Taghanic event 386 million years ago in Early Devonian period
Followed by
Taghanic event 386 million years ago in Late Devonian period
The Taghanic event (Taghanic unconformity, Taghanic crisis or Taghanic onlap) was an extinction event that occurred about 386 million years ago during the Givetianfaunal stage of the Middle Devonian geologic period in the Paleozoic era.[1] It was caused by hypoxia from an anoxic event. The event had a period in which dissolved oxygen in the Earth's oceans was depleted. The Taghanic event caused a very high death rate of corals. The loss of the coral reefs caused a high loss of animals that lived in and around the reefs. The extinction rate has been estimated between 28.5% and 36%, making it the 8th largest extinction event recorded.[2][3][4] The reduced oxygen levels resulted from a period of global warming caused by Milankovitch cycles. In the Taghanic event sea levels were higher.[5] After the Taghanic Event, sea life recovered in the Frasnian faunal stage starting 382.7 million years ago. The Taghanic event was followed by the Kellwasser event (372 ma) and the Hangenberg event (359 ma).[6][5][7]
The period of global warming that caused the Taghanic event melted ice caps causing sea levels to rise. This caused the Taghanic onlap, the submergence of land by the advancing sea. The advancing sea laid down strata deposits on the seafloor. The flooding of what is now the southwestern United States created a shallow marine environment.[3][11][12]
The Taghanic event was just before the Late Devonian (Late D) event. The chart gives a comparison of the extinction event to other mass extinction events in Earth's history. Plotted is the extinction intensity, calculated from marine genera.
Marcellus Formation Shale from Middle Devonian sedimentary rock, location of the Taghanic event rocks
^Marshall, John E.A.; Brown, John F.; Astin, Timothy R. (April 2011). "Recognising the Taghanic Crisis in the Devonian terrestrial environment and its implications for understanding land–sea interactions". Palaeogeography, Palaeoclimatology, Palaeoecology. 304 (1–2): 165–183. Bibcode:2011PPP...304..165M. doi:10.1016/j.palaeo.2010.10.016.
^Sepkoski, J. John (1996). "Patterns of Phanerozoic Extinction: A Perspective from Global Data Bases". Global Events and Event Stratigraphy in the Phanerozoic. pp. 35–51. doi:10.1007/978-3-642-79634-0_4. ISBN978-3-642-79636-4.
^McGhee Jr GR, Clapham ME, Sheehan PM, Bottjer DJ, Droser ML (January 2013). "A new ecological-severity ranking of major Phanerozoic biodiversity crises". Palaeogeography, Palaeoclimatology, Palaeoecology. 370: 260–270. Bibcode:2013PPP...370..260M. doi:10.1016/j.palaeo.2012.12.019.
^Aboussalam, Z. Sarah; Becker, R. Thomas (April 2011). "The global Taghanic Biocrisis (Givetian) in the eastern Anti-Atlas, Morocco". Palaeogeography, Palaeoclimatology, Palaeoecology. 304 (1–2): 136–164. Bibcode:2011PPP...304..136A. doi:10.1016/j.palaeo.2010.10.015.
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