Terrestrial Catastrophism

My web page on Volcanos and Earthquakes lists resources providing information about these destructive agents. As various authors point out -- see, for example, Stephen Harris in his book Agents of Chaos -- impact events can trigger volcanic eruptions and earthquakes by tectonic slip. Harris suggests the enormous volcanic activity in the Deccan flats in India at the close of the Cretaceous stemmed from an impact which penetrated the earth's crust down into the mantle. Harris further suggests an impact origin for the Columbia River plateau and associated Snake River plateau and Yellowstone volcano.

Large volcanic eruptions can effect global climate changes. For example, 1816 -- the year following the eruption of Tambora in 1815 which was among the largest volcanic eruptions in recorded history -- became known to Europeans and North Americans as the "year without a summer." New England and Canada suffered unusually severe snows and frosts, while Western Europe withered under heavy rains. Many crops failed. Famine and disease followed. This uncharacteristic weather may have been caused by the dust veil thrown up by Tambora's eruption.

Dewey McLean's Dinosaur Volcano Greenhouse Extinction page argues for extended vulcanism instead of asteroid impact as the cause of the demise of the dinosaurs. McLean originated the volcano theory, which couples the end-Cretaceous extinctions to a major perturbation of earth's carbon cycle caused by the Deccan Traps mantle plume vulcanism.

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Last modified by pib on May 12, 2009.