Textural and geochemical window into the IDDP-1 rhyolitic melt, Krafla, Iceland, and its reaction to drilling

Abstract The unexpected intersection of rhyolitic magma and retrieval quenched glass particles at the Iceland Deep Drilling Project-1 geothermal well in 2009 Krafla, Iceland, provide unprecedented opportunities to characterize genesis, storage, behavior subsurface silicic magma. In this study, we analyzed complete time series retrieved after was intersected, terms distribution, chemistry, vesicle textures. Detailed analysis revealed them represent bimodal compositions Early-retrieved clear vesicular has higher SiO2, crystal, contents than later-retrieved dense brown glass. size distribution also reveal several populations. vary δD from −120‰ −80‰ have dissolved water spanning 1.3−2 wt%, although majority exhibit a narrower range. Vesicular textures indicate that volatile overpressure release predominantly occurred prior late-stage ascent, infer vesiculation response drilling-induced decompression. chemistry glasses are consistent with variable partial melting host felsite. drilling recovery sequence indicates (lower degree melt) overlays (higher melt). isotopes species support high temperature hydration these melts by mixed meteoric magmatic composition fluid. textural evidence for lack crystallization imply production is ongoing, growing body thus potential energy extraction. summary, transfer heat fluids into felsite triggered degrees produced hydrated rhyolite chemical heterogeneities were then enhanced perturbations. Such could occur extensively crust above chambers, where complex intrusive systems can form supply required re-melt rock. Our findings emphasize need resolution geophysical monitoring restless calderas both hazard assessment prospecting. We insight how shallow reacts drilling, which be key future exploration use bodies energy.