Cataclysms by Michael R. Rampino

Author:Michael R. Rampino
Language: eng
Format: epub
Publisher: Columbia University Press

FIGURE 9.1  The distribution of continental flood basalts of the past 250 million years, and related hotspots.

FIGURE 9.2  Iguazu Falls, on the border between Brazil and Argentina. The stair steps in the falls are the eroded individual flows of the Serra Geral flood basalts (133 million years ago).

Despite the evidence for impact, several people continue to maintain that the Cretaceous/Paleogene extinctions were primarily related to the environmental effects of the volcanic Deccan Traps. For example, Dewey McLean, a paleontologist at Virginia Tech, was one of the first to suggest a connection between the paroxysmal Deccan eruptions and the end-Cretaceous extinction boundary. At a conference in 1979, even before the impact layer was discovered, he proposed that a global warming from increased atmospheric carbon dioxide was to blame for the extinctions. In a later paper, he noted the close occurrence of the extinctions with the Deccan lava flows and proposed that the eruptions released large amounts of carbon dioxide. In McLean’s view, there was no need for the impact hypothesis, so he ignored the evidence for impact in the latest Cretaceous.

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