Controversies in Science/What killed the dinosaurs/A critique of Volcanoes and extinctions: Round Two

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Massive Volcanic Erruptions and Extinction[edit | edit source]

Evidence has indicated a connection between the three largest Phanerozoic mass extinctions and the three largest continental igneous provinces (LIPs). LIPs comprise of basaltic lava and igneous rock formed over a relatively brief period of time. These LIPs include the Siberian and Deccan Traps. [1]

Methods[edit | edit source]

Deccan eruptions in India cover an area the size of France. This area contains 1 million cubic kilometres of volcanic material that included poisonous gases (ultimately what killed the dinosaurs. The Deccan eruption is known to be the largest volcanic event in 200 million years and the time period K-T (2 geological layers: Cretaceous (thriving dinosaurs) to Tertiary (beginning of dinosaur extinction and beginning of thriving mammals), therefore it is plausible from the size of the eruption and the time period in which it occurred that it was the likely cause of the dinosaur extinction. This article suggests the same happened in Kilauea, Hawaii where a volcano erupted, dispensing minerals and soot worldwide. Scientists believe that if materials and minerals from this fission can be found globally, then it is likely that the minerals and deposits from the Deccan eruptions caused the extinction of dinosaurs [2].

Results[edit | edit source]

During the Deccan eruptions 30,000 tons of iridium was emitted, which is also found in meteorites and contributed to that theory. However, the amount of iridium emitted from the eruptions was slightly less than the amount found in the K-T boundary layer [2].

Volcanism causes toxic gasses to be released into Earth’s atmosphere. The Deccan Traps and NATIP (North American Tertiary Igneous Province) are two of the largest basalt deposits ever recorded. The volume of these deposits alone is phenomenal, the Deccan Traps comprising of 512,000 cubic KM and the NATIP canvassing 2,000,000 cubic KM in volume. The lava flows alone were enough to take out a great deal of dinosaur life. Along with lava eruption, toxic gas is released into the atmosphere allowing for debris to be carried over a large surface area causing a hazardous environment for living creatures such as dinosaurs. Not only was debris and lava flow a factor, the toxic gas initiated caused the skies to darken and acid rain to form which eventually led to climate cooling. A catastrophic event took place in the Earth’s mantle allowing for plumes to form and rise eventually resulting in fissures and other volcanic explosions inevitably leading to the death of the dinosaurs. All of these events can be seen in diagnosing the geology found in the K-T boundary by varying fossils shown through carbon dating. Courtillot made the diagnosis that Volcanism played a much larger factor than meteorite impact in dinosaur depletion and believes this will lead to better understanding of how convection in the Earth works. [2].

References[edit | edit source]

  1. Olsen, E., P. (1999). Giant Lava Flows, Mass Extinctions, and Mantle Plumes.Science, 284, 604-605.
  2. 2.0 2.1 2.2 Weisburd, S. (1987),”Volcanoes and extinctions: Round Two”. Volcanoes and extinctions: Round Two. Science News, 131(16), 248-250.