Emeishan Traps

The Emeishan Traps constitute a flood basalt volcanic province, or large igneous province, in south-western China, centred in Sichuan province. It is sometimes referred to as the Permian Emeishan Large Igneous Province or Emeishan Flood Basalts. Like other volcanic provinces or "traps," the Emeishan Traps are multiple layers of igneous rock laid down by large mantle plume volcanic eruptions. the Emeishan Traps eruptions were serious enough to have global ecological and paleontological impact.[1]

It is named for Emeishan, a mountain in Sichuan.

The Traps

The eruptions that produced the Emeishan Traps began 265 million years ago (Ma) or earlier.[2][3] The main eruptive period is between 262 Ma and 261 Ma, and the volcanism activities end 259 Ma.[4][5]

In volume, the Emeishan Traps are dwarfed by the massive Siberian Traps, which occurred, in terms of the geological time scale, not long after, at c. 252 Ma. The Emeishan basalts covers an area of more than 2.5 × 105 km2 with thicknesses ranging from several hundred meters up to 5.5 km (the average flood basalt thickness throughout the entire region is estimated to be ~700 m), but the Emeishan traps may have initially covered an area as much as 5 × 105 km2.[6] Thus the entire volume of the Emeishan basalts to be 0.3 × 106 km3.[7] Evidences of Emeishan volcanology suggest that the initial volcanism of the central ELIP occurred in a deep submarine environment without any significantly pre-volcanic uplift.[8]

The Emeishan Traps are associated with the so-called end-Guadalupian Extinction or End-Capitanian extinction event, the extinction of animal and plant life that occurred at the end of the Capitanian stage of the Guadalupian epoch of the Permian period.[9] Intertrappean limestone show the extinction to occur immediately below the first eruptive unit and marked the mass extinction occurred at the onset of explosive Emeishan volcanism.[2] The onset of volcanism is violent phreatomagmatic-style eruptions forming volcaniclastics suggest that such effects are likely to have been severe.[3] The synchrony between the Emeishan Traps and the end-Guadalupian extinction has been taken to support the argument, supported by Vincent Courtillot among many others, that volcanism is the main driver of mass extinctions.[10]

See also

Notes

  1. ↑ Bond, D. P. G.; Wignall, P. B.; Joachimski, M. M.; Sun, Y.; Savov, I.; Grasby, S. E.; Beauchamp, B.; Blomeier, D. P. G. (2015-04-14). "An abrupt extinction in the Middle Permian (Capitanian) of the Boreal Realm (Spitsbergen) and its link to anoxia and acidification". Geological Society of America Bulletin. doi:10.1130/B31216.1. ISSN 0016-7606.
  2. 1 2 Wignall, PB et al., (2009). "Volcanism, Mass Extinction, and Carbon Isotope Fluctuations in the Middle Permian of China". Science. doi:10.1126/science.1171956.
  3. 1 2 Jerram, DA et al., (2015). "Submarine palaeoenvironments during Emeishan flood basalt volcanism, SW China: Implications for plume–lithosphere interaction during the Capitanian, Middle Permian ('end Guadalupian') extinction event". Palaeogeography, Palaeoclimatology, Palaeoecology.
  4. ↑ Zheng, LD et al., (2010). "Magnetostratigraphic constraints on two‐stage eruptions of the Emeishan continental flood basalts". Geochemistry, Geophysics, Geosystems. doi:10.1029/2010GC003267.
  5. ↑ Zhong, YT et al., (2014). "CA-TIMS zircon U–Pb dating of felsic ignimbrite from the Binchuan section: Implications for the termination age of Emeishan large igneous province". Lithos.
  6. ↑ Zhou, MF et al., (2002). "A temporal link between the Emeishan large igneous province (SW China) and the end-Guadalupian mass extinction". Earth and Planetary Science Letters.
  7. ↑ Ali, JR et al., (2005). "Emeishan large igneous province, SW China". Lithos.
  8. ↑ Zhu, B et al., (2014). "No pre-eruptive uplift in the Emeishan large igneous province: New evidences from its 'inner zone', Dali area, Southwest China". Journal of Volcanology and Geothermal Research.
  9. ↑ Wignall, PB et al., (2001). "Large igneous provinces and mass extinctions". Earth-Science Reviews.
  10. ↑ Courtillot, VE et al., (2003). "On the ages of flood basalt events". Comptes Rendus Geoscience.

References

External links

This article is issued from Wikipedia - version of the 11/13/2016. The text is available under the Creative Commons Attribution/Share Alike but additional terms may apply for the media files.