the following Jurassic Period.(2)Stephen L. Brusatte et al. (2008-09-12) “Superiority, Competition, and Opportunism in the Evolutionary Radiation of Dinosaurs” Science, Volume 321, Number 5895, Pages 1485–1488

Earth 220 Million Years Ago

Earth 220 Million Years Ago

The vast super-continent of Pangaea existed until the late-Triassic, after which it began to gradually rift into two separate landmasses, Laurasia to the north and Gondwana to the south. The global climate during the Triassic was mostly hot and dry, with deserts spanning much of Pangaea’s interior. However, the climate shifted and became more humid as Pangaea began to rift apart. The end of the period was marked by yet another major mass extinction, the Triassic-Jurassic extinction event, wiping out many groups and allowing dinosaurs to assume dominance in the Jurassic.

The Triassic-Jurassic mass extinction approximately 201 million years ago was particularly severe in the oceans; the conodonts disappeared, as did all the marine reptiles except ichthyosaurs and plesiosaurs. Invertebrates like brachiopods, gastropods, and molluscs were severely impacted. In the oceans, 22% of marine families and up to 34% of marine genera disappeared.(3)Graham Ryder et al. (1996) “The Cretaceous-Tertiary Event and Other Catastrophes in Earth History” Geological Society of America, Page 19 Though the Triassic-Jurassic extinction event was not equally devastating everywhere in terrestrial ecosystems, several important groups of large reptiles disappeared, as did most of the large amphibians, groups of small reptiles, and some synapsids. Some early, primitive dinosaurs also went extinct, but other more adaptive dinosaurs survived to evolve in the Jurassic. Surviving plants that went on to dominate the Mesozoic world included modern conifers and cycadeoids. This event happened in less than 10,000 years and occurred just before Pangaea started to break apart.

A Group of Triassic Reptiles

A Group of Triassic Reptiles

What caused this Triassic-Jurassic extinction is not known with certainty. It was accompanied by huge volcanic eruptions that occurred as the super-continent Pangaea began to break apart about 202 to 191 million years ago,(4)Sébastien Nomade et al. (2007) “Chronology of the Central Atlantic Magmatic Province: Implications for the Central Atlantic rifting processes and the Triassic–Jurassic biotic crisis” Palaeogeography, Palaeoclimatology, Palaeoecology, Volume 244, Pages 326-344 forming the Central Atlantic Magmatic Province (CAMP),(5)Andrea Marzoli et al. (1999) “Extensive 200-million-year-old continental flood basalts of the Central Atlantic Magmatic Province” Science Volume 284 Pages 618-620 one of the largest known inland volcanic events since the planet cooled and stabilized. The eruptions from the CAMP would have released both a massive amount of carbon-dioxide which has a warming effect on the atmosphere,(6)Lawrence H. Tanner et al. (2001) “Stability of atmospheric CO2 levels across the Triassic/Jurassic boundary” Nature, Volume 411, Number 6838, Pages 675–677 and a massive amount of sulphur dioxide and aerosols which have a cooling effect.(7)Terrence J. Blackburn et al. (2013) “Zircon U-Pb Geochronology Links the End-Triassic Extinction with the Central Atlantic Magmatic Province” Science, Volume 340, Number 6135, Pages 941–945 The expected net effect would have been a stormy environment, but not an extinction event. The eroded Rochechouart crater in France has most recently been dated to around 201 million years ago,(8)Martin Schmieder et al. (2010-10-05) “A Rhaetian 40Ar/39Ar age for the Rochechouart impact structure (France) and implications for the latest Triassic sedimentary record” Meteoritics & Planetary Science, Volume 45, Number 8, Pages 1225–1242 but at 25 km (15 miles) across and possibly up to 50 km (31 miles) across originally, appears to be too small to have had a global ecological impact.(9)Roff Smith (2011) “Dark days of the Triassic: Lost world” Nature, Volume 47, Number 7373, Pages 287–289

This 10,000 years long extinction event is virtually identical to current 12,000 years long Holocene extinction event. In the modern case, the event is being caused by humans. It appears as if the Triassic-Jurassic Extinction Event was caused by an intelligent species, however there does not appear to be anything in the fossil record that supports the evolution of an intelligent creature in the late Triassic. If this event was caused by an intelligent species, then it seems likely they were extraterrestrial in origin.

References   [ + ]

1. Sarda Sahney and Michael J. Benton (2008) “Recovery from the most profound mass extinction of all time,” Proceedings of the Royal Society B, Volume 275, Number 1636, Pages 759–65
2. Stephen L. Brusatte et al. (2008-09-12) “Superiority, Competition, and Opportunism in the Evolutionary Radiation of Dinosaurs” Science, Volume 321, Number 5895, Pages 1485–1488
3. Graham Ryder et al. (1996) “The Cretaceous-Tertiary Event and Other Catastrophes in Earth History” Geological Society of America, Page 19
4. Sébastien Nomade et al. (2007) “Chronology of the Central Atlantic Magmatic Province: Implications for the Central Atlantic rifting processes and the Triassic–Jurassic biotic crisis” Palaeogeography, Palaeoclimatology, Palaeoecology, Volume 244, Pages 326-344
5. Andrea Marzoli et al. (1999) “Extensive 200-million-year-old continental flood basalts of the Central Atlantic Magmatic Province” Science Volume 284 Pages 618-620
6. Lawrence H. Tanner et al. (2001) “Stability of atmospheric CO2 levels across the Triassic/Jurassic boundary” Nature, Volume 411, Number 6838, Pages 675–677
7. Terrence J. Blackburn et al. (2013) “Zircon U-Pb Geochronology Links the End-Triassic Extinction with the Central Atlantic Magmatic Province” Science, Volume 340, Number 6135, Pages 941–945
8. Martin Schmieder et al. (2010-10-05) “A Rhaetian 40Ar/39Ar age for the Rochechouart impact structure (France) and implications for the latest Triassic sedimentary record” Meteoritics & Planetary Science, Volume 45, Number 8, Pages 1225–1242
9. Roff Smith (2011) “Dark days of the Triassic: Lost world” Nature, Volume 47, Number 7373, Pages 287–289