Young basalts from Kilauea, on the big island of Hawai’i, frequently feature visually striking, white, orange and blue
coatings, consisting of a 10-50 μm layer of amorphous silica, capped, in some cases, by a ~1 μm layer of Fe-Ti oxide [1].
The coatings provide an opportunity to study the early onset of acid-sulfate weathering, a process common to many volcanic
environments. Silicon isotopes fractionate with the precipitation of clays and opaline silica, and have been
demonstrated to be an indicator of weathering intensity [2,3]. Here we report in situ measurements of δ^(30)_Si of the silica
coatings and their implications for coating formation
