A discussion of: long or short silicic magma residence time beneath Hekla volcano, Iceland?

Recently reported major element, trace element, and volatile compositions of dacites erupted from Hekla Volcano, Iceland are inconsistent with an anatectic origin. In contrast, all of the data are consistent with dacitic melts being derived by modest amounts of crystallization of an anhydrous assemblage from an andesitic melt. Models that apply straightforward Gd, Yb, Th, and U concentrations, instead of ratios, to the problem show that the crystallization hypothesis remains valid, especially when uncertainties are propagated.