Volcanism

The scenario favored by Officer and Page (1996) involves massive volcanic eruptions that might have spewed sunlight-obscuring dust into the atmosphere initiating a global crisis like that caused by the extraterrestrial impact envisioned by Alvarez et al. (1980) (see Section 11.5). Poisonous gases such as chlorine and sulfur dioxide are also part of volcanic eruptions. The Officer and

Page volcanic hypothesis is essentially an alternative to the Alvarez et al. impact hypothesis. Its major flaw is the timing of the eruptions.

The location of the greatest of the volcanic eruptions around K-T time discussed by Officer and Page is in India; the lavas that flowed formed the Deccan Traps (see Section 9.4). As discussed in Section 9.4, the basaltic lava of the Deccan Traps erupted during an interval of a few million years, beginning long before the end of Cretaceous time and continuing into earliest Paleocene time. In contrast, the K-T extinctions were abrupt; by all possible measurement, they were geologically instantaneous. As with the hypothesis of climate change failing because it is inconsistent with the record of abrupt extinction at the K-T boundary, no meaningful linkage can be found between volcanism and the K-T extinctions. Furthermore, the possibility that volcanic emanations darkened the skies and thereby lowered atmospheric temperatures is falsified by the data of Huber et al. (1995) and Wilf et al. (2003), who show a warming trend associated with Deccan volcanism. In short, although major volcanic eruptions can have devastating effects locally and be the cause of local extirpations of flora and fauna, there is no evidence that they do so on a global scale or specifically that they did so at the K-T boundary.

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