ABSTRACT

A basaltic rock sample heated up to 1, 300° releases only a part of the total Rn, whereas substantial fractions of the other rare gases are expelled at lower temperatures. The experimental results obtained for Rn release are considerably different from the observations on the ²³⁶Ra-²²²Rn disequilibrium in fragments of erupting magmas, which generally show much greater Rn-releasing efficiencies. The role of major volatile components in the degassing of felsic magmas is discussed.