Uncovering Hotspot Volcanism: Mantle Melting, Magmatic Plumbing, Explosive Eruptions and Crustal Contamination at Kilauea Volcano, Hawaii

University Of Hawaii, Honolulu

Investigators

Abstract

Hawaii's Kilauea Volcano is one of the best places on Earth to study processes within basaltic volcanoes. Its high eruption frequency, easy access to lavas, distinct geologic setting in the central Pacific far from plate boundaries or continents, and the extensive knowledge base on Kilauea allows research us to address fundamental problems related to active volcanoes. The tasks and issues we propose to address are: 1) Monitoring the magmatic evolution of lavas from Kilauea's two ongoing eruptions to evaluate mantle melting processes and the magmatic architecture of the volcano; 2) Documenting the extent and origin of crustal contamination in its recent lavas; 3) Determining the controls of Kilauea's effusive-explosive cycles during the last 2200 years; and 4) Creating an education module to engage students in learning science through studying active volcanoes. Hawaii is a superb location for petrologic and geochemical research on basaltic volcanoes. Prior NSF support has allowed the Principal Investigator and colleagues to monitor the petrologic and geochemical variations of lava from the current rift eruption and to witness the dynamic changes in the melting process and mantle source composition during this long-lasting magmatic event. Our published work has shown that melt is transported through the mantle in open channels to the surface without significant pooling and homogenization, preserving remarkable short-term (~10 years) Pb isotopic variations. The new summit eruption (ongoing since 2008) provided the first samples from Kilauea's central magma storage reservoir since 1982. These new samples indicate a geochemically distinct mantle-derived magma was delivered to the summit reservoir in 2009 that has not yet (as of 2012) erupted at Pu'u 'O'o. If the geochemical differences between these two eruptions persist, they suggest there are separate conduits to the mantle for each vent, a major departure from current models for Kilauea's magmatic system. New studies have shown that explosive eruptions have dominated Kilauea's last 2200 years and that geochemistry may be a harbinger of explosive eruptions. NSF funding will be used to: 1. Monitor the magmatic evolution of Kilauea lavas from its two ongoing eruptions; 2. determine whether the O isotope variations we have observed for Kilauea lavas are related to crustal contamination or source heterogeneity; and 3. extend our study of temporal geochemical variations of Kilauea's rocks ~2000 years into its explosive past to determine whether enriched magmas are indicators of explosive eruptions. Our geochemical results have been and will continued to be integrated with observations from Hawaiian Volcano Observatory's field, geochemical and geophysical monitoring programs, and interpreted in consultation with their staff. Our holistic approach to evaluating magmatic processes at Kilauea is critical for understanding how this and other basaltic volcanoes work.