EarthRef.org Reference Database (ERR) -- Shepherd 1938

Shepherd reviews the methods of study and the difficulties in obtaining good volcanic gas collections. He concludes that the distribution of volatiles in rocks is largely fortuitous--that, due to contamination of gases on their way to the surface, neither the composition nor the quantity of primitive magmatic volatiles can be deduced. He demonstrates how this contamination occurs at Kilauea. The minimum volatile content of unaltered rocks shows 80 percent or more H (sub 2) O, nearly complete oxidation of the gases, and absence of notable amounts of hydrocarbons and rare gases. The suggestion that volcanic heat may arise partly from reaction of FeO with H (sub 2) O, giving Fe (sub 2) O (sub 3) and H (sub 2) , is inconsequential; rather, the important equilibria are with ferrous silicates, in which case the sign of the heat change is reversed. The paper contains several new chemical analyses of lavas of Kilauea and Mauna Loa.

Journal
American Journal of Science
http://plate.geology.yale.edu/level5/Ajs.html

Publisher
The American Journal of Science, Yale University
P.O. Box 208109
New Haven, CT 06520-8109
USA
203-432-3131
203-432-5668
ajs@yale.edu