Abstract
Much remains unknown about submarine explosive eruptions. Their deposits are found to great depths in all the world’s oceans, but eruptions are typically described by analogy to a subaerial nomenclature that ignores the substantial and inevitable infl uences of hydrostatic pressure and magma-water interaction at submerged edifi ces. Here we explore magmatic volatile exsolution and magma-water interaction for a pyroclastic cone-forming eruption at ~1 km depth on Loihi Seamount, Hawaii. We examine vesicle textures in lapilli—the physical manifestation of degassing; dissolved volatiles in matrix glasses and olivine-hosted glass inclusions—the geochemical record of ascent and volatile exsolution; and fi ne ash morphology—the evidence for if and how external water assisted in fragmentation. This approach allows a submarine explosive eruption style to be defi ned: the magma achieved ~40% vesicularity through almost perfectly closed-system volatile exsolution from ~3 km below the vent, which accelerated and weakened the melt, allowing it to be fragmented by explosive magma-water interaction. We introduce the name “Poseidic” for this end-member style of submarine basalt explosivity. Poseidic eruptions are identifi able from measurable features in pyroclasts, and are possible at all subaqueous basaltic volcanoes.
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Disclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.