The Triassic-Jurassic
The Triassic-Jurassic
Boundary Extinction
There have been five major extinction events in geologic history. The largest of which was the Permian-Triassic extinction that occurred approximately 251 million years ago. During this extinction, 96% of marine species and 70% of terrestrial vertebrate species went extinct. Other extinction events include the Cretaceous- Tertiary and the End Ordovician. The Triassic-Jurassic boundary extinction occurred 200 million years ago during the Phanerozoic eon. The extinction occurred just before Pangaea broke apart. This extinction affected land, sea and faunal species like the Permian-Triassic extinction. There is a lot of evidence supporting the extinction at the Triassic-Jurassic boundary. The hypothesis of Sudden Productivity Collapse Associated with the Triassic-Jurassic Boundary Mass Extinction is that many species of the Triassic Period did not survive the mass extinction between the Triassic and Jurassic Periods and that this extinction was very quick and detrimental to many species. P.D. Ward suggests that this extinction was similar to but not as extreme as the Permian-Triassic and the Cretaceous-Tertiary extinctions. The research conducted by P.D. Ward and his team of scientists is supported mainly by carbon isotope evidence collected from the Queen Charlotte Islands, British Colombia, Canada. The evidence of the carbon isotopes that were unaffected by diagenesis is synchronized with the sudden extinction of marine plankton which leads one to infer that the two extinctions happened around the same time. The scientists also collected “bulk samples of black shale (Ward, 2001).” These samples varied from location to location which also contributes to the hypothesis that extinction occurred. Another piece of evidence recorded is the fact that monotid bivalves went extinct in the lower Kennecott Point section where the researchers also studied. The Triassic-Jurassic extinction was also marked by
Boundary Extinction
There have been five major extinction events in geologic history. The largest of which was the Permian-Triassic extinction that occurred approximately 251 million years ago. During this extinction, 96% of marine species and 70% of terrestrial vertebrate species went extinct. Other extinction events include the Cretaceous- Tertiary and the End Ordovician. The Triassic-Jurassic boundary extinction occurred 200 million years ago during the Phanerozoic eon. The extinction occurred just before Pangaea broke apart. This extinction affected land, sea and faunal species like the Permian-Triassic extinction. There is a lot of evidence supporting the extinction at the Triassic-Jurassic boundary. The hypothesis of Sudden Productivity Collapse Associated with the Triassic-Jurassic Boundary Mass Extinction is that many species of the Triassic Period did not survive the mass extinction between the Triassic and Jurassic Periods and that this extinction was very quick and detrimental to many species. P.D. Ward suggests that this extinction was similar to but not as extreme as the Permian-Triassic and the Cretaceous-Tertiary extinctions. The research conducted by P.D. Ward and his team of scientists is supported mainly by carbon isotope evidence collected from the Queen Charlotte Islands, British Colombia, Canada. The evidence of the carbon isotopes that were unaffected by diagenesis is synchronized with the sudden extinction of marine plankton which leads one to infer that the two extinctions happened around the same time. The scientists also collected “bulk samples of black shale (Ward, 2001).” These samples varied from location to location which also contributes to the hypothesis that extinction occurred. Another piece of evidence recorded is the fact that monotid bivalves went extinct in the lower Kennecott Point section where the researchers also studied. The Triassic-Jurassic extinction was also marked by
Cited: Hesselbo, Stephen P., and Stuart A. Robinson. 2002. Terrestrial and marine extinction at the Triassic-Jurassic boundary synchronized with major carbon-cycle perturbation. A link to initiation of massive volcanism? Geology 30 number 3, 251-254. McElwain, C.J and D.J Woodward.1999. Fossil Plants and Global Warming at the Triassic-Jurassic Boundary. Science 285 number 5432, 1386-1390. Olsen, PE and NH Shubin. 1987. New early Jurassic tetrapod assemblages constrain Triassic-Jurassic tetrapod extinction event. Science 237 number 4818, 1025-1029. Olsen, Paul E. and Peter M. Galton. 1977. Triassic-Jurassic Tetrapod Extinctions: Are They Real? Science 197 number 4307, 983-986. Palfy, Jozef and Attila Demeny. 2001. Carbon isotope anomaly and other geochemical changes at the Triassic-Jurassic boundary from a marine section in Hungry. Geology 29 number 11, 1047-1050. Palfy, Jozef and James K. Mortensen. 2000. Timing the end-Triassic mass extinction: First on land, then in the sea? Geology 208 number 1, 39-42. Ward, P.D., Haggart, J.W. 2001. Sudden Productivity Collapse Associated With the Triassic-Jurassic Boundary Mass Extinction. Science 292, 1148-1152.