Key Earth Science Links
End-Triassic extinction—Opening the door for dinosaurs
Extinction Files, BBC. Articles on mass extinctions.
Wikipedia. Short article discussion various explanations for the Triassic-Jurassic extinction event, and the lack of conclusive evidence for each.
Geophysical Research Abstracts. Short, technical abstract by R. Perry and others, University of Washington, concerning discovery of fullerenes (buckeyballs) at the Triassic-Jurassic boundary that may indicate a bolide impact similar to the Cretaceous-Tertiary extinction.
Geological Society of America. Short, technical abstract by S.G. Lucas, new Mexico Museum of Natural History, which disputes idea that there was a mass extinction at the end of the Triassic, and attributes suddenness of species changes to correlation errors. Lucas argues for several, protracted, smaller extinctions.
Lecture 12--Mass extinction at the beginning of the age of dinosaurs, Columbia University. Part of an online lecture series for Dinosaurs and the History of Life. Scroll toward the end of this site for brief discussions of several Triassic extinction theories.
Some key references (technical articles)
You may be able to get these online through JSTOR, Science Direct or other online technical journal searches, or you may be able to get them through interlibrary loans
- Benton M.J., 1993, Late Triassic extinctions and the origin of the dinosaurs: Science, v. 26, no. 5109, p. 769-770 Short discussion of the Late Triassic mass extinction and why it was important for the evolution and diversification of dinosaurs.
- Hallam, A., 1990, The end-Triassic mass extinction event, in Sharpton, V.L., and Ward, P.D., eds., 1990, Global catastrophes in earth history: an interdisciplinary conference on impacts, volcanism, and mass mortality: Geological Society of America, Special Publication no. 247, p. 577-583. Examines floral and marine and terrestrial faunal changes, and compares them to a series of possible causes. The paper infers there is a connection between regression (sea-level drop) and anoxia, and the sea-level change is hypothesized to have resulted from the inception of tensional tectonics (sea-floor spreading).
- Hodych, J.P, and Dunning, G.R, 1992, Did the Manicouagan impact trigger end-of-Triassic mass extinction? Geology, v.20, p. 51-54. Uses U-Pb age dates of zircons to date the Manicouagan impact site in Quebec and compares those dates to the end of the Triassic, to determine if the impact could have been responsible for the end-Triassic mass extinction.
- McElwain, J.C., Beerling, D.J., and Woodward, F.I., 1999, Fossil plants and global warming at the Triassic-Jurassic boundary: Science, v. 285, no. 5432, p. 1386-1390. Measurements of fossil leaf dimensions are used to show that there was an increase in carbon dioxide at the end of the Triassic. Studies of modern leaves have shown that leaf stomata vary with CO2 content, so that stomatal density can the stomatal index of leaf cuticles can be used as a proxy for CO2 content in the past. The hypothesized increase in late Triassic CO2 would have led to a 3-4°C increase in global temperature.
- Pálfy, J., Smith, P.L., and Mortensen, J.K., 2002, Dating the end-Triassic and Early Jurassic mass extinctions, correlative igneous provinces, and isotopic events, in Koeberl, C., and MacLeod, K.G., eds., Catastrophic events and mass extinctions: impacts and beyond: Geological Society of America, Special Publication no. 356, p. 523-532. This study presents a revised time scale with high-precision U-Pb age dates and ammonoid biochronology to correlate peak volcanism in the Central Atlantic Magmatic Province, which formed during the opening of the Atlantic Ocean, to end-Triassic extinction. The paper also reports on a smaller, early Jurassic extinction event 18 million years after the end-Triassic extinction that based on isotopic evidence, is hypothesized to have been caused by methane hydrate release and ocean anoxia.
- Spray, J.G., Kelley, S.P., and Rowley, D.B., 1998, Evidence for a late Triassic multiple impact event on Earth: Letters to Nature, v. 392, p. 172-173. Suggests that five Late Triassic impact sites around the world were part of a fragmented comet or asteroid that struck the earth in succession, similar to the impacts of the Schumaker-Levy comet with Jupiter in 1994.
- Tanner, L.H., Lucas, S.G., and Chapman, H.G., 2003, Assessing the record and causes of late Triassic extinctions: Earth Science Reviews, v. 65, p. 103-139. Summarizes the biotic (marine and terrestrial) record of extinctions toward the end of the Triassic and summarizes the possibilities of gradual vs. sudden catastrophic causes for the extinctions. Some of the hypotheses investigated include sea-level change (regression), climate change (aridification), bolide impact, volcanism from the Central Atlantic Magmatic Province, and the release of methane hydrates from the sea floor.
- Ward, P.D., and others, 2001, Sudden productivity collapse associated with the Triassic-Jurassic boundary mass extinction: Science, v. 292, no. 5519, p. 1148-1151. Documents a carbon isotope excursion at the Triassic-Jurassic boundary that is coincident with the Late Triassic mass extinction. This spike corresponds to the sudden extinction of marine Radiolaria (a large group of fossil plankton).
- Wignall P.B., 2001, Large igneous provinces and mass extinctions: Earth Science Reviews, v.53, no. 1-2, p. 1-33.Examines the coincidence in timing of several large extinction events to the formation of large igneous provinces, and shows where there is good correlation and where there may be problems with direct correlations. In some cases, the major eruption phases appears to post-date some of the extinctions. Notes that 6 of 11 large igneous provinces (which represent periods of large volcanism) coincide with global warming and marine anoxia, suggesting that volcanic CO2 emissions have a profound effect on global climate.