The Chemical kinetics of the Katmai eruption : Part 1

Fenner, C

In papers published several years ago, I gave a description of the pumices ejected in the great eruption of Mt Katmai in 1912. These pumices in innumerable specimens show remarkable association of contrasting felsitic and mafic material, an effect that was ascribed to the assimilation of basic rocks by the new silicious magma. This view aroused skepticism among geologists as to whehter assimiation on such a large scale was credible. In the present article the possibilities of exothermic reactions in the magma are explored and the large quantities of heat that may be developed are indicated. This conclusion is based upon well recognized chemical principles, but whatever might be deduced in this manner, the real basis for conclusions is preeminently the pumice themselves. Therfore the greater part of the present paper is devoted to detailed descrition of their field relations, their petrography and their chemistry from every relevant standpoint. Most of the evidence presented is new. It points directley and unmistakeably to the assimilaton of great quantiies of last rock by the new magma. The phenomena are different in kind and in magnituded from effects that have been described in other volcanic eruptions. Because of this and because the Katmai regon is so difficult of access for study by geologist descriptions will be given in rather more detail than is usually required.

The Chemical kinetics of the Katmai eruption : Part 1

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