Upper Triassic

Coelophysis, one of the first dinosaurs, appeared in the Upper Triassic epoch.

The Upper Triassic is the last epoch in the Triassic period. It began 237 million years ago, and ended 201.3 million years ago. It was after the Middle Triassic epoch, and before the Lower Jurassic epoch.

Many early dinosaur species appeared for the first time during the Upper Triassic. These included Plateosaurus, Coelophysis, and Eoraptor. The discovery of Herrerasaurus and Saurosuchus makes it quite clear that the dinosaurs were taking hold of the land environments.

Pterosaurs were common in the air, and ichthyosaurs dominated the seas.

At the end of the Upper Triassic some event or events caused the extinction of many animal species worldwide. This was the end–Triassic extinction event. It was similar to the more famous event that lead to the extinction of the dinosaurs. No one knows for sure what caused the event.

Carnian pluvial event

Although the Triassic period was, in general, a dry period with the inland areas often being deserts, the Upper Triassic epoch saw a big change.

The Carnian Pluvial Event (CPE) was a major global climate change and biotic turnover with many extinctions. It was early in the Upper Triassic, about 230 million years ago.^[1][2] Shifts in carbon and oxygen isotopes suggest a global warming.^[3][4][5]

Major changes in organisms responsible for calcium carbonate production occurred during the CPE.^[6][7][8] Carbonate sedimentation stopped in deep water settings of Southern Italy.^[9]

High extinction rates occurred among ammonoids, conodonts, bryozoa and crinoids.^[1] Major evolutionary innovations followed the CPE. The dinosaurs became established. In the seas there were calcareous nannofossils and scleractinian corals.^[2][3]

References

1. Simms, Michael J.; Ruffell, Alastair H. (1989). "Synchroneity of climatic change and extinctions in the late Triassic". Geology. 17 (3): 265–268. doi:10.1130/0091-7613(1989)017<0265:SOCCAE>2.3.CO;2.
2. Furin S.; et al. (2006). "High-precision U-Pb zircon age from the Triassic of Italy: implications for the Triassic time scale and the Carnian origin of calcareous nannoplankton and dinosaurs". Geology. 34 (12): 1009–1012. doi:10.1130/G22967A.1.
3. Dal Corso J.; et al. (2012). "Discovery of a major negative δ13C spike in the Carnian (Late Triassic) linked to the eruption of Wrangellia flood basalts". Geology. 40 (1): 79–82.
4. Hornung T.; et al. (2007). "Multistratigraphic constrains in the NW Tethyan "Carnina Crisis"". New Mexico Museum of Natural History and Science Bulletin. 41: 59–67.
5. Rigo, Manuel; Joachimski, Michael M. (2010). "Palaeoecology of late Triassic conodonts: Constraints from oxygen isotopes in biogenic apatite". Acta Palaeontologica Polonica. 55 (3): 471–478. doi:10.4202/app.2009.0100. S2CID 128833509.
6. Keim, L.; Schlager, W. (2001). "Quantitative compositional analysis of a Triassic carbonate platform (Southern Alps, Italy)". Sedimentary Geology. 139 (3–4): 261–283. doi:10.1016/S0037-0738(00)00163-9.
7. Hornung, Thomas; Krystyn, Leopold; Brandner, Rainer (2007). "A Tethys-wide mid-Carnian (Upper Triassic) carbonate productivity crisis: Evidence for the Alpine Reingraben Event from Spiti (Indian Himalaya)?". Journal of Asian Earth Sciences. 30 (2): 285–302. doi:10.1016/j.jseaes.2006.10.001.
8. Stefani, Marco; Furin, Stefano; Gianolla, Piero (2010). "The changing climate framework and depositional dynamics of Triassic carbonate platforms from the Dolomites". Palaeogeography, Palaeoclimatology, Palaeoecology. 290 (1–4): 43–57. doi:10.1016/j.palaeo.2010.02.018.
9. Rigo M.; et al. (200). "A rise in the Carbonate Compensation Depth of western Tethys in the Carnian: deep-water evidence for the Carnian Pluvial Event". Palaeogeography, Palaeoclimatology, Palaeoecology. 246: 188–205. doi:10.1016/j.palaeo.2006.09.013.