Hangenberg event

The Hangenberg event is a bioevent that occurred at the end of the Famennian epoch (late Devonian) associated with the Late Devonian extinction (roughly 358.9 ± 0.4 million years ago); it was an anoxic event marked by a black shale. It has been proposed that this was related to a rapid sea-level fall due to the last phase of the Devonian Southern Hemisphere glaciation.[1] It has also been suggested that it was linked to an increase in terrestrial plant cover, leading to increased nutrient supply in rivers. This may have led to eutrophication of semi-restricted epicontinental seas and could have stimulated algal blooms.[2]

It is named from the Hangenberg Shale, part of a sequence that straddles the Devonian-Carboniferous boundary, from the Rhenish Massif in Germany.[3]

Following the extinction, vertebrates experienced reduced body size for the following 36 million years, at least in part because smaller taxa diversified more successfully.[4][5]

See also

References

  1. ↑ Sandberg, C.A.; Morrow, J.R.; Ziegler, W. (2002). "Late Devonian sea-level changes, catastrophic events, and mass extinctions". In Koeberl, C.; MacLeod, K.G. Catastrophic Events and Mass Extinctions: Impacts and Beyond: Boulder, Colorado (PDF). Special Paper. 356. Geological Society of America. pp. 473–487.
  2. ↑ Algeo TJ, Scheckler SE, Maynard JB (2001). "Effects of the middle to late Devonian spread of vascular land plants on weathering regimes, marine biotas, and global climate". In Gensel PG, Edwards D. Plants invade the land - evolutionary and environmental perspectives. New York: Columbia University Press. pp. 213–36.
  3. ↑ Kaiser, S.I., Steuber, T., Becker, R.T. & Joachimski, M.M. 2006. Geochemical evidence for major environmental change at the Devonian–Carboniferous boundary in the Carnic Alps and the Rhenish Massif, Palaeogeography, Palaeoclimatology, Palaeoecology 240, 146–160.
  4. ↑ Sallan, L.; Galimberti, A. K. (2015-11-13). "Body-size reduction in vertebrates following the end-Devonian mass extinction". Science. 350 (6262): 812–815. doi:10.1126/science.aac7373.
  5. ↑ Feltman, R. (2015-11-13). "After mass extinctions, the meek (fish) inherit the earth". Washington Post. Retrieved 2015-11-16.


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